Extending caliper reach?

Discuss light weight issues concerning road bikes & parts.
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WeightySteve
Posts: 293
Joined: Wed Jun 09, 2010 10:44 am

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?

Irish
Posts: 787
Joined: Mon Jul 26, 2004 8:57 pm
Location: Ireland

by Irish

How about drilling 2mm from the caliper pad holder holes?

Irish
Posts: 787
Joined: Mon Jul 26, 2004 8:57 pm
Location: Ireland

by Irish

How about drilling 2mm from the caliper pad holder holes?

WeightySteve
Posts: 293
Joined: Wed Jun 09, 2010 10:44 am

by WeightySteve

They only have about 3mm from hole to bottom edge.

WeightySteve
Posts: 293
Joined: Wed Jun 09, 2010 10:44 am

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 :)

WeightySteve
Posts: 293
Joined: Wed Jun 09, 2010 10:44 am

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.

BobSantini
Posts: 292
Joined: Sun Jul 10, 2011 9:03 am

by BobSantini

Drop bolt?
http://sheldonbrown.com/dpdropbolt.html" onclick="window.open(this.href);return false;

No. Forget I mentioned it. :oops:
r o y g b i v

budgetweenie
Posts: 47
Joined: Fri Feb 17, 2012 5:33 pm
Location: Louisiana USA

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.

WeightySteve
Posts: 293
Joined: Wed Jun 09, 2010 10:44 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.

WeightySteve
Posts: 293
Joined: Wed Jun 09, 2010 10:44 am

by WeightySteve

2mm off a 7900 pad would be nearly half of it.

budgetweenie
Posts: 47
Joined: Fri Feb 17, 2012 5:33 pm
Location: Louisiana USA

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.

thisisatest
Shop Owner
Posts: 1980
Joined: Sat Jun 13, 2009 4:02 am
Location: NoVA/DC

by thisisatest

this is what you need but it looks like theyre not around anymore. im still looking.
Image

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