Brake blocks question

[radger]

My stupid bicycle has a stupid carbon fork which has the hole for the front brake about 0.25mm too high. As a result, the blocks rub on the front tyre, and I have just destroyed it while trying to keep my speed down on a rather steep hill while attempting to go to the shop for the missing ingredient for my dinner . Fortunately, the rim appears unharmed.

The blocks are shimano dura ace, and the brake is a tiagra - I would like to know if anyone has a suggestion for some blocks that will fit the brake, but are about ½ a millimetre less tall, so I don't lose another tyre. I suppose I could trim the blocks with a stanley knife, but knowing me I'll also trim my thumbs.

 

[Milo]

Can you not adjust the blocks a bit?
If not sandpaper.

 

[Smokin Joe]

Ideally you need calipers with a deeper drop as your frame is made with clearence for mudguards and touring tyres. However, you can get away with filing metal from the slot in the caliper so the blocks sit lower and clear the tyre. 1/2mm is next to nothing and won't do any damage to the brake.

 

[dodgy]

Sounds to me like you're using the wrong blocks for your Tiagra calliper.

 

[gavintc]

no it is a deep drop problem. You need new brake calipers or file down the hole

 

[radger]

Thanks all - I realised I needed to file the hole down a bit on my walk in this morning. I will eventually get new callipers.
And it means I have to get some GP tyres now.

 

[John the Monkey]

Probably a daft question, but your wheel is seated properly in the dropout, isn't it? I've heard people say that prior to the final closure of the Qr lever, it's a good idea to lean on the bike slightly to make sure the wheels are in there properly.

 

[dodgy]

I'm having difficulty understanding why your bike is configured this way. Have you added the forks later on, or maybe the callipers are new?

 

[radger]

I have double-checked the wheel's seated right.

The bike came set-up like it - I should have noticed/corrected the problem before the bike was 2½ really, especially as I'm on my 2nd set of brake blocks and they need replacing too.
Maybe I'll get a new front brake along with my new tyres, as I don't think I have a file the right size to make the hole longer.

 

[John the Monkey]

Useful article on measuring the required reach range of your new calipers here, radger.

http://sheldonbrown.com/gloss_ra-e.html#reach