HELP!!!! V brakes - cantilever brakes

MadammeMarie

Hello everyone. I'm in desperate need for help. Just spent £70 changing my brakes, and now i'm worse off than before. Here's a bit of background:

Almost a year ago, I bought a Specialized TriCross sport, size 52cm, all good. Except that the handlebars (drops) were not too comfortable, so I changed the stem from the original flat, to anotherone, same size, but that lifts the bars a bit (hope this makes sense). The original brakes were cantilever, but after a couple of days of riding the bike, everytime I pushed the brakes, the whole bike shook! So I went back to the bike shop where I bought it (Cycle Surgery), explained what was happening and left it. When I went to pick it up, the brakes had been changed to V brakes. I never got to speak to the mechanic who did the job b/c he had gone on holiday that day, and nobody there could explain the change. So off I went, bike didn't shake anymore, but the damn brakes kept touching the rim and no matter how many times I adjusted them, no matter what I did, never could get rid of the problem. So I thought that the bike shop had done a crappy job b/c it was under the guarantee, therefore, free. After months of battling with the brakes, I decided to go back to the originals, so I took it to my local where they did the job. Now i'm £70 poorer and I almost fell off today from the "bike shakes". Luckily, I kept the old V brakes, which I'm thinking of putting back on.

I obviously need to get to the root of this problem; can't keep spending money on this bike, might as well sell it! Could the problem be related to the fact that the handlebars have been raised? How can this affect the performance of the brakes? Has anybody here had handlebars changed in their bikes? Did you have to change the brakes also?

I so wish I had been able to speak to the mechanic who put the V brakes on...!

Apologies for the long post, but any help and knowledge on this would be very, very helpful.

I'm dreading my commute home today.... And to make things worse, it's pissing down....!

Thank you.

nicklouse

well V brakes and cantis need a different brake lever as they both require differing amounts of cable pull. (sme levers can be switched between two settings to allow either type of brake to be used).

So make sure you use the correct brakes for the levers.

jpembroke

Not quite sure I understand your post. Can you clarify if you are now using drop bars and STis or flat bars with MTB levers?

jpembroke

Re-read your post and it appears that you are using drop bars and v-brakes. The only way you can get Vs to work with STi levers is by fitting a travel agent to allow for the extra cable that needs to be pulled. Alternatively you can fit mini V-brakes but these need to be run so close to the rim that any deviation in the rim will cause it to rub.

You are right to have the cantis refitted but to eradicate the fork judder may require a new set of forks. You should, of course, start by trying different brake pads and making sure your headset and stem are tight. However, if this makes no difference then new forks may be required.

Google 'fork judder' and 'tricross' for more information. It appears that this is a common problem with this bike. There's some info on the CTC forum for starters.

MadammeMarie

jpembroke wrote:

Not quite sure I understand your post. Can you clarify if you are now using drop bars and STis or flat bars with MTB levers?

Still using drop bars, don't know what STis nor MTB are (sorry, I'm not very technical). The levers are the ones that came with the bike: http://www.specialized.com/bc/SBCEquipPopup.jsp?equipimage=/OA_MEDIA/2008/bikes/08TricrossSptBlk_UK_l.jpg&equipmodel=Tricross%20Sport%20Triple

MadammeMarie

jpembroke wrote:

Re-read your post and it appears that you are using drop bars and v-brakes.

Mmm...nope. I got the cantilevels put back on. The V brakes didn't make the bike shake, but they kept rubbing the rim.

Google 'fork judder' and 'tricross' for more information. It appears that this is a common problem with this bike. There's some info on the CTC forum for starters.

Thanks for that, will do.

MrBlond

It's a known problem - few threads about it over on STW, e.g.:

http://www.singletrackworld.com/forum/r ... ly_3491966

bill reay

I,too, had a similar problem with cantis except I had brake squeal. Like you, this disappeared when I fitted V-brakes. You can use V-brakes with STI levers. But, as you have found you have to keep the pads close to the rim. The easiest way to adjust the pad clearance is to fit an in-line cable adjuster in both cables. These a very cheap (£5 each) but would get your bike shop to fit them for you if you haven't the experience.

jpembroke

The only V-brake that will really work with an STi lever is a Mini V-brake with a 75mm arm. Standard V-brakes (100mm arms) will only work if set up in conjunction with a travel agent (or similar cable pulling gadget) or with Dia Compe 287v levers (not STi). My experience with Mini-Vs was not a positive one (they had to be set up a gnat's wing width from the rim otherwise you had to pull the lever back to the bars to get them to bite and also couldn't be quick released to allow wheel removal) and so I swapped them for a set of Tektro Oryx cantis instead - big improvement.

Anyway, as the original poster points out, they have now got the cantis refitted but now have the problem of fork judder back again. I sympathesise as I currently have this issue on my cross bike. New pads have calmed things down a bit but it's not completely sorted and I am now left wondering if the forks are stiff enough for the job.

