Note: this isn’t a save-the-rim-brake post or attempt to get people to rethink what brakes they use. Just one point in understanding bicycle tech trend history.
I frequently read things like "road bikes moving to disc brakes allowed the trend toward wider tires" - which always strikes me as a major over-attribution.
By locating the braking near the hub, disc brakes allow flexibility on rim diameter that’s not available (or at least way trickier) with rim brakes. Disc brakes also simplify issues faced by rim brakes (whether canti/v or caliper) around very wide tires or significant difference between tire width and rim width.
But while the road-racing market largely used short-reach rim brakes (typically with pad adjustment from 39-49mm below the brake bolt) from ~1980 until shifting to disc brakes, longer-reach rim brakes had been around for decades and worked well, if racing had shifted toward wider tires. Here’s the brakes that would have been used if racing had shifted toward wider tires in the following years:
1980 - the shift toward short-reach brakes (and frames designed around them) simply wouldn’t have finalized, and “standard” reach sidepull brakes would have continued to be used. Racers could have switched to centerpull brakes (which had less arm flex by locating the pivot between the brake bolt and the pad attachment) if they wanted more braking power
In the 1980 Tour, the balding guy has centerpull brakes on his Colnago
mid-reach Dia-Compe centerpull from the 1970s has tons of clearance over a 38mm tire
2000 - mid-reach dual-pivot sidepulls arrived a few years after Shimano first introduced the design in short-reach rim brakes. Shimano introduced the 6500-level BR-R600 (47-57mm reach) dual pivot in the late 90s. And if racing had wanted brake reach earlier, Shimano would have introduced a medium-reach dual pivot earlier.
Tektro mid-reach dual pivot clearing a 38mm tire even on frame with less clearance, with brake pad near top of adjustment slot
2015 - there were a bunch of mid-reach dual-pivot brakes on the market (from Shimano, Tektro, TRP, and Velo Orange), before disc brakes had made any inroads into the road bike market. (Tektro also had been making the long-reach R55X for a decade, originally introduced as a collaboration with Rivendell, although with 55-73mm reach and wider opening designed to clear fenders, its braking power wasn’t as good as the mid-reach designs.) Paul also made a modernized dual-pivot brake, and original-design dual pivots were still available at least from Dia-Compe. A couple overviews from that time:
- Jan 2016 Bicycling Magazine article
- Dec 2016 medium-reach brake clearance overview from Black Mtn Cycles
This was still very much in the rim-brake era of road bikes, even at the high end. This photo from fall 2016 was missing the two fastest guys and their deep-section carbon rims, but they were on rim brakes as well.
There was a slight timing issue in the road market because Shimano’s repeated altering of brake-cable-pull requirements across 10- and 11-speed groups meant that none of the available mid-reach brakes were optimally compatible with 11-speed STI levers. I think SRAM was somewhat similar (though not as significantly different as 11-speed Shimano). Campagnolo had kept their cable-pull more similar across generations, but they were already becoming a lesser player.
Had the shift to wider tires hit a year or two earlier than it did, mid-reach rim brakes would have shortly been tailored to compatibility with current 11-speed brifters. But disc brakes took over road bikes within a product cycle, signaling the demise of mechanical braking as well as rim-braking across most of the road bike market.
