Lower profile and ride quality mc

[dalecan]

I've decided to buy 4 new Michelon pilot super out tyres for my z4 mc. What I am debating is sticking with the original tyre sizes or upping them to 245-40-18 Fronts and 265-35-18 Rears. I'm on OEM wheels and nothing has been changed to the suspension. My concern with the lower profile is a dramatic increase in feeling bumps in the road. The roads here are appalling. I know the ultimate solution is to change the suspension, but I'm considering an upgrade to an AMV8 in a couple of years, so don't want to spend the money. So, would the change in profile increase the ride harshness much?

Thanks guys.

 

[mr wilks]

Not sure what size tyres you have on now but on standard 18s the front profiles should be 45 & rears 40 so upsizing the widths & reducing the profiles won't help ride comfort .

 

[mmm-five]

I think the Supersport has quite a stiff sidewall so a change to a Supersport from another tyre of identical size might increase harshness anyway.

265/35/r18 has a smaller sidewall than a 255/40r18 - so that will also increase harshness. I went for the 265/40r18 and it doesn't feel an different to the OE Contis in 255/40r18.

The 245/40r18 front may catch your arch/suspension on full lock and the extra width may make the car tramline more on uneven roads.

Neither change size sounds ideal if you're trying to improve harshness and behaviour on poor roads. Maybe you need to find a tyre with a softer sidewall in OE sizes - or spend a little on new Eibach springs (couple of hundred, rather than thousands for completely new suspension).

 

[David-H]

Agree with mmm-five re the stiff sidewall of MPSS tyres.

Having put 19" 313s on my ///M, I found the ride too harsh and have gone back to 18 inch rims with 265/35/18 rears and 235/40/18 fronts with Eagle F1 AS2 tyres and am happy with the ride (although, I should tell you that my suspension isn't OEM as I have Eibach springs!).

With these sizes you lose approx 0.37 inches off the depth of the sidewall and about 5% of the air volume in the tyre compared to OEM size tyres and I don't think that that's enough to cause a dramatic increase in harshness of ride.

 

[Angelus666]

Also, I'm guessing reducing the wall size will make the arch gap huge and ugly....not a good idea all round!

 

[dalecan]

OK thanks guys, you all confirmed my suspecions. I will stick with OEM sizes. Thanks for the input.