Hi
I need to use my cyclocross bike on the road for a while , ive got crest rims on , how narrow can i go with road tyres, local store has 25c in stock

Have a look here

25s might be pushing it, I’ve used 28 and 32 no problem ona crest, all the nerds are saying 28s have less rolling resistance than 23/25 now anyway so I’d go bigger and have the extra comfort/control

I often run 23s on mavic 729 rims, which are a similar size. No problems. I seem to remember that the problem with Stans mtb rims is less the size and more the pressures you can get away with.

I’ve been using 28s on Stans Podium MMX rims on a recumbent bike. They’re sublimely comfortable, but I’ve had a couple of scary moments, due, I believe, to the low pressures – Stans recommended a maximum pressure of 40psi and an absolute maximum of 50psi. There’s a bit of uncontrolled ‘bounce’, most noticeable when trying to keep a straight line up steep hills (not easy on a recumbent). The scary moments came when cornering, and probably when the tyre pressures had dropped – presumably the tyre rolled slightly or the sidewall deformed, but I seemed to be drifting and about to high-side. The feeling made me sit up in my seat to try and regain control, whilst quickly offering up a silent prayer! I’ve recently stopped using the wheels – I was out on a ride and the rear tyre started to leak, and I couldn’t get it fully sealed at the roadside. When I got home I replaced them with the original wheels, and although they’re not as comfy or fast, I feel a bit happier with them.

I’ve used 28 and 25mm road tyres on Crest 29ers (with tubes) and they’ve been fine.

Stans themselves told me that the psi limits only apply to tubeless setups.

I’ve just emailed Stans to double-check, and they said that it’s definitely not okay to run high pressures with the Podium rim, even with an innertube. They said to always go by the maximum pressure stated for the rim, whether running tubeless or with an innertube. It’s possible the Crest rims are different, but I’d certainly check before using higher pressures.

I’ve sometimes had conflicting advice between Stans USA and the UK, but I’ve received strong warnings on this issue, and have always heeded that advice.

Heard the same, I went for Alpha 340 rims over the Iron Cross rims (which are built for thinner tyres and higher pressures than Crest, presumably) because Stans said the Iron Cross rims weren’t suitable for road tyre pressures.

But, I’ve heard a few stories of people running 28c on Crest and not having problems. But then, if they had had problems, would they be in a position to tell us about them?!?! 😯