Ride quality trade off between 18's, 19's and 20's

[London Lad]

The overall radius of 18 19 or 20 is the same so fuel economy is only effected by the wider tyre having more wind resistance and the increase in rolling resistance.

Frazer is correct in that the lower side-wall will transmit more bumps to the car and the wider tyre will cover more road area and 'find' more bumps.

The main problem on tracks and ruts is with the lower side-wall the rim is nearer to the ground and more prone to damage from the side of ruts and rocks etc in the road.

I went for 19s but I have to say if I was spec'ing the car again I would stick with 18s and save £900.

[grey]

Originally Posted by London Lad

The overall radius of 18 19 or 20 is the same so fuel economy is only effected by the wider tyre having more wind resistance and the increase in rolling resistance.

Frazer is correct in that the lower side-wall will transmit more bumps to the car and the wider tyre will cover more road area and 'find' more bumps.

The main problem on tracks and ruts is with the lower side-wall the rim is nearer to the ground and more prone to damage from the side of ruts and rocks etc in the road.

I went for 19s but I have to say if I was spec'ing the car again I would stick with 18s and save £900.

Thanks, You made some great points again.
In summary going to a 20" wheel (low profile wheels) could potentially cause more suspension damages than just to the wheel itself, and transmit more wear and tear to axels, CV joints, struts and eventually causing rattles in the cabin, especially on bad roads. Sydney roads are quite bad. I think you guys have convinced me to stick with my existing set of 19"s

BTW:
I made some calculations.
going from 19" 255/50 R19 to 20" [275/40 R20W and 315/35 R20W] you loose approximately 13% of sidewall height.