Saturday, June 14, 2008


I get to try and test a variety of things bike-wise as part of being a builder. After all, its important to understand what works, and what doesn't. Lately my focus has been on brakes. Looking at alternatives that work in various situations. One challenge, in particular, is fitting brakes over fenders and wide tires - especially if the rims are on the narrow side.

I set up a prototype bike with a fork sized to use the longer armed Tektro double pivot brakes, and the brake bridge is set to test the Paul center pull brakes. For testing, the wheels are Mavic MA3 on Record hubs - something purchased used (cheaply) on eBay a couple of years ago. The tires are a pair of 700C x 28 Hutchinson Top Speed - which no longer appear to be in their catalog (nor is there anything else like it). Which is a pity.

This has been a favorite tire of mine lately. It's not an expensive or fancy tire. Some folks look at it and don't believe it's a 28 - but that's just the cross-section (egg like) at the top of the rim throwing them off. In reality, it's an easy rolling tire despite having low thread count and an anti-puncture layer. Typically, I run them at about 90 psi - which seems to sag about right under my weight. As we've discussed before, a compliant tire reduces rolling resistance on the road (as opposed to a test drum). So I've used these tires many times in roll offs to try and convince the reluctant of the benefits of soft and fat (tires, not bellies).

The Top Speed corners very nicely, as wider tires are wont to do. Hands and butt feel much better after hours on these tires than they do when riding on 23s. Very comfy is my official rating. And these two factors are often forgotten when folks evaluate tires. If you're riding for long periods, faith in road holding and physical comfort make a big difference, and probably allow you to gain more speed than a new set of expensive aero wheels.

My test setup is Campy based, which means that there are two (2) quick releases for each brake. One is in the brifter, and one at the brake. Theoretically, one can open the brakes wider for wheel removal. The theoretical part relates to how wide the brakes open when they have no cable tension on them. The Paul appears to do a bit better than the Tektro in this regard, but both open plenty wide for a set of 700C x 28s. They should handle 700c x 32s as well, and it looks like the Paul's will also clear 35s or even 38s.

Both brakes are positioned so that the brake shoes are at the bottom of their slots. This isn't the ideal location, but it's what demonstrates the greatest tire/fender clearance. The Paul's, again, offer more clearance. Having said that, my preference is to use cantilever brakes with fenders.

With fenders, its ideal to set the hight of the fork crown or brake bridge based on where you want the fender to sit relative to the wheel/tire. When using crown or bridge mounted brakes, the position of the crown/bridge is dependent on the needs of brake in order to get a good interface between the rim and the brake pads. Sure, there's a slot where the brake pad can be raised or lowered on the brake arm. But this still offers only limited range with which to work - and ideally (if only for aesthetics) we'd like to have the brake pad centered in its slot.

The net of this is that two different factors want to determine the distance from the axle to the crown/bridge - and sometimes these factors disagree as to the proper position.
Back in the old days, there were many more lengths of brake arms available - making this particular fitting issue less difficult. Because we don't have those choices today, a cantilever (or other frame mounted brake) makes life easier. It is fitted to assure good rim/pad fit, while leaving the crown/bridge to be set at a distance that works well for the tire/fender combo chosen. And, that's why I feel partial to cantilevers for fenders.

It should be noted that the Paul center pull brakes are available for mounting on pivots brazed to seat stays/fork legs - making this another good combo.

But, what about the brakes I tested? Are they any good? A couple of points that should be noted. First, both act very rigid, avoiding brake squeal. This is impressive given the length of these brakes from the pivot to the brake pad (again this was maximized on the test bike). They also feel very firm under hand, and grab harder the stronger one squeezes them. This is an area where many modern brakes are superior to many of the older brakes. Too many older brakes seemed to flex more as more pressure was applied. Not these two.

Neither was the hardest grabbing brake that I've ever tried, but both did fine for me, and under these extreme circumstances (note that bike and rider all up are approaching 240 lbs, while the wide tires provide great braking traction). Having said that, brake grab can be tuned with various brake pads, and different riders like firmer or sticker pads. Stock, these worked fine for me, but some riders will want softer pads.

Taken as a whole, its clear I prefer other solutions for mounting fenders. But, having said that, either of these is a great brake - and I'd be happy to have a pair of either one under me out on the road.

Often, the press pans Tektro (or private label versions thereof). But I think that this is marketing bias. They are nicely finished, smooth operating, easy to fit and adjust, and have the fundamental key attribute of good brakes - they're stiff. And, again, we're talking about the long arm version. The more common short arm version can only be better for stiffness. Yes, lighter brakes are available, but this isn't a critical component for weight reduction. And typically, Tektros are so nicely priced that I have to encourage folks to give them fair consideration if the need arises to replace their brakes.

That's it for now. See ya soon