achoo

I'd like to replace the old front caliper on my 23-year-old Peugeot with a new dual-pivot that I have lying around (Cane Creek SCR-5). The old caliper is more than a bit beat up, and looks somewhat bent. Given its age and usage I'd really like to replace it, since I think it needs it. And since I already have the SCR-5, I'd really like to use that.

The old caliper uses a long bolt that goes all the way through the fork, with a normal nut to hold it on. The new Cane Creek uses a shorter bolt and the now-standard blind nut. While the fork is in good shape, it's not designed for a blind nut to hold the brake caliper on, and I'm not equipped to properly machine it to do so, even if there's enough material around the brake hole in the fork to support doing that (which I doubt).

In theory I could just drill out the rearward hole on the fork just enough to pass the body of the blind nut but not the little shelf that holds it in place, but that would put all the pressure on just two points of the fork, as the fork doesn't have a flat spot there. And I don't trust my ability to drill to tight enough tolerances on an odd-shaped piece like a fork anyway given how thin the shelf on a blind nut is, even with a drill press.

And I can't seem to find a longer pivot bolt for the SCR-5.

Ideas?

rydaddy

Drill the back of the fork crown.

https://sheldonbrown.com/gloss_ra-e.html#recessed

nextreme

Hi, I'm looking at doing the same operation, specifically with Tiagra BR-4500 model brakes.
According to here it states the brakes have a 49mm reach. Does that mean the pivot bolt extends beyond the brake calipers by 49mm? Meaning there is 49mm of bolt to cross through the fork or frame ? In that case, would it be long enough to fit a regular old 12 speed from the 80's (Fuji DelRey) ?

Many thanks for your help
Steven

desconhecido 

The 49mm does not refer to the length of the fixing bolt -- it refers to the distance of the braking surface of the rim. I'm not sure exactly where this is measured from, my guess is that the 49mm is the distance from the center of the fixing bolt to the center of the brake pads. 49mm is a short reach caliper. This may not be long enough for the pads to reach the rim braking surface on an old bike.

added:

There is a good possibility that the brake that you want to use will not have caliper arms long enough to reach the brake surface on the Peugeot's rim. I understand the desire to use a part that you already have on hand, but even if the pads will reach the rim, it's going to require some effort and messing around to get it to work. If that's what floats your boat, then go for it. I understand that too. But, something to consider is that you can buy new Tektro standard/long reach dual pivot brakes with nutted mounting for about $60 a pair. Maybe that's a significant portion of what the bike is worth and it's an excessive expense. But, it's not really much more than a good set of tires/tubes/rim tape so you could just look at it as a maintenance issue -- sort of like white bar tape.

nextreme

Thanks for the info desconhecido

cheers

Kimmo

Just make sure you use the right-sized bit to drill out the rear hole and you'll be fine.

If you're really worried about the minimal contact area you can improve the situation by using a couple of those curved ally spacers from the nutted brakes... but this is unnecessary IMO, since it's only really adding unneeded lateral strength. Maybe just use one on the back...

And if your pads don't quite reach the rim you can just cut a chamfer off the top of them so they don't foul your tyre.

velo-orange

Tektro makes standard nutted calipers for older bikes. R538 mid reach (47-57mm) and R556 (55-73mm) long reach. Harris cyclery carries them, SJS cycles stocks them, Velo Orange stocks them.

It avoids the need to drill out your frame and fork to accept a recessed nut. If you have a cane creek brake in hand, then this is probably too much information.

HillRider

The drill size to open up the rear of the fork crown is 5/16" or 8 mm and almost any steel crown fork is plenty strong enough to have this done.

I'd be more concerned as to whether the Cane Creak has enough "reach" to allow the brake pads to align with your rims.

joejack951

One more thing to think about is the clearance for installing the wheel and tire. Dual pivot calipers need to be set quite close to the rim and barely open up when using the quick release. If you're using a tire significantly wider than your rim, you'll have to deflate the tire every time you want to remove or install the wheel. For reference, I've had pad clearance problems using 25mm tires (Specialized Armadillos which do run large) on a standard width road rim.

desconhecido 

I have one bike with Campagnolo Chorus dual pivot brakes from 1997. The QR is in the lever not the brake and I can squeeze a Panaracer 28mm tire through without deflating. That's with the brakes adjusted very close to the 17mm, well-trued rim. I think the brakes with QR mounted on the brakes probably allow a little more room. So, tire clearance is something to consider, but it might be ok.

Haven't messed with old side-pulls for quite some time and just recently worked on a mid 80s Bianchi that we haven't had on the road for about 10-12 years. Dual pivot brakes are, in my opinion, so much better than those old Campagnolo side-pulls that a little inconvenience when removing/installing a wheel is well worth it. But. life is a series of tradeoffs.

achoo

The brake pads reach the rim fine. I've test-fit the new caliper already.

Hadn't thought of that. And since I've got a 28 on the front, that might be an issue. But I don't pull the wheel off this bike all that often. Hopefully if I ever flat the front I'll remember that before I put my last CO2 cartridge into the tire. I probably should just get a pump, since this bike is a commuter and it's already too heavy.

Thanks everyone for all the help.

I'm still a bit nervous about it, but I'll probably drill out the hole this evening after I get home from work. Assuming I have a 5/16" bit somewhere. I should have one in my set of bits, but I don't recall ever using it.

joejack951

In my experience (low end tektros, Ultegra 6600, and a few misc. others), the brake mounted QR's don't do much. They'll let you get a 23mm tire through without touching the pads but anything bigger can be annoying to miserable.

HillRider

The ideal set-up is Shimano (or Tektro) brake calipers with Campy brake levers or brifters. You get a qr in both the calipers and in the brake levers. Open both and you can probably get an MTB tire in there.

joejack951

A few times I just loosened the cable pinch bolt rather than deal with deflating tires just to remove them from my bike (when a floor pump wasn't handy). I would agree with your description of the ideal setup. One more reason for my next bike (or bike upgrade) to be Campy.

Kimmo

Ergos rock.

The only bummer about those lever QRs is how many pics of sweet machines are ruined by leaving them open.

achoo

I haven't drilled the fork yet. I forgot yesterday was tax day. Hopefully I'll get to it this weekend.