sorry im to impatient right now to write anything better
talk amongst yourselves
talk amongst yourselves
MTB with a drive shaft
- Thread starter HTFR
- Start date
Um. Woo. Hoo?
It's a URT because the driveshaft can't cope suspension movement.
It looks like the shifting is accomplished through some kind of chintzy tiny rear hub which couldn't have more than a few gears on it.
Plus, someone correct me if I'm wrong, but I don't think a driveshaft is as efficient as a chain/cassette/derailleur system.
It's a URT because the driveshaft can't cope suspension movement.
It looks like the shifting is accomplished through some kind of chintzy tiny rear hub which couldn't have more than a few gears on it.
Plus, someone correct me if I'm wrong, but I don't think a driveshaft is as efficient as a chain/cassette/derailleur system.
they feel funny to pedal. We have a hardtail, slick tire, drive shaft bike at the shop i work at as lunch go getter.
I'd imagine that a budget level bike like that would have some crazy flex in the driveshaft when really pushing... Might account for the "funny feel".HippieKai said:
it's not flex...it engages better than a chain and casset/free wheel so it's very touchy. almost like a fixed gear without the fixedness.
Well, the "slack" you feel in a chain setup isn't really due to the chain, it's mostly due to the gap in the engagement points of the hub. Something like a Hadley trials hub or a CK remove most of the slack... I still want to try one of those True Precision Stealth hubs with instant engagement.HippieKai said:
I assume your setup has some kind of proprietary hub? How is the gearing setup - internally in the hub?
I tried to get info on those a couple years ago at interbike. Other than not being able to find the booth, everything I heard was that they were intended for only casual riding, not performance based situations, such as mountain biking or road riding.
One more thing, they were not retrofittable to existing frames. You had to buy one of theirs.
I think shaft drive is a great idea, and one that will eventually replace the chain driven drivetrain we all know, but it is not there yet. I have also read that they are more efficient than a chain system, though someone on here once posted the contrary. (I don't know where they got their info from)
One more thing, they were not retrofittable to existing frames. You had to buy one of theirs.
I think shaft drive is a great idea, and one that will eventually replace the chain driven drivetrain we all know, but it is not there yet. I have also read that they are more efficient than a chain system, though someone on here once posted the contrary. (I don't know where they got their info from)
Chain drives are up to 98% efficient (link - this is not the only place this information is found either). Isn't one of the major problems of efficiency when you change the direction of the torque? The drive shaft has to change the direction of the torque from the pedals, then change it back again at the hub.
I'm Googling a good source for shaft drive efficiencies, but have not found a reputable one. There are numerous ones that report 99% efficiency from a shaft drive, but they are all selling shaft drives. Considering the load of repeatedly-debunked B.S. that Specialized still publishes about the Horst link, I don't consider those to be good sources.
I did find this which seems to be just speculation, but sounds like educated speculation
- I've got to get back to work - someone take up my quest for a good source! 
I'm Googling a good source for shaft drive efficiencies, but have not found a reputable one. There are numerous ones that report 99% efficiency from a shaft drive, but they are all selling shaft drives. Considering the load of repeatedly-debunked B.S. that Specialized still publishes about the Horst link, I don't consider those to be good sources.
I did find this which seems to be just speculation, but sounds like educated speculation
- I've got to get back to work - someone take up my quest for a good source! 
If shaft drive is so great, why do the majority of motorcycles still run chains?
Driveshaft's on a bicycle is just another piece of weight that you must spin. There's no way a driveshaft is going to weigh the amount of a chain. Even a fancy Carbon one 
Good idea, bad implementation for a bicycle.
Yeah, stealth hubs rock. The company is just up the street from me. Just don't be like their workers and leave their bikes outside of cheap grocery stores and get them stolen. I think it happened to one or two of their employee's. So some dirtball has some hubs on his stolen ride that rock
Good idea, bad implementation for a bicycle.
Yeah, stealth hubs rock. The company is just up the street from me. Just don't be like their workers and leave their bikes outside of cheap grocery stores and get them stolen. I think it happened to one or two of their employee's. So some dirtball has some hubs on his stolen ride that rock
HRDTLBRO said:I had read an article online about a dude out west who had made one. It may be the same dude who does the Heim 3 guide...but I can't remember. Interesting idea.
