One for the chassis dynamic experts??? It's a common opinion that 18 inch wheels on a classic produce a poorer ride than 17"'s... But, why is this?

It cant be down to rolling radius as this would be the same with lower profile tyres on 18's. So, is it an unsprung weight thing, or the stiffer tyre sidewall flex on the lower profile tyres??? If so, would lightweight alloys &/or a "better" tyre cure any reduction in handling or ride quality????

Interested to know...

 

I think it is down to the lower profile / stiffer sidewalls on the tyres.

But I`m no expert.

 

Think about it..

On a 17" you'd run 205.45.17 (sidewall height 92mm)
On a 18" you'd run 215.35.18 (sidewall height 75mm)

You've lost 17mm (18%) of tyre cushioning by going up a size.

 

So the concensus of opinion is that it is the reduced ability of the tyre sidewall to flex...? Seems the most logical reason for me, & could explain why some people see more of a detrimental effect than others if they have "stiffer" tyres....

 

Bridgstones on an MY00 classic with 16's seems harder then 17 and 18 inch with Toyo's IMHO.

The Bridgstones used to ping quite loudley as I drop off my drive at an angle. So loud that you wonder if the wheelnuts are loose.

Swapping to 17 inch and Toyo's improved the ride.
Then changing to 18 inch and Toyo's didn't seem any different.

 

I think I'd agree. Had 17" Yokohamas on my old Scoob before changing to Toyos & I noticed the difference in a better ride. I just wondered if this was the main cause of the apparent negative effect on handling when moving up to 18"'s? Guess if this is on the cards tyre choice is even more important..

 

I've just gone from 17" and Goodyears to 18" and Toyos, the ride is improved, it's just as noisy and for me the handling certainly isn't worse.

 

nope you need to run 215x40 profile tyres on 17's not 20545...you should run 45's on new age cars tho. my MY00 came with 18's (215x35), changing to 17's (215x40), improved it no end.

i ran toyo's on both 17's and 18's, so there you have a direct comparison of wheel size with the same make tyre

ian