This company is really famous for selling really expensive "upgrades" that do very little for actual speed.
The resistance of the chain & pulleys is a very tiny percentage of the whole unless they're gunked up and not maintained/lubricated or are broken.
Pretty much all mechanical resistance on a bike is dwarfed by aerodynamic resistance. When the aerodynamic resistance is broken down the contribution of the bike is dwarfed by the contribution from the rider and his/her body position on the bike. When you start getting into the resistance from gear the helmet & clothes are more significant than the bike.
None of this stops them from selling $10,000 bikes to amateurs who are slow though.
It is free but hard work to go on a core strength + flexibility program that lets you access more aerodynamic riding posture. Working with a good fitter/coach will cost a little but help get there with less guesswork. Everything about getting fast on a bike is harder work than buying stuff.
When people start talking about bicycle upgrades to shave a few ounces here and there, I just point at my belly and the 10's of pounds I could drop from my body before I worry about a couple ounces on my bicycle.
I think the fastest bikes in a straight line are recumbent bikes because of the small frontal area. Nobody talks about it much (probably because nerdy middle age men are the only demographic with enough devil-may-care attitude to ride one in public)
First, from an engineering perspective, this product is really cool and maybe for some well-funded Tour de France team it could make sense to test this out. But the price point, the lack of compatibility with components of existing drivetrains and the lack of compelling reasons to make the change, are going to be headwinds to adoption.
On page 3 of their brochure (https://www.ceramicspeed.com/media/2979/driven_brochure.pdf), they're showing 0.5% - 1.0% efficiency gains over a traditional drivetrain that is cross-chained, meaning that if you use a traditional drivetrain correctly (i.e., shifting so as not to cross-chain) the gains are likely significantly smaller.
As ben7799 said, this company is primarily in the business of selling very expensive products that have minimal impact on performance.
I'm sure this is a neat system, but it's worth noting that bicycles are already very efficient, the difference between their claimed efficiency and a properly set up traditional drivetrain is maybe one or two percent.
And any weight savings are probably useless due to the minimum weight required for racing. Pro bikes are basically at the point where they're having to add weight just to pass inspection. This system might have a bit less rotational mass in the "cassette" than a traditional cassette which would help.
I've ridded a half-decent street bike a summer or two. This thing was light enough that as a tall slightly chubby man I felt uneasy just getting on it, I kept thinking "this thing will crumble from my weight". I knew it was stronger than that, but my brain kept telling me something wasn't right.
chains are a pain. But belt drives have been around for 10 years now and you hardly see them.
Chains are the most complex part of the bike with the most moving parts. You have to lubricate them, they stretch.. But they work well in all variety of conditions (even rusty and squeaky) and are fairly cheap.
Sheldon Brown's (RIP) bike pages have some good articles on the good old chain.
Off-topic, but how sad to see the state of that website today. I read Sheldon's website religiously before he died, but hadn't seen it in over 10 years.
This[1] is how it looked like when he was alive. Now it's stuffed full of ads, and the first thing you see is a pop-up cookie warning about "our social media, advertising and analytics partners".
Belt drives are comparatively expensive and don’t work with derailleur gears. Internal gears, especially cheap systems, still cannot offer as many gears as a derailleur. Belts also need to be pretty tight and thus cannot be used on most bicycles with a rear suspension as the distance between the pedals and the sprocket changes under load. So many people opt against belts.
The above video doesn't show it changing gears... I was wondering how it did it. It is (sort of) covered in the "fully explained" YouTube video: https://www.youtube.com/watch?v=-9gQ1KRhesM
Explanation: very complicated with a battery powered wireless electronic shift mechanism embedded in the drive shaft. The "fully explained" video doesn't show it changing gears either, just explains how they would do it. My take-away is that it doesn't change gears as of the making of the video (July 9, 2018) but "they have a plan..."
How do they keep the bearings from skipping over the rear gear/disk? That disk and driveshaft would have to be extremely stiff to avoid flexing, especially in lower gears where the contact point is further out, and it looks like just a couple millimeters of flex will give enough space to skip.
