I received a couple of questions in regard to the TA front rack mounted to the Weinmann calipers on my 1970 touring Paramount. This rack is designed for Mafac calipers, and some modification is needed to use with 70's Weinmann calipers and their DiaCompe clones, although the TA rack fits early 60's Weinmanns without modification.
These photos show a TA rack with normal installation on an old engraved Weinmann on my 1962 Schwinn Superior.
http://www.wooljersey.com/
http://www.wooljersey.com/
http://www.wooljersey.com/
http://www.wooljersey.com/
http://www.wooljersey.com/
Note that there are three attachment points for the rack. A rear mount plate is sandwiched between the back of the brake rear mounting yoke and the concave washer that butts against the front of the fork crown. The brake mounting bolt runs through a hole in this rack plate thus securing both the rack and the caliper to the fork. The other two attachment points are the legs of the rack that bolt under the brake pivot bolts. The brake pivot bolts are long enough to accomodate the extra thickness of the rack legs, so the original bolts can be used. The horizonal distance from the rack mount plate that secures to the fork to the two legs that attach to the brake pivots is designed to match the overall thickness of the Mafac Racer brake, from the front of the pivots to the back of the brake mount yoke. By happy coincidence, the overall thickness of the old engraved Weinmanns in the early 60's was nearly identical to Mafac, so the TA rack fits those old Weinmanns without modification.
However, the 70's era Weinmanns were are more familiar with and their DiaCompe clones, have a completely different cross section and a significant;y greater overall thickness than the older Weinmanns. Thus modifications are required to fit the TA rack. There may be other approaches, but my method is shown in the following photos:
http://www.wooljersey.com/
http://www.wooljersey.com/
To address the greater thickness, I've shifted the rack forward so that instead of being sandwiched between the fork crown and the brake mounting yoke, the rack's rear mounting bracket is now between the brake mounting yoke and the rear caliper arm, and pressed up against the front of the mounting yoke. This is not as robust an attachment, as the brake mounting bolt no longer inserts through the rack bracket, but the TA is a small rack design for a small or medium front bag, not for front panniers, so the attachment is still stong enough to support the loads for which the rack was designed. In the photo, Ive added a little more support by threading a couple of plastic zip ties through the hole in the rack plate and securing around the brake mounting yoke.
In order to shift the rack forward, one inserts spacers between the brake pivots and the rack legs as shown in the photo. I picked these up at the local hardware store. They are 1/4" ID x 3/8" OD x 1/2" long. I used stainless steel because it look nice, but they come in several materials. On the DiaCompes on my 1974 Schwinn Sports Tourer, these spacers were perfect. On the Weinmanns on the 1970 Paramount the brakes binded just a bit, so I inserted a thin M6 washer between the calipers and the brake mounting yoke, which required filing a couple of mm off the spacers. Don't know if this is a difference between DiaCompe and Weinmann calipers or just manufacturing variation.
With the spacers inserted between the brake pivots and the rack legs, you need longer brake pivot bolts. Happily these bolts are standard M6 (0.8 pitch I believe), easily obtained at the hardware store. You'll need them about 45 mm long.
If you have a bike equipped with Weinmann or DiaCompe CP's and want to add a small to medium front bag, this may be worth a try, or if you have Mafacs it's much simpler. I hate clamping racks to frame tubes or fork blades, and I don't think there are any currently made racks that attach to CP brakes. It would be nice if Nitto made a CP version of their rack for cantilaver brakes, but if they do, I've never seen it. Chris at Velo Orange says in his blog that he is considering making a retro CP brake and a rack to mount to it. That will be great if it happens, and even better if the rack works out to fit 70's Weinmanns and DiaCompes.
Regards,
Jerry Moos
Big Spring, Texas, USA