Toeing in blocks

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Matthames

Über Member
Location
East Sussex
I am having a bit of trouble with getting the rear brake blocks toed in correctly. Currently they are squealing like one of those dinosaurs off Jurassic park.

Any tips for getting the angle right?
 

HJ

Cycling in Scotland
Location
Auld Reekie
Angle the pads so that there’s about a .5mm gap at the backs of the pads when the front edges strike the rim. Some mechanics slip a piece of cardboard under the rear of the pad to set the angle right. Hope that helps.
 

MartinC

Über Member
Location
Cheltenham
Sometimes brakes (especially V's) will squeal despite toeing them in correctly, cleaning the rims, changing the pad compound, etc. etc.
 

HJ

Cycling in Scotland
Location
Auld Reekie
HLaB said:
I'm told toeing in is actually useless, as the blocks quickly become worn square to the rim; but I still do it as above. With the pads fairly lose I put a piece of card under the rear 1/4 of the block, tighten the brakes and then tighten the blocks.

If you think about how the blocks wear you will realise that they do not wear square to the rim, due to the rotation of the rim under braking. Hence as they wear down, they start to squeal...
 
It probably depends on how hilly the terrain you ride in is, and how fast you ride. If you do a lot of fast downhills with vigorous braking at the bottom, then the brake arms will deflect quite a lot under braking, and need toe-ing in, especially the front. If you ride mostly on the flat with gentle braking, don't toe-in.
 

gwhite

Über Member
With the more sophisticated brake mechs which use a series of cups and washers to achieve the correct angle of the pad, it's wise to grease these before attempting to toe-in the pad. An elastic band over the rear of the pad is often the easiest way to achieve toe-in.
 
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