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-   -   Belt drive - finally? (https://www.bikeforums.net/general-cycling-discussion/341393-belt-drive-finally.html)

atbman 09-07-07 02:08 PM

Belt drive - finally?
 
http://www.bikebiz.co.uk/news/28798/...e-transmission

Belt drive, finally?

bbattle 09-07-07 02:12 PM

It's been around as long as the shaft-drive. Funny how things that sound like a great idea often don't pan out. But a lot of motorcycles have belt drive these days so who knows.

Da Tinker 09-07-07 03:07 PM

This new belt contruction may make a go of it. The only big problem I see is length adjustment. It's either gonna be a lot of belt sizes or a tension idler.

Retro Grouch 09-07-07 04:30 PM


Originally Posted by Zumba (Post 5228419)
Internal gearing has to take over first.

Rohloffs have been around for a long time and they're still not popular.

Derailleurs and chain drive are so wonderfully mechanically efficient that they set the bar real high. Whatever is going to supplant them (and I have no doubt that will happen someday) is going to have to be very mechanically efficient even during it's early development.

calamarichris 09-07-07 04:35 PM

Belt-tensioner = squandered energy.
Leaving us either:
~lots of belt sizes
~fixed chainstay (erm... beltstay) & trackbike monogears
~internal gearing

Belt drives are wonderful for underpowered bikes like Harleys, but they haven't exactly revolutionized motorcycle drivetrains either.
http://blog.modernmechanix.com/mags/..._belt_bike.jpg
-CCinC

wahoonc 09-07-07 04:50 PM


Originally Posted by Retro Grouch (Post 5228907)
Derailleurs and chain drive are so wonderfully mechanically efficient that they set the bar real high. Whatever is going to supplant them (and I have no doubt that will happen someday) is going to have to be very mechanically efficient even during it's early development.

Actually they aren't that far apart. IIRC the total efficiency spread between an internal gear and a dérailleur was only around 3% and quite often in certain gears the dérailleur was less efficient than the IGH. And quite often there are greater losses from wind resistance, riding style, low tire pressures, etc. Those items probably contribute more to speed loss than drive train efficiency.

My biggest issue with the belt drive would be roadside repair...kind of hard to take out a broken link, adjust the wheel and keep on riding...and yes I have broken a link in a chain before.

Aaron:)

Velo Dog 09-07-07 06:15 PM

To me, this is like electric or hydraulic shifters: Even if you work out all the bugs and get them working wonderfully, how much better can they be than a modern derailleur, or in this case a modern chain drive? It's quiet, efficient, easy to work on, shifts beautifully and doesn't cost much. My road bikes are nothing special--105-level components, mostly, with XT on the Atlantis--but I wouldn't pay a dime for them to work better than they do. They're already as good as I need or want them to be.

Retro Grouch 09-07-07 08:24 PM


Originally Posted by wahoonc (Post 5229038)
Actually they aren't that far apart. IIRC the total efficiency spread between an internal gear and a dérailleur was only around 3% and quite often in certain gears the dérailleur was less efficient than the IGH. And quite often there are greater losses from wind resistance, riding style, low tire pressures, etc. Those items probably contribute more to speed loss than drive train efficiency.

I'm not convinced about your statement regarding internal gear efficiency. I've read some quite different numbers but, honestly, it's not the kind of thing that interests me so I haven't studied it in any depth.

As to the greater speed losses, I fully agree. Once you get over about 12 or 15MPH, compared to the effort that's required to push your torso through the air, everything else, including drive train efficiency, is small potatoes.

AEO 09-07-07 10:45 PM

forget gears... CVT for bikes. They already have them for 3ton SUVs and cars, can't see how it wouldn't work for a bike.

on second thought I like having gears, and in manual.

Da Tinker 09-08-07 05:02 AM


Originally Posted by AEO (Post 5230886)
forget gears... CVT for bikes. They already have them for 3ton SUVs and cars, can't see how it wouldn't work for a bike.

Done. http://www.atcnuvinci.com/products_bicycle.php

Retro Grouch 09-08-07 06:55 AM


Originally Posted by AEO (Post 5230886)
forget gears... CVT for bikes. They already have them for 3ton SUVs and cars, can't see how it wouldn't work for a bike.

The issue is that the high pressures required to make today's CVTs work eat up power. On an SUV you can just stick in a more powerful motor. A bicycle, on the other hand, has no power to spare.

My bet is it's coming but it's going to take a design breakthrough to make it competitive on a bicycle.

gregfisher87 09-19-07 02:04 AM

rohloff's might be more popular if they werent $1500 a pop.

gcl8a 09-19-07 02:52 AM


Originally Posted by Zumba (Post 5228419)
Internal gearing has to take over first.

N.B., Eurobike.

gcl8a 09-19-07 02:55 AM


Originally Posted by bbattle (Post 5228038)
It's been around as long as the shaft-drive. Funny how things that sound like a great idea often don't pan out. But a lot of motorcycles have belt drive these days so who knows.

But this one is carbon. So it must be good.

-=(8)=- 09-19-07 04:15 AM


Originally Posted by wahoonc (Post 5229038)
My biggest issue with the belt drive would be roadside repair...kind of hard to take out a broken link, adjust the wheel and keep on riding...and yes I have broken a link in a chain before.

Aaron:)

They do make kits to repair them for motorcycles.
In one of my previous lives I rode Harleys for years.
I never saw a belt break or heard of one breaking
but I suppose they must, because of said repair kit. Chains
on-the-other hand.....who hasnt broken one ? :eek"
Id like to see belts ! :)
Weighing a bike down with 25lbs of clothes, tools, lunch etc,
Im just not at all concerned about theoretical power loss.
:roflmao:

gcl8a 09-19-07 04:27 AM


Originally Posted by wahoonc (Post 5229038)
My biggest issue with the belt drive would be roadside repair...kind of hard to take out a broken link, adjust the wheel and keep on riding...and yes I have broken a link in a chain before.
Aaron:)

You could always carry a spare belt for what is probably a very rare event (ie, only worth worrying about if you're touring).

dynaryder 09-19-07 07:16 AM


Originally Posted by calamarichris (Post 5228939)
~internal gearing

Internal gear hubs make alot of sense for commuters. Less maintenance than derailleur setups and they don't suffer the effects of weather.


Originally Posted by calamarichris (Post 5228939)
Belt drives are wonderful for underpowered bikes like Harleys, but they haven't exactly revolutionized motorcycle drivetrains either.

:rolleyes:

Someone's never ridden a built Harley.

BenLi 09-19-07 02:43 PM

well the christini's have both chain and shaft drive... I think belt drive is next.


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