Cantis brake with road levers

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whoof
Posts: 2519
Joined: 29 Apr 2014, 2:13pm

Cantis brake with road levers

Post by whoof »

Can anyone direct me toward a device to increase the braking on my touring bike?
It's a 90s mountain bike with LX cantilever (not V) brakes. The brake levers I'm using are road Tekro RL340, these have a button on them so I can get the blocks close to the rim and still remove the wheel when necessary.
http://www.ribblecycles.co.uk/sp/road-t ... ektbrlr170

The braking is pretty poor is there some device to improve this? The blocks come in contact with the rim and this might slow you a little and I need to squeeze really hard to stop on anything other than the flat and even then the stopping distance is very long. If I put in anywhere near the same amount of effort with callipers brakes I would lock the wheel up. It's not a brake block problem I think it's a mechanical advantage or something. Can anyone recommend an add on to solve this problem (other than flat bars and mountain bike brake/gear levers).

Many thanks.
beardy
Posts: 3382
Joined: 23 Feb 2010, 4:10pm

Re: Cantis brake with road levers

Post by beardy »

The Too Good To Lose is a good place to start reading.

viewtopic.php?f=5&t=64417
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Cantis brake with road levers

Post by Brucey »

lower straddles, better brake blocks, decent cables, well lubricated, ought to work OK. If you manage to improve each of those things by (say) ~10%, your brakes could improve by about 50% overall.

IIRC 90's LX brakes used some pretty hard brake blocks; if this is what you have, I can guarantee that age will not have improved them.

However there is a fundamental problem in that the RL-340 levers are designed to operate DP calipers and therefore pull slightly more cable than you really need, thus reducing the MA. IMHO the best dropped bar canti-brake setups use older brake levers that are designed to operate single pivot side-pulls. Some 'super SLR' shimano brake levers with variable MA can be made to work OK too, but are still second best.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
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RickH
Posts: 5832
Joined: 5 Mar 2012, 6:39pm
Location: Horwich, Lancs.

Re: Cantis brake with road levers

Post by RickH »

You could swap the levers for RL520s (currently £16.99 at SJS) plus V brakes of your choice (such as these Tektros for £13.99 as set. That would almost certainly improve the braking.

Rick.
Former member of the Cult of the Polystyrene Head Carbuncle.
hamster
Posts: 4131
Joined: 2 Feb 2007, 12:42pm

Re: Cantis brake with road levers

Post by hamster »

A lot depends on the cantis. If they are the MTB low profile ones then they need a bit too much cable pull to work well conventional road levers. Diacompe 287s (NOT 287V) pulled this extra cable and worked well. YOu can get them to be just acceptable by running them so the canti arms are as far from the wheel as possible - push the brake stud as far as it will go. Irritatingly then you will need to adjust again as the pad wears. Alternatively fit super thin pads (like v-brakes) on re-usable stud type carriers.
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Cantis brake with road levers

Post by Brucey »

hamster wrote: ....If they are the MTB low profile ones then they need a bit too much cable pull to work well conventional road levers....


I think it is the other way round; you need a lever that pulls less cable with more force if (as the OP reports) the brakes are not powerful enough.

If you have a lever that comes back to the bar easily and brakes that seem too powerful, then you have a lever that pulls too little cable. Feeble wooden-feeling brakes arise from levers that pull too much cable with too little force.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
whoof
Posts: 2519
Joined: 29 Apr 2014, 2:13pm

Re: Cantis brake with road levers

Post by whoof »

Thanks for the replies. The problem is more basis than can be sorted with new blocks and cables. I've considered v brakes but I think this may give other problems regarding stops etc. I'll give the people at Spa Cycles a ring and see what they suggest.
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531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Cantis brake with road levers

Post by 531colin »

Image

this is CJ explaining how to set up cantis not too different from yours its all here.....http://forum.ctc.org.uk/viewtopic.php?f=5&t=57410

I'm sure Spa will tell you that you can use full-size Vee brakes with the appropriate levers, or mini-Vees with road STIs, although that may bring you clearance problems for big tyres, and also pad to rim clearance.
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Cantis brake with road levers

Post by Brucey »

whoof wrote:Thanks for the replies. The problem is more.... than can be sorted with new blocks and cables.....


you say that, but you have not said what blocks you have or what state you cables are likely to be in.

If you have crappy old pads and draggy cables each can cost you up to 50% of your braking effort.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
ukpacker
Posts: 49
Joined: 28 Sep 2015, 8:26pm

Re: Cantis brake with road levers

Post by ukpacker »

I used the cheapest Shimano Altus cantilever brakes and BlR400 levers for over a decade, if there was any problems with braking performance it was invariably due to the wrong angle being set on the straddle wire. Try lowering the yoke first, basically the more resistance to pulling that can be felt at the lever the weaker is the pressure which is being applied by the pads at the rims. Properly set up cantilevers result in minimal pressure being felt at the levers. Look at some pictures of the straddle wire angle on set up brakes then compare to the straddle wire angle on your own brakes. Good luck.
ukpacker
PRL
Posts: 607
Joined: 21 Jan 2007, 9:14pm
Location: Richmond upon Thames

Re: Cantis brake with road levers

Post by PRL »

I have the same levers (RL340) and mini V brakes.(RX6) Not that much leeway in the spacing but the braking is seriously impressive.
Paul
whoof
Posts: 2519
Joined: 29 Apr 2014, 2:13pm

Re: Cantis brake with road levers

Post by whoof »

Just thought that I would give an update.

The original 90s LX cantilever brakes/Tektro levers on my tourer were terrible, on the descent from work I once had both feet on the ground to be sure to stop at the junction. I was going a lot slower that I would have been on my regular commuter and had started to brake a lot earlier. The commuter has dual pivot callipers and 50p a pair brake blocks. I'd tried new cables and blocks on the Cantis with no improvement.

I've fitted Tektro RX-6 Mini-vs and the difference is like night and day. Previously on a steep downhill I was pulling on the levers with four fingers as hard as I could and I was slowing down but stopping was such an effort my hands were aching. With the mini-vs it's just a case of a light squeeze with two finger to come to a halt.

The only downside is mudguard clearance, but I've made some adaptions to get around this. And that in a few months I will no longer be unable to crush steel tubing with my bare hands.
Brucey
Posts: 44521
Joined: 4 Jan 2012, 6:25pm

Re: Cantis brake with road levers

Post by Brucey »

one of the things I like about canti brakes is that you can adjust the geometry so that the mechanical advantage suits your needs. With a Mini-V brake, there is no such adjustment.

Quite often it works out that the MA of a mini-V is as high or appreciably higher than the maximum MA you can achieve with a canti brake (which may be useful if you have brake levers that are really meant for use with newer DP calipers; these pull more cable than is required for most cantis and the MA suffers as a consequence).

The mini V also has the benefit that it is almost impossible to set the brake up so that the MA is significantly reduced.

BTW you never said exactly which model of LX cantis you had, but whichever type the recipe for good MA is the same; arms wide, straddle low. However this is easier said than done with some types eg this sort;

Image

because there are only a few brake blocks that will give the required spacing. For this model of brake a good option is to use the brake shoes from current shimano BR-CX series brakes; they come with suitable spacers etc to allow the right spacing. You can also DIY road brake shoes (with long bolts and spacers) to work in a similar way.

If they look a bit like this when installed

Image

i.e. high straddle, arms too close in, then the brake will be feeble.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
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