Tyre Profile

1972_911t · Post by **1972_911t** » Sat Aug 19, 2006 6:36 pm

Im wanting to run 7 and 8 x 15 wheels im planning on using 205 and 225 tyres, what profile should I be using with these wheels. To match same tyres front to back I can either use 60s front and back or 55's front with 50's rear to make up for the wider rear tyre. Is this too low for this size tyre and wheel combination?

Thanks Steve

FLY 7 · Post by **FLY 7** » Sat Aug 19, 2006 7:37 pm

Of the available matching sizes you should consider;

185/70 or 195/65 and 215/60s (for the correct original profile and rolling radii)

Or,

205/55 and 225/50s (for a lower profile, but shorter rolling radii)

Glenn75S · Post by **Glenn75S** » Tue Aug 22, 2006 8:52 am

Just a word of caution, if you have done nothing to your rear arches I think 8Js with 225s may be too much.

I have a narrow body 75 911S identical to the 911T with regards to the rear archs and am running 7Js all around with 205/60/15s. To be honest clearance is quite tight, I have been considering using wider tyres, but am concerned with the tyres and arches touching.

I have seen a narrow body road/track car running 225/50/15s on 7Js but this will reduce the rolling radius, and I believe that they have their rear arches rolled.

I would recommend that you mock up before you buy

sladey · Post by **sladey** » Wed Aug 23, 2006 1:54 pm

do a search on tyre sizes (and tire sizes - some iffy spellers here!)

I can't remember the width of mine but I'm running the same as Mike and I know the ratio is 55 front and 50 rears

This give a smaller rolling circumference that original but I'm quite happy with it (speedo is about 10% out)

Plenty of pics of mine here
http://www.ddk-online.com/phpBB2/viewto ... &start=150

and Mikes here

http://i7.photobucket.com/albums/y256/M ... ontage.jpg

However Mike has the RS rear arches on his and mine is an 87 3.2 carrera so there is room under these arches

1972_911t · Post by **1972_911t** » Thu Aug 24, 2006 7:37 pm

I dropped a bo**ock ordered 225/50/15's for the back and 205/50/15's for the front thats about 10% difference in profile is this going to cause any problems other than asthetics?

Thanks Steve

Lightweight_911 · Post by **Lightweight_911** » Thu Aug 24, 2006 8:06 pm

Can't you change your order ?

1972_911t · Post by **1972_911t** » Thu Aug 24, 2006 8:58 pm

No the company already shipped them before I noticed, so means £15 each way on shipping fees. £30 may not be all that much but on £80s worth of tyres its quite a bit. Is it worth paying to get the correct size?

Steve

Lightweight_911 · Post by **Lightweight_911** » Thu Aug 24, 2006 9:37 pm

You will probably find that there's too much of a gap between the tyre & wheelarch lip.

Here's a shot of my '73 RS Touring 'conversion' when I first got it (with 205/50 front tyres):

& here it is after I fitted a new set of 205/55 & 225/50 tyres:

Lightweight_911 · Post by **Lightweight_911** » Thu Aug 24, 2006 9:38 pm

sorry - double post...

1972_911t · Post by **1972_911t** » Sat Aug 26, 2006 10:08 am

Ive just got the tyres, the difference is quite noticeable, im going to send them back and get the correct size.

Thanks Steve