MadammeMarie

MrBlond wrote:

It's a known problem - few threads about it over on STW, e.g.:

http://www.singletrackworld.com/forum/r ... ly_3491966

I know now, I've been finding out about this for the last couple of hours and I'm horrified that Specialized haven't fixed this problem with the 2008 model, when the 2007 model had the same problem. What were they thinking?????

I see from the chain reaction forum that I might get the "mini v" brakes for free. Lets hope.....

Thanks to all of you for your replies. I would still be in the dark if it wasn't for all the info you gave me.

jpembroke

I would rather push for a new fork than Mini-Vs. Seriously, I think they suck.

caeser

there is a problem with certain frt brakes and what you should have is a mini v or canti not a normal mtb type brake as the pull ratio on sti is less than mtb levers so you have to put the pads closer to the rim what happens is you will get no feel from the brake then all of a sudden the brake will slam on you can get a travel modulater for about £13 this will take the play up on the cable but you should have had a correct calipers fitted FOC

geoff_ss

As I read this your brakes started to judder after you changed the handlebar extension. I assume they were OK before?

Is it possible that you affected the headset adjustment when you changed the extension. If it was loose heavy braking could well cause juddering.

There will be a problem using V brakes with drop bar levers. V brakes are really just cantilevers with more leverage and hence need more movement to apply. Straight bar levers have varying leverage as the lever's moved to give a lot of movement initially and less as block contacts the rim.

Brake judder can also be caused by incorrect setting of the brake block. They should slightly toe in at the front. It can be a bit tricky to get right but I've had no problems with cantilevers with drop levers (not STI my drop bar tandem and solo trike pre-dates them ) once correctly adjusted.

Geoff

PHcp

A brake booster might help, it just fits behind the brakes and restricts how much the fork can flex.
A bit of a long shot, but they're cheap enough...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0222594044

MikeyP

jpembroke wrote:

You are right to have the cantis refitted but to eradicate the fork judder may require a new set of forks. You should, of course, start by trying different brake pads and making sure your headset and stem are tight. However, if this makes no difference then new forks may be required.

I had the very same problems with the carbon Wound-Up forks on my Airborne; Shimano canti's were an improvement over the original Avids, but the judder issues were completely eradicated when I swapped the fork for a (albeit heavier) pair of steel Kona Project 2's. Might be worth a shout if all else fails, and pretty cheap through somewhere like Wiggle.

grahamharpin

I had a similar problem with Avid Shorty Canti's on carbon cross forks. Eventually I changed the forks so I could fit a mechical disc brake which works well. However before changing the forks I did manage to eliminate the brake squeal and judder by fitting a brake booster and regular adjustment of the brake blocks (about 300 mile intervals). I would also suggest checking the steering head bearing adjustment, if there is play in the bearings then it will allow the forks to judder.

This was the brake booster I fitted............

http://www.sjscycles.co.uk/product-Thor ... -10362.htm

................I still have it if you are interested.

Gary D

Interesting that yours is a 52cm frame size? The general consensus is that it is the larger frames worst affected.
However, in saying that, I have an '06 Tricross in a 58cm size and have not experienced the fork judder.

As others have said, check that the headset bearings are adjusted correctly first.

I did have issues with the brakes on mine but it was just that they were cr*p :shock:

I changed them to a set of Suntour Cantis which improved things - but I think the biggest improvement came from changing the brake pads. I went for Kool Stop Red ones and they made a big difference in stopping power. I'd also had slight problems with brake squeel but the new pads eliminated that as well.

Rather than going to the expense of changing forks and buying other expensive bits and pieces, I would try just changing the pads first. BUT make sure they are set up correctly with the toe-in etc. If you are unsure, either refer to Sheldon's site for guidance or get someone who knows about these things to do it for you.

Hope this helps.

Gary.

paulinwalthamstow

Hi, have just had the same problem as you on my new cross bike, flipped the bar clamp to raise the bars, test rode it and the judders appeared from my avid canti's. The bike is one day old and was built by Epic cycles , so set up perfectly. I called Epic's workshop who pointed out that the cable carrier for the front brakes has an allen bolt in it which would need to be slackened off and re tightened, but only after re - tensioning all the other bolts on top of the forks and on the stem / bar clamp first. Slacken all bolts in the stem, then re -tighten in the followaing order - bolt in top of forks first -( tighten only till the stem spacers stop moving), then the clamp bolts, and lastly the cable carrier bolt. this worked like magic, judders all gone, and something that is easily overlooked (especially by a clutz like me!) The clamp bolt on the cable carrier stops you from setting the correct tension on the forks and then the judders set in. Hope it is of some use to you, however if it does fix it, its frustrating to think that one small bolt caused all your woes!

robbarker

Vivian, there's almost certainly nothing wrong with your bike, it just needs to be set up properly.

As others have said, use the cantilever brakes.

First, adjust your headset bearings as per this guide:

http://www.parktool.com/repair/readhowto.asp?id=65

Scroll down to where it says "headset adjustment - threadless type"

Then set your brakes up according to this guide:

http://www.parktool.com/repair/readhowto.asp?id=19

And all will be well.

Just a thought - this isn't the bike you crashed is it, and the judder didn't start after the crash by any chance?