[pmkdlk]

I put a set of continental GP urban 35mm tyres on my gravel bike for some comfortable road riding. All the tyre pressure calculators I’ve used suggested 45 – 50 psi as optimal for this tyre size based on total weight of 75kg , but the tyres themselves say min 65 psi. Any idea why the manufacturer min would be so high relative to the calculators?

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[pmkdlk]

Cool I will try that, was on
Cool I will try that, was on massive cobbles yesterday and wanted to stop the shaking. I even have front suspension (bike is a nukeproofdigger rs) and a suspension dropper. But softer tyres is the main thing for cobbles I find. I’m doing a tour of castles near where I live in Germany so miles of road generally with a cobbled climb to finish

[Simon E]

Being a titchy lightweight I

Being a titchy lightweight I find the minimum pressures shown on bike tyres are considerably higher than I would use.

It sounds like you’ve established a sensible starting point at 50 psi. You could try dropping 5 psi in the front and see if you like it (most people run less in the front than the back). If that feels OK then try 5 psi less 40 F /45 R) in both and give that a go.

How it actually feels on the road depends on the tyre structure, notably the sidewalls, but if it gets a bit too squishy or you think you might get a punch puncture on a pothole or kerb then put it back up. There are no hard and fast rules.

[pmkdlk]

Thanks good to hear I’m not
Thanks good to hear I’m not missing something. I’ll stick with the 50 psi , no issues so far. There are a stack of cobbles where I live so not looking to go near 65 !

[Geoff Ingram]

Completely agree. At 80kg or

Completely agree. At 80kg or so all up 45psi is good for my gravel bike with 39mm tyres. And after a fair while, when it drops to 35 I put it up to 45 again. 65psi is for my bike with 28mm tyres.

[Backladder]

That is a massive pressure

That is a massive pressure for those conditions, I run 65 psi for 32mm tyres with 110kg all up weight and don’t have a problem with pinch flats even on our rough roads. I would use the chart pressures which seem reasonable to me and ignore the manufacturer as they are probably assuming heavier all up weight and lack of maintenance.  

[Hirsute]

Says it can go up to 85 psi.

Says it can go up to 85 psi. All I can think of is something about the tyre wall that needs a higher pressure but it is out of step with the charts as you say.

[Author]

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