Tyre size advice please

[officerbrooks]

Any advice please, I have a 2001 C70 T5 and am about to replace the 17" canisto alloys with 18" pegs. Using tyre size calculators 225/40x18 would seem to be the almost perfect mathematical match for the original 17"'s but with the new pegs being 8" wide would they not appear under tyred in the width? I'm considering 235/40x18" tyre fitment, with an increase in diameter of 1.7% over standard will there be a real on road effect to the gearing, my speedo runs fast anyway so perhaps this would help correct it. I have some 5mm spacers if required with this new fitment. Thanks.

[castellsmith123]

The rule of thumb is if you go up a size ,you go down a profile! If you go to say " Kiwk-Fit" they should have a michelin data book! This book give's you the running circumfrence of each size of tyre! You just have to match up to the nearest! You will not get the same measurment on diameter changes! Cheer's

[MisterC1501]

Try this linky

http://www.euroshina.com.ua/calc.php?lng=en

I found when I went up a rim size to 18 inch, my overall diameter of tyre also increased by an inch. I went from 205/45/17 to 225/40/18. I don't believe that the rim is undersized with the 225 wide tyre.......it was what was fitted when I bought the wheels. A wider tyre may increase tyre rub on the inside of the front wheel arch liners, especially when on full lock.

What I did not know, since a friend told me through his experience, was that different tyre makers can vary with the aspect ratio even though the profile is the same...that is, the depth of the tyre can be 8 or 9 inches with an aspect ratio of 40

[LeeT5]

Any advice please, I have a 2001 C70 T5 and am about to replace the 17" canisto alloys with 18" pegs. Using tyre size calculators 225/40x18 would seem to be the almost perfect mathematical match for the original 17"'s but with the new pegs being 8" wide would they not appear under tyred in the width? I'm considering 235/40x18" tyre fitment, with an increase in diameter of 1.7% over standard will there be a real on road effect to the gearing, my speedo runs fast anyway so perhaps this would help correct it. I have some 5mm spacers if required with this new fitment. Thanks.

I know that V70s and S60s from 2001 on have 'lock stops' bolted to the wishbones. The R models have the biggest at 18mm but they also do smaller sizes. If you find your tyres rub on your wheel arch liners then check your stops haven't worn away or fallen off. You could also consider the next size up from whatever you have fitted however this will increase your turning circle but at least you won't scrub your tyres or burn a hole in the wheel arch liner!

Here's the link to the steering stops:

http://www.partsforvolvosonline.com/...=steering+stop