effect of rim width on handling

I scored a set of 5 16x7.5 alloy wheels, unblemished. I went to local
tyre emporium to get some 245/50R16 tyres on them. The guy tried to tell
me that I need 8.5 inch rims for such tyres. Although mine would be
legal, he muttered that I will have caved-in sidewalls, and handling
is degraded (but would be more comfy). For good handling, I am supposed
to use wide rims so that the sidewalls are more vertical.
Is this a significant factor?

Wider rims are just a fashion statement. Ideally we'd have taller rims with shorter sidewalls, maintaining the same overall diameter and stock width.


A narrower wheel/tire is actually more stable and tends to keep rolling in the same direction with less caster than does a wider one.

wrote:
> I scored a set of 5 16x7.5 alloy wheels, unblemished. I went to local
> tyre emporium to get some 245/50R16 tyres on them. The guy tried to tell
> me that I need 8.5 inch rims for such tyres. Although mine would be
> legal, he muttered that I will have caved-in sidewalls, and handling
> is degraded (but would be more comfy). For good handling, I am supposed
> to use wide rims so that the sidewalls are more vertical.
> Is this a significant factor?

Yes. Handling when cornering will likely be quite odd.
If you go with the 245's, you might want to take turns very slow.
Try to match tread width to wheel bead width.
The section width typically bulges out about 1" more than the tread.
Your tires are 245mm or about 9.5". Subtracting 1" gives a wheel
bead width 8.5".
A 7.5" wheel is about ~192mm. The correct tire would
be in the 220mm section width range.