Help with tyre sizes on 440i
Discussion
Hoping to get some clarification on tyre sizes if anyone can help.
Finally getting round to replacing the runflats on my 440i (RWD) and have ordered some PS4S. Standard tyre sizes are 225/40r19 and 255/35r19 and I was originally looking to go a bit wider to 235/40r19 and 265/35r19 for a bit more rim protection and to help with grip etc. I've done this previously on my old 1 series (215/225 and 245/255) and was really pleased with how it drove so was planning the same again.
Anyway it turned out that 235 tyres were actually cheaper than 225's which was great but the 265 were nearly £140 more expensive for the pair so I stuck with 255 and ended up ordering 235/40r19 and 255/35/r19.....
Stupidly it's only just crossed my mind that this will now have affected the rolling diameter and according to the online tyre calculators the new 235 tyre will have a diameter of 670.6mm whereas the 225 is 662.6 meaning a difference of 8mm. This will in turn increase the ride height at the front by 4mm and the speedo will be out by 1.2%. I'm told this is just within the acceptable tolerance/differential but I feel uneasy about it.
What I'm thinking I should have done was either sucked up the extra cost and gone for the 265 tyres as well which would have increased the tolerances almost identically to the front, or just simply stuck with the 225/255 setup. Just to clarify I have the tyres sitting in my garage but haven't had them fitted yet.
Thanks in advance
Finally getting round to replacing the runflats on my 440i (RWD) and have ordered some PS4S. Standard tyre sizes are 225/40r19 and 255/35r19 and I was originally looking to go a bit wider to 235/40r19 and 265/35r19 for a bit more rim protection and to help with grip etc. I've done this previously on my old 1 series (215/225 and 245/255) and was really pleased with how it drove so was planning the same again.
Anyway it turned out that 235 tyres were actually cheaper than 225's which was great but the 265 were nearly £140 more expensive for the pair so I stuck with 255 and ended up ordering 235/40r19 and 255/35/r19.....
Stupidly it's only just crossed my mind that this will now have affected the rolling diameter and according to the online tyre calculators the new 235 tyre will have a diameter of 670.6mm whereas the 225 is 662.6 meaning a difference of 8mm. This will in turn increase the ride height at the front by 4mm and the speedo will be out by 1.2%. I'm told this is just within the acceptable tolerance/differential but I feel uneasy about it.
What I'm thinking I should have done was either sucked up the extra cost and gone for the 265 tyres as well which would have increased the tolerances almost identically to the front, or just simply stuck with the 225/255 setup. Just to clarify I have the tyres sitting in my garage but haven't had them fitted yet.
Thanks in advance
You're fine with the 255s
You always want to stick within the 2.5% +/- range, of which you're well in.
Personally I'd have gone for the 265s with the 235s,straighter sidewall all round and better rim protection.
Can you return & re-order in the 265s?
Check Camskill for prices too if you haven't already
You always want to stick within the 2.5% +/- range, of which you're well in.
Personally I'd have gone for the 265s with the 235s,straighter sidewall all round and better rim protection.
Can you return & re-order in the 265s?
Check Camskill for prices too if you haven't already
d_a_n1979 said:
You're fine with the 255s
You always want to stick within the 2.5% +/- range, of which you're well in.
Personally I'd have gone for the 265s with the 235s,straighter sidewall all round and better rim protection.
Can you return & re-order in the 265s?
Check Camskill for prices too if you haven't already
Thanks, these are actually from Camskill due to being the cheapest and they also have a Cashback offer for Michelin’s currently.You always want to stick within the 2.5% +/- range, of which you're well in.
Personally I'd have gone for the 265s with the 235s,straighter sidewall all round and better rim protection.
Can you return & re-order in the 265s?
Check Camskill for prices too if you haven't already
Despite being within the recommended tolerances with the 235/255 I feel like I need to either have the original 225/255 setup or go for the 235/265. The cost with replacing the 235 for 225 would be negligible whereas the 265’s are an extra £170 than the 255. That’s quite a lot in my books!
Will drop them an email and see what I can sort out.
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