Is there any way your calf can touch that rotor? I seriously would not want to have that happen.
the gearbox thread
- Thread starter xy9ine
- Start date
That's always been my fear with setting up a bike with an inboard disc... The fear of it getting hot and burning you or catching on clothing, skin, etc... kinda freaks me out... I'm sure you could sheath it with something though...
Dodzies in the sth Island so can't answer questions easily right now.
That split cycle conveyor belt gearbox is interesting because they are real common and Hondas one was so close to this design. I wouldn't call it a whip drive as IMO that means cables taking the reciprocating drive to the back wheel where its converted by 2 parallel sprag clutches into smooth, seamless torque. Like the one I prototyped in the late 90's.
That split cycle conveyor belt gearbox is interesting because they are real common and Hondas one was so close to this design. I wouldn't call it a whip drive as IMO that means cables taking the reciprocating drive to the back wheel where its converted by 2 parallel sprag clutches into smooth, seamless torque. Like the one I prototyped in the late 90's.
I wonder if that thing would have brake jack with that kind of setup?
Depends on the gearing (chainline) they use. There wouldn't be the direct couple moment applied on the axle that the caliper usually applies, but it would be quite literally like pedalling backwards (if you didn't have a freewheel).
Firstly the caliper is mounted inboard of the rotor ( usually outboard ie on dropout ) so it needs to be backwards.
The rotor is tucked away such that it pretty much impossible to burn yourself on, maybe you could if you had large rolls of fat that could sneak into touch the rotor!
As far as brake squat goes, imagine a motorcycle downshifting, effectively the chain is operating like a floating brake. ie the effective brake pull angle is reduced therefore reducing the squat effect of the braking force on the rear end. Like Aaron says, just motorcycle theory......... conclusion inboard brake is a great idea, was used on motorcycles in the 70's but banned because if you break your chain you have no rear brakes.
The little gearbox is from a conveyor, max torque 25 inch pounds not quite up to the task. like Aaron says seamless torque transfer. For an input rpm of 1800 rpm you can get an output rpm of 0 - 600 rpm. Thats a super granny gear!!
The rotor is tucked away such that it pretty much impossible to burn yourself on, maybe you could if you had large rolls of fat that could sneak into touch the rotor!
As far as brake squat goes, imagine a motorcycle downshifting, effectively the chain is operating like a floating brake. ie the effective brake pull angle is reduced therefore reducing the squat effect of the braking force on the rear end. Like Aaron says, just motorcycle theory......... conclusion inboard brake is a great idea, was used on motorcycles in the 70's but banned because if you break your chain you have no rear brakes.
The little gearbox is from a conveyor, max torque 25 inch pounds not quite up to the task. like Aaron says seamless torque transfer. For an input rpm of 1800 rpm you can get an output rpm of 0 - 600 rpm. Thats a super granny gear!!
yeah yeah yeah, I realize there are major differences, but seriously, I couldn't resist.......the inboard brake is rad. talk about low unsprung weight. i love seeing more independant builders / designers coming out of the woodwork with advanced designs. seems the big companies are playing catchup now. that whip drive looks neat as well. good to see some big brains working out there!
i didn't even think of that! scary.
nice,yeah yeah yeah, I realize there are major differences, but seriously, I couldn't resist.......
with that bike when the sus compressed it really was like you were pedaling backward...
Big mistake the market paid for ever since IMO when gt deleted the Idler gear from their RTS. Looks like those guys made the mistake of following to me.
there is something going on with GT and Suntour (as mentioned earlier in this thread).
If it's a DHi with vboxx, a new IT-1 or a trailbike with gearbox is not certain yet - but on eurobike, one of the GT guys told some partners to "....check out the suntour gearbox....".
And that combined with the rumours that they've ordered 200+ vboxx indicates that something is going on....
There where some rumours that Honda had bought a huge amount of parts for their gearbox' last year...any followup on that?
If it's a DHi with vboxx, a new IT-1 or a trailbike with gearbox is not certain yet - but on eurobike, one of the GT guys told some partners to "....check out the suntour gearbox....".
And that combined with the rumours that they've ordered 200+ vboxx indicates that something is going on....
There where some rumours that Honda had bought a huge amount of parts for their gearbox' last year...any followup on that?
Great thread here guys.
Is Metzy's bike the "NZO"?
And what gearbox is it using? The Conveyor one? If so, how is shifting taken care of, and efficiency?
Or is it just a Nexus or Rohloff setup?
Is Metzy's bike the "NZO"?
And what gearbox is it using? The Conveyor one? If so, how is shifting taken care of, and efficiency?
