tyre pressure advice

[stevieb]

hi
i have marathon tyres [ standard not plus] on my rigid framed mountain bike .
they have proven excellent on normal roads and i,ve clocked up a high mileage
the max recommended inflated pressure of 100 psi is too high now that i have started using canal towpaths and slightly rougher cycle paths
if i put them down to 20 psi the ride is great but the rolling resistance is more, and the possibility of pinch punctures is increased.
so the obvious answer is to gradualy decrease the pressure to get the ideal compromise.
this is what i,m about to embark on but to speed up the proccess can anyone tell me their own findings with a similar problem?
i have used this bike/tyre combination before fitting my kit and it was ok but the added weight of the kit makes it heavier and harsher on rougher ground
thanks

 

[eHomer]

The best compromise between maximum and minimum pressure is going to depend on a number of factors:

• weight of rider and gear (as you mentioned)
• width of tyre
• make and model of tyre
• surface (as you mentioned)
• bike's suspension (if any)

Also, the ideal compromise pressure will be quite a bit less for the front than the back. If the ideal for the back is say, 60psi, then the front might be around 40 psi, because there's less weight over it on most bikes.

Tyres usually have a recommended range of psi moulded on the side, rather than just a max. If you go too low, it could blow off the rim , (as happened to me once !)

 

[Emo Rider]

I usually run 10% over max and have done since my triathelon days. Now I ride an ebike and a Marin 29er and my competition days are behind me. I still put up with the stiffer ride knowing that it decreases rolling resistance and lessens the risk of puncture due to less surface contact of the tyre to the road. If I was going for comfort, 10% less than max would be my preferance. Any less and you would feel like you were cycling on a muddy field and your risk of puncture would greatly increase.

 

[EddiePJ]

I certainly wouldn't put them down to 20psi. As well pinch flats, you also run the risk of damaging the carcass of the tyre.

I run my Marathon plus tyres on the hybrid at about 65psi, and the superb Panaracer xc fire pro tyres that are fitted to the BH at 40psi. The BH now hardly ever gets near any tarmac, and from speaking to countless riders that run these tyres, 40psi is the number that everyone appears to run them at.

When I fitted the Shwalbe CX Pro cyclocross tyres to the Hybrid for last weeks event, I ran them at 60psi but still managed to totally destroy three inner tubes, after hitting flint that was sticking up from the compacted chalk trails. One pinch flat is bad enough, but a further two at the same instance is bloody annoying.

 

[stevieb]

thanks folks
gives me a great starting point
front tyre preesure less than rear is something i used to do when seriously into mountainbikes but had forgotten that little trick so thanks for reminding me.
starting point now 10% less
ta

 

[Emo Rider]

A point worth mentioning: I went from standard 26×2.10 MTB tyres to 26×1.50 Schwalbe City Jets on a mountain bike I use to have. At recommended inflation of 85psi I found them to be slippery on wet roads when cornering. If going for higher pressures this shold be a consideration.

 

[awol]

Also, the ideal compromise pressure will be quite a bit less for the front than the back. If the ideal for the back is say, 60psi, then the front might be around 40 psi, because there's less weight over it on most bikes.

I never knew that,thanks. Think I will go and adjust my back pressure to just below max and front pressure to just above min to see how it goes.