Training tyre size


My gravel bike has 700x50 tyres. I want to add a training wheel/tyre. Can I just stick a 700x28 wheel/tyre just for use on the turbo trainer?

Any issues with this?

If you just change the tyre: the width of your wheel’s rim is what you need to look at. if you are running a 50 on it I doubt it would fit a 28. But I’m not an expert.

But if you have another wheel that fits a 28 and fits your cassette then that would work but either you’d have to change your cassette over (need tools) or you’d be using your chain on different cassettes (not good for chain and cassette wear).

Yes that’s what I assumed, thanks

Normally Gravelbike and modern road bikes have rims with around 18-21mm internal width.
50mm wide tyres works okay with that and 28mm tyres would fit perfectly, even 23mm.

In the early times we put 52mm mountain bike tyres on 17mm rims. :shushing_face:


Executive summary: Just do it.

According to the standard (can’t remember exactly which but see the tire and rim width table on eg ), 28 mm tires should be used on rims with an internal width between 15 and 19 mm. That recommendation is quite conservative (I have used tires up to 42 mm on rims with an internal width of 15 mm for years without problems), and even if your rim happens to be wider than that, any of the potential safety considerations when using too narrow tires don’t apply to indoor use.

Edit: The standard is ISO 5775

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