Cantilever brake recommendations

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andyh2
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Cantilever brake recommendations

Postby andyh2 » 8 Jul 2012, 6:52pm

So on putting together a nice 90s Galaxy frame (bought from here a while back) I have discovered that the canti-boss distance at the front is 70mm and my v brakes won't fit :(

Canti recommendations please.

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gaz
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Re: Cantilever brake recommendations

Postby gaz » 8 Jul 2012, 8:30pm

Canti's require different lever pull to V brakes.

If you are using drop bars with STI/ergo/standard levers then late 80's Shimano cantis like BR-MT60 are suitable.

If you are ebaying then the BR-AT50 is a budget version of the above (no spring tension adjustment), the BR-M732 is the XT model and IIRC BR-MT62 is the SLR version of the Deore.

If you are using flat bars then you'll need canti specific levers (although some V brake levers are adjustable to a cantilever setting).
It's got nothing to do with vorsprung durch technic you know...

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gaz
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Re: Cantilever brake recommendations

Postby gaz » 8 Jul 2012, 8:54pm

Mrs gaz's late 90's Super Galaxy came with V brakes, front bosses are 74mm apart c-c.

I've not much experience of V brakes but understand that they sometimes have a thin washer and a thick washer on the threaded stud. Can you swop the spacing washers around?
It's got nothing to do with vorsprung durch technic you know...

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cycleruk
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Re: Cantilever brake recommendations

Postby cycleruk » 8 Jul 2012, 8:56pm

andyh2 wrote:So on putting together a nice 90s Galaxy frame (bought from here a while back) I have discovered that the canti-boss distance at the front is 70mm and my v brakes won't fit :( Canti recommendations please.


I presume the bosses are too close together and you have removed the washers from behind the pads?
And have you seen this thread:- viewtopic.php?f=5&t=65686
Does that help?
Good health & a following wind. :D

andyh2
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Joined: 24 Oct 2007, 8:49pm

Re: Cantilever brake recommendations

Postby andyh2 » 8 Jul 2012, 11:33pm

I've doubled checked the c-c boss distance and it's 70mm for the fork (77mm for rear).

I've got the thinner spacing washer between brake arm and pad. With the Mavic A 719 rimmed wheel I'm trying to use there's very little space between the rim and inner fork leg for brake pad and its actuation. If I removed the washer altogether I can't see that would help.

I'm not actually sure if canti brakes would solve the issue, although it might improve the angle of the brake arms.

I was hoping to use 37mm pasela's, and whilst they fit (and I think there will just be clearance for mudguards) the brake pads won't clear them when fitting/removing wheel unless it's deflated.

I am lucky enough to have V and caliper brake levers in the spares box.

I'm beginning to think that my options might be a narrower rimmed wheel with max 32mm tyre and cantis (or possibly the V brake might then work) or the current wheel and 37mm tyre with a side pull brake. I do have a long reach tektro one which was for a 27" to 700 conversion and that might be worth trying. mmmm

And just to spice up the build a bit I've discovered that the fork ends are a touch out and need re-aligning too. Ahh the joys of bike building :|

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gaz
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Re: Cantilever brake recommendations

Postby gaz » 9 Jul 2012, 7:10pm

andyh2 wrote:So on putting together a nice 90s Galaxy frame (bought from here a while back) I have discovered that the canti-boss distance at the front is 70mm and my v brakes won't fit :(


andyh2 wrote:...With the Mavic A 719 rimmed wheel I'm trying to use there's very little space between the rim and inner fork leg for brake pad and its actuation. If I removed the washer altogether I can't see that would help...


Whoops, I misunderstood the problem first time around :oops: . I stand by the canti recommendations. You are right, removing the washer won't help.

I have that problem on my Bob Jackson. It's fitted with cantis (BR-MT60) and I've changed the rear blocks to V type cartridges. I can't change the front because there's simply too little space to get a cartridge block between the fork and the rim (Sputniks). :evil:
It's got nothing to do with vorsprung durch technic you know...

