Cycling in Sydney Australia
I am looking at a new bike, without gears - but a 'ball bearing' hub (Nuvinci N360).
Hub systems are perhaps growing in popularity? Without the need for a derailleur (or gears) with these, belt drive bikes seem to offer benefits over chains, especially for the 'joy of riding'.
Pro: Much lighter, quieter, no maintenance, no loss of efficiency if chain is not lubed enough, no greasy chain to soil clothing, lasts much longer than chains, works better in muddy conditions, interesting and new...
Con: Frame needs a cut-out for belt access, belt needs correct tension, 'may' be marginally less efficient? (but not all of us aspire to compete in the Tour de France, and not all keep chains lubed)
1. Do you prefer belts over chains - and why/why not?
2. Which is the best belt system to consider?
3. Any estimates on efficiency loss - (if any) on a belt over a chain?
Some say none, + if there was very slight loss mechanically, this could be countered by loss of 'time and hassle' putting chains back on, lubing them, not having them lubed enough etc...
4. Best place to get an existing frame 'split' to accommodate a belt / belt gate?
Also - I could not believe how many different and amazing bike power drive systems there are out there... So while I 'think' belts are perhaps the next technology after chains, there are lots. Who knew! Shaft drive ... Chainless direct ... and so many more!
Off topic - but a bike with no hubs.. seriously?
In principle, belt drives look like a good idea. However, hub gears are heavy which sort-of excludes them from sport cycling. While I "don't aspire to compete in the Tour de France" (:rolleyes:) I ride as a sport, as well as commuting utility cycling and simply do not have space for a bicycle for each purpose. My CX does pretty much everything, but needs standard derailleur gears.
Also, needs more time in the market so any as yet unknown problems come to light until I look at one. Someone else can pay for the beta testing :). I also doubt there would be much over using a normal hub geared (or single speed) system with chain guard. Chain lube is cheap, and the frames do not need to be specially designed.
Add a bit of weight with a hub gear system .. but lose a bit of weight with no chain, guard, derailleur, second front cog... The additional weight of hub gears is less if you consider weight savings that follow in other areas. I accept sport riding may not be 'quite' ready for them though - however it seems this is the way it will go eventually I think, given the significant weight savings hub gear manufactures are making in last few years.
But rather than belts at all, I'd have thought the string drive would be the lightest and most efficient?
And with a 19 gear ratio range as well! But not as easy to use with an existing bike retrofitted, where a hub/belt combo can be done reasonably easily to most.
Hub gears have the weight where it is most problematic, i.e. on the wheels. Rotating mass is the worst kind of mass :).
Haven't tried one, but sounds like a great option for utility/commuting/recreational bikes.
For touring though I'd be hesitant as getting spare parts and servicing a hub gear may be difficult on the road.
Friction Facts did an analysis of relative power requirements, not sure if it's mentioned in your links anywhere
My takeaway from it: can be more efficient in some cases - above 208W constant power output. Track riders could make the best gains in terms of efficiency. Commuters will gain in the maintenance and convenience stakes. Weekend racers might find it nice for their weekly commuter bike if the gearing could work - I can average over 200W based on Strava's estimators, for example, so I might be able to find some minor gains in efficiency.
I don't think they can replace chains any time soon - gearing is too critical in sporting disciplines and chain systems, while imperfect, are highly developed, have very strong inertia in the marketplace, and are the current standard. Still, if someone can come up with a belt system that can handle a 30-gear spread at a similar or lower weight than a Dura-Ace Di2 chain based system, I'm sure Andy Schleck would be interested.
There have been a number of cases of catastropic belt failure generally in the first 1,000 km. Travellers therefore must carry a spare. Different size belt any time you change a cog size of course.
Personally, even with Rohloff I'll stay with the chain.
I've looked at this before, biggest plus IMO, is there are "no more lube" concerns
Downsides are that:
a/ it narrows the target market to applications with single speed or Internal Geared Hubs
b/ and has a bigger downside/ impediment of requiring a belt drive specific frame.
c/ low take up rate probably means if for some reason if/when the belt goes cactus, it'll probably require a specialist fix.
If a & b dont concern you because you want to use SS/IGH and/or are getting a new bike or a new bike comes with this setup, I really don't see why not.
(a) is probably a large majority of bikes on the planet, so the target market, while narrowed, is not narrow. If a belt could be made as cheap as a chain I reckon it would dominate that market.
If a belt could be made as cheap, as reliable and as easy to maintain as a chain I reckon it would dominate that market.
Looked into this and it seems:-
The belt requires a lot of tension to avoid skipping teeth - if you are a sedate cyclist then maybe not a problem. The tension may put sideways loads on the crankset and hub bearings which will cause them to wear out. And the high tension reduces the efficiency of the drain train.
If you modify an old frame to use belts you need to ensure that the chain stays on the frame don't flex much as this may cause the belt to skip under load.
I wouldn't mind a belt drive, but a belt coupled with a Nuvinci is likely to be somewhat less efficient than gear and chain.