Need advice

[Akakubi]

My front Victoracers are just about done. I will need to order a new set of Fronts, but would like to get a wider footprint if I could.

Will a 245/45/17 work on a 7.5" LTW rim? And will it clear the wheel well of my 330Ci? I wish Kumho had a 235/40/17 size for that tire...:confused:

[Kaz]

245/45? That's awfully big. Probably a tad too wide for a 7.5 for proper mounting as well.

It'll fit in the front wheelwells but it'll be tight. On a 8.5" wheel (which the factory 245/40 on the back is on), that size might fit if the offset is about 45mm. A good test might be to mount the rears on the front of the car and see how the clearance is.

[Akakubi]

Thanks Kaz! That's what I was going to try in the end. Just wanted to see if I could avoid buying two more rims. :):angel:

[Kaz]

Originally posted by Akakubi
Thanks Kaz! That's what I was going to try in the end. Just wanted to see if I could avoid buying two more rims. :):angel:

Now, I think the stock M68 rears are ET50. My experience is with my rear Alpinas (18x8.5ET50 with 235/40/18) which I tried fitting to the front just for fun (no driving). It cleared the front strut by about 3-4mm. Since it's fairly common for people to run that same tire on that wheel size with less (~42mm) offset without rubbing the outer lip, I think there's enough wiggle room to make your setup work with a little tweaking.

[Gary@Tirerack]

We found that experienced drivers have gotten better lap times using a narrower tire that is within the recommended rim width range, rather than a wider tire that is stretched with a sidewall deformation on a too-narrow rim beyond the rim width range recommendations. I strongly recommend that you reconsidering using 245/45R17 on a 7.5" wheel. The sidewalls are so pulled in that you're negating any benefit in width, and as we've found in the majority of cases, you'll actually hurt your lap times verus using the correct size.

[LMC]

Given that point, Gary, let me back up (and perhaps diverge further from Akakubi's original question): What is the optimum size for those running the same size front and rear? I would love to go wider than 225/45R-17, but it sounds like 245/40R-17 all-around will have the same problem as the 245/45. Are 235/40s the answer if staying with a 17" setup?

Originally posted by Gary@Tirerack
We found that experienced drivers have gotten better lap times using a narrower tire that is within the recommended rim width range, rather than a wider tire that is stretched with a sidewall deformation on a too-narrow rim beyond the rim width range recommendations. I strongly recommend that you reconsidering using 245/45R17 on a 7.5" wheel. The sidewalls are so pulled in that you're negating any benefit in width, and as we've found in the majority of cases, you'll actually hurt your lap times verus using the correct size.

[Gary@Tirerack]

235/40R17 is more ideal. It is technically still not within the recommended rim with range. Kumho lists 8-9.5 as ideal. I do have many customers who use 235/40R17 all around anyway, and they've not reported problems. 225/45R17 will also fit all four corners and lists rim with ranges up to 8.5", and this setup is fairly common.

[Akakubi]

Thanks for the input guys!

See, here's what I found out. 225's all around are not grippy enough. The rear end does not have sufficient grip and I can actually see how the car starts to slide way before my car loses it. I run 255/40/17 on the back. But my front starts to push just a bit too soon - the grip is just not balanced enough. And the I ened up eating the fronts completely, while the rear are barely showing any wear...:dunno:

So here is another question: Can I use 235/45/17 V700 while still using 255's Victoracers on the back? Will the grip balance still be within reason. I have seen people using BFG's R-1 up front and Hossiers at the back...

[Akakubi]

Adding to that, I just looked over at the Kumho website and they say that 245/45/17 can be fit on 7.5"-9.0" rims... :dunno: What do you guys make of it?