Or is it just a Nexus or Rohloff setup?
Hey Mr Plow,
The NZO is Dodzys bike, the gearbox is a derailleur in a box arrangement that dodzy made from scratch.
The efficiency numbers that have been thrown around these forums never seem to relate to how the bike feels when you ride them, ignoring the pedaling geometry (most of which are pretty crap, one exception being Lahar) and focusing on drive efficiency only ( ie imagine the gearbox and required chains on a hardtail). The nexus/rohloff units i have ridden all honestly felt draggy. They get away with it for DH which has been confirmed by Juniour world champ riding a lahar on a reasonably pedally course.
Dodzys derailleur in box setup runs 2 inline well lubed chains, honestly you think you are pedalling a normal bike, no drag, no noise just pedal and go.
Thats my experience, interested to her other feedback re gearbox configurations.
The NZO is Dodzys bike, the gearbox is a derailleur in a box arrangement that dodzy made from scratch.
The efficiency numbers that have been thrown around these forums never seem to relate to how the bike feels when you ride them, ignoring the pedaling geometry (most of which are pretty crap, one exception being Lahar) and focusing on drive efficiency only ( ie imagine the gearbox and required chains on a hardtail). The nexus/rohloff units i have ridden all honestly felt draggy. They get away with it for DH which has been confirmed by Juniour world champ riding a lahar on a reasonably pedally course.
Dodzys derailleur in box setup runs 2 inline well lubed chains, honestly you think you are pedalling a normal bike, no drag, no noise just pedal and go.
Thats my experience, interested to her other feedback re gearbox configurations.
metzy, that foam prototype looks hot, and the gearbox system, is that a diab (derailleur in a box)?
Keep up the good work and I can't wait to see the rideable version.
Can you tell us anything else about the design?
Are you also using the inboard disk brake?
Keep up the good work and I can't wait to see the rideable version.
Can you tell us anything else about the design?
Are you also using the inboard disk brake?
Ditto that with the drag feeling. All the bikes with Rohloffs that I've tried have felt like there's a bit more friction (like a chainguide roller that's pressed up tight against the moving plates on an MRP or something), especially in the lower gears. Not really a big deal or anything, but it is there.
New Rohloffs do take a bit to loosen up.
Thanks guys.
Well I am sitting here continuing designing my own bike. An ongoing project for the past few years. Got my Nexus beside me (beer too
) New deadline is February.
Anybody aware of any durability issues with the nexus 8 speed? Looks pretty good internally.
Well I am sitting here continuing designing my own bike. An ongoing project for the past few years. Got my Nexus beside me (beer too
) New deadline is February.Anybody aware of any durability issues with the nexus 8 speed? Looks pretty good internally.
so has any of you kiwis got any ride time on the inboard disc bike?
EVRAC
The lump of foam is the male mold for my front tri. I have made a der in a box gearbox, i won't use an inboard brake because i am building a trail/xc bike, the inboard brake would result in a bike a little wider than I want, also I want the pedalling geometry to be spot on for me (6'3") which meant that i struggled to make it work with a concentric output shaft/main pivot which you also need for the inboard brake. COG height ( rider + bike) is an important factor in determining the correct pedaling geometry ( Contrary to the crap the specialized, ellsworth.............etc spoon feed us in crap magazines).
Anyway - the end result will be high pivot (for good axle path), der in a box, 9 speed biased toward granny, true temper cromo rear end with 20mm axle, carbon front end, 6 - 8" travel trail bike. put some light ish gear on it and it should be a nice ride.
Attached a pic of my old bike, high pivot double chain ring, really a proto for the gearbox bike. A couple of years old now and she goes great.
VITOX - I have ridden Dodzys bike a bit. I can tell you the brake works fine, sensitive enough to manual with, no chatter, no chain breakage........ Dodzy is a top rider here in NZ he rides hard and has put quite a few miles on this bike. It's all good.
The lump of foam is the male mold for my front tri. I have made a der in a box gearbox, i won't use an inboard brake because i am building a trail/xc bike, the inboard brake would result in a bike a little wider than I want, also I want the pedalling geometry to be spot on for me (6'3") which meant that i struggled to make it work with a concentric output shaft/main pivot which you also need for the inboard brake. COG height ( rider + bike) is an important factor in determining the correct pedaling geometry ( Contrary to the crap the specialized, ellsworth.............etc spoon feed us in crap magazines).
Anyway - the end result will be high pivot (for good axle path), der in a box, 9 speed biased toward granny, true temper cromo rear end with 20mm axle, carbon front end, 6 - 8" travel trail bike. put some light ish gear on it and it should be a nice ride.
