[_Wintermute]

> That "magic carpet" ride does come at a price but it is not monetary: the softer the tyre, the more resistance and with that the slower the ride.

Unless you're riding on a velodrome, pumping your tyres up to 120+psi doesn't decrease rolling resistance, infact the the opposite is true. If the tyre can deform around small bumps it rolls much more easily. This is why very expensive and fast tyres have casings with a high thread count (sometimes even made of silk) so they are more supple.

[Lio]

Fast Fitness produced a little spreadsheet to calculate optimal pressure based on tyre width, bike+rider weight and a very granular assessment of surface.[1]

Something else to take into account is the aerodynamic trade off as tyre width grows. I think I read somewhere that 25mm is roughly the sweet spot. What you gain in lower rolling resistance by going up to 28mm you loose in drag. That's a bit anecdotal (sorry) but I have heard it mentioned in a couple of places. The best source I could come up with was from Zipp's web site.[2]

Of course that might well be worth it to be more comfortable if it means you can keep your body in a more aero position as that will dwarf any loss from the tyres (again a guess).

Hopefully there's some numbers somewhere to back that up. Maybe Bicycle Quarterly or Tour Magazine might be a good bet for anyone interested.

Also https://www.bicyclerollingresistance.com/ is always very interesting ...assuming you obsess over bike tyres as I'm sure everyone does. :P

[1] https://www.youtube.com/watch?v=Clk_LLBYFzA [2] https://zipp.com/support/faq/faq.php

[adrianN]

It makes a big difference if you ride on asphalt or similarly flat surfaces, which many bike commuters do.