The T bike, Torq Radical project

[coops]

Thanks again,

Disc brake is out then. I think sub-42" gears may still be useful for me, so I'd likely have to buy another chainwheel, or at very least a new freewheel & rear mech to keep my existing lowest gear about the same with 52-34 instead of 40-25... just to fit V-brakes comfortably for the chain...

I'd still prefer more braking power, but I'll have to think about this some more I think... .

For now, as a stopgap measure, I think I'll remove the rubber cap & try wrapping the brake post in slippery thin PTFE tape to see how well that sits in 4th gear while I reconsider V-brakes, before deciding if I really need to remove that post...

[Ian]

I wouldn't worry too much about V brakes on the rear Stuart. As I have posted elsewhere I replaced the front V with a Shimano Deore XT parallel action V brake, in a really quick stop the rear wheel now leaves the ground making the rear brake irrelevant, and the existing roller brake is adequate for gentler stops.

[flecc]

I agree with Ian there, with a really good front brake a rear brake is almost redundant for emergency stops. In it's Torq form I only used the rear roller brake as a routine slowing brake, the front for the odd emergency situation.

I added the rear V brake partly because I could, partly because the rear wheel was gaining the motor weight so would be more firmly glued to the ground for braking, and partly because I knew it was to gain quite a lot higher performance.
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[Ian]

I seem to remember using stillsons to get mine out, the post did get badly butchered by the stillsons teeth so theres no chance of re-using it. An alternative would be to simply cut it off with a hacksaw, the disadvantage being you'd have to drill the stump out if ever you wanted to replace it.

[flecc]

There is another way on the Torq Ian, which I used as I'd butchered one on the front fork and used the one I'd turned and ground there instead, leaving me with a butchered post with sound thread, which I cut from it to use as thread only in the rear frame tube.

The rear mount is not critical since the braking force is towards the frame tubes.

Therefore a post can be cut off with a hacksaw, a new post minus the thread section turned, then assembled onto the thread left in the frame with a through bolt. This photo shows just behind a spoke the black head of the high tensile through bolt I used on the right hand side to hold the new threadless post section and brake arm onto the old thread left in the frame:


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[coops]

Thanks very much for the good advice Ian & flecc,

On reflection, I hadn't thought the brakes through, and I can see the purpose of the roller brake now though it doesn't seem to slow me down much; the 100kg limit bothers me when my bike plus a small load is already over 125kg; with panniers, extra battery, & say a few kg of extras, could be nearer 135-140kg... and I can't lose that much weight!!

I never use the roller alone, for fear of overloading it, but at least I've never had a problem stopping when using both brakes.

While on the subject, I can't remember Ian - did your new V-brake reduce/stop the front brake judder, or did it return? Mine is back again .

As for the rear V-post, I'm reasonably happy that, with rubber cap removed, the post doesn't foul the chain while pedalling (chain tension pulls it clear, even in 4th gear) so I'll leave as is for now. I hope too that the larger megarange 4th gear sprocket will give a little more clearance too, as I said earlier.

I'm definitely getting soft grips though, hopefully m+ too and my seatpost is creaking, so thats in for a change too - think I'll go for a non-suspension post if I can.

Stuart.

[flecc]

You can load that roller brake as much as you like Stuart, the effect of pressure is cumulative to some extent. I could and often did lock the rear wheel momentarily just by maintaining a high brake pressure, the braking increasing second by second.

Similar advice can sometimes help with front judder. The instinct is to slacken off a bit when it occurs, but if you very firmly increase the pressure instead as soon as it occurs, you might find the judder disappears then as the clamping grip on the rim increases.

Try it, you might be pleasantly surprised.
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[coops]

That's very helpful, I'll try both .

I tend to try to keep rolling wherever possible, rather than have to stop, so I'll try to use the roller for gentle slowing and the V-brake for firm stops as you say .