Based on my experience with motorcycles, chains are better than shafts for transmitting torque. Shafts tend to twist over their length in high torque settings, whereas chains just "pull" with minimal stretching.
Specific to this product, how the hell would you keep the 20-30 "gear" bearings on the shaft clean and operating smoothly in anything but lab conditions?
I couldn’t find it on the mobile version of the site but a video of the pinion based drivetrain showed up somewhere else the other day, I think the post is likely in reference to that chain-less system
ben7799|6 years ago
The resistance of the chain & pulleys is a very tiny percentage of the whole unless they're gunked up and not maintained/lubricated or are broken.
Pretty much all mechanical resistance on a bike is dwarfed by aerodynamic resistance. When the aerodynamic resistance is broken down the contribution of the bike is dwarfed by the contribution from the rider and his/her body position on the bike. When you start getting into the resistance from gear the helmet & clothes are more significant than the bike.
None of this stops them from selling $10,000 bikes to amateurs who are slow though.
It is free but hard work to go on a core strength + flexibility program that lets you access more aerodynamic riding posture. Working with a good fitter/coach will cost a little but help get there with less guesswork. Everything about getting fast on a bike is harder work than buying stuff.
asynchronous13|6 years ago
m463|6 years ago
freefal|6 years ago
On page 3 of their brochure (https://www.ceramicspeed.com/media/2979/driven_brochure.pdf), they're showing 0.5% - 1.0% efficiency gains over a traditional drivetrain that is cross-chained, meaning that if you use a traditional drivetrain correctly (i.e., shifting so as not to cross-chain) the gains are likely significantly smaller.
As ben7799 said, this company is primarily in the business of selling very expensive products that have minimal impact on performance.
rhinoceraptor|6 years ago
And any weight savings are probably useless due to the minimum weight required for racing. Pro bikes are basically at the point where they're having to add weight just to pass inspection. This system might have a bit less rotational mass in the "cassette" than a traditional cassette which would help.
folkrav|6 years ago
And it was a pretty mid-range bike.
berbec|6 years ago
acomjean|6 years ago
Chains are the most complex part of the bike with the most moving parts. You have to lubricate them, they stretch.. But they work well in all variety of conditions (even rusty and squeaky) and are fairly cheap.
Sheldon Brown's (RIP) bike pages have some good articles on the good old chain.
old school html ahead: https://www.sheldonbrown.com/chains.html
https://www.sheldonbrown.com/chain-wear.html
avar|6 years ago
This[1] is how it looked like when he was alive. Now it's stuffed full of ads, and the first thing you see is a pop-up cookie warning about "our social media, advertising and analytics partners".
1. http://web.archive.org/web/20080111140407/http://www.sheldon...
rhinoceraptor|6 years ago
Xylakant|6 years ago
mbritton72|6 years ago
SlowRobotAhead|6 years ago
kitd|6 years ago
https://www.youtube.com/watch?v=UFAQ6CzNm7s
gvb|6 years ago
Explanation: very complicated with a battery powered wireless electronic shift mechanism embedded in the drive shaft. The "fully explained" video doesn't show it changing gears either, just explains how they would do it. My take-away is that it doesn't change gears as of the making of the video (July 9, 2018) but "they have a plan..."
aidenn0|6 years ago
https://www.ceramicspeed.com/media/2979/driven_brochure.pdf
GhostVII|6 years ago
AstralStorm|6 years ago
Can't this pulley system be trimmed down even further to one bar transmission?
falcolas|6 years ago
Specific to this product, how the hell would you keep the 20-30 "gear" bearings on the shaft clean and operating smoothly in anything but lab conditions?
hamiltonkibbe|6 years ago
kevin_thibedeau|6 years ago
jtms|6 years ago
joerickard|6 years ago
"The front wheel shall be steerable; the rear wheel shall be driven through a system comprising pedals and a chain"
However, the rules do change and have been recently (like the removal of the 3:1 restriction).
notatoad|6 years ago
orliesaurus|6 years ago