Mark Petry wrote:
> Also, on the topic of brake boosters, the Mafac Competition brakes looked
> real sexy with the aluminum brake boosters that were fabricated by Cupertino
> bike shop, and the booster resulted in a very solid brake feel with
> dramatically reduced mechanical hysteresis. Jan Heine has my last pair of
> these brake boosters, I don't know if he's used them yet however. A bike
> with brazed on brake pivots (see Jan's article in a past Riv Reader on this
> topic) will have even better brake feel because of the very solid connection
> of the brake arms to the frame, and better distribution of loads thru the
> fillets rather than via a brake center bolt which is just a skinny steel
> shaft.
>
>
> I've never tried a bike with Campy brake spindles brazed on... I know Cuevas
> and maybe others offered bikes configured like this... my thought was that
> the long Campy spindle if brazed on would be vulnerable to damage and would
> be expensive to repair (rebraze the fork crown?). But the brazed on
> spindles for mafacs are a sweet combination.
>
> Would like to hear what Bill Bryant remembers on this topic !!
Hi Mark-- Well, since you asked... Spence Wolf was very proud of his "hot rod" Mafac brakes, as he called them. He took a lot of time to instruct us on how to do things just right, and what pitfalls to avoid in the set-up procedure. And yes, as you say, they were sweet brakes: Excellent stopping force in exchange for little hand strength, nice modulation of speed, pretty light spring action on the longest mountain passes that could be more tiring when using the stiff-spring Campy sidepulls... Yes, they were very nice. When you got a pair of Competitions (not the Criteriums as I incorrectly wrote previously--sorry, brain fade) set up, they were indeed as fine a brake as you could want, IMHO. The brazed-on version of the Competitions were probably the best center-pull of all, but of course re-brazing the frame wrecked the frame's paint, so the Booster plates were a good compromise.
On the other hand, if putting the plates on was easy, the rest of the procedure took quite a lot of time to set up properly. In comparison, the Campy sidepulls offered similarly excellent performance, very quick installation time, and less maintenance chores over thousands of miles of hard usage. The finned Mathauser pads were a key component to the system, but they weren't trouble free the way Campy brakes were. Still, more than a few Singers and Saturns went out the shop door with these nice brakes and the owners never seemed to want to change to Campy sidepulls later on.
If the Mathauser pads were a little finicky, the Brake Boosters were great! I'm surprised they didn't catch on more. You just bolted them on and got a big improvement in braking performance. When the firm who made them went under, Spence had a small run made by a local machine shop, and when those ran out, that's when we started doing the hand-made units I wrote about recently. We couldn't justify paying for a minimum run in the face of ever-increasing Campy brake sales, but we also couldn't not use them since we knew what an improvement they made to the humble Mafacs. If memory serves, the Brake Booster version for Universals required a special relief to provide proper clearance, and was trickier to produce. So, when those were gone we just focused on the Mafac booster plates since they were a simple piece of flat stock. Easy to make, no stamping required.
I have one pair of plates the Spence-produced run left, will try to get some sort of a j-peg photo available over the weekend since several of our CR members have sent notes wanting to see what they looked like. Also, I could be wrong, but I seem to recall some sort of framed photo of one of our "hot rod" Competitions with the booster plates still on display at the current Cupertino Bike Shop during my last visit there. If this sort of stuff is of interest, Bay Area CR members might want to visit the shop and say hi to the owner, Vance Sprock. He'll treat you right--and if he does some deep digging through the old stuff in the "morgue", you never know what he might uncover! ;-)
Bill Bryant Santa Cruz, CA
Ps--I rode a Cuevas for a time with the brazed on brake center bolt; couldn't tell any difference in braking performance from a normal set-up. As you say, damage in a crash could be really expensive to repair since it would mean a repaint of the fork after re-brazing the the replacement. Just a weight-saving gimmick, IMHO.