yeah, i'd like to see a paddle on each bar F1 style. Maybe the brake levers themselves. Bernie was working on electric shifting 5 years ago but I don' think anythin came of it.
funky new lahar (carbon exoticness)
- Thread starter xy9ine
- Start date
I really hope you don't mean anything like shimano's sti system! I'd rather run gripshift over that!LaharDesign said:
Its not so bad if you run the shifting backwards- twist the throttle to go faster, and rolloff your gears as you go for the brakes to be in the right gear to exit the corner.
a single paddle per bar would be spunky. Not too difficult with the no-index shifters that Rohl run.
a single paddle per bar would be spunky. Not too difficult with the no-index shifters that Rohl run.
No worries, 63-64 degrees sounds a bit more reasonable than the 62 somebody quoted before. What's frame weight including the Rohloff hub?LaharDesign said:My observation here is that going down a hill changes the vector the centre of gravity is acting through. If you are going down a 27deg slope- not particularly steep- then the vector is parallel to wheelpath.
Its a hypothesis that inertia duplicates this effect in corners.
The fact that my bikes have had big wins in flat pedally gravelly races and are considered rails in these conditions leads me to believe that weight transfer forward in cornering is perhaps a good thing. Certainly the dhv series with its extremely high rear sprung/ unsprung weight is not short of rear traction.
Fair call, assuming you're travelling down a 27 degree slope. I would hypothesise that superior cornering in loose conditions is likely to be due to the long wheelbase and progressive rate (which IMO gives very good traction) rather than the weight transfer. My personal opinion/experience is that bikes with more vertical axle paths and generally shortening wheelbases under compression, tend to corner better.
independant is where drive torque has no +ve or -ve force on the suspension action and suspension doesn't feedback thru drivetrain. I'm anal enough to include inertia squat in this definition, at least for my own use.
By the design community I would say that everyone grounded in chassis design science since the physics were completed around 1900. I'd say most every bike designer who's tested the theory and many more besides. Almost BD's will admit it privately though sometimes their commercial obligations prevent public statement. Certainly anyone who's been near motorised suspension has no illusions.
I'm not saying geometry for these bikes should be identical to conv's anyway.
No feedback, I'd agree with as being "independent" (although Mr Weagle has made a good point in the past about feedback only mattering if it's perceptible). I would like a better definition of your idea of neutral squat though (I have an idea in my head but I don't want to put words into your mouth). And I would say that it is fairly speculative to say that a high pivot is outright "better" in the minds of the entire design/engineering community. Due to the lower CoG of a motorcycle/rider combination, as well as the larger tyres and longer swingarm, the resulting pivot heights (which give axle tangents far less rearwards than your bike, on all production bikes I've seen, which would contradict what you say about the design community agreeing that higher pivots are necessarily better) are used more for squat control and traction due to weight distribution under compression/extension. I do not believe that these characteristics can be transferred directly to mountain bikes, and I would also argue that your bike does not possess these characteristics (which may well be for the better, since motos and mountain bikes have different requirements).
Couldn't have said it much better myself.
Yes theres a little chain lockout in the initial travel of the Lahars, the axle pivot line is inside the radius of a 24t chring and the rear sprocket is a 18t so its sod all. It does allow the pivot to be 2" lower than it needs to be for neutral inertia effects in my experience. This allows riders to get straight on a Lahar and immediately feel better and go faster. There is big hit advantage to higher pivots and they can be ridden v fast.
Another performance hypothesis in my precise layout is that in the top part of travel, as the riders enduring G-force it is helpful to soften the pedal as the mainframe rises a little with the bump. impact felt thru the foot is reduced. On rebound some of the spring energy acts via the inertia of the drivetrain and leg to drive the wheel forward and the frame down into the hollow. Net effect a smoothing of pedal resistance and ground contact that no doubt contributes to the legendary rep they have for putting down power over big rough.
The bike has a surprizingly wide anti squat envelope- usually riders have to biomechanically compensate for much more eg/ just the varying thrust/chainforce ratio in different gears with rear transmissions. you are correct, best results are with the right springing.
From looking at the pictures, I have noted two things: firstly, at full extension the chainline has a positive gradient relative to the swingarm (by which I mean, would cross the line of the swingarm anywhere in front of the rear axle - a negative gradient being the opposite, where the chainline would cross the line of the swingarm somewhere behind the axle), and secondly, the driving sprocket is in front of the swingarm pivot (and not significantly below it). This means that in the initial parts of the travel at least, there will be positive chain tension under suspension compression (as the axle is moving slightly backwards relative to the chainline, not perfectly perpendicular). Without going into a full analysis (which I'm not going to do because it would take me hours/days), it appears that at some point in the travel, this condition would gradually reverse itself until you had negative chain tension under compression, which would lead to the phenomenon you describe with feedback. However, I would still argue the toss over whether your idea about the negative feedback is accurate, because I think that is similar to some of the "inchworming" ideas of the late 90s. The idea was apparently to use high pivot systems (with a conventional chainline setup), which had heaps of chaingrowth, because whenever the suspension compressed, it would force the chain to "unravel" around the cassette, which would in turn accelerate the bike... so every bump you hit actually made you go faster! I personally think that this is unlikely to work, however softening the blow to a weighted foot may have some advantage. Anyway this is largely academic because it would also appear to me that the amount of feedback would be VERY minimal as you say.
