wouldn't a rearward axle path be the best for square edge hits? why is lahar the only bike with a serious rearward axle path?
axle paths
- Thread starter _*sTiTcHeS*_
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I've always though so, and personly I think a rearward path helps with stability too. Corsairs' freeride bike has rearward axel path, and I'm sure there are a few others that elude my mind right now. The problem faced with alot of rearward axel paths is: how to keep massive chain growth in check?
yeti 303, morewood, orange
I've heard that the Cove Shocker has a rear axle path, at least for the first third of its stroke.
Not sure if its true.
It came from a guy who had just bought the bike and was hyping it up... You know how that is.
Not sure if its true.
It came from a guy who had just bought the bike and was hyping it up... You know how that is.
none of those have a noticeable rearward axle path. you should have added kona and supercycle to that list while you were at it.
Canfield Bros.
Chain growth can be counter-acted pretty easily with an idler pulley or similar. Another problem with a high single pivot is the increasing chainstay length as the suspension compresses so as the bike sinks into its travel in a corner it becomes less nimble.
2stage do a really good job of getting the best of both worlds, the initial stage is a low pivot so under low-speed situations like turns the chainstay length is unaffected. Then under big hits the wheel starts moving backwards in its second stage to clear the impact.
under hard cornering the front is compressing as well; with a slack ha, fork compression effectively shortens the wheelbase while the rear is extending (ie, parallel wheelpaths). the net result is a ~static wheelbase. high pivots can have a different cornering feel, but not detrimental, imo.
Yeah, it starts rearward and moves to a more vertical wheel path.
I didn't just buy it, but I'm still hyping it
Marketing is the best axle path.
There has never been a truer statment.
I just moved between bikes. The first had a relatively low single pivot, and the second has a very high one. In spite of the new bike only having a 24" rear wheel it still takes hits better than it's predecessor.
I for one don't think it's all hype.
I for one don't think it's all hype.
A path that becomes rearward only toward the end of the travel is not at all ideal. Square edged bumps are normally encountered in first two thirds of the travel, not near the end. Think about it, when was the last time you bottomed out your suspension when hitting a bump? The forces that cause the suspension to move into the second half of the travel tend to be more vertical (caused by the 'horizontalness' of the ground) The forces that want to push the rear wheel backward (bumps) tend to be encountered at the beginning of the travel.
Vermont? I've bottomed more than a couple times from bumps.
Because bikes with shrinking chainstays corner insanely well. I owned 2 DH bikes with rearward axle paths with the assumption that they would handle square hits better than a low pivot. I was wrong.
My Turner is a bit harsher on square fast stuff but the cornering and poppy suspension is worth it.
My Turner is a bit harsher on square fast stuff but the cornering and poppy suspension is worth it.
i'm with you to an extent. low pivot bikes do seem to feel 'livelier' & more dynamic in corners (popping out of exits, while the high pivots tends to stay more planted / neutral), though i'm not sure actual cornering speed varies much. while the lahar is the best high speed chunder leveller i've ever ridden, i do kinda miss that 'poppy' playfulness of the lower pivot bikes i've ridden. bit of a tradeoff i guess. though in the end both ends of the wheelpath spectrum can work really well.
axle path is the most important part of a bike that everyone has heard of, yet few actually understand. Rearward is good, but not at all points in the suspension travel. Take a little time to read the archives on this site and you will find a lot of imformation posted by yours truly on this subject.
I think NSM is the only person qualified at answering this.
I'm not qualified at all. I'm just the same as everyone else.
I can't see any logic to say that anything is better at square edge hits than a rearward axle path,be it a virtual high pivot,a high single or a window of travel like BCDs twin shocked bike. That's why I like them. I think the point of suspension is to absorb irregularities in the trail,keep your tires on the ground and keep you in control.In DH,you're riding into most obstacles,and having a wheel absorb that impact helps you maintain speed and control,rather than it slowing the bike and bucking it over it,. All bikes are a compromise of sorts. Yes low singles take less effort to turn with their shortening wheel bases,as you slam into a corner it all turns faster,giving the rider a fast sensation.A low pivot may take less effort to turn,but I'm not sure if it's actually faster for it.it jsut takes a more aggressive style with a rearward axle path,but the bumps before the corner won't be slowing you,I also like a more consistent wheelbase,gradually getting longer or staying the same with the front wheels travel,no shortening then lengthening or anything like that.
There's a few notable other rearward axle path bikes.
Brooklyn Race Link,Slope Ranger and their predessors.
