Just wondering what 18" tyre size works with the v70. Have just bought some 18" medusa alloys. ( centre bore has been enlarged to fit) they have the correct 43 mm offset. The plan is to fit coilovers as it's cheaper than lowering springs and shocks and they're adjustable too.

 

Assuming you want to keep the same rolling circumference and you have a 2000 or so V70, the standard tire size by rim would be 195/60-15, 205/50-16, 205/45-17 and 205/40-18. Being off by one size (ie 215/40-18) would only make a difference of about 1.7% ie at 60 mph you'd be reading 61... if you did 225/40-18s you'd be off by 3.1% or 2 mph at 60... so 205/40-18 seems the best upgrade.

 

To be honest I'm more worried about rubbing issues than the speedo being. Most car speedos over read by about 10% anyway (33 on the clock is usually actually 30). I'll just use my satnav's speedo

225 40 18's are my preferred choice as they are the most popular size and hence a lot cheaper. But they are obviously no good if they are going to rub. I could go slightly narrower with 215 40's or lower profile with 225 35's but I've read they give a harsh ride