By "wide anti-squat envelope" what do you mean? Wide range of anti-squat, or wide area with similar/same/high anti-squat?
I guess I mean NET
Actually I run a touch of brake induced jack. The major force is when the wheel locks (transferring rotational inertia to swingarm compression on non-floating systems). Utilising a touch of this kick to drive the wheel into the ground results in an instant ABS effect.
the braking tendancy is to sink equally at both ends. Even slamming something real big in a real bad way doesn't rotate the mainframe forward /buck the bike. This is because any impulse that acts along the swingarm line is tugging above the bike COG providing a backward torque on the mainframe. Thats what sold Nathan Rankin on them in 2003. He tried hard but " nothing I can do will make this bike buck." Actually the size of rearward impulses along the swingarm is at least 10 times higher on conventional bikes and this like going for a quick sprint with your ankles tied to a tree as the horizontal swingarm makes the bike unwind under inertia.
I disagree with that - I firmly believe that your specific floating brake geometry will allow for some amount of SQUAT under braking. The instant centre is in front of, and higher than both the tyre's tractive patch, and the axle. There is no component of this geometry, unless I am hugely mistaken (which I'm confident that I'm not), that will cause extension (jacking) due to brake and axle forces. The only thing causing/allowing extension of the suspension is the rider/bike mass transfer forwards due to deceleration (well, rearwards acceleration technically).
I am also not convinced by the idea that the line of force along the swingarm is above the CoM, because even if this is the case, it is certainly below that of the rider/bike combined CoM; keeping in mind that while a bike/rider combo is a multiple D.O.F. system, they are not separate. If the bike decelerates suddenly, regardless of any rotation about its own centroidal axis, it will decelerate the rider from points of input below his or her own centre of mass, and thus you will still be able to be thrown forwards. I would theorise that any less bucking of the bike would simply be due to the fact that with a rearwards axle path, as you say, you have a far superior axle path tangent for absorbing large bumps (as it won't "hang up"), rather than anything to do with the line of force through the swingarm. Again, hardly a huge criticism of your bike, just nitpicking your claims
Happy to discuss ongoing. Its refreshing to meet someone with a brain not washed by the ongoing tripe of the industry,
Likewise. I appreciate your honesty and input, and in spite of my arguments (which are, to be honest, mostly about relatively minor details) I believe that you're a fair leap ahead of most of the bike designing world in terms of real-world physics. And I would love to have a ride of your bike one day. If you're feeling especially charitable, I would also be more than happy to publicly review one for Farkin.net
Leverage ratio starts about 4.2- we're running soft initial travel and stabilises at ~2.5 for the 2nd half.
The geometry is basically Nathan Rankin specified after his nationals win on the m8.
Chainstay is 445mm 17.75inch
Wheelbase 1192mm 46.9 inch
BB height 370mm 14.6inch (zero sag sitting on hard ground)
Top tube 560mm 22 inches as measured horizontally centre of steerer at stem to centre of seatpost.
The forward set and layed back seatpost gives a wide range of cockpit size as it moves rearward as it goes up.
Head angle is 63-64degr depending on 8"/ 7.5"/ 7" setting of Fox40 fork.
Frameweight is 5.1 lb + fox dhx5.0 = 6.5lb.
Complete bikes w F40 and full dh rubber is 41pounds
Cheers for your time. I very much appreciate your personal and in-depth input. Beats the living crap out of "isolates pedalling forces on the seatstay and stays 100% neutral under brakes" for a sales pitch
Fair call, assuming you're travelling down a 27 degree slope. I would hypothesise that superior cornering in loose conditions is likely to be due to the long wheelbase and progressive rate (which IMO gives very good traction) rather than the weight transfer. My personal opinion/experience is that bikes with more vertical axle paths and generally shortening wheelbases under compression, tend to corner better.
Close to ideal maintenance of wheelbase and weighting on slopes, forward weight transfer on flat corners. Perfect characteristics for a dh bike!
Shortening wheelbase makes bikes squirrelly and their sweet spot for rider weighting small and easily lost.
I think if Youd ridden some good HP bikes for a while you might understand.
No feedback, I'd agree with as being "independent" (although Mr Weagle has made a good point in the past about feedback only mattering if it's perceptible). I would like a better definition of your idea of neutral squat though (I have an idea in my head but I don't want to put words into your mouth).
Terms the mtb population understand often dont translate to technical ones. active means independent etc. Neutral squat would be no movement of susp under drive force.
And I would say that it is fairly speculative to say that a high pivot is outright "better" in the minds of the entire design/engineering community. Due to the lower CoG of a motorcycle/rider combination, as well as the larger tyres and longer swingarm, the resulting pivot heights (which give axle tangents far less rearwards than your bike, on all production bikes I've seen, which would contradict what you say about the design community agreeing that higher pivots are necessarily better) are used more for squat control and traction due to weight distribution under compression/extension. I do not believe that these characteristics can be transferred directly to mountain bikes, and I would also argue that your bike does not possess these characteristics (which may well be for the better, since motos and mountain bikes have different requirements).
