Widest tyre on a 7J rim?

Widest tyre on a 7J rim?

Author
Discussion

MrFlibbles

Original Poster:

7,601 posts

264 months

Saturday 19th February 2005
quotequote all
are 235s too wide for 7Js?

GreenV8S

29,467 posts

265 months

Saturday 19th February 2005
quotequote all
Yes, too wide. General rule of thumb is rim width plus one inch for road tyres, plus or minus half an inch. 205mm is about right for that rim.

interloper

2,747 posts

236 months

Saturday 19th February 2005
quotequote all
Have to agree with GreenV8S here, the ideal tyre width on a 7J is 205. You can get away with 225 but for best results (handling wise) 205 cross section is the way to go.

GavinPearson

5,715 posts

232 months

Sunday 20th February 2005
quotequote all
235 is possible.

Every manufacturer designs their tyre to suit a range of rim widths and each tyre has an optimum. You can obtain the data from the manufacturer direct.

I know the Jag XJS used a 235/60 VR 15 tyre on a 7J rim HOWEVER the actual dimensions of the tyre were closer to a 225/65, it came within the tolerances allowed though so it got badged as a 235/60 because that seemed 'sportier'.

What confuses many is that road tyre width is the width at the sidewall whereas slicks are measured as width of tread.

A slick should be fitted to a rim ideally 1" wider than the tread width to control flex, on a road car you want it to be pleasant to drive so flex is to some degree desirable.

Again, you need to follow the manufacturer's recommendations.

Pulsatingstar

1,705 posts

229 months

Sunday 20th February 2005
quotequote all
Presume on the XJS example it fitted due to the large sidewall taking the flex. If this is a 17 and something like a 40 profile its going to be a bit different.

MrFlibbles

Original Poster:

7,601 posts

264 months

Sunday 20th February 2005
quotequote all
Im thinking 235/40/17. Thats what I have on my rears at the moment, but im looing to change my wheels. The particular wheels im after are quite rare in 7.5J, ad I dont want to lose grip at the rear end.