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meic
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Re: Cantilever brake recommendations

Postby meic » 9 Jul 2012, 7:28pm

I'm not actually sure if canti brakes would solve the issue, although it might improve the angle of the brake arms.

I was hoping to use 37mm pasela's, and whilst they fit (and I think there will just be clearance for mudguards) the brake pads won't clear them when fitting/removing wheel unless it's deflated.


If you use cantilever pads, they are in my experience short enough that they clear the forks or seatstays. So I was going to say that will cure your problems about getting the 37mm tyres out at full pressure.

Then it crossed my mind that it may mean you can still use V brakes but with canti pads.
If you think canti pads are too big and compressible, there are some V brake pads which look backwards to others (Shimano LX do some like this) which may also clear the frame.
Yma o Hyd

andyh2
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Joined: 24 Oct 2007, 8:49pm

Re: Cantilever brake recommendations

Postby andyh2 » 9 Jul 2012, 9:02pm

Thanks for the pointers.

Now I've stopped being grumpy about it and had another look :wink: I realise the first thing I need to sort out is getting the fork dropout aligned. If the wheel's in straight I think there could be sufficient clearance to operate the V brakes. And as suggested I might be able to increase that clearance by using canti blocks. So before I rush to buy a set of cantis I'll check which LBS has one of those Park dropout tools and get the fork sorted.

GregLR
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Re: Cantilever brake recommendations

Postby GregLR » 11 Jul 2012, 4:39pm

I've had this problem on my 1991-vintage touring frame when fitting V-brakes (XT) in the late 90s & cantilevers (BR-R550) in 2007. With the latter the cartridge type brake shoes were replaced with cheaper, shorter brake shoes that didn't extend into the tight space between the fork crown lugs and the front rim on the A719 rims. However more recently I've been unable to find replacement brake pads that are short enough, so I've had to solve the problem by filing away the pads a bit at the end that extends into the tight space. I used to do this with the V-brakes in the late 90s until I abandoned the front V-brake for a set of Tektro mini-v brakes that i used until 2007. The mini-Vs (also with shorter non-cartridge brake pads) worked very effectively though they had very little space between the cable straddling the two brake arms and the front mudguard.

Greg

andyh2
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Joined: 24 Oct 2007, 8:49pm

Re: Cantilever brake recommendations

Postby andyh2 » 11 Jul 2012, 5:45pm

So the LBS had one of those lovely Park tools for checking dropout alignment and a minor tweak has centred them. Upon closer inspection the canti-bosses are not 100% symetrical and contrary to my earlier assertion it does matter which way round the wheel goes in. :oops:

I think the 3 elements were conspiring against me!

I have now got the V brakes working, but not with sufficient clearance to remove the wheel without first deflating the tyre and that is with 37mm or 32mm tyres.

Unfortunately mudguards can't be accommodated with the 37mm tyres so I'll have to go to 32mm as the mudguards are a must. Just cables, chain and mudguards to fit and then hopefully I'll be gliding along with a smile on my face :)

andyh2
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Re: Cantilever brake recommendations

Postby andyh2 » 13 Jul 2012, 11:03pm

Brakes now fine, 32mm good for road and OK for gentle riding on tracks, it has indeed put a smile on my face, though a rather bemused one initially.....

It's a 63cm frame, which is big for me, but I 'knew' it would be fine because I've been riding an early '80s 27" wheeled Galaxy at that size and enjoying the feel and the stand over is fine and I like the low BB. At first I couldn't understand why the stand over height had become very marginal and it was definitely more of a stretch to get a foot down. Turns out that in the change over to canti bosses and 700 wheels it seems they also saw fit to reduce the BB drop by around 1cm.

Not sure why, did everyone suddenly need longer cranks or were they taking them off road more in the '90s?

Seems a bit of a shame really as whilst it makes no real difference once moving I like a low BB to make starts and stops easier with a load.


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