Balfa BB7.
Apalche Real.
Trek DH thingy
BCDs lovely creations
and lots more.
I found the rearward path gave me lots more control and speed. and the lengthened wheelbase off big jumps or drops makes the bike more stable giving more confidence.
If you want the rear sus to lock out when pedalling,or if you like the hardtail feel through bumps or if you don't like to be that physical in corners,get something else.
There's lots of great bikes that don't have the axle path of a high single pivot,obviously the Sunday,the Cove Shocker,I'm sure the Yeti and new Banshee would be great.
Don't let a bikes geometry confuse things. The Lahar for example is longish feels lazy and docile at low speed,and requires a real aggressive style,but it is really fast if ridden this way,and rewards the rider with speed and confidence.
Any tiny low,short bike,with quick geometry will feel fun and fast,but it won't necessarily be.BMX bikes feel fast,but for DH they're not.
That's exactly what I thought when 2stages first appeared amidst a whole lot of marketing hype but once you're on the trail it definitely works, and that's where it matters right? Their all-mountain bike eats bumps waaaay better than my fsr-equipped khs and a workmate of mine has said the rear sus on their DH rig works better than his Yeti 303.
Has anyone ever just done a roll test comparison between different suspension configurations?
ie Get a fairly rough bit of track and just roll them from a standing start with the rider providing no input (pumping or pre-jumping) and all components being equal. If it was repeatable and actually showed a measurable difference it might at least provide a basis for all this "seat of the pants" analysis/theorising. At the moment it just looks like "it feels faster" and "it ought to be quicker" and that isn't very scientific.
Just how much difference are we talking, can it actually be measured?
ie Get a fairly rough bit of track and just roll them from a standing start with the rider providing no input (pumping or pre-jumping) and all components being equal. If it was repeatable and actually showed a measurable difference it might at least provide a basis for all this "seat of the pants" analysis/theorising. At the moment it just looks like "it feels faster" and "it ought to be quicker" and that isn't very scientific.
Just how much difference are we talking, can it actually be measured?
indeed. where be these fabled archives? i'd love to see some unbiased bicycle suspension theory by someone more qualified than we armchair speculists. in a concise, easy to read format, of course.
Mmmm.... Axle Path.... Mmmmmm....
Just do a search on dw's posts from over a year ago......search on 'anti-squat' and you'll probably find some good info.
I remember the discussions but not thread titles etc..... There is quite a bit if it hasn't been deleted.
Ya, DW isn't qualified at all.
Neither are any of the other fully fledged Mechanical Engineers on here.
The thing about the 2stage though, is that the suspension behavior is highly dependent upon the difference (or lack of difference) in air pressure between the two shocks. There is no guarantee that the wheel is ever going to follow a particular path with a 2 degree of freedom design. If the "2nd stage" shock uses considerably higher air pressure than the "1st stage" shock, then the path will tend to be like you described. (and how the bike is marketed) If similar pressure is used in both shocks, then the path will probably be much more rearward at the beginning of the travel. I have yet to see a recommended setup for those bikes, and would love to hear what pressures you used. (if you remember)
try these
I tried a revolutionary approach of searching the term 'axle path' and 'dw'
http://www.ridemonkey.com/forums/search.php?searchid=1766619
Just a little something I have been working on. This is the axle path of the frame design I have been playing around with. It has a rearward axle path. May try to build it over the winter. The bike will have two different travel modes 5" and 7" that can be changed on the fly. I designed it around the RS Totem 2 step sense it can be changed from 5" to 7" on the fly. Now only if RS will get the 2 Step working right.
do'h. anyways, those threads dont contain much information.
and dw has been giving the same reply since 04:
http://www.ridemonkey.com/forums/showpost.php?p=1191242&postcount=8
and thats the oldest thread there was.
Sorry man. There's plenty of non dw info out there too.
Look under the user name 'zedro'
What is it you want to find exactly?
The new Canfield F1 Jedi is 7in vertical 2in rearward.
The bike is designed so the transition between the two stages starts when the first shock is about 2/3rds of the way into its stroke (ie its not bottoming out every time) and I think the recommended set-up is 50% sag on the first shock then twice whatever that pressure was in the second. 2stages product manager set it up for me but it was about 60psi in the first shock. They had set-up info on their site but they have a new site and its not on there yet. Each new bike comes with a big manual on setting it up though.
Since sag is at 50% and the second shock activates just after 65ish% then there is very little upwards movement before the wheel starts moving backwards.
