sovende

Don’t know for sure if this thread belongs here in C & V or Bike Mechanics but I’ll start here. One of my Winter projects is an 1980 Schwinn LeTour 10 speed. I have a separate thread for it but this question may be more general in nature. The bike had languished in a state of partial disassembly for many years. I was pretty sure that I had all of the OEM components but they were in different parts boxes in my shop. I had what I assumed to be the OEM “Schwinn Approved” (Weinmann vs DiaCompe?) center pull brake set. Part of the refurb project included complete disassembly of each brake caliper for an intense “fluff & buff” as there was some surface corrosion on the ferrous parts and the aluminum had dulled quite a bit.
Anyway, finally completed both calipers and installed them on the bike. I had kept all of the parts for each caliper in separate trays during the clean up process so each was reassembled as they came from the factory. I don’t know why I hadn’t noticed it before but once they were mounted on the bike and I was admiring how nice they looked , it became obvious that the “reach” on the front caliper was considerably longer than that of the rear caliper . Is this possibly correct? I’m pretty sure that they are the OEM calipers. The brake pads are all the same brand, style and color. I have other center pull caliper sets in my brake parts box. One set, DiaCompe branded with matching pads is the same way, one caliper long reach the other short. Another set, “Schwinn Approved” has equal reach for each caliper.
So I guess my question is, “is it possible for a bike to be “spec’d” with front and rear calipers that differ in their “reach”? I do suppose that frame size and style i.e. touring vs racing, could make a difference. Also, placement of the brake attachment strut between the seat stays could require a shorter reach. I would just like to know if it’s normal . Any thoughts, opinions or even actual facts?

BFisher

Yep. I've had several '70s road bikes that came with a Weinmann 610/750 combo. I think the longer reach is usually the rear.

merziac

Especially Schwinns, sometimes.

Choke 

It's not unusual at all. For example, the Universal 61 brakes on my Frejus have a front reach of 49-60mm and a rear reach of 56-72mm.

https://velobase.com/ViewComponent.a...70e67&Enum=117

top506

Yes to both.

Top

Road Fan

I can't say about whether the front or rear allows more clearance. But if you have a set of wheels, pop them on the frame and measure the distance from the brake track to the brake caliper hole, or just bolt on the calipers both ways and see what works.

BFisher

There was another thread not too long ago that touched on this same thing. Can't remember what it was.

My Raleigh Super Course came with a 750 rear/610 front. I had to go to a 750 up front when I went to 700c wheels.

ollo_ollo

+1 on BFisher Exactly my experience on several 700c conversions. Don

sovende

Well, it is good to know that brakesets with unequal reaches was not uncommon . My mind is now somewhat at ease. A few replies suggested that the longer reach was usually on the rear caliper. My set on the ‘80 LeTour appears to be the opposite but it is POSSIBLE that somewhere along the process, the mounting bolt arrangements were swapped. The DiaCompe set I mentioned in my OP (assuming the mounting bolts are with the correct caliper) would have the longer reach caliper on the rear. Placing wheels on the frame to see which configuration is best does seem to be the most reasonable solution and is what I will do!

I do have a related question. Is there a significant difference in the mechanical advantage of long reach vs short reach calipers that would necessitate the use of straddle cables of different lengths? On the aforementioned DiaCompe brakeset, the long reach caliper has a much longer straddle cable. However, on the Schwinn Approved / Weinmann set on the LeTour, the straddle cables are of equal length. While I’m definitely not a mechanical engineer, I do suspect that, theoretically, different lengths of these components make a difference but is there any real significance? I do suppose that this question might belong as a separate thread in the Bike Mechanic section of the forum .

bikingshearer 

Agree with all of the above, especially Choke's comment about the difference in reach in Universal 61 brakes, which went along with some influential Italian frame builders BITD insisting on building their frames to fit comparatively short reach front brakes and comparatively long reach rear brakes. But I have never seen a frame, Italian or otherwise, built to take longer reach brakes in the front and shorter reach brakes in the back. That certainly does not prove that it never happened, but it it is strong evidence that it was not the norm.

Mr. Spadoni 

I have one of those abnormal bikes. My 1972 Fuji came to me without brakes. As it was built for 27” wheels, and I wanted to run 700 c to mimimize the number of tires/wheels I knew I’d need some long reach brakes so I built it up with Tektro 559s . As it turned out, the rear pads are at the shortest possible adjustment. The front pads are 12 mm lower. Same rims on front and rear. One of these days, I’m gonna have put a shorter brake on the rear. Every time I look at the bike, the pad level difference looks like there’s something out of adjustment

JohnDThompson 

Yes, that was pretty common BITD. The rationale went something like this: the longer reach caliper has less mechanical advantage, so putting it on the back reduced the likelihood of locking up the wheel with hard braking.

John E

Every road frame I own (see signature) has this feature of a higher brake bridge/fork crown in back than in front. For the reason you stated, I think the short front / long rear caliper configuration makes a lot of sense. If you grab both brake levers with equal force and closing speed, the rear will come on slightly before the front, but the front will exert more stopping force. I am not sure how much difference this really makes, since (correct me if I am wrong) bikes with cantilever brakes take equal-leverage arms front and rear. (Of course, in that case and with MAFAC centerpull calipers, one can change the leverage by altering the length of the straddle cable.) I have never evaluated the difference in leverage between my mountain bike's rear U-brake and front RollerCam, but I am delighted with both, and the 4-finger motorcycle-style Shimano brake levers.

T-Mar

If you look at boom era bicycles you'll see that this feature is found predominantly on lower level models. As you moved up in price it started to wane. By the time you reached pro level level bicycles, equal reach calipers were dominant. This supports the rear lockup argument. Entry level cyclists were more apt to grab both levers with equal force and consequently lock the rear wheel. Owners of pro level bicycles were typically avid cyclists with lots of experience and the ability and knowledge to modulate each caliper individually. Equal reach brake calipers slowly started to appear at progressively lower levels of sport bicycles over time, as the American consumer became more educated on the proper operation of caliper brakes.

sovende

Well, the jury is back I the courtroom and the verdict seems to be, short in front and long in the rear! Fortunately, it’s an easy fix that shouldn’t take more than a few minutes (but I can easily stretch it out to 30). Just when I think I know a lot about bikes, I realize just how much I don’t . Thanks to all for the enlightenment .