Avid Shorty Cantis - Poor performance

Steve I

Had a first ride on my new road bike last week and, seriously, I nearly went over the bars first time I braked (Tiagra, dual pivots). This has made me realise that the Avid Shorty cantis on my other bike are totally crap in comparison. The strange thing is, I thought they were great when I first rode the bike. The front one is just about ok, but the back one won't even lock up the rear wheel. I know there's definitely something wrong there, it should be easy to lock up the back wheel on any bike, regardless of the brake type. Anyone any ideas, I've read the article by Sheldon Brown but it's a bit too complicated and I'm usually ok with technical side of things.

Nigeyy

One easy thing to do to improve brake performance is to install decent pads. I heartily recommend the Koolstop salmons (have them on all of my bikes and I throw away the Shimano pads which might as well be made out of cement I've found).

Having said that, it also sounds like you might have some issues with cable routing, or the cables themselves. How old are the cables? Do you need new housing and cables perhaps? Can you see if the routing causes kinked or badly bent cables, etc? You might also want to change your straddle cable length (can't remember if you can do that on the Avids) but I usually think that's a last resort (particularly since you say the brakes were working well. Obviously should go without saying that you might need to adjust your brake levers if the cable has stretched too.

Oh, one last thing -are the rims out of true or dirty? You might be running the brakes too wide apart to compensate for some out of true wheels, or the pads can't grip a dirty rim and hence losing braking power...... once the rims are trued up the pads can ride closer to the rim without dragging and clean rims should enable a pad to grip better.





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Steve I

Thanks for the suggestions nigeyy. You're right, the first thing to do would be to try new pads on clean rims. I'll give the Salmon pads a try, they seem to recommended everywhere. The cables are ok, the bike's only 6 months old and has always been used with mudguards (or should I say fenders). I've just dug out the Avid manual. The manual recommends that the arms are parallel when the pads contact the rims and both brakes are ok in that respect. It also recommends that the straddle wire should be at a 90 degree angle when the pads contact the rim, the front is roughly at 90 degrees, but the back one is at an angle greater than 90 degrees. I might be able to improve it with a shorter straddle wire. Thanks again.

Nigeyy

Yes, I like doing the cheap options first! I honestly think brake pads can be one of the best value for the buck upgrades you can do. I usually clean my rims using a Brillo pad at the kitchen sink (fortunately the wife doesn't read this board).

As you mentioned, another (obvious) thing to do to improve the brake performance is..... read the brake system manual! Just my opinion, but I'd not mess with the straddle cable until you've done everything else to optimize the brakes.

Good luck with your brakes, hope they work out well. And not to worry, I'm an ex-pat so fenders are still only a type of guitar to me :-)

p.s. just for a bit of a link with the famous, I live a couple of towns over from Sheldon and go into Harris Cyclery quite a bit. He's a really good guy.



Fight Cystic Fibrosis: do something. http://www.cycleforhaylee.org http://www.cff.org

jumbolugs

I used Avid Shorties on one of my bikes for a while last year and they were really good - I'd say they were slightly more powerful than Shimano dual-pivots - so there's nothing wrong with the brakes themselves.

The angle of the straddle wires can make a big difference with canti brakes, as you will have gathered from reading Sheldon.

What type of levers are you using? Are they STI or old-fashioned "aero" levers? Years ago I had a Dawes Galaxy with Tektro Oryx cantis and aero levers and the braking performance was truly dire - almost put me off cantis for good. I suspect the aero levers don't work as well as STI levers, when used with modern cantis such as Oryx and Shorty?

Steve I

Thanks for that Jumbolugs. I'm using Sora sti's, so it's good to know that the lever/brake combination are capable of working ok.