When I say high Pivot I mean rear suspension geometry that agrees with the formulas for wheelpath-CoM that all applications of wheel driven suspension design hold to.
Obviously motocycles with their low mass and long wheelbase produce a much shallower swingarm solution from these inviolable formula (deriving as they do from Conservation of momentum and the action of offset forces on free bodies).
Keeping the market confused and having flaws to point to in the performance of every last years model has served the industry well in the revolving door sales program.
Im interested in final destinations, not the next big thing so I say Ye Basta! (enough is enough)
From looking at the pictures, I have noted two things: firstly, at full extension the chainline has a positive gradient relative to the swingarm (by which I mean, would cross the line of the swingarm anywhere in front of the rear axle - a negative gradient being the opposite, where the chainline would cross the line of the swingarm somewhere behind the axle), and secondly, the driving sprocket is in front of the swingarm pivot (and not significantly below it). This means that in the initial parts of the travel at least, there will be positive chain tension under suspension compression (as the axle is moving slightly backwards relative to the chainline, not perfectly perpendicular). Without going into a full analysis (which I'm not going to do because it would take me hours/days), it appears that at some point in the travel, this condition would gradually reverse itself until you had negative chain tension under compression, which would lead to the phenomenon you describe with feedback. However, I would still argue the toss over whether your idea about the negative feedback is accurate, because I think that is similar to some of the "inchworming" ideas of the late 90s. The idea was apparently to use high pivot systems (with a conventional chainline setup), which had heaps of chaingrowth, because whenever the suspension compressed, it would force the chain to "unravel" around the cassette, which would in turn accelerate the bike... so every bump you hit actually made you go faster! I personally think that this is unlikely to work, however softening the blow to a weighted foot may have some advantage. Anyway this is largely academic because it would also appear to me that the amount of feedback would be VERY minimal as you say.
HA!
Those extreme jack-ass theories had me in stitches too. The idea that your pedal coming up 3-4 inches as you take a hit is good was just wild. The effect was that you only had ½ the suspension travel unless you got used to back-pedalling on big hits. And when the wheels rebounding into space the pedal drops from beneath your foot!
The reverse situation- reclaiming rebound energy that would otherwise be wasted in the damper is a far more attractive theory. The feedback is helping you weight the pedal on a bike in flight and get the rear down. As you correctly point out the feedback on the mark 9 is very small. Also its mostly in the beneficial direction, at least compared to the feedback on modern conventional bikes and, needing as they do a very large chain tension contribution to lock out squat- producing a good sized dose of the Jack-ass effects. Of course this means that Conventional bikes are badly flawed and if its not perceptible to someone its because people only know what they know.
It did seem perceptible to some with several active susp cycles milked by the market.
Actually we are just agreeing with each other here and should limit high jargon verbosity to avoid excluding the less technically literate.
By "wide anti-squat envelope" what do you mean? Wide range of anti-squat, or wide area with similar/same/high anti-squat?
I mean It doesnt move at all with no pro- pedal whether your seated or upright and isnt anywhere as sensitive to inappropriate springing as multilink conv bikes.
I disagree with that - I firmly believe that your specific floating brake geometry will allow for some amount of SQUAT under braking. The instant centre is in front of, and higher than both the tyre's tractive patch, and the axle. There is no component of this geometry, unless I am hugely mistaken (which I'm confident that I'm not), that will cause extension (jacking) due to brake and axle forces. The only thing causing/allowing extension of the suspension is the rider/bike mass transfer forwards due to deceleration (well, rearwards acceleration technically).Sorry, its a scalene quadrangle (unequal links). You cant just find an instant centre by intersecting lines along the links. Actually its tuneable to give you a tweak in either direction by adjusting the struts rod ends.
I am also not convinced by the idea that the line of force along the swingarm is above the CoM, because even if this is the case, it is certainly below that of the rider/bike combined CoM; keeping in mind that while a bike/rider combo is a multiple D.O.F. system, they are not separate. If the bike decelerates suddenly, regardless of any rotation about its own centroidal axis, it will decelerate the rider from points of input below his or her own centre of mass, and thus you will still be able to be thrown forwards. I would theorise that any less bucking of the bike would simply be due to the fact that with a rearwards axle path, as you say, you have a far superior axle path tangent for absorbing large bumps (as it won't "hang up"), rather than anything to do with the line of force through the swingarm. Again, hardly a huge criticism of your bike, just nitpicking your claims
Its important to realise that this is high speed impulse analysis rather than static force vectors. Since the elapsed time of the impact event (time of most wheel acceleration) is around 1/1000sec- 1/200 sec the force is very large but short duration means it can only effectively rotate rigidly attached mass. The point here is that this is known to induce a fierce forward rotation of the mainframe on low pivot bikes. While they are in a very bad position to start with due to the wheel tripping on the bump, its the component of impulse acting along the swingarm, and well below the CoM of rigid mass that is producing this bucking of the mainframe and cockpit. This force does no good and is significant in loss of forward energy on bumpy surfaces. It is demonstrable with a vertical wheelpath that on bumps of 4, half of the bump energy is directly subtracted from forward speed rather than suspension activation.
