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Old 05-01-21, 11:16 AM
Ride, Wrench, Swap, Race
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Bikes: Cheltenham-Pederson racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.

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OP mentioned comfort as a priority, so a bigger tire can be run safely at a much lower pressure to give a softer ride.

But the pressure aspect is more important here than one might imagine, since a bigger tire actually presents a harder surface to the road unless the pressure is reduced. That's right, as the tire width increases, the tension in the casing fibers increases, making it less resilient. So the pressure first needs to be dropped proportional to the size increase just to equal the resilience of the smaller tire, with the pressure then dropped yet further to make the bigger tire more resilient than the smaller one!

Because of the bigger tire's larger width AND larger height, the pressure can fortunately be dropped quite a bit without losing any pinch-flat protection compared to the smaller tire, making wider tires better for dealing with rougher surfaces.

The choice of increasing the front or rear tire size comes down to which end of the bike is giving the particular rider discomfort.

A further advantage of using bigger tires at much lower pressure is that the tread lasts longer, not to mention improved traction when traversing perhaps-hidden bits of gravel.
There will definitely be some increase in smooth-road rolling resistance, but which tends to pay back in both efficiency and comfort as the road surface becomes rougher.
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