Quote:
Originally Posted by d_douglas
Which raises the question: why don’t builders/manufacturers just build the bridge 5mm higher and then riders could make full use of the slots for the brakepads - I am sure that using 23mm tires doesn’t get you at the top of the slot with no more room to adjust, right? Move it down and where you were once in the middle of the slot, you are now 5mm higher. People with 32mm tires would likely be able to use regular-reach calipers from the big 3 manufacturers - all of whom make amazing brakes.
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The answer about why bike manufacturers aren't making rim brake bikes with more tire (anymore) depends on your perspective. It could either be: Because bike buyers haven't wanted them; or because bike buyers have let them get away with it.
In the last half of the 20th century, people became convinced that narrow high pressure tires were faster. Those who were interested in going fast would use tubular tires, because they could be run at higher pressures, and were often narrower than clinchers; those who were more interested in practicality/economy/comfort used clincher tires, which were typically wider and run at lower pressures. Bikes made for both types of tires used caliper rim brakes, which could easily handle tires up to 35mm or so.
Then around 1980, things started to change. Clincher rims developed hooks, which allowed narrower, higher pressure clincher tires to be used. Also around that time, the MTB was being introduced, and soon after the Hybrid Bike, so those who wanted wider tires could ride these bikes instead of road bikes. Around 1990, bike racing became more popular (both road racing and triathlon), and people started thinking they needed racing bikes for general riding. Road bike geometries started becoming tighter, with less tire clearance. By around the year 2000, HWNWNBM (He Whose Name Will Not Be Mentioned) became a media darling, and now everybody had to ride a bike like his. That meant road racing bike geometries, components, wheels (and tires) for the masses.
With the move to narrower tires and tighter geometries, short reach brakes (which had previously been a niche product for racing bikes) became the norm. Road bike designers no longer had to worry about providing clearance for wider tires because there was little demand for it. Wider tires were relegated to MTBs and hybrids, which used other types of brakes - first cantilevers, then for linear pull brakes, and then disc brakes.
Starting in the 2010s a number of other factors came into play leading to people choosing to ride wider, lower pressure bikes. These factors include the downfall of HWMNB (reducing people's desire to ride bikes like his), the rise in the All Road Bike movement (possibly a backlash against the harsh ride of high pressure narrow tires), and the growth of gravel riding. Also during this time period, consumers became convinced (with the help of the bike companies) that disc brakes were necessary for road riding. And even for road racing, science had shown that wider, lower pressure tires were usually faster, so the pros started riding wider tires. So why didn't rim brake bikes start getting more tire clearance? Because the industry and the bike buying public colluded in form a collective amnesia about the rim brake bikes being ridden just a few decades before, and convinced themselves that tires wider than 28mm could only be used with disc brakes. And so with little demand for rim brake bikes with clearance for wider tires, the mass manufacturers simply didn't make them.