Canti break help please.

[3narf]

It's about mechanical advantage with canti brakes; look at the angle between the tie wire (? can't remember, it's been so long- the link wire between the two arms) and the canti arm as the pad contacts the rim. It should be as close to 90 degrees as possible, because as you pull more on the lever, this angle opens up and the mechanical advantage drops. Hence the wasted motion at the lever.

This is the reason cantilever brakes are obsolete on everything except cyclo X bikes! Why oh why are they still used? Is it something to do with mud clearance or is it just tradition?

 

[ColinJ]

I had a quick look and found some useful-looking videos on YouTube but you might as well watch them yourself to see if they help you, rather than ME watching them and telling you whether I THINK they will be helpful! (Search for 'cantilever brake adjustment')

I hated faffing about with the canti-brakes that I had on my first mountain bike!

 

[Hugh Manatee]

I like to meditate for seven hours. Then, I sit cross legged under a waterfall wrapped in the skin of an oxen.

Now, with my mind clear and pure I can get to grips with the brakes on my mountain bike. Within minutes I'll be wailing and biting the cursed and hateful things.

Good advice with the mechanical advantage thing. I like to start so that the pads make full contact with the rim.

Once you have done this get the straddle wire as described, you'll be ready for battle proper. Shimano made this little round gizmo that you used with a short, half straddle wire. It was designed to show the perfect cable angle and was supposed to make life easier: http://www.ebay.co.uk/sch/i.html?_f...ide.TRS0&_nkw=shimano+straddle+guide&_sacat=0


One little tip I'll offer is that rather than try to adjust everything perfectly, I adjust that little screw tensioner thing, the one at the brake lever, out a bit as if the pads have already worn some. Then I finally tighten the cable with the blocks against the rim. Then I'll screw the lever adjuster right back in thus allowing the blocks to move away from the rims about the right amount.

Then I'll throw the whole sorry mess back into the garage and go out on the road bike instead.

 

[3narf]

STRADDLE wire! That was it.

 

[Dirk]

This is the best thing to do with cantis.
https://www.cyclechat.net/threads/improving-touring-bike-brakes-cantis-to-mini-v-conversion.205631/

 

[screenman]

First thing I did was strap the blocks tight to the rim with a toe strap before starting any adjustments as this seemed to make the job easier for me. I cannot remember a bike without an inline adjuster, I would certainly have fitted one if that was the case.

 

[Dirk]

[QUOTE 4668319, member: 45"]It is, but you'll still have some issues with lever pull on a drop bar bike with standard brifters.[/QUOTE]
What issues?

 

[Dirk]

[QUOTE 4668327, member: 45"]The pull ratio is different on standard brifters to levers designed specifically for v-brakes. You'll get more power in the brakes but still have a fair bit of movement in the levers to get them to work. Unless the blocks are set right against a nicely trued wheel you might even end up with them verging on pulling right back to the bars.[/QUOTE]
Maybe with standard V brakes; but I used mini V brakes, which don't give any issues with lever travel.
I get powerful, two finger, braking with normal lever travel and sufficient block to rim clearance.
No issues at all......apart from how crap the original cantis were.

 

[Dirk]

[QUOTE 4668340, member: 45"]I've had issues in the past with mini-v's on normal brifters.[/QUOTE]
I haven't.
Let's leave it at that.

 

[Hugh Manatee]

Thats with a flat bar bike, this is a drop bar and theres no little tensioner on the bars to twist,I know what you mean though.

Then you are quite, quite doomed. I think a lot of the faff is down to the rims. If the brakes were well set up previously and have worn evenly, it isn't too bad.

If there is a wear step, it's a lot harder.

Before I tighten the blocks into their final position, I trap a match stick between the rim and the back of the block. This ensures about the correct amount of toe in. This way they won't squeal.

 

[bigjim]

Best thing I,ve done is replace them with sidepulls.

 

[Hugh Manatee]

[QUOTE 4668366, member: 45"]I've never once set up toe-in with bike brakes and never had problems with squeal. I just push the blocks square against the rims then tighten the cable, before backing the adjuster off until there's no rub.[/QUOTE]

V brakes set flat. I have always toed my blocks on cantilevers in. Squeal and judder was a real issue BiTD with MTBs. I suspect it was to do with the relatively spindly nature of the forks in the early days. I remember the woods alive to the sound of a hundreds howling brakes during wet races!

Once things went over sized in the mid 90s maybe the problem started to go. I have always had the habit though as it cured my squeal; I remember reading about it in a late 80s MBUK Grime Squad!

It should be noted that all my mountain bikes are late 80s or 1990 vintage.

 

[mmmmartin]

Slightly OT but BiTD I had a Dawes Galaxy - 12 years old when I bought it from a friend and I put in new cables and blocks on the canti brakes - and was shocked when going downhill in Spain to discover that the brakes had a mind of their own. They'd sort of think: "OK, the lever has been pulled, perhaps I'll start to slow down in a little while." This, I need not say, was very alarming. No matter how much I tightened the cable, etc etc, they simply didn't work well enough. And this on a bike designed for touring with luggage. The kit I had on that tour was for credit card touring - not even front panniers. On another tour, I was with someone who had a Dawes Galaxy and in a Pyrenees rainstorm they simply didn't work at all.
That was then. This is now: Thorn was very happy to sell me a brand new Raven. Yes it was pricey - but to put it in context, it was about the same as filling the car tank 80 times with petrol which would then disappear to nothing. The bike will last a lifetime. I paid £50 (I think) extra for better brake levers. In Patagonia on steep gravelly descents with full camping kit and front-and-back panniers the V brakes worked a treat: you can stop the bike no problems with one finger.

 

[Drago]

Why oh why are they still used? Is it something to do with mud clearance or is it just tradition?

Because they're light, simple, effective and simple to set up and maintain.