Ba-bam!
http://leelikesbikes.com/Stories/110304b/
The question is... are they ever going to produce their mountain bike hubs again?Spunger said:Yeah, stealth hubs rock. The company is just up the street from me. Just don't be like their workers and leave their bikes outside of cheap grocery stores and get them stolen. I think it happened to one or two of their employee's. So some dirtball has some hubs on his stolen ride that rock
Their previous ones seemed to have a sporadic problem with the freehub blowing up. They have had stuff on their website about a redesign to make the hubs lighter and stronger (the rear was a boat anchor... as heavy as an XT), but they've been vaporware for many years now.
correct me if i read this wrong, but i know of many driveshafts that flex inward and outward like when a car shock compresses due to axle flex, using a car for example..binary visions said:
they have those internal gear hubs with the flawless shifts, wouldn't it be possible to stick that in there?
as for the efficency, i think it would be more efficient, but definately adding a few pounds, though there would be some anual maitnence which would be optional but a good idea..that would be u-joints, though they are relatively inexspensive, probably 15 bucks, as for trucks they are 30 each..some oil here and there wouldn't hurt, but i think you'd get more response, consistency, durability and one less thing to hit a tree or break since most driveshafts are made of steel, and i'm guessing this one would be no different..driveshafts can take more wait, and by the looks of it, i think that driveshaft could take 300 pounds easily.
We saw this last year at the NYC bicycle show. Frankly, after riding it...it sucked. NO shifting feel at all and very proprietary. Yech.
i wouldn't get one on a full suspension, if anything i'd be on a hardtail.
Many years ago I won a 2 wheel drive mountain bike that used a flex drive shaft to run the front wheel. It was kind of a cool idea, but the bike sucked ass. I forget the name of the company now.
I got it from 91x in San Diego in '93. Man, I feel old.
I got it from 91x in San Diego in '93. Man, I feel old.
I rode one of those Christini AWD, driveshaft bikes in PA one time. It kind of felt cool on climbing, but otherwise was pretty crappy, IMO.
they could make retractable shafts, so theoretically is posible for a full suspension bike to be driven by a shaft.
spiral bevel gears are not particularly inefficient. and the moment of inertia of a shaft along its z axis is almost negligible. specially when compared to the I of a casette plus chainguide/crank/pedals/chainrings together...
http://www.sdp-si.com/herb/spk/sdp-si/D220/PDF/D220T119.pdf
spiral bevel gears are not particularly inefficient. and the moment of inertia of a shaft along its z axis is almost negligible. specially when compared to the I of a casette plus chainguide/crank/pedals/chainrings together...
http://www.sdp-si.com/herb/spk/sdp-si/D220/PDF/D220T119.pdf
that is a fine example of fabrication faeces
BurlyShirley said:
Christini, that was it! Climbing was cool, but there was a stress release when you break with the front or rear only so the shaft wouldn't flex too much that made this awful POP, POP, POP sound.Mine was a full rigid and was the base of base models with the worst built kit ever.
Wumpus said:
More and more are coming with shaft drives now, Not counting Dirt bieks that is, which one is better???? My SHaft drivin Shadow rides quite smoothly, cant really tell teh Differnce though between that or Belt Driven, Only chain Drivin i have done are a totaly different class of bike though so cant really compare. Question does make me think, still havent seen a Crotch rocket with a shaft...
Quote of the day...DirtyMike said:
ink:
habitatxskate said:
jimmydean said:
Mine was a full rigid and was the base of base models with the worst built kit ever.
I got to ride there FS Model from 04, was pretty cool had a lever to Disengage the front drive and such, great climber, little heavy cool idea. thats about it, didnt have a whole lot of travel. Wouldnt want one unless it was a freebie, too heavy for what they cost for me
Serial Midget said:Quote of the day...
HAHA
Dug a Hole on that i did!!!
You think wrong. A chain driven drivetrain is about the most efficient mechanical system around. Drive shafts are very inefficient by comparison.habitatxskate said:
"by the looks of it"? I'm glad you can do FEA with your eyes, will you please teach me how? I'm especially interested in learning how you can tell things like what material it's made out of, and whether or not it's hollow.
This is a cheap bike. I give a 300 pound guy five minutes on that thing before it breaks.
Chains are more efficient than shafts so long as the chain-line does not get too out-of-whack. They are usually lighter also.
There is no reason that shaft drive cannot work with suspension, just google BMW r1100gs if you are in doubt.
There is no reason that shaft drive cannot work with suspension, just google BMW r1100gs if you are in doubt.
