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Yeah, so comparing the Nordest Lacrau 2 ti frame with the belt drive kit, and the Nordest Bardino frame (they're idenctical, the Lacrau is the bardino with a gearbox), with an XT groupset and Hope pro 4 hub, at wiggle prices it comes out at £1845 initial cost vs the £2715 initial cost of the gearbox option, and 6.27kg vs 4.05kg.
£870 more
2.2kg heavier.
A cassette and chain are £130, so a couple of those and you're down to £600 difference.
You think you'd only go through 2 cassettes and 2 chains in 5 years using your bike for 15-20 hours a week? You must ride in a much dryer place than I do.
When I only had the one bike I would go through 1 cassette, 1 chainring, 2 chains and a set of jockey wheels a year. Could be even more. A rear mech would only last a couple of years as well.
I reckon I'd only go through a 1 belt, 1 chainring and 1 rear sprocket every 18 months on the Pinion gearbox (this is not based on my own experience but looking at the reviews I read of the Pinion). So over 5 years (which is the general time I keep a bike for) the costs are comparable.
No that wasn't for 5 years use, just for initial cost and then maybe a years or so's worth of use.
Interesting
That Shimano system looks the most likely to be successful. It looks fixable by a bike mechanic.
Especially if they used a smaller pitch chain to get the dimensions/weight down.
One thing I wonder about is the the number of ratios. I find I often change 2 ratios at once when I'm on an Alfine or Rohloff, so I'd probably be just as happy with a wider spread between the gears, i.e. for the same overall spread of gearing I could get by with less intermediate cogs.
One problem with the video analysis is that he's assuming Shimano will use standard pitch chains. I don't see any reason why they wouldn't use a smaller pitch chain. For example, long ago, they tried using 3/8" pitch chains, but never took off. The weight of a 3/8" pitch sprocket with the same number of teeth would be 56% (9/16) that of a 1/2" sprocket. For a proprietary gearbox, compatibility with existing drivetrains would be irrelevant and sprocket sizes wouldn't be limited by rear hub compatibility, so I would expect they would use whatever chain pitch turned out to be optimal for the specific application. Chain deflection shouldn't be an issue because one cassette moves to keep a straight chainline.
I also don't find the speculated drivetrain efficiency convincing. I think it's unlikely that an enclosed chain drive with oil lubrication would lose much efficiency against a regular derailler, and I do not see how it would be less efficient than a gearbox with gear teeth that have to slide over each other.