Originally Posted By: scoobie
what about if I went from 155 80 R13 to 175 70 R13. i expect better handling and stopping distance, possibly slightly less mileage, but more unsprung weight, at the level of the tire tread - and what effect would this have on the compliance of the suspension, cushiness of the ride etc?
Since the tire sidewall height will remain practically unchanged, I wouldn't expect much difference in terms of handling or ride comfort.
By handling I mean steering response. To improve steering response, you would need shorter sidewalls, which in your case would mean upgrading to larger rims. Shorter sidewalls also result in more firm/stiff ride.
A lot also depends on a specific tire model - some are stiffer than others in the same size.