What size tyres

[proletaratOne]

I have a bike that has 18 mm internal rim width and 25 mm outside

What size tires fit in there best to give a nice aero mate with the outside of the rim

I want to run tubeless

 

[Cycleops]

The current trend is for wider tyres run at lower pressure for a more aero profile. This would seem to be at odds with thinking that says narrower tyres run at high pressure are better. 28c tyres are the popular choice.
I'm not really qualified to give to the pros and cons but I'm sure someone will be along to give you the run down. In the meantime have a read of this: https://www.cyclingnews.com/features/why-wider-is-better-the-death-of-23c-tyres/
28c should be fine on those rims. The other thing to consider is does your frame have the clearance? Are the rims tubeless ready?

 

[Ming the Merciless]

For aero you want as close to an aero foil shape as possible. So the rim should be the widest part, that means 25mm or 23mm for the tyre.

 

[DCBassman]

Hello!
Are the rims ready for tubeless? Can't just choose it, the rims have to be correct.
Aero: why? Not a rude question. Are you racing? If not, 28s will be fine and comfortable, or 25s if you must. 23s if you have no loose fillings...
My 'fast' bike (meaning that it's actually a real road bike, I'm not capable of riding it fast) is limited to 25s. The other bike, a steel mixte (just as fast, or slow, with me on it!) has the same wheels, but can take 28s.
28s all the way for me, but I'm no speed merchant.

 

[raleighnut]

For aero you want as close to an aero foil shape as possible. So the rim should be the widest part, that means 25mm or 23mm for the tyre.

Yep got 25mm on my Roval Classique Pave wheels (25mm outside rim width) for that very reason

 

[Cycleops]

Don't know why but I never had you down as a very 'aero' sort of person @raleighnut

 

[raleighnut]

Don't know why but I never had you down as a very 'aero' sort of person @raleighnut

I was when I built that up about 12 years ago as a fast road bike (it's a handbuilt 653 time trial frame) that rear cassette is a 10 speed 'semi corncob' 12-23 (1 tooth difference apart from the last 2 which are 2 teeth apart for climbing) so bottom is 39-23 and top 53-12

 

[proletaratOne]

Hello!
Are the rims ready for tubeless? Can't just choose it, the rims have to be correct.
Aero: why? Not a rude question. Are you racing? If not, 28s will be fine and comfortable, or 25s if you must. 23s if you have no loose fillings...
My 'fast' bike (meaning that it's actually a real road bike, I'm not capable of riding it fast) is limited to 25s. The other bike, a steel mixte (just as fast, or slow, with me on it!) has the same wheels, but can take 28s.
28s all the way for me, but I'm no speed merchant.

Yes I will be racing....that’s the plan... so trying to build a faster bike

 

[proletaratOne]

Thanks fellas for the answers and advice. I’ll be going with 25s

 

[Milzy]

Thanks fellas for the answers and advice. I’ll be going with 25s

If you put 24’s on that rim they would probably measure 25 & you’d save money.

 

[Ajax Bay]

I have a bike that has 18 mm internal rim width and 25 mm outside.
What size tires fit in there best to give a nice aero mate with the outside of the rim?

Thanks fellas for the answers and advice. I’ll be going with 25s

What (tubeless) tyres did you go for, and what width do they come to at what pressure, on these rims?