Canti brakes not good enough - change?

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jbstumpy
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Canti brakes not good enough - change?

Postby jbstumpy » 11 Jun 2012, 6:51pm

Hi all, My first technical post on CTC.

I went for a small tour over the weekend, fully loaded however, in preperation for coast to coast in a couple of months. I really noticed how poor my Shimano exage canti brakes performed. I've excepted their performance in the past, but lost confidance in them this time, the ride was perticularly hilly. I think also having been riding my road bike a lot with dual pivot calipers recently I am surprised how superior they have been. Last time I rode my tourer I had been mountain biking a lot with disc brakes and expected to notice the significant difference. My other co-riders were using canti's at the weekend and theirs performed better than mine.

I would really appreciate advice on making improvements to the braking.

Some observations -

Shimano exage canti's do not have 'typical' canti pads/shoes, so I doubt I could simply upgrade the pads. I've Heard lots of good reports about Koolstops.

One of my co-riders bike uses Tektro Oryx, which as stated already were much better than mine. I suspect this is due to the pads fitted.

I wonder if the Pads on my exage have hardened with age, they were new old stock (NOS) last year, 20 years old however.

I could perhaps change to v-brakes, but feel they would maybe be too hard on the rims, and that would also mean replacing the levers.

I'm currently considering buying a set of Tektro Oryx or Tektro 520's/720's.............

Cheers

johnb
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Re: Canti brakes not good enough - change?

Postby johnb » 11 Jun 2012, 6:56pm

viewtopic.php?f=5&t=63112

A recent discussion covering some of your topics.
The lead Greyhound never has to look at another Greyhounds derrière.

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CREPELLO
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Re: Canti brakes not good enough - change?

Postby CREPELLO » 11 Jun 2012, 7:30pm

Changing the pads would be a sensible first choice. Koolstop pads are available
http://www.dotbike.com/p/3106 & http://www.spacycles.co.uk/products.php ... 69s104p817.
Also consider using an adjustable straddle wire if the type you have now is fixed length. This will help your brakes obtain a bit more power. The lower the straddle wire the better.

What type of handlebars do you have? Your decision on whether to upgrade will need to take into account the bars and brake levers you have and along with the brake type will guide what you could upgrade to.

Brucey
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Re: Canti brakes not good enough - change?

Postby Brucey » 11 Jun 2012, 7:32pm

Brakes like this?

Image

IIRC these are the same blocks as fit BR-M550, BR-M454, BR-M450, BR-M351, BR-M350, BR-M250 brakes. They were hard on day one.

The brake arms are IIRC 55mm long. The brake blocks look as if they could be replaced with 'V' blocks but in fact the bolt on most 'V' shoes isn't long enough for the thicker BR-M450/454 arm. On some cartridge shoes you can remove the bolt and replace it with a longer one + washers, but a small amount of engineering is required to do this. Once done, the brake will accept any cartridge pad though.

A simpler solution is to fit these;

Image

but I've not BTDT myself, they may not give the correct spacing without washers etc. If they fit, they should improve the brake power. Several different compounds available.

Mechanical advantage of the brake is geometry sensitive. In a nutshell with these brakes the lower you can get the straddle wire the better. If you can space the brake blocks out to make the arms as wide as is practical, the geometry will change a little less harmfully as the brake comes on.

Note also that brake levers that pull enough cable for DP brakes pull a little more than is needed for these cantis, and this correspondingly reduces the brake power acheived. These brakes were originally paired with a long four-finger lever with a high MA on flat-bar bikes.

I'd try with a lower straddle cable first, then try brake blocks.

However you could just buy mini-Vs if you have DP pull levers and do it that way. Much less faffing about.

cheers
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CREPELLO
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Re: Canti brakes not good enough - change?

Postby CREPELLO » 11 Jun 2012, 7:56pm

Have I got the wrong brake type? - opps :roll: I was thinking of these...
shimanoaliviobrmc12msystem3765.jpg
...which are post mount, unlike the Exage that Brucey shows above.

jbstumpy
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Re: Canti brakes not good enough - change?

Postby jbstumpy » 11 Jun 2012, 10:39pm

Thanks a lot guys, They are almost identical to the brakes shown by Brucey. I have not come across the Koolstop Eagles pads, they look well worth investigating. I was looking at the different adjustable staddle wires that the Oryx use, mine is fixed, so i'll investigate an adjustable straddle wire also.

Helpful to know that the original pads that came with the exage were known to be hard.

My bars are drop and currently i'm using standard older '105' road levers used normally for side pull calipers, they might be SLR, I need to check......

Regarding mini V's, what manufacturers are worth looking at, not come across them before. If they need dual pivot specific levers, aren't they always STI's? I know Tektro do a specific V-brake drop lever reasonably priced.....

Brucey
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Re: Canti brakes not good enough - change?

Postby Brucey » 11 Jun 2012, 11:03pm

your levers sound like they might be BL-1051, ideal for side pulls and cantis, not so good for DPs and mini-Vs.

The standard straddle wires in the exage brake picture are the sort I'd suggest you use, because they are adjustable. The m-system or later unit-link wires are not adjustable so I prefer the standard wires. The trick is to adjust for brake pad wear by moving the brake blocks or shortening the straddle; this keeps the straddle low as the pads wear, whereas the main cable barrel adjuster won't.