Likewise. I appreciate your honesty and input, and in spite of my arguments (which are, to be honest, mostly about relatively minor details) I believe that you're a fair leap ahead of most of the bike designing world in terms of real-world physics. And I would love to have a ride of your bike one day. If you're feeling especially charitable, I would also be more than happy to publicly review one for Farkin.net
Ive received email warnings about you eg/ smart cooky
that'll argue a barely relavant point just to prove it
exists and fight to the death
Warnings aside, Itd be good to have your contribution to a review, dont know about the whole thing as unfortunately Ive learnt most of mtb market switches off at the first technical phrase, and Im not convinced you can restrain yourself!
Close to ideal maintenance of wheelbase and weighting on slopes, forward weight transfer on flat corners. Perfect characteristics for a dh bike!
Shortening wheelbase makes bikes squirrelly and their sweet spot for rider weighting small and easily lost.
I think if Youd ridden some good HP bikes for a while you might understand.
No feedback, I'd agree with as being "independent" (although Mr Weagle has made a good point in the past about feedback only mattering if it's perceptible). I would like a better definition of your idea of neutral squat though (I have an idea in my head but I don't want to put words into your mouth).
Terms the mtb population understand often dont translate to technical ones. active means independent etc. Neutral squat would be no movement of susp under drive force.
And I would say that it is fairly speculative to say that a high pivot is outright "better" in the minds of the entire design/engineering community. Due to the lower CoG of a motorcycle/rider combination, as well as the larger tyres and longer swingarm, the resulting pivot heights (which give axle tangents far less rearwards than your bike, on all production bikes I've seen, which would contradict what you say about the design community agreeing that higher pivots are necessarily better) are used more for squat control and traction due to weight distribution under compression/extension. I do not believe that these characteristics can be transferred directly to mountain bikes, and I would also argue that your bike does not possess these characteristics (which may well be for the better, since motos and mountain bikes have different requirements).
When I say high Pivot I mean rear suspension geometry that agrees with the formulas for wheelpath-CoM that all applications of wheel driven suspension design hold to.
Obviously motocycles with their low mass and long wheelbase produce a much shallower swingarm solution from these inviolable formula (deriving as they do from Conservation of momentum and the action of offset forces on free bodies).
Keeping the market confused and having flaws to point to in the performance of every last years model has served the industry well in the revolving door sales program.
Im interested in final destinations, not the next big thing so I say Ye Basta! (enough is enough)
From looking at the pictures, I have noted two things: firstly, at full extension the chainline has a positive gradient relative to the swingarm (by which I mean, would cross the line of the swingarm anywhere in front of the rear axle - a negative gradient being the opposite, where the chainline would cross the line of the swingarm somewhere behind the axle), and secondly, the driving sprocket is in front of the swingarm pivot (and not significantly below it). This means that in the initial parts of the travel at least, there will be positive chain tension under suspension compression (as the axle is moving slightly backwards relative to the chainline, not perfectly perpendicular). Without going into a full analysis (which I'm not going to do because it would take me hours/days), it appears that at some point in the travel, this condition would gradually reverse itself until you had negative chain tension under compression, which would lead to the phenomenon you describe with feedback. However, I would still argue the toss over whether your idea about the negative feedback is accurate, because I think that is similar to some of the "inchworming" ideas of the late 90s. The idea was apparently to use high pivot systems (with a conventional chainline setup), which had heaps of chaingrowth, because whenever the suspension compressed, it would force the chain to "unravel" around the cassette, which would in turn accelerate the bike... so every bump you hit actually made you go faster! I personally think that this is unlikely to work, however softening the blow to a weighted foot may have some advantage. Anyway this is largely academic because it would also appear to me that the amount of feedback would be VERY minimal as you say.
HA!
Those extreme jack-ass theories had me in stitches too. The idea that your pedal coming up 3-4 inches as you take a hit is good was just wild. The effect was that you only had ½ the suspension travel unless you got used to back-pedalling on big hits. And when the wheels rebounding into space the pedal drops from beneath your foot!The reverse situation- reclaiming rebound energy that would otherwise be wasted in the damper is a far more attractive theory. The feedback is helping you weight the pedal on a bike in flight and get the rear down. As you correctly point out the feedback on the mark 9 is very small. Also its mostly in the beneficial direction, at least compared to the feedback on modern conventional bikes and, needing as they do a very large chain tension contribution to lock out squat- producing a good sized dose of the Jack-ass effects. Of course this means that Conventional bikes are badly flawed and if its not perceptible to someone its because people only know what they know.
It did seem perceptible to some with several active susp cycles milked by the market.
Actually we are just agreeing with each other here and should limit high jargon verbosity to avoid excluding the less technically literate.
By "wide anti-squat envelope" what do you mean? Wide range of anti-squat, or wide area with similar/same/high anti-squat?
I mean It doesnt move at all with no pro- pedal whether your seated or upright and isnt anywhere as sensitive to inappropriate springing as multilink conv bikes.