I kind of dig the whole concept of a front wheel drive bicycle. Talk about an incredible climber! I can't think of a practical way you could make it work though. If anyone could crack that nut though (without adding a ton of weight), I think it could be something revolutionary.
The Christini bike was all-wheel-drive via a driveshaft run up the frame to the front wheel.dogwonder said:
I could see a driveshaft replacing a chain on bikes where all-out pedalling performance can be sacrificed for the reliability of a sealed system. Freeride... touring... commuters... etc.
However, one issue with a driveshaft on a bike compared to either car or motorcycle applications is that on a bicycle, the gear system is almost always in overdrive (pedalling RPM less than wheel RPM) whereas auto/motos are always in underdrive at the differential.
So at the cranks, there would need to be a relatively larger ring gear applying torque to a comparitively small pinion gear. Both pieces would need to be relatively stout to keep from breaking or wearing quickly. The system would also need to be sealed and run in an oil bath or in all likelihood it would wear rather quickly.
Anyone who knows about setting up differential gear lash knows this is not a difficult operation, but can be a bit time consuming. Another drawback on a cheap system designed for mass-production. If set incorrectly, you'll get excessive wear and noise.
Suspension movement can easily be handled by a CV joint - especially since most current suspension designs limit overall chainstay growth, but of course this would add complexity, weight and cost.
Then there is the whole issue of variable gearing... A nice CVT system could be useful here...
None of these issues is a deal breaker, but the simple fact is all of them combined make the simple chain very hard to beat.
However, one issue with a driveshaft on a bike compared to either car or motorcycle applications is that on a bicycle, the gear system is almost always in overdrive (pedalling RPM less than wheel RPM) whereas auto/motos are always in underdrive at the differential.
So at the cranks, there would need to be a relatively larger ring gear applying torque to a comparitively small pinion gear. Both pieces would need to be relatively stout to keep from breaking or wearing quickly. The system would also need to be sealed and run in an oil bath or in all likelihood it would wear rather quickly.
Anyone who knows about setting up differential gear lash knows this is not a difficult operation, but can be a bit time consuming. Another drawback on a cheap system designed for mass-production. If set incorrectly, you'll get excessive wear and noise.
Suspension movement can easily be handled by a CV joint - especially since most current suspension designs limit overall chainstay growth, but of course this would add complexity, weight and cost.
Then there is the whole issue of variable gearing... A nice CVT system could be useful here...
None of these issues is a deal breaker, but the simple fact is all of them combined make the simple chain very hard to beat.
Yeah I looked a long time at that, even talked with the guys at Christini, but I'm thinking even more radical. Drop the rear wheel drive completely, front only. I don't like the idea of the drive shaft for all the reasons stated before. I'm thinking a gear box is a must have somewhere...binary visions said:
Well, the gear box doesn't help a whole lot since you still have to get the power from the pedals to the front wheel.
And then, you'd end up with a bike that was great for climbing, and sucked at everything else
. It'd be impossible to wheelie and difficult to manual since you can't give the rear wheel a kick to get started/keep it up. You'd have to transmit the power a much longer distance so you'd end up with all kinds of issues with the drivetrain...
And then, you'd end up with a bike that was great for climbing, and sucked at everything else
. It'd be impossible to wheelie and difficult to manual since you can't give the rear wheel a kick to get started/keep it up. You'd have to transmit the power a much longer distance so you'd end up with all kinds of issues with the drivetrain...
Funny thing , is there HQ , is less than a mile form My Houes.
Also If i am not mistaken I think Pip3r works for them at the moment
Also If i am not mistaken I think Pip3r works for them at the moment
Weight, Cost and HP loss are all more on a shaft then chain.Wumpus said:
Shafts are nice because you dont have to do anything to them but that is about it.
Well if you want to dash all my dreams...binary visions said:Well, the gear box doesn't help a whole lot since you still have to get the power from the pedals to the front wheel.
And then, you'd end up with a bike that was great for climbing, and sucked at everything else
But alas, I still think it would be cool, and in Dogwonderland, everyone would have one.
would it really be that hard to make an instant ingagement, cause on all my fishing reels, there is no back play whatso ever in them ,and they are made by the same company.
jeep made an all wheel drive bike by driveshaft, and a chain in the back, looked cool but i dont know about performance
AY! Ever think the SLACK you feel just MIGHT be because he's a SLACKER BIKER!?binary visions said:
OOOOooooo!
Had to put that one in there. Ya left the door wide open.
just doing my part to stir the caldren...