bigger wheels / low profiles - again!!

[kjay]

There's been lots of threads on this subject.
Going to bigger wheels with lower profile tyres will reduce the ride quality due to the smaller height of the sidewall. No arguments from me on that one.

But, here's a question.....
Suppose, you go to a larger diameter wheel but keep the same width/aspect ratio tyre?? Theres' the same amount of sidewall between the rim and the road. Rolling circ. will be larger, but I'm not concerned about that here.

Example:
265/35-18
265/35-19

Both tyres have the same sidewall height. So, I'm trying to convince myself, there 'should' be no difference in ride quality.

Opinions please.

PS. No prizes for guessing the reason for my post

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[Rovinghawk]

As a 19" wheel is bigger, it will not go as deep into potholes, therefore the ride will be smoother regardless of sidewall height.

RH

 

[BTB 500]

If sidewall height and tyre pressure is the same then the ride should be the same. As RH said, there will be a fractional benefit from the larger circumference in terms of potholes etc.

I suspect the difference in ride quality when changing 1" in wheel diameter (so 0.5" difference in side wall) is somewhat exaggerated. Unless you have exactly the same brand/model of tyres fitted to both sets of rims you can't really compare.

 

[kth286]

depends if a bigger wheel circumference will fit in both front and rear arches without fouling and being dangerous.

Will you be happy with less fast acceleration.

You will be happy with more economy.

You will get more speeding tickets because your speedo reading will be out

 

[popuptoaster]

unpsrung weight will go up unless you choose your wheels and tyres very carefully, and thats bad for ride AND handling as the springs and shocks have more momentum to deal with, also your acceleration will be slower and the car will be fractionally slower to stop, on the plus side your MPG may go up if you soend more time cruising the motorway on light throttle than sitting in town.

 

[pupsi]

Ride wont be the same.

 

[Dieselman]

I agree with popuptoaster.
The larger wheels will cover indentations more easily so should theoretically give a smother ride, but the increase in unsprung weight will reduce ride quality, acceleration, steering feel and input speed and probably mpg.

If upstepping wheels and tyres you need to pay special attention to wheel and tyre weight otherwise performance and ride quality suffer a lot.

The gearing uplift will be 4% so might help with cruising mpg.

I've actually wondered about this myself just for the gearing uplift, that's one reason why I'm interested in wheel/tyre combo weights of 17" wheels.

 

[kjay]

Thanks for the replies.

Think I'll keep an eye on DM's wheel weight thread and do a little research. The car handles like a dream with the 18's and Eibach mods so I don't want to spoil it.

Jay.

 

[tudu]

I still think even without getting the wheelarches rolled with a 265 tyre you will defo have rubbing issues when carrying rear passengers hence, 255 gives comfortable ride.

 

[kjay]

I still think even without getting the wheelarches rolled with a 265 tyre you will defo have rubbing issues when carrying rear passengers hence, 255 gives comfortable ride.

Yeah, 255 is supposed to be the widest you can fit to the rear. But I was 'width greedy' and fitted 265's. There was rubbing sometimes with the lowered springs and No.1 perches. I now run No.3 perches and everythings ok.

Going to 265's on 19's would probably require removing some of the plastic inner arch and probably a section of the bumper where it lips in.