T-Mar

I believe the pin and slot were added by Weinmann in 1966. Old catalogue diagrams showing the pin and slot specifically mention "model 1966" and the suffices for these arms are 66.

Metacortex

I was unsure of the debut date, thanks for clearing that up!

T-Mar

Speaking of Dia-Compe centre-pull clones, here is a Crossbow brand from my collection. Originally, I thought it might be a private branded Dia-Compe or an alternate Yoshigai brand but I've found references of this brand being manufactured by a company called Tokyo Brake.

T-Mar

While not specifically mentioning any of the standards by number, here is an excerpt from a mid-1960s catalogue that mentions JIS bicycle component standards.

Don Buska

I don't see the pin & slot on that 1966 diagram though. The pin is on the back of the outer arm and the slot is on the front of the inner arm. Neither can be viewed in that diagram. Am I missing something?

Metacortex

I see it clearly behind the sticker in that diagram.

Don Buska

OK I see it now. Wow you have better eyes than me . That picture is so small and by the time I blow it up it's not clear. So I must be doing something wrong when viewing.

Thanks for pointing it out and also for that Weinmann ad describing the pin/slot.

TallRider

I've seen plenty of Weinmann and Dia-Compe centerpulls with different branding on the sticker. Usually "Schwinn Approved." But the back aluminum piece (mounting plate) usually says who produced it. What does the Crossbow brake say back there?

T-Mar

Umm, nobody needs to prompt me when it comes to checking frames and components for markings. I've been doing it, routinely, for decades. If there was something, I would have reported it.

Vintage_Cyclist

Was the plastic coating over those pin prone to falling off? I've seen plenty of Weinmann and Dia Compe C/P brakes with just a bare metal pin. Never one with the covering.

Don Buska

That would seem to be the case. I was able to measure one I took apart that was bare metal (see photo below) and it measures 4.8mm diameter. I have a newer set that are red and it measures 5.1mm or that's the best I could measure it as I didn't want to take it apart and just slid the tips of the digital caliper between the two arms.

So that Weinmann ad which states it's a Delrin sheathed stud appear to agree with what I'm seeing and what you suspect. The pair I have with the Delrin intact are on a 1980 bike with only 100 miles on it. The piece I took apart without the Delrin is from an old Centurion beater bike I picked up this summer as a parts bike. It obviously had a ton of miles on it. So it appears the Delrin doesn't last forever.

TallRider

Fair enough. I don't hang around here much, so I only recognize people who post frequently in the mechanics forum.

Metacortex

Yes: https://www.bikeforums.net/bicycle-me...ll-brakes.html

Don Buska

Not sure it was a silly question at all. It made me think further, especially about the later Gran Compe (GC) version that I have without any pin/slot at all. Perhaps due to that Derin wearing off they realized that the pin/slot wasn't really that important, considering all the play that was there once it was worn. So that got me to thinking. Has any one seen a later DC (red sticker) version without the pin/slot? A set used on a 83-84 bike with low original miles perhaps. That will take us even closer to eliminating a distinction between the DC and GC versions, i.e. the purpose of this thread.

My set of NOS GC 610's should be arriving in a couple of days so I'll have another pair to check the pin/slot situation on. Sadly this item is rarely photographed in ads or on bikes to allow seeing that pin. The natural is to do a front and rear photo, as who cares about a top down view.

Keep the observations and questions coming folks. The overall picture is getting clearer everyday.

Metacortex

I have a low-mile original unrestored 1983 Schwinn Continental (built on Wed. April 20th 1983) that has Dia-Compe 610/750 calipers with Schwinn Approved sticker branding dated 01-83 and 02-82 respectively, both of which have intact Delrin sheathed studs. I believe the guide pin/slot existed on the DC center-pull calipers from 1977 until the present. I can see part of the stud in the 3rd pic in this listing of what seems to be a current production caliper: Genuine Dia-Compe DC750 Centre Pull Caliper Freestyle Silver - Old School BMX | eBay

Don Buska

Wow you have eagle eyes on that eBay ad. Just think how long this original engineering investment has held out for Dia Compe. Talk about a great return on their original engineering investment. Not so sure it was as great for the engineers though

Thanks for the additional insight into the modern (or newer) versions.

Don Buska

Today I received my two NOS Gran Compe versions of the 610 and neither has the pin & slot system. So with the three that I own none of them have it. The two new ones also have that wrench extension on the mounting bolts.

3speedslow

Hey T-Mar, if you have a collection of these clones let me get some pics of a set I have seen in my friends LBS boneyard. Very nice looking copies of the D.C. Brand. Trying to remember the name...Carthage or something like that.
Give me a day or two.

EDIT: got a second look at those clones. They have the name Claridge across the front. But the bolt has CS on it. I take that meant Chang Star. Looked just like a D.C. Brake.

Mike89

Man you guys get all the cool stuff

reroll

~ ~ ~

I have a Japanese-made Puch bike with all-Japanese components, its 27x1-1/4" IRC tires and reddish brake pads are hardly worn and by its frame numbers it was made 83 07. The brakes are both 'red sticker' Dia-Compe cold forged DC610, the rear brake has the pin and groove feature but no Delrin, and the front brake does not have the pin and groove at all.

pfaustus

Didn't Weinman also switch from Red to Black labels in the very late 70s or early 80s? Dia Compe's image at that point in time was very much "copy".

reroll

Toward Dia-Compe brake model identification, let me add some speculation. Suppose Dia-Compe produced different models of their brakes, say, one model having the pin and groove/slot feature and a black or red label on them for their own marketing purposes and another model being the same brake but without the pin and groove/slot to be rebranded with a different label for somebody else's marketing purposes, yet market demand for bicycle brakes would have its ups and downs which Dia-Compe would anticipate and then deliberately produce somewhat fewer of their own pin and groove/slot models, and then when market demand was down for the pinless and grooveless/slotless models those models would be used as substitutes to supplement Dia-Compe's own market needs. For instance, maybe that could explain why I have a 1983 bike in fine condition which has a rear brake WITH the pin and groove/slot AND a front brake WITHOUT the pin and groove/slot while BOTH brakes have a red Dia-Compe cold forged label on them.

tjfastback66

Yes they came on my '81 Univega Specialissima. Now I need to find the correct brake levers...

dddd

The Centerpulls on my Pro Tour with it's brazed studs are polished/ano'd and have the "G" designation forged into the front arm, this from 1977 or so.

Best-working caliper brakes I've used, and even with their 44-y-o brake pads!!! Power is outstanding and there's no noises and very low system flex.

DiaCompe C-P calipers use 3-coil springs for less hand resistance as the lever comes in (Weinmann versions have stiffer 2-coil springs made from the same wire thickness).

As-found (and I still haven't changed out the pads after two solid years of use since rescuing this from the bike shop dumpster):


Post-resusitation:

bertinjim 

tjfastback66-

Try SJS Cycles in the UK: https://www.sjscycles.co.uk/brake-le...evers/?geoc=CA