I decided to get a second set of (summer) wheels for my commuter/allrounder.
The idea was to run high end 28mm tubeless tyres on extra wide rims to maximise the volume and allow running sensiblly low pressure.
A lengthy search revealed that the widest road clinchers go only up to 21-22mm (inner width) unless you splash out on something like Enve 4.5… or Bontrager ATR. Wide enough for 25mm tyres but 28mm requires ideally something wider…
I then mounted my 28mm Schwalbe Pro Ones on Mavic XA MTB wheels as an experiment. The moment the first tyre was seated and streteched to 32mm at 70PSI on a 25mm (internal width) rim, I knew I was onto something.
At just under 80kg and some light commuting gear, after experimenting for a while, I settled on 60PSI and 40PSI front. I know what you’re thinking right now… It’s too low, it must be slow and sluggish and the rims will be destroyed after hitting the first pothole… In reality nothing could be further from the truth. From speed to comfort and cornering the setup is perfect
As for concerns regarding low max pressure warnings on mtb rims, we can safely assume that they refer only to wide mtb tyres. At the same time though one should look at the actual, not nominal tyre width when working out the optimal pressure or seating tyres. E.g. my 28mm Pro Ones are effectively 32mm tyres and 70-80PSI would be absolute maximum I’d ever go to with them.
So the take home message from this post? If you have a disc brake bike with generous clearance and want to maximise the volume of your fast +28mm road tyres, get wider MTB wheels instead. They really do make a better match than typical 17-21mm road rims. With disc brakes becoming standard on almost all bikes and increasing popularity of gravel/adventure bikes the boundaries between various types of cycling equipment are blurring anyway. Mtb or road are just labels.
Without any intention of sparking another tyre width debate I’ve firmly believed for quite a long time that 30-35mm wide tyres are an optimum width for the vast majority of non-competing road riders, particularly on UK roads. Emulating pros with their 25mm tyres by slower, heavier and less aero amateurs makes no sense no matter how we look at it.