New bike build, hub gears & brakes, belt drive

[Brucey]

I like your thinking.

BTW if you have a chainstay cable stop in the right place, you can drill this out to ~3.9mm and then push-fit a short length of 4mm pneumatic hose to it. This then makes a 'lined cable guide' that might give a bit more tyre clearance for the cable, possibly at the expense of the cable entry angle onto the hub spool.

A variation on this is a reshaped V-pipe fitted in a similar way.

cheers

[bobc]

good tip - let's see if it's needed!

[mig]

to me there's something aesthetically pleasing about a chainwheel/sprocket selection that gives a horizontal chain (belt) run as in the picture upthread. maybe it's years of mashing large racing gears and the slog involved in that.

[Brucey]

if anyone wants an OTP belt-drive touring/commuting bike (but with rim brakes) this;

http://www.tritoncycles.co.uk/road-bikes-c5/touring-bikes-c41/civia-kingfield-complete-bike-p1851

looks cracking value at the price. It uses the J-tek shifter and a Nexus 8 hub ( I assume the red band version but do check this). 50/24 gearing and a 118T Gates belt, giving gears from 29.6" to about 90".

cheers

[rideone]

wow, this is intriguing. your chainring with the cutouts for dirt/snow are genious! that is a major gripe amongst gates users. i am actually working a similar project titled "winter bike" and only discovered your thread when searching google for some input. i'd like to pick your brain if you don't mind. maybe you already made some experience with a gates drive that you don't mind sharing. maybe we can take up correspondence via pm?

[Vaya]

wow, this is intriguing. your chainring with the cutouts for dirt/snow are genious! that is a major gripe amongst gates users. i am actually working a similar project titled "winter bike" and only discovered your thread when searching google for some input. i'd like to pick your brain if you don't mind. maybe you already made some experience with a gates drive that you don't mind sharing. maybe we can take up correspondence via pm?

Hi rideone, This was the first build that bobc did, it may be helpful for your project.

[bobc]

Hi Rideone - I'll try to answer anything & if you want any drawings just let me know. PM would be fine, but if it's general interest by all means whack it on the forum.
FWIW the bike is nearly together (it's proving a little awkard to get the back wheel right) & I can't wait to put a few miles on it! The seat post pinch bolt & mudguards arrived from Mr. E Bay today so it shouldn't be long now!

[bobc]

And finally, first ride on the bike, complete with dynamo lighting the road! No real issues to report, felt a bit funny compared to the old bike, steering feels a bit 'dead', pedalled OK (no hint of skips or jumps) - but it was only 2 miles.....
I think the bike looks pretty good; I think I over-egged the pudding with the 35mm back tyre, I'll probably swap for a 32mm before too long. I've not stood on the pedals yet & given it any serious grief. It's a bit heavy with all the hub gears/brakes/dyno. Hopefully I'll get used to it over a couple of weeks cycling & it will be interesting to see if the transmission holds up (so far so good)

Bob

[Brucey]

it doesn't look too bad, that! I guess what, about 32lbs?

I can see you have had the usual rear brake cable routing trauma. Some suggestions;

1) route the brake cable down the down tube, and use the top tube eyes for some (RF spec coax) electrical cable for powering a rear light.

2) remake the reaction arm (e.g. by welding or bolting on an extension) so that the brake cable fittings are aligned with the seat stay, but the reaction force is still taken by the chainstay.

BTW whilst it is impossible to say for sure, the combination of that seat angle, the inline seat post, and the Brooks saddle would put most people too far forwards. You may find that you have a little too much weight on your hands, and this can make the steering feel a bit peculiar.

cheers

[bobc]

Thanks for the comments Brucey
TBH I'm fairly happy with the slightly unsightly brake cable routeing, it's showing no danger of clattering in the spokes & avoids sharp bends; another possible route is along the top tobe, down the seat tube & back along the chainstay, but it's not long enough......
I'll avoid butchering my brand new hub as long as I can!!!
I'm sure you're right about the way I'm sat on there, I'll move the seat back & down (reach to the pedals is about right) & try to get hold of a longer quill stem (what you see is made of free & skip rescue parts.....)
I just weighed it - not far off, 33.3lbs!

[Brucey]

More bends in the brake cable makes for a squashier action, so the fewer the better if you can.

Re. butchering the reaction arm; a simple way of doing this would be to drill a couple of 6mm holes in it then bolt a steel or aluminium plate in it which then reacts to the chainstay, allowing the cable run to be straight down the seatstay. I don't think that will hurt the hub and if it upsets you it is just a case of getting another brake plate.

BTW the similar hub brakes on the bike I built for my chum ( see the 'supercommuter' thread) have finally just about bedded in now. In the same time the bike has chewed through two or three chains and freewheels, as expected.

cheers

[bobc]

Actually, the main problem with this setup is all the faff to get the back wheel off if I ever need to. I'm used to carrying a hefty 15mm spanner for the old bike, but on this I also need to remove the small screw in the reaction arm (wonder why they didn't repeat the perfectly good system on the front brake) and getting the gearchange cable off is quite a bit more awkward than it was on the shimano. Whatever, many punctures can be fixed without removing the wheel & the BIG tyres are an attempt to avoid that particular problem...
I'll do a few more shorter local journeys before I try the 15mile commute....

[Brucey]

.... but on this I also need to remove the small screw in the reaction arm (wonder why they didn't repeat the perfectly good system on the front brake)....

because if you slide the wheel back to take up chain wear, the reaction arm can drop out....?

This arrangement is made easier to deal with if you make a new clip which has a captive nut in it.

cheers

[[XAP]Bob]

Or use a bolt with a square shoulder and a wingnut on the outside.

[bobc]

"because if you slide the wheel back to take up chain wear, the reaction arm can drop out....?"
yeah that would test your sense of humour....
Thanx bob too - got methinking now - those spring clips they use on trailer flat sides... hmmmmm