info on 215's on stock rims..

[KeithB]

I had a chat with one of the engineers from Hankook Canada about some tires I'm considering.
When asked about using a 215/45 series tire on a 6.5" rim, he was clear that it was NOT recomended.The rim needs to be at least 7 but 7.5 is the sweet spot.
This is the same as the info I have seen on 2 major manufactures sites.
His explanation was that with a low sidewall height like a 45, the beads will be drawn in slightly and cause the contact patch to change.
The edges will be lifted slightly and the disribution of weight over the contact patch changes.
The whole point of the wider tire is compromised.
You could lower tire pressure slightly to compensate but that changes the load capacity of the tire.
I know that some of you are running this setup and that some shops say it's "OK" and while it "works" and no one has "had any problem" I would think that the engineers at the tire manufacturer would probably have the right info.
As such, I am either going to stay with 205/50/17 or buy new 7.5 rims and strap on 225/45/17 which are , by the way,exaxtly the same diameter as stock.
This is in no way an indication that any of you or your suppliers is wrong,but it's worth considering the sorce of the info.

[wingnut12]

Good write up. Every source I've ever seen indicates that 215's need a 7" rim.

The only reason I was considering a 215 is that most UHPs don't come in exactly the size I want, and I really don't want to spend an extra 1200.00 on rims. Damn Mazda for saving rim weight by giving us a 6.5" rim.

[TB76]

I did some reading on a formula used to determine how wide the tire can be for a specified rim width...you can find it on google somewhere.

It really depends on the 'series'.....45 series will require a wider rim than 50 series.

I have 215/50/17s on stock rims. No issues at all. Fill up the fender gap a little bit.....look perfect. These are fine on a 6.5" rim - but I don't plan on lowering the GT so I'm not worried about any rubbing issues.

215s ride better (for comfort) as well and with the right tire you can gain on cornering quite a bit from the stock RSAs :chuckle

And if this info isn't decisive enough...I know the 2002 Acura TL-S OE 6.5" rims have 215/50/17 OE tires. I'm sure the Acura engineers know a few things.

So 50 series - no problem....45 series...might be pushing it for the reasons given in this thread.