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Extending caliper reach?

Posted: Thu Jul 19, 2012 8:39 pm
by WeightySteve
Any suggestions for getting about 2mm extra reach from my front DA 7900 calipers?

I am loathed to have to replace them for a BR650 (57mm drop), just for the sake of 2mm, but can't find a way out.

I tried flipping the DA pads around L/R because they kinda point upwards when normally installed, but this didnt really work (top of pad just off the rim, not on the tyre, but with a bit of wear it would be). Theoretically I could attempt to dremel/drill out 2mm from the fork dropouts but that's a bit scary!

Maybe a different shoe would give me just that extra bit of drop?

Re: Extending caliper reach?

Posted: Thu Jul 19, 2012 8:55 pm
by Irish
How about drilling 2mm from the caliper pad holder holes?

Re: Extending caliper reach?

Posted: Thu Jul 19, 2012 8:55 pm
by Weenie

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Re: Extending caliper reach?

Posted: Thu Jul 19, 2012 8:56 pm
by Irish
How about drilling 2mm from the caliper pad holder holes?

Re: Extending caliper reach?

Posted: Thu Jul 19, 2012 8:57 pm
by WeightySteve
They only have about 3mm from hole to bottom edge.

Re: Extending caliper reach?

Posted: Thu Jul 19, 2012 9:08 pm
by WeightySteve
Now something like this would work...

http://www.imperialsupplies.com/item/0765320" onclick="window.open(this.href);return false;

I can angle the bolt downwards with this get just about a 2mm drop, then use the toe-in on the shoe to level it up with the rim. Now to find them in the uk...

Edit: Turns out they are not so difficult to make with an inner tube nut and a dremel :)

Re: Extending caliper reach?

Posted: Thu Jul 19, 2012 11:35 pm
by WeightySteve
So after about 90 mins dremelling, fitting those brake a shoes just simply refuse to toe in at such an angle, and so a. BR 650 now looks like the only realistic solution.

Re: Extending caliper reach?

Posted: Fri Jul 20, 2012 12:14 am
by BobSantini
Drop bolt?
http://sheldonbrown.com/dpdropbolt.html" onclick="window.open(this.href);return false;

No. Forget I mentioned it. :oops:

Re: Extending caliper reach?

Posted: Fri Jul 20, 2012 12:29 am
by budgetweenie
You can try something that worked for me when converting a frame designed for 27 inch wheels to 700c.

All I did was shave 2mm from the top edge of the brake pad where it would contact the rim. Leave the part inside the shoe holder intact.

You probably won't even notice the decrease in braking force due to the decrease in contact area.

Re: Extending caliper reach?

Posted: Fri Jul 20, 2012 12:34 am
by WeightySteve
Seems there no one selling them anymore, and not sure how they perform A specially designed shoe would be perfect, but doesnt look like they exist.

http://www.bentrideronline.com/messageb ... hp?t=54096" onclick="window.open(this.href);return false;

sums it up pretty nicely.

Re: Extending caliper reach?

Posted: Fri Jul 20, 2012 12:36 am
by WeightySteve
2mm off a 7900 pad would be nearly half of it.

Re: Extending caliper reach?

Posted: Fri Jul 20, 2012 12:53 am
by budgetweenie
The pads I have (Blue Reynolds) are 7.5 mm wide, so 2 mm is less than a third, closer to a fourth.

Older pads (like from sidepulls) are about 11 mm so 2 mm from that would be negligible indeed.

Re: Extending caliper reach?

Posted: Fri Jul 20, 2012 1:44 am
by thisisatest
this is what you need but it looks like theyre not around anymore. im still looking.
Image

Re: Extending caliper reach?

Posted: Fri Jul 20, 2012 1:44 am
by Weenie

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Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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