I disagree with that - I firmly believe that your specific floating brake geometry will allow for some amount of SQUAT under braking. The instant centre is in front of, and higher than both the tyre's tractive patch, and the axle. There is no component of this geometry, unless I am hugely mistaken (which I'm confident that I'm not), that will cause extension (jacking) due to brake and axle forces. The only thing causing/allowing extension of the suspension is the rider/bike mass transfer forwards due to deceleration (well, rearwards acceleration technically).Sorry, its a scalene quadrangle (unequal links). You cant just find an instant centre by intersecting lines along the links. Actually its tuneable to give you a tweak in either direction by adjusting the struts rod ends.
I am also not convinced by the idea that the line of force along the swingarm is above the CoM, because even if this is the case, it is certainly below that of the rider/bike combined CoM; keeping in mind that while a bike/rider combo is a multiple D.O.F. system, they are not separate. If the bike decelerates suddenly, regardless of any rotation about its own centroidal axis, it will decelerate the rider from points of input below his or her own centre of mass, and thus you will still be able to be thrown forwards. I would theorise that any less bucking of the bike would simply be due to the fact that with a rearwards axle path, as you say, you have a far superior axle path tangent for absorbing large bumps (as it won't "hang up"), rather than anything to do with the line of force through the swingarm. Again, hardly a huge criticism of your bike, just nitpicking your claims
Its important to realise that this is high speed impulse analysis rather than static force vectors. Since the elapsed time of the impact event (time of most wheel acceleration) is around 1/1000sec- 1/200 sec the force is very large but short duration means it can only effectively rotate rigidly attached mass. The point here is that this is known to induce a fierce forward rotation of the mainframe on low pivot bikes. While they are in a very bad position to start with due to the wheel tripping on the bump, its the component of impulse acting along the swingarm, and well below the CoM of rigid mass that is producing this bucking of the mainframe and cockpit. This force does no good and is significant in loss of forward energy on bumpy surfaces. It is demonstrable with a vertical wheelpath that on bumps of 4, half of the bump energy is directly subtracted from forward speed rather than suspension activation.
Likewise. I appreciate your honesty and input, and in spite of my arguments (which are, to be honest, mostly about relatively minor details) I believe that you're a fair leap ahead of most of the bike designing world in terms of real-world physics. And I would love to have a ride of your bike one day. If you're feeling especially charitable, I would also be more than happy to publicly review one for Farkin.net
Ive received email warnings about you eg/ smart cooky
that'll argue a barely relavant point just to prove it
exists and fight to the death
Warnings aside, Itd be good to have your contribution to a review, dont know about the whole thing as unfortunately Ive learnt most of mtb market switches off at the first technical phrase, and Im not convinced you can restrain yourself!
rad discussion. i really love the clean slate ideology. the bike is really growing on me. the specter of service issues is my biggest concern, though - an exotic bike with lots of proprietary bits - from a tiny obscure company on the other side of the globe (flashbacks of a crappy time dealing with a cracked trimble carbon years ago). hmmm...
i'd love to see some detailed pictures of whats going on in the rohloff area. what shock stroke is it using?
i'd love to see some detailed pictures of whats going on in the rohloff area. what shock stroke is it using?
Its designed as a bike for reliable unsupported international racing, and to still be competitive and reliable when some junior buys it years down the track. This has been proven in previous models and I wouldn't give a 5 year competition guarantee if I couldn't trust them. Unlike most companies my frames don't cost $50 from asia and so they have to be worthy of their guarantees.
Its usual for these bikes to do a whole season without a single mech issue, or even adjustment and we use the most trustworthy gear to make this possible. (lower quality forks, brakes, rims would risk this)
Its usual for these bikes to do a whole season without a single mech issue, or even adjustment and we use the most trustworthy gear to make this possible. (lower quality forks, brakes, rims would risk this)
A single paddle on each bar operated by your thumbs would be cool, I think your fingers should be left to do the braking and hold the bars, hence why I run a sram shifter on my rig!LaharDesign said:
May be true.
personally I like opposable thumbs gripping the bar along with at least a couple of my lesser digits.
personally I like opposable thumbs gripping the bar along with at least a couple of my lesser digits.
Liking the bike - looks like it's come of age compared to the older ones. I know they're good bikes too and have taken a beating by top riders over the years. The new ones just look the biz over the old.
Do yaself a favour tho - make some more pics available and sort out that website - looks ultra cheap.....you may sell some more bikes
Do yaself a favour tho - make some more pics available and sort out that website - looks ultra cheap.....you may sell some more bikes
Oh darn!!benno said:
I'm ALWAYs doin that..
ya put that site together as my 1st attempt with frontpage and a couple of other programs that didn't really work in 24 hrs to start with and its an evolving thing. Pic's are a bit scarce since the usual phenomenon of top riders dissapearing with bikes as soon as the last bolt is tightened is in strong evidence.Kram said:Liking the bike - looks like it's come of age compared to the older ones. I know they're good bikes too and have taken a beating by top riders over the years. The new ones just look the biz over the old.
