Tyre size help....URGENT!!!

Tyre size help....URGENT!!!

Author
Discussion

porschecrazy321

Original Poster:

115 posts

129 months

Monday 21st July 2014
quotequote all
Hi all
I have 265 40 18 on the front and 265 40 18 on the rear of my 987 Boxster s , my question is can i put a 255 on the rear? or maybe a smaller side wall 35 even?,sorry for my ignorance i'm not sure what impact this will have if i did change to a smaller width i.e. 255
regards

996TT02

3,308 posts

139 months

porschecrazy321

Original Poster:

115 posts

129 months

Monday 21st July 2014
quotequote all
Spot on m8 thanks so much, think i will be going for a 35 profile !!

mrdemon

21,146 posts

264 months

Monday 21st July 2014
quotequote all
keep the profile it was on

also the front seems very wrong

sidicks

25,218 posts

220 months

Monday 21st July 2014
quotequote all
mrdemon said:
keep the profile it was on

also the front seems very wrong
Agreed - surely having a narrower tyre at the rear than the front is asking for trouble.....

Lost soul

8,712 posts

181 months

Monday 21st July 2014
quotequote all
sidicks said:
Agreed - surely having a narrower tyre at the rear than the front is asking for trouble.....
I was told that it is illegal

Trev450

6,314 posts

171 months

Monday 21st July 2014
quotequote all
As above, fronts are wrong. Should be either 225 or 235 at biggest.

Chris Stott

13,179 posts

196 months

Monday 21st July 2014
quotequote all
Surely the tyre sizes are a (f)225/40/18 and (r)265/35/18?

A 265/40/18 would never fit on the front of a Boxster.

porschecrazy321

Original Poster:

115 posts

129 months

Monday 21st July 2014
quotequote all
Lol sorry type error !!! front is indeed 235 40 18 rear 265 40 18, so i am i right in saying i could put a narrower profile on the rear?

sidicks

25,218 posts

220 months

Monday 21st July 2014
quotequote all
porschecrazy321 said:
Lol sorry type error !!! front is indeed 235 40 18 rear 265 40 18, so i am i right in saying i could put a narrower profile on the rear?
Why would you want to?

Chris Stott

13,179 posts

196 months

Monday 21st July 2014
quotequote all
Your rears will be a 265/35/18, not a 265/40/18.

Don't see why you couldn't go to a 255/40/18, but not sure why you'd want to!

Orangecurry

7,396 posts

205 months

Monday 21st July 2014
quotequote all
Chris Stott said:
Your rears will be a 265/35/18, not a 265/40/18.
I believe you are incorrect for a 987 - they have crazy sizes.

mollytherocker

14,365 posts

208 months

Monday 21st July 2014
quotequote all
I don't get why you want to do this? You are going to fundamentally change the handling characteristics of the car.

And in a bad way.

It will affect the geo too.

Chris Stott

13,179 posts

196 months

Monday 21st July 2014
quotequote all
Orangecurry said:
Chris Stott said:
Your rears will be a 265/35/18, not a 265/40/18.
I believe you are incorrect for a 987 - they have crazy sizes.
Just checked and you're right.

edc

9,230 posts

250 months

Monday 21st July 2014
quotequote all
mollytherocker said:
I don't get why you want to do this? You are going to fundamentally change the handling characteristics of the car.

And in a bad way.

It will affect the geo too.
Why would a tyre size affect the geo. I can see why some people would want to go to 255 on the rear as a Boxster is largely over tyres on the rear anyway. In 986 flavour the 17 inch wheel comes with a 255 tyre.

IREvans

1,126 posts

121 months

Tuesday 22nd July 2014
quotequote all
porschecrazy321 said:
Lol sorry type error !!! front is indeed 235 40 18 rear 265 40 18, so i am i right in saying i could put a narrower profile on the rear?
Leave the tyres the correct size, just as the manufacturer intended. Change them to a non standard size at your own peril.

If you change them, not only will the handling balance be affected, but should you be unfortunate enough to be involved in an accident, your insurer may well choose not to pay out if you've made unauthorised modifications to the car.

Just out of interest, why do you want to fit a narrower rear tyre..?

Matt Seabrook

563 posts

250 months

Tuesday 22nd July 2014
quotequote all
Also ABS brake performance could be affected. It measures wheel speed, so if you muck about with tyres sizes it's could adversely affect ABS.

porschecrazy321

Original Poster:

115 posts

129 months

Tuesday 22nd July 2014
quotequote all
I have not changed anything and now don't intend to ,i was offered 2 x 255 40 18 by a good friend and wanted to know if i could fit them, i have seen plenty of posts on here and other sites regarding people mix and matching but never thought i would so never took much notice

DiscoColin

3,328 posts

213 months

Wednesday 23rd July 2014
quotequote all
Lost soul said:
sidicks said:
Agreed - surely having a narrower tyre at the rear than the front is asking for trouble.....
I was told that it is illegal
Don't tell Audi then - the RS3 famously has wider fronts than rears as standard (reputedly the first car to be so).