Hi guys
After speaking to a well respected RTA engineer in my region about engineering my 17x7.5" wheels on the CC EVO1-3 he had given me this feedback:
The rules on wheels and tyres specify that for FWD and "four wheel drive vehicles with constant front wheel drive", the front rim width is only allowed to increase by 1" over the original widest option, even with an engineering certificate. That's hidden in a section titled "Front wheel drive vehicles" at the bottom of page 3 of VSI 9.
However, the starting point in this case would be the widest original rims fitted to a vehicle of the AWD spec. If the FIA homolgated model with 6.5" wide rims was ever officially a "standard" production vehicle (whether from Mitsubishi, Ralliart or someone else) that was complianced and road legal anywhere in the world, then we can certify the 7.5" rims provided that they meet all the criteria specified in the COP / VSI 9. Note that if the tyre diameter is more than 15mm different to the original ones for the drivetrain installed, you'll also need to re-calibrate the speedo drive to compensate.
If you need to compare tyre diameters, this link is very useful, as it gives the same results as digging the numbers out of standards manuals: http://www.miata.net/garage/tirecalc.html . Click on the "metric" box and select the 2 tyre sizes and it'll provide the diameters, % different, etc..
Now I know he is 100% correct in saying what he does as I pretty much suspected as much after reading up on it.
Problem is, from a scan of the FIA homologation papers on the EVO 3, and from heresay over the years, the EVO 3 DID come out with 16" Enkei wheels at some stage (were 16"x6.5") . Problem is, where????? and who sold it??? Was it Ralliart only in England? Was it in Europe? In Japan? I am desperately counting on you guys to help me track down the info, or someone who will know for sure (ie someone who has been in the rally or Mitsu/Ralliart biz since the EVO's were introduced in the early 90's). This would assist all EVO I-III owners for engineering larger wheels and would be good to confirm a little bit of history. Please find below a scan of the FIA Homologation page for the EVO clearly showing a 16" wheel.
Thanks guys.
Rob
After speaking to a well respected RTA engineer in my region about engineering my 17x7.5" wheels on the CC EVO1-3 he had given me this feedback:
The rules on wheels and tyres specify that for FWD and "four wheel drive vehicles with constant front wheel drive", the front rim width is only allowed to increase by 1" over the original widest option, even with an engineering certificate. That's hidden in a section titled "Front wheel drive vehicles" at the bottom of page 3 of VSI 9.
However, the starting point in this case would be the widest original rims fitted to a vehicle of the AWD spec. If the FIA homolgated model with 6.5" wide rims was ever officially a "standard" production vehicle (whether from Mitsubishi, Ralliart or someone else) that was complianced and road legal anywhere in the world, then we can certify the 7.5" rims provided that they meet all the criteria specified in the COP / VSI 9. Note that if the tyre diameter is more than 15mm different to the original ones for the drivetrain installed, you'll also need to re-calibrate the speedo drive to compensate.
If you need to compare tyre diameters, this link is very useful, as it gives the same results as digging the numbers out of standards manuals: http://www.miata.net/garage/tirecalc.html . Click on the "metric" box and select the 2 tyre sizes and it'll provide the diameters, % different, etc..
Now I know he is 100% correct in saying what he does as I pretty much suspected as much after reading up on it.
Problem is, from a scan of the FIA homologation papers on the EVO 3, and from heresay over the years, the EVO 3 DID come out with 16" Enkei wheels at some stage (were 16"x6.5") . Problem is, where????? and who sold it??? Was it Ralliart only in England? Was it in Europe? In Japan? I am desperately counting on you guys to help me track down the info, or someone who will know for sure (ie someone who has been in the rally or Mitsu/Ralliart biz since the EVO's were introduced in the early 90's). This would assist all EVO I-III owners for engineering larger wheels and would be good to confirm a little bit of history. Please find below a scan of the FIA Homologation page for the EVO clearly showing a 16" wheel.
Thanks guys.
Rob