Do yaself a favour tho - make some more pics available and sort out that website - looks ultra cheap.....you may sell some more bikes
I've had flashy sites before and they always ended up with hypy bul**** that I hated being associated with so I'magone keep the con this time.:mumble:
i like the philosophy of longevity. so many high end (aluminum) bikes have surprisingly short lifespans when used hard. that's what i thought was cool about my tmx (apart from the weight) - which at over 5 years old is still going strong. carbon is definately a promising material in this area.LaharDesign said:
are the bearings, etc (wearing bits) readily available (ie standard spec) parts?
I can only estimate at the number of races I've done on a Lahar, but it has to be 80-100. In that time I've had two equipment related problems.... two flat tyres. One front, one back. The back flat episode happened half way done a NZ nationals track. It was only a local race but I still won the race by 5seconds over the previous years #1 nationally ranked rider.LaharDesign said:
So, as far as reliability goes, I don't think you could find anything remotely as good. And that still rules with 0 psi in the rear.
I can answer this for Aaron, all the bearings are widely used are of a standard size. A bearing set might, incl hub bearings, cost circa $150NZD, maybe a little more. The good thing is the headset, and BB bearings are big **** off style bearings. Unlikely to wear out fast at all.xy9ine said:
Is this not a bit long? It's longer than on most XL size bikes from other manufacturers.
Our experience is that with the tight grouping of weight in the middle of the bike, this is perfect.
Its the same as the geo that they only let factory pro's ride, with other companies. Its better at any skill level,speed and often racing a "standard" bike is dangerous and slow due to to short and steep geometry. The pros have their weight distr further back due to aerodynamic drag at speed so its arguable that "pro" geometry is actually more of an advantage to lower skill levels.- Maybe the big Co's only want their publicised star pro's to be able to win races?
The Lahar M9 is the 11th geometry evolution since 97 on the DHV series so we know very well what works best.
Its the same as the geo that they only let factory pro's ride, with other companies. Its better at any skill level,speed and often racing a "standard" bike is dangerous and slow due to to short and steep geometry. The pros have their weight distr further back due to aerodynamic drag at speed so its arguable that "pro" geometry is actually more of an advantage to lower skill levels.- Maybe the big Co's only want their publicised star pro's to be able to win races?
The Lahar M9 is the 11th geometry evolution since 97 on the DHV series so we know very well what works best.
LaharDesign,
I've been reading recentlly about the prices of carbon fiber rising enormously due to a huge demand from the aerospace and military industries. Do you forsee any production problems or price increases in the near future because of this rise?
I've been reading recentlly about the prices of carbon fiber rising enormously due to a huge demand from the aerospace and military industries. Do you forsee any production problems or price increases in the near future because of this rise?
raw fibre prices might be up but it doesn't affect processed retail too badly. World CF production has been rising pretty exponentially over the last decade and CF consumption by aerospace and Mass Murder industries isn't that large compared to the total. I don't see it being more than a blip convenient to some companies wanting to spin an opportunity to raise their prices.
Sorry if I come across that way. I thought I had made it pretty clear that I was much more interested in discussing the technical stuff than bagging your bikes (which I sure as hell am not trying to do). I've spoken to Rod about this, I think he's just taking my debating the wrong way.LaharDesign said:Close to ideal maintenance of wheelbase and weighting on slopes, forward weight transfer on flat corners. Perfect characteristics for a dh bike!
Shortening wheelbase makes bikes squirrelly and their sweet spot for rider weighting small and easily lost.
I think if Youd ridden some good HP bikes for a while you might understand.
Fair call. Subjective at that point I suppose, but I'll accept your arguments there. For the record, the only high pivot bikes I've ridden are BB7s (and 222s if you'd call them that - definitely not as pronounced as the Balfa or your bike). What I noticed with regards to cornering is that they don't seem to weight your back wheel as much as a low-pivot bike (whether that's better or worse I can't say for sure but it felt weird to me). Maybe it's because my riding style is geared towards low-pivot bikes (since that's what I have owned for the last few years) and I would concede that it probably takes a while to get used to the different handling characteristics. Worth trying at any rate.
Terms the mtb population understand often dont translate to technical ones. active means independent etc. Neutral squat would be no movement of susp under drive force.
Yep ok. For the sake of clarity, I believe this is usually referred to as "100% anti-squat". I wasn't sure if you meant 0% anti-squat (which is in effect what some companies try to claim, by claiming drive forces induce no force on the suspension whatsoever - including those balancing the inertial forces acting to compress it), thanks for clearing that up.
When I say high Pivot I mean rear suspension geometry that agrees with the formulas for wheelpath-CoM that all applications of wheel driven suspension design hold to.
Obviously motocycles with their low mass and long wheelbase produce a much shallower swingarm solution from these inviolable formula (deriving as they do from Conservation of momentum and the action of offset forces on free bodies).
Keeping the market confused and having flaws to point to in the performance of every last years model has served the industry well in the revolving door sales program.
Im interested in final destinations, not the next big thing so I say Ye Basta! (enough is enough)
Again, makes more sense when you put it that way. Your first explanation sounded to me like Chris Porter's (Mojo head honcho) interview in Dirt, where he pretty much claimed we should be using exactly the same technology/layouts as motorcycles do. Sorry for continually arguing the toss here, I am really just interested in the physics you use - not trying to put you or your bikes down.
