25-02-2025, 09:33 PM
On a recent outing I thought my late Ruby was down on power - it was reluctant to go over 40, but seemed to be pulling okay up to 30 in 3rd.
So I suspected it might something other than the engine. On checking, the brakes were free, but I found a front tyre down at 14 psi from 25 - the result of a slow puncture. At that pressure, the tyre didn't look very different. I was surprised how much this lower pressure affected the rolling resistance - even just pushing the car around was harder.
Having fitted a spare - another Longstone, I ran the car out again and it pulled away happily at over forty now all the tyres were at the right pressure. But the difference made me think about the effect of rolling resistance.
I have a couple of spare wheels with the heavier 4.50 x 17 Avon tyres on them, so I replaced the two Longstones on the rear. The car then went a bit better than before. But whether this was from reduced rolling resistance or better gearing from the larger tyre circumference on the rear, I am not sure.
Has anyone else considered the effects of rolling resistance for different tyre types and pressures?
So I suspected it might something other than the engine. On checking, the brakes were free, but I found a front tyre down at 14 psi from 25 - the result of a slow puncture. At that pressure, the tyre didn't look very different. I was surprised how much this lower pressure affected the rolling resistance - even just pushing the car around was harder.
Having fitted a spare - another Longstone, I ran the car out again and it pulled away happily at over forty now all the tyres were at the right pressure. But the difference made me think about the effect of rolling resistance.
I have a couple of spare wheels with the heavier 4.50 x 17 Avon tyres on them, so I replaced the two Longstones on the rear. The car then went a bit better than before. But whether this was from reduced rolling resistance or better gearing from the larger tyre circumference on the rear, I am not sure.
Has anyone else considered the effects of rolling resistance for different tyre types and pressures?