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

jbstumpy
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Re: Canti brakes not good enough - change?

Postby jbstumpy » 11 Jun 2012, 11:20pm

so sounds like I have suitable levers and straddle wires. I will adjust them lower. I think I will still need to change the pads though, so will investigate.....

Thanks very much for your help.

bealer
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Re: Canti brakes not good enough - change?

Postby bealer » 12 Jun 2012, 12:52am

If you want mini-v's Tektro RX5's are probably the best bet. Spa do them at around £15 a pair, so well priced.

I raised the post mentioned above. In the end I went with mini-v's although have a second bike with disc brakes. I personally really love disc brakes. They last ages, need little adjustment and run with a buckled wheel, and are exceptional in the wet. That said, they cost more, weigh more and I've yet to find a disc fork as comfortable as a nice curved fork.

My mini-v's are great too. However, a few things I find frustrating:
- Removing the wheel. You'll need to file down the brake noodle in so that you can unhook the brake in order to remove your wheels
- No inbuilt cable adjusters, you'll need to buy a set
- Limited clearance, I found getting my 45cm SKS mud guards under them a fiddly affair, but once done, they've been fine since.
- Compared to discs, once they're wet and there's grit in there, they just don't work as well.
- Compared to discs they require more attention to ensure they're always perfectly set.
- Damn they can be noisy if not set correctly! Safety bonus as it alerts *everything* around you.

Would I get mini-v's again. Yes until I find a comfortable disc fork, then I'm sticking with mechanical discs.

snibgo
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Re: Canti brakes not good enough - change?

Postby snibgo » 12 Jun 2012, 3:39am

jbstumpy wrote:I wonder if the Pads on my exage have hardened with age, they were new old stock (NOS) last year, 20 years old however.

Welcome to the forum.

I would expect 20-year-old pads to be useless. That's the easiest upgrade, and will probably make a huge difference.

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honesty
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Re: Canti brakes not good enough - change?

Postby honesty » 12 Jun 2012, 7:19am

I've got some tektro oryx in my bits box that you can have for a few quid if you don't want to pay full price to try them. PM me if you're interested...

Brucey
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Re: Canti brakes not good enough - change?

Postby Brucey » 12 Jun 2012, 7:36am

snibgo wrote: I would expect 20-year-old pads to be useless. That's the easiest upgrade, and will probably make a huge difference.

if they were (say) rubber that clearly degraded over time I'd agree. But they are not, they are 'something else'. They were rock hard on day one and they seem to stay that way. I agree 100% that they can likely be improved upon, but the original ones (good or bad) will probably be in the same condition in another 20 years....

cheers
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pete75
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Re: Canti brakes not good enough - change?

Postby pete75 » 12 Jun 2012, 7:57am

Tektro CR520 might be the thing and at 24 quid for a full set don't cost that much more than 4 koolstop brake pads

http://www.zepnat.com/component/page,sh ... Itemid,48/

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meic
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Re: Canti brakes not good enough - change?

Postby meic » 12 Jun 2012, 11:24am

Brucey wrote:Brakes like this?

Image

IIRC these are the same blocks as fit BR-M550, BR-M454, BR-M450, BR-M351, BR-M350, BR-M250 brakes. They were hard on day one.

The brake arms are IIRC 55mm long. The brake blocks look as if they could be replaced with 'V' blocks but in fact the bolt on most 'V' shoes isn't long enough for the thicker BR-M450/454 arm. On some cartridge shoes you can remove the bolt and replace it with a longer one + washers, but a small amount of engineering is required to do this. Once done, the brake will accept any cartridge pad though.

A simpler solution is to fit these;

Image

but I've not BTDT myself, they may not give the correct spacing without washers etc. If they fit, they should improve the brake power. Several different compounds available.

Mechanical advantage of the brake is geometry sensitive. In a nutshell with these brakes the lower you can get the straddle wire the better. If you can space the brake blocks out to make the arms as wide as is practical, the geometry will change a little less harmfully as the brake comes on.

Note also that brake levers that pull enough cable for DP brakes pull a little more than is needed for these cantis, and this correspondingly reduces the brake power acheived. These brakes were originally paired with a long four-finger lever with a high MA on flat-bar bikes.

I'd try with a lower straddle cable first, then try brake blocks.

However you could just buy mini-Vs if you have DP pull levers and do it that way. Much less faffing about.

cheers


I have these canti brakes (though with the word Mountain on as well) and they do work very well with the MTB levers. I bought lots of cheap brake blocks, because they can be hard to find, that look the same, not Shimano, in France and they are nice and soft.
These pads are surprisingly deep, if I was to use the Eagles I would need to pack lots of spacers on the stud to avoid the canti arms being almost vertical, that may be due to my frame but I doubt it.
Yma o Hyd

jbstumpy
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Joined: 2 May 2012, 12:48pm

Re: Canti brakes not good enough - change?

Postby jbstumpy » 12 Jun 2012, 11:27am

pete75 wrote:Tektro CR520 might be the thing and at 24 quid for a full set don't cost that much more than 4 koolstop brake pads

http://www.zepnat.com/component/page,sh ... Itemid,48/



I had thought along these lines, but Tektro's as with a number of manufacturers tend to supply pads that can be improved on, so then going for the better pad such as koolstop makes sense. Still I'd guess that the stock Tektro pads would perform better than the Shimano one I have fitted.