Could A Belt Drive Single Speed 29″er Be In Your Future?
September 11th, 2007 by Guitar Ted
Editors Note: The picture is courtesy of Spot Brand Bikes web page
Spot Brand bicycles is currently planning on showing a belt drive system for single speed use. It is claiming a radical low weight for the belt and special cogs that work with it. Certainly this will cause quite a stir if it’s efficiency can be anywhere close to a traditional chain driven drive train.
Note the drop out, which allows the belt to be passed between the chain stay and seat stay of the bike. Pretty clever, since you can’t really break a belt to put it on.
I’ve put on many a serpentine belt in my days as an auto technician, but I’ve yet to mess with one on a bike. This looks to be an interesting drive train which I’ll be taking a closer look at soon. Stay tuned!
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I would be very interested in trying this system. Being a collegiate cyclist and mechanical engineering student this is right up my alley so to speak. I hope to work on project like this after I graduate. I currently run a ‘07 Kona Unit 2-9 and would love to be able to retrofit. I see the need for a specific frame as the only major downside to this belt drive system. However, since my frame is steel I still might retrofit if Spot ends up selling these nifty dropout separately. I hope you guys get one to test and let us know the how well it really works!
-Brandon
I’d be concerned about the life - the belt is right in the line of fire from rear tire debris. A serpentine belt on a car leads a sheltered life, but not here. Will that belt be able to stand the abuse? One muddy race and by-by?
Ever see what happens to a Harley Davidson when you get a rock in the belt?
This has showed up in the UK with orange bikes and so far the prototypes have had a better life than a chain drive bike, so I personally don’t think durability will be an issue. However the cog on this version from spot doesn’t have the innovations that orange has to combat problems with contaminants and slipping. It does have an interesting dropout, and if the frame can handle the torque of a belt drive system then it should be an interesting alternative for single speeders.
In articles I have seen on this, the cogs have little windows cut right through where the teeth mesh with the belt to help evacuate mud, dirt, and grime. Rocks or small debris? Don’t know about that one. My chain drive snaps twigs in two and keeps on truckin’ though, so It’ll have to be better than that.
I would be worried about belt wear, Here in Reno, temps flux as much as 30° day to night, and 110° yr-round, Plus the dry desert conditions.
I am completely interested in this type of drive train. The only problem I see is that it will be proprietary, and so you must buy a certain frame and so forth. If some sort of master link could be put into the belt that would allow you to retrofit the drive train to your current bike, then that would be very cool. But I am sure that any master link type of design will inherently weaken the belt.
BTW, I know that belts on cars are often protected some, but how often do you guys replace those belts. And just how much horse power is your car putting through that belt. Even if your car only puts say 2 bhp into the belt, that is still way more than any person on earth could put into the belt. And I am sure your car puts way more torque into the belt than you can too, even with low gears and their mechanical advantages. I personally believe the crux of this particular system would be cost, and also weather abuse. Will the belt crack and weaken. Too bad the website has NO info what so ever for either the new projected bike using the system, or the belt manufacter of the said belt. I am really excited and interested to check it out.
I think a belt drive to a high end internal geared hub would be really cool!!!
Peace out
Yep, I can see one in my future!
I had a chance to test ride a prototype and found it to be very impressive to say the least. Talk about direct drive. The is system is very nice. I was amazed at how responsive and quiet the bike was with the belt drive.
As for mud. That was a concern that I had also. In talking to a couple of people they tested the belt drive by packing the entire drive train with mud and with a few turns of the crank it was cleared out.
The belt has a large amount of carbon fiber in it. Yep, carbon fiber. Pretty cool to see it up close. I guess this helps with wear and possible stretch issues.
Of course the verdict is still out. I’ve seen enough to give it a go. After all you can always run a chain system if you want to switch it out. The crank is a standard 4 bolt crank system.
Didnt Jericho bikes try something like this a number years ago and it never saw perduction?
Belt drives are already used in industrial applications under conditions that make the worst off road ride look like a surgical clinic. They take high heat, typically have less stretch, and require no lube. It sounds like they have finally made sprockets small and light enough to work on a bike. Remember Harley Davidson have been using belt drives on their motorcycles for years. There are also a few bike companies using them on commuter bikes.
My buddy has a buell motorcycle. Never had a problem with rocks in the belt. And a properly designed belt technically should last longer than a chain.
Could also open up the possability for a weight saving and sweet looking “Drive gear / Disc brake combo” on one side
Could be awsome like sliced bread or sucky like other sucky things.