Attached a pic of my old bike, high pivot double chain ring, really a proto for the gearbox bike. A couple of years old now and she goes great.
VITOX - I have ridden Dodzys bike a bit. I can tell you the brake works fine, sensitive enough to manual with, no chatter, no chain breakage........ Dodzy is a top rider here in NZ he rides hard and has put quite a few miles on this bike. It's all good.
So I was reading about the nexus bike on the BCD history page and Alex describes how the brake affected the rear suspension. It seems to me that if the rear brake was locked up, the whole rear end would lock up. Am I wrong? If you were riding downhill and braking, the bottom chain would be in tension, preventing the suspension from compressing. Very different situation if the brakes are locked up while stationary and bouncing up and down. Is it because of the different sized cogs? What am I missing?
Nice, this thread just hit 10,000 views!
never thought you'd see that day coming.......right EVRAC!
How good is this dodzy character I hear you say.
good enuff to place 2nd in senior men at the occeania's on the worlds course, only 31 or so sec's off Barels pace, on a trailbike, a GT ID5 I beleive. Pity he's a ginga
500 to 1000 kms to lossen up but once done are awesome
I had that same thought when Dodzy was thinking about doing the inboard brake. So I made a little mock up, turns out that as the rear wheel goes through its travel the chain just wraps onto the bottom of the inboard sprocket and unwraps off the base of the swingarm mounted sprocket. This meant the contact patch (tire/ground) was the same all of the way through it's travel, interesting! (not the case with most bikes) Yes the chain is under tension but the wheel doesn't know the difference between a chain force and disc brake force.
Yeah, except that the side of the chain that's under tension becomes the bottom side rather than the top.
Except your running a smaller rear ring than the fron ring, thus reversing that theory?
I think he's pointing out the fact that it's fairly similar to a floating brake actually.
As am I. But I believe from both mine and a friends research the inboard brake on the moto above converses on the centre of mass, because the rear cog is smaller than the front.
The opposite is the case on the mountain bike where the smaller rear, larger front effectively creates a diversing instant centres of pivot and brake, the moto theory looks to concentrate the centres around the centre of mass.
I guess then, brake squat and jack could be tuned by changing the gear ratios. Not the best solution thinking about it
Below was the final (8th) generation of my bike design, which I now have to change again after a bit more research
This may also be of interest for those who haven't found it already.
http://www.tonyfoale.com/Articles/Dive/DIVE.htm
PS sorry, this has strayed a bit of topic, but the gearbox is a tool that enables different suspension design??
nice work on the bike...
That looks awesome.
Hey BCD, this looks a bit like the Vite, eh?
Maybe u 2 should team up, and u could make the swingarm or something.
I've been designing something similar as well.
After everything mr. Lahar has been saying I'm starting to think that a gearhub nice and high would be better than the new gearboxes available.
edit: how do I quote a pic used earlier in the thread?
i say. the orange with the suntour box is the nicest looking implementation to date, bar none. Though i won't say no to a lahar with the new crankset.
Nice work yourself Evrac, got a long way to go yet though hey?
That looks awesome.
Hey BCD, this looks a bit like the Vite, eh?
Maybe u 2 should team up, and u could make the swingarm or something.
I've been designing something similar as well.
After everything mr. Lahar has been saying I'm starting to think that a gearhub nice and high would be better than the new gearboxes available.
edit: how do I quote a pic used earlier in the thread?
It's the damn details that take so long hey!?
Whats wrong with the crankset on a lahar dude???
Thanks but I don't get the credit. That's BCD's "Vite" pictured.Nice work yourself Evrac, got a long way to go yet though hey?
It's the damn details that take so long hey!?
I think he was just refereing to some prototype Carbon cranks Lahar where playing with,I don't think there's any plans for production of them yet.
I'm not sure if this has been brought up yet - (been out of this thread for quite a while) but since we are on the subject of suspension design around a gearbox platform:
How the hell can DW pull off his DW-Linkage system around one of these things? I mean how could he retain all of the necessary geometry points, leverage ratios, and linkage locations of the DW-Link system without doing something drastic?
I was thinking about this the other night and could'nt quite see how it would work.
DW - any thoughts here?... how is it coming along?
How the hell can DW pull off his DW-Linkage system around one of these things? I mean how could he retain all of the necessary geometry points, leverage ratios, and linkage locations of the DW-Link system without doing something drastic?
I was thinking about this the other night and could'nt quite see how it would work.
DW - any thoughts here?... how is it coming along?