[peterlonz]

Never thought I'd have to ask for help but I have drawn a total blank in my search for some plastic parts which are components of this Shimano design.

Overall the design seems sound, & whilst not as readily adjusted as more modern sets, the brakes have all the required stopping power.

For some unknown reason Shimano seems to have incorporated plastic shrouds which cover the 3 turn coil return springs, & as you might guess the plastic just fractures & fails.
My wifes bike has not really seen much work, & is stored out of sunlight, but these suckers just fail anyway!
At first I though these shrouds were merely dust covers but that's not the case as one in each pair carries an adjusting limit screw - creating some more stress in this thin walled component.
Can anyone suggest how I might obtain replacements. LBS - no stock of these bits, "cantilevers are pretty old now".

Thanks,
Peter O

 

[Sghost]

You can get Shimanos good canti that cross racers use for like 25 bucks a wheel off ebay.

 

[peterlonz]

I think the canilevers you suggest are not Altus & don't have the plastic shrouds.
I don't know therefore whether a direct replacement is possible.

I can buy locally a generic cantilever set, front & back for about $40 to $50.
Problem here is would they be any good or prone to fail in some structural way & allow you to loose braking?

 

[slimshady]

Why not change to Vs? you could spend maybe 50 bucks, including the brake lever replacement, and you'll get more modulation and stopping power. Go for an old pair of LX-XT Servo Wave levers, and you'll be more than happy.

 

[zebrahum]

That part is called a brake cowling I believe, and from what I know even Shimano isn't making too many of them these days. It is probably in your best interest to get a set of cantis without the plastic cowling, Avid is a good choice. Switching to Vs is a good idea, but in practice, your frame may have some issues. Mine needed a bolt on cable stop for the top tube.

 

[peterlonz]

Thanks guys for the suggestions.
I have decided against Altus as replacements, that would just raise the same cowling failure problem in a year or two at best.
So I will hunt for the Avid, a brand I don't yet know if I can buy in Australia, maybe Ebay??

Meantime as a matter of pride I have reinforced the 2 best of the failed cowlings by finding a piece of steel tube from which I cut a band about 7 mm wide & epoxied it in place thus repairing the crack. So we will have front brakes at least while I search around for permanent replacements.
I remain totally baffled by Shimano's choice of plastic for these cowlings, you might expect this sort of crap in a $100 Supermarket bike. Does anyone have an insight on this?
"Better modulation" is claimed for V's, is this always so, or does it depend on rim material & pad selection? The geometry of Canti's certainly seems to promote grabbing & lock up when that's not intended at higher levels of brake lever activation.

 

[slimshady]

Thanks guys for the suggestions.
I have decided against Altus as replacements, that would just raise the same cowling failure problem in a year or two at best.
So I will hunt for the Avid, a brand I don't yet know if I can buy in Australia, maybe Ebay??

Meantime as a matter of pride I have reinforced the 2 best of the failed cowlings by finding a piece of steel tube from which I cut a band about 7 mm wide & epoxied it in place thus repairing the crack. So we will have front brakes at least while I search around for permanent replacements.
I remain totally baffled by Shimano's choice of plastic for these cowlings, you might expect this sort of crap in a $100 Supermarket bike. Does anyone have an insight on this?
"Better modulation" is claimed for V's, is this always so, or does it depend on rim material & pad selection? The geometry of Canti's certainly seems to promote grabbing & lock up when that's not intended at higher levels of brake lever activation.

Vs will always outcome cantis. They have more leverage, more control, and more strength.

To start with, and resorting to basic Physics, the angle at which the cable is pulled is around 90 degrees in Vs (measured against the brake braces), while is at best 45 deg in cantis. This causes the actuating force to decompose in two ways in the cantis: one along the line joining the brake braces (the one providing the actual braking force), and the other perpendicular to the first one, pointing up, paralell to the rim's side (this force component is lost, simply because it does not actuate against the rim). In a nutshell, you almost double the force applied to the rim by simply switching to Vs. Plus, the lever length is doubled in the Vs, simply because the brace lenght is longer.

However, you will have to change the brake levers too, because the canti ones are designed to give you that extra strength you are losing because of the brake braces design. If you mix canti brake levers with V brake braces, you'll end up with unpredictable brakes.

As I said before, go with a pair of old Shimano LX and ServoWave brake levers, you can't go wrong. If you like Avid, they keep making the Single Digit brake line, with several models in it. you should be able to get them in Australia without too much hassle. Fetch a pair of Speed Dial brake levers, and you'll have a killer combination.