HA!
The reverse situation- reclaiming rebound energy that would otherwise be wasted in the damper is a far more attractive theory. The feedback is helping you weight the pedal on a bike in flight and get the rear down. As you correctly point out the feedback on the mark 9 is very small. Also its mostly in the beneficial direction, at least compared to the feedback on modern conventional bikes and, needing as they do a very large chain tension contribution to lock out squat- producing a good sized dose of the Jack-ass effects. Of course this means that Conventional bikes are badly flawed and if its not perceptible to someone its because people only know what they know.
It did seem perceptible to some with several active susp cycles milked by the market.
Actually we are just agreeing with each other here and should limit high jargon verbosity to avoid excluding the less technically literate.
I think some of this is a bit subjective, but yeah I can't really see any substantial reason to disagree with that.
I mean It doesnt move at all with no pro- pedal whether your seated or upright and isnt anywhere as sensitive to inappropriate springing as multilink conv bikes.
Righto. Didn't really answer my question but it doesn't matter as the end result is clear.
Sorry, its a scalene quadrangle (unequal links). You cant just find an instant centre by intersecting lines along the links. Actually its tuneable to give you a tweak in either direction by adjusting the struts rod ends.
I still disagree with this. I have found no literature or analyses that effectively criticises instant centre theory when it comes to braking performance. My own argument is that in addition to the brake torque, the rearwards force on the axle (ie the net force that pulls the bike up) will try to compress the suspension due to the moment it generates about the main pivot. Again, not a big deal and if you still disagree I'm not going to continue trying to push the point.
Its important to realise that this is high speed impulse analysis rather than static force vectors. Since the elapsed time of the impact event (time of most wheel acceleration) is around 1/1000sec- 1/200 sec the force is very large but short duration means it can only effectively rotate rigidly attached mass. The point here is that this is known to induce a fierce forward rotation of the mainframe on low pivot bikes. While they are in a very bad position to start with due to the wheel tripping on the bump, its the component of impulse acting along the swingarm, and well below the CoM of rigid mass that is producing this bucking of the mainframe and cockpit. This force does no good and is significant in loss of forward energy on bumpy surfaces. It is demonstrable with a vertical wheelpath that on bumps of 4, half of the bump energy is directly subtracted from forward speed rather than suspension activation.
Fair point, I'll concede that one.
Ive received email warnings about you eg/ smart cooky
that'll argue a barely relavant point just to prove it
exists and fight to the death
Warnings aside, Itd be good to have your contribution to a review, dont know about the whole thing as unfortunately Ive learnt most of mtb market switches off at the first technical phrase, and Im not convinced you can restrain yourself!
For the record, the only reason I choose to even try to criticise your bikes on such a technical level, is because you appear to be in a position to actually defend your ideas with real, pointed arguments, and you are clearly on the ball with the technical stuff. I rarely bother to argue head-to-head with bike designers (on this forum or others) because in most previous cases they've simply changed the subject or dodged the questions. You have clearly shown, in my eyes, that you have enough faith in your design, and enough understanding of the physics (I don't mean to sound condescending by implying that you somehow need my seal of approval
) that you ARE able to argue the technical merits purely as they stand without going round in circles like some people like to do (and if you're reading this DW, no I don't mean you). For what it's worth, I am far more likely to consider buying one of your bikes for having been able to get your technical input (same reason I bought my SGS actually) rather than just a marketing spiel. As for reviewing one, yeah that's understandable. I can speak plain english when I want to, but for better or worse the technical jargon makes life easier in discussions like this one. Anyway, just putting the suggestion out there.
Oh and as xy9ine said - what stroke shock does it use (and how much travel does it have btw? I think I missed that somewhere)?
It has 9" travel measured straight from point to point or 10 if you measure the wheels travel in an arc. I'm fairly sure the shocks a shade under 3" stroke. I'm sure Aaron will confirm all this.
Can't wait to see one in the flesh.
Can't wait to see one in the flesh.
"the rearwards force on the axle (ie the net force that pulls the bike up) will try to compress the suspension due to the moment it generates about the main pivot."
Exactly. this is the equal and opposite effect to the thrust jacking force that stops suspension compressing under drive. It balances the tendancy for the rear suspension to rise as inertia transfers weight to the front wheel under braking. It doesn't interfere with independant drive or braking, allowing them to perform their function without naughty symptoms and the sticky plaster solutions that bad suspension geometry invites.
The principle of anti squat, anti jack geometry is a result of conservation of momentum.
For those still a little confused by this the principle is easily demonstrated with a can of beer and your finger.
If you poke it sharply near the base it will tip over backward towards your finger. If you direct your poke through the centre of mass off the can then no rotations are produced.
No offence intended by my dig above, just fun.
You remind me of myself at your age back 1990-93 when I was drawing my first gearbox bike designs
Exactly. this is the equal and opposite effect to the thrust jacking force that stops suspension compressing under drive. It balances the tendancy for the rear suspension to rise as inertia transfers weight to the front wheel under braking. It doesn't interfere with independant drive or braking, allowing them to perform their function without naughty symptoms and the sticky plaster solutions that bad suspension geometry invites.
