Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: Bianchi Boy on 19 April, 2019, 04:58:35 pm
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I have a Condor Frettello with caliper brakes and there is not clearence for my GP 4000 28mm tyres. SKS Longboard guards are in place and I have maxed out the height at the rear brake where I get the contact.
Are the any guards that people believe I will get more clearence? Or will I be limited to 25mm?
BB
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The Condor Frettello takes 57mm long drop calipers.
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gp4000s are oversized tyres, so if you want (or your bike can accept) 28mm, get 25mm and they will be 29mm on wider rims, if that makes sense. or use 28mm tyres without the mudguards, 'tis the season!
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mudguards vary in their exact clearance because
a) the mudguard bridge takes up space between the caliper and the mudguard, or the brake bridge and the mudguard esp on frames with allen key fitting brakes. If you can do (eg by filing out the hole and using spacers etc), it is a good idea to fit the mudguard bridge behind the brake bolt, so that it doesn't take up any space.
b) the mudguard can interfere with the bottom of a DP brake caliper. This can be the return spring on the brake (which can be reshaped to avoid this) or with one or other part of the caliper itself. Sometimes you can ease the clash by playing with the centring screw and swinging the entire caliper around slightly; this can move the offset arm out of the way, but it can't move the centre pivoted arm relative to the mudguard.
You can sometimes pack out brake block fittings so that the brake caliper is always slightly further open; this can ease a clash between the centre pivoted arm and a mudguard too. Of course this extra clearance can disappear as the brake blocks wear. Some calipers have an internal shape that makes more room for the mudguard, and some mudguards have a better shape (to match the caliper) than others. Note that if the mudguard comes closest to the tyre behind the rear brake, then this signifies that a spacer at the chainstay brace might be required, so bring the mudguard curve to better match the wheel/tyre.
IIRC the fratello is meant to use 25mm tyres and mudguards, so with 28mm ones it is always going to be a bit tight, if not too tight.
There are various butchering techniques which allow you to fit mudguards to any bike, which involve things like cutting a mudguard so that none of it goes under the brake, and using brackets which loop over the brake calipers. This works but does nothing to protect the brake calipers from road crud; the calipers therefore tend to seize up, at least as badly as if the bike had no mudguards at all.
cheers