Tyre pressure query

[RobF]

As a general point the more air volume in the tyre the less pressure you need.

Volume is a function of width and profile.

Schwalbe's balloon tyres are very big so can run at very low pressure, almost single psi figures.

At the other end of the scale, a roadie might have his skinny tyres at 100psi or more.

The range printed on the tyre sidewall is the best guide.

 

[Paultr]

A bit off topic but how feasible/wise would it be to have two fairly radically different tyres on the bike ?

At the moment I have Panaracer Comet Hardback tyres. These were supplied on the bike and I did not realise just how much they are designed for off-road use. These will have a lot of rolling resistance with no puncture resistance. As mentioned on another thread when I am forced to take off the rear wheel to fix a puncture I will swop the tyres over to Marathon Plus.
So I was thinking I could easily switch the front wheel over now which would reduce my puncture risk by 50%. It may not be good to mix such radically different treaded tyres however .....

 

[Fat Rat]

A bit off topic but how feasible/wise would it be to have two fairly radically different tyres on the bike ?

At the moment I have Panaracer Comet Hardback tyres. These were supplied on the bike and I did not realise just how much they are designed for off-road use. These will have a lot of rolling resistance with no puncture resistance. As mentioned on another thread when I am forced to take off the rear wheel to fix a puncture I will swop the tyres over to Marathon Plus.
So I was thinking I could easily switch the front wheel over now which would reduce my puncture risk by 50%. It may not be good to mix such radically different treaded tyres however .....

It’s not a race car so you would be fine doing that
But why not just change them both and finish the job nicely

 

[Paultr]

To return to my original post I have just looked at the Panaracer web site and in this case the 44psi marked on the tyre wall is the lowest recommended level. The site states their operational window is 44-73psi. I just shudder at the thought of how hard the ride would be at 73 although to be fair these are not road tyres so in mud or gravel etc it might not be too bad. It does make me reluctant to reduce the pressure to say 35psi as previously discussed.

 

[flecc]

A bit off topic but how feasible/wise would it be to have two fairly radically different tyres on the bike ?

No problem to do this, I often have with a free rolling front tyre and a Marathon Plus rear to minimise puncture chances there.

As for pressure, best not to go below the makers minimum to avoid problems.
.

 

[seosamh1977]

give it a go at 35, you'll know immediately if they are too squishy. I reckon you'll be fine at 35. It'll not hurt you or the tyre to try. I reckon, you'll be able to go down to 25 psi tbh.

my xkings max is 65psi, recommended 50 on the manufacturers website(ridiculously hard for an mtb tyre). I run them at 32 back 27 front.

 

[RobF]

give it a go at 35, you'll know immediately if they are too squishy. I reckon you'll be fine at 35. It'll not hurt you or the tyre to try. I reckon, you'll be able to go down to 25 psi tbh.

Certainly true for a push bike.

Given it's a rear hub motor ebike I would be a bit more cautious.

Probably best to stick to plenty of air in the tyres, particularly at the back.

 

[seosamh1977]

why? the motor make no difference to the tyres, not like you are running it at speeds that aren't achievable on a non motorised bike..

 

[RobF]

Hub motor ebike suppliers won't be too keen to tell you about the number of sidewall failures you get with a lightweight tyre and a rear hub motor.

I'm not familiar with the Panaracer, which is why I advised caution.

Nor am I familiar with the weight of the OP, but the bike will be heavy like all ebikes.

As a general point, a tyre will better carry a load when well-inflated.

All of which adds up to not going below the recommended minimum in this case.

 

[seosamh1977]

fair do's. never actually realised it was a hub motor, nor realised hub motors have that issue. Still think 44 is too high though, and I would go lower.

i'm a heavier rider myself, 115kg, so I've got 40kgs on a 75kg rider(so more than a 10kg motor and battery combo would add), and my pressures don't go much higher than they'd use. And I'll quite happily plow myself downhill through to fairly severe rock gardens with no issues.

 

[RobF]

I should point out the sidewall problem is generally gradual.

Lots of hairline cracks appear which ultimately lead to failure.

Regular inspection would spot the problem before it got too bad.

If the OP tries lower pressure in the rear it's most unlikely anything will go bang in the first few miles.

But the life of the tyre could be significantly shortened.

 

[seosamh1977]

interesting point, I don't have any longer term experience of ebikes yet, so dunno, I'll bow to your knowledge on that. Got mine coming soon though, mid drive mind, but lower tyre life expectancy + more grip is a compromise i'd happily make.

 

[anotherkiwi]

I think that a hub motor is much better off with a large volume tyre.

 

[Paultr]

Thanks for all the useful advice

As to weight, I am not so heavy but the bike certainly is ! It started off as an average hybrid bike at 12.28kg but it is significantly heavier now. I wish there was a way to weigh it but I can't think of an easy way to do it. I've got some luggage scales that came free with a cheapo suitcase but they don't give any max weight and I reckon they would snap if I tried to lift the bike with them and anyway I'm not sure how accurate they would be at such a high weight.

 

[VictoryV]

Thanks for all the useful advice

As to weight, I am not so heavy but the bike certainly is ! It started off as an average hybrid bike at 12.28kg but it is significantly heavier now. I wish there was a way to weigh it but I can't think of an easy way to do it. I've got some luggage scales that came free with a cheapo suitcase but they don't give any max weight and I reckon they would snap if I tried to lift the bike with them and anyway I'm not sure how accurate they would be at such a high weight.

If you have bathroom scales then weigh yourself, then weigh yourself picking the bike up. The difference will tell you the weight of the bike. I would take the scales downstairs rather than the bike upstairs