The principle of anti squat, anti jack geometry is a result of conservation of momentum.
For those still a little confused by this the principle is easily demonstrated with a can of beer and your finger.
If you poke it sharply near the base it will tip over backward towards your finger. If you direct your poke through the centre of mass off the can then no rotations are produced.
No offence intended by my dig above, just fun.
You remind me of myself at your age back 1990-93 when I was drawing my first gearbox bike designs
Ahhh it just clicked what you're doing; the way I was thinking of it was (whilst technically accurate) not using the same integral approach you have obviously adopted. I think I see where you're coming from and what you're using each individual input to the suspension to tune now.LaharDesign said:
You use the horizontal force on the axle alone, regardless of whether the acceleration is forwards or backwards, to balance the tendency of the suspension to extend or compress (depending obviously on which direction you're accelerating), and separate/tune the other inputs (chain tension force and brake torque) with the chainline being (very nearly) parallel to the swingarm (hence little to no compressive or extensive moment) and the floating brake meaning no torque-induced compression/extension... VERY elegant. Kudos mate, that is a truly excellent idea. :teacher:
That simple notion opens up so many doors in my head. Ahh possibilities!
me too.........
Thanks Steve.(thaflyinfatman)
I've enjoyed your peer review of the principles in my design.
The can't really accept the Kudo's for the principle as Its textbook performance suspension design for the last 100 years. Really I'm just anal enough to insist on doing it right and understanding what you are dealing with is essential to doing it right!
I've enjoyed your peer review of the principles in my design.
The can't really accept the Kudo's for the principle as Its textbook performance suspension design for the last 100 years. Really I'm just anal enough to insist on doing it right and understanding what you are dealing with is essential to doing it right!
is the rohloff a standard bolt-axle unit, or do you do some special mods? (ie, could a customer toss in one they had kicking around). i'm assuming the drive cog is somehow bolted to the hub flange. are all dimensions / angles set for production, or is there some degree of customizability? I imagine there's some degree of adjustability possible by altering the forward shock mount brackets (not to mention shock dims).
Good discussions here…need more of this on RM and less: “x” is the sweetest! No way dude, “y” is the knar!
I would be interested in Lahars take on the use of linkages to isolate these horizontal forces.
I think you and DW (and other full sus engineers) are on the same righteous path here to isolate forces that contribute to unwanted suspension action. His linkage design, bump absorption aside, is attempting to do just what an inline chain design (parallel and in line with swingarm) such as yours does inherently. But what I like most about your thought process is to solve several problems at once: the drivetrain conundrum, brake and pedal force isolation, material selection and most importantly major sexiness in design. Perhaps you should call your new model the “Panacea”?
I would love to ride one of these to see if its as good as certain parts of brain think it should be.
I would also like to offer my services to test and analyse your latest creation free of charge! And living in NZ, the shipping charges would be quite small. I am that kinda guy.
Oh and where do you get that carbon fiber mat from here in NZ?
I would be interested in Lahars take on the use of linkages to isolate these horizontal forces.
I think you and DW (and other full sus engineers) are on the same righteous path here to isolate forces that contribute to unwanted suspension action. His linkage design, bump absorption aside, is attempting to do just what an inline chain design (parallel and in line with swingarm) such as yours does inherently. But what I like most about your thought process is to solve several problems at once: the drivetrain conundrum, brake and pedal force isolation, material selection and most importantly major sexiness in design. Perhaps you should call your new model the “Panacea”?
I would love to ride one of these to see if its as good as certain parts of brain think it should be.
I would also like to offer my services to test and analyse your latest creation free of charge! And living in NZ, the shipping charges would be quite small. I am that kinda guy.
Oh and where do you get that carbon fiber mat from here in NZ?
It's not the principles man, it's the execution and integration of them! Up until now I had always considered all the facets of suspension reaction to acceleration independently (as you would have guessed from my commentary), because with conventional bikes it's more obvious/necessary to do it that way. Seriously cool setup, to find something that so elegantly deals with all the issues simultaneously.LaharDesign said:
One more question - what's the frame weight with shock AND with the Rohloff?
hahahahahaha. Sorry man, I was a little turd back then and I'm not afraid to admit it.BeerDemon said:
LaharDesign said:
Not G-con but G-boxx none the less. Pivot looks up and rearward to me, sort of like what is on the Lahar no? Maybe not the exact placement but what exactly are you seeing that makes it a 'bad' suspension design?
About your bike, You must be happy about developments in nano technology. I know some say its a 'buzz word' (an in a sense it is) but knowing a co-writer of this book has shown me some of what the future has to offer and its exciting.
xy9ine said:
The pivots so low that it will squat worse than any conventional bike on the market today due to lack of any chainlockout. Also will brake jack and trip on large bumps. My mainpivot is closer to this bikes upper link, where it needs to be to eliminate squat, jack and bucking on big bumps.atrokz said:
I've designed some theoretical nano textured surfaces that would convert the kinetic energy of air molecules into electricity. Your bike would sit there with fog pouring off it and develop 100hp outof contact with the air!:love:
I have ridden the TST with G-Box and it rode very similar to my turner DHR. Felt ok to me