Another wheek/tire fitment question thread

[Newoldschool]

I have a '71 240z that's been built for autocrossing. When I got it, it came with some 15x7's, offset unknown, with 225's. The 225's rubbed at full wheel lock and whenever I went over bumps. Since then, I went down to a 205 and have no clearance issues... but over the course of this season, I'm left just wanting more tire. Currently have Tokiko springs (looks like it may have been lowered an inch) with adjustable shocks.

 

Pic attached is current wheels with old 225 tires

 

I definitely want to go with a squared configuration, so I can rotate mid season. It look on here that a lot of people can fit 225's on a 7" wide rim with zer offset (seen both 15" and 16" rims cited for this.) I want to go at least 225 width, 235 or beyond if possible, without flaring the fenders (would be willing to roll the inner lip) and no rub. I'd also like a 8" wide rim, but these seem to be kind of rare. Also would like to avoid spacers.

What wheels (including offset) and tires would you recommend? Seems my choices are...

 

15x7

15x8

16x7

16x8

 

Thanks in advance...

[beermanpete]

We run 225/50-15 tires on 15x7 without any rubbing with stock fenders and the Tokico springs on a '73. It requires the correct offset wheel. If your tires are rubbing on the fenders the solution is different wheels.

[thedarkie]

A good start would be to measure your current wheels so you know which direction to go in. 

Here's a guide: https://www.rsracing.com/tech-wheel.html

 

From there I'd get the car up on dollies or a platform lift, and measure inside clearances to suspension bits so you know how much room you have to push your wheel and tire combination inwards. Its simple math from there. Also be advised that not all tires of a given section width are actually the same physical width, especially when mounted on different size wheels. Manufacturers will have physical dimensions on their sites for the most part.

Edited September 25, 2014 by thedarkie

[Phantom]

I agree with thedarkie. If you have Tokicos you should have more room that stock. I have 225/50-16 tires on 16x7 wheels tin 0 offset on my 280Z. With coil overs you should be able to squeeze in some 245's on 8" rims with 10-12mm of offset (moving the center of the wheel toward the differential). After that do a thorough study on your tire options (Tirerack.com is good for this) to compare actual cross-sections and diameters as it varies from brand to brand. Just a little but sometimes that is what makes the difference as to whether it will fit or not. If I could put a new set of Wheels/tires on my car now that I have coil overs I'd go with 245/40-17's with 12mm of offset - after I did the measurements to confirm it.

[thedarkie]

I agree with thedarkie. If you have Tokicos you should have more room that stock. I have 225/50-16 tires on 16x7 wheels tin 0 offset on my 280Z. With coil overs you should be able to squeeze in some 245's on 8" rims with 10-12mm of offset (moving the center of the wheel toward the differential). After that do a thorough study on your tire options (Tirerack.com is good for this) to compare actual cross-sections and diameters as it varies from brand to brand. Just a little but sometimes that is what makes the difference as to whether it will fit or not. If I could put a new set of Wheels/tires on my car now that I have coil overs I'd go with 245/40-17's with 12mm of offset - after I did the measurements to confirm it.

 

Are your wheels Panasports by any chance? I have 16x7 Pannys with (I think) 0 offset running 205mm tires and I desperately want more rubber on the back. Can you snap some photos of how your 225s look on a 7" wheel?

[Leon]

Here are two examples, both on 16X7 Panasports. Both have 225/50-16 tires mounted, orange car has all-seasons and green car has sticky summer rubber. You can see the difference in size even though the tires are the same size on paper.

 

*Green car has zero rear camber in this photo, orange car has -1.5deg.

 

[thedarkie]

Doesn't look like a huge difference but it illustrates the point regardless... different tires with same section widths can be different dimensions.

 

Those 225s look alright! Maybe I'll go that route. My car is about the same height +/- as the green car in your photo... those 225s don't stick out beyond the fender? Looks close. Probably because of the 0 camber...

 

I know Im asking too much now, but do you have a shot from low behind the whole car? I hate how skinny my 205s look from the rear of the car... Im wondering if the 225s will satisfy my aesthetic need. thanks

 

Also, no rubbing up front with the Panasports and 225s? 

Edited September 26, 2014 by thedarkie

[Leon]

The tires were different enough that the ones on the green car rubbed when put on the orange car. The tires on the orange car NEVER rubbed. The green car is untested, but once I install the camber plates it'll clear just fine. It does have trimmed rear fender lips and front valence.

 

I don't have any good pics from the back and the orange car is no longer in my possession. I can take one of the green car sometime this weekend though, if I can remember...

[thedarkie]

That's disconcerting.. which ones rubbed, front or rear? And where? If its just the rears rubbing on the fender then as you said, camber will probably fix that readily... but if the fronts are rubbing when turning, its a different ballgame. I'd prefer not to roll fenders or modify the bodywork in any circumstance.

 

Thanks for the input, can you update us as you go along? I'd hate to spend a G on new tires only to find them rubbing when mounted on my current Panasports

[Leon]

The rears rubbed with the fatter tires on the orange car. I suspect two reasons for this: the tires are wider (duh) and I think the wheel offset is different. I never measured but I believe the orange car's wheel offset is +6 and the green car's is 0.

 

Neither of the tires rubbed on the front. The only time you'll encounter rubbing issues with 225s is running a stock, untrimmed front valence. I've heard 205mm is the max front section width you can run without running into issues there. I've not dealt with it so I can't offer any proven solutions besides trimming the stock valence. If you have an aftermarket air dam like the Xenon, you'll be fine up front.

 

I'll try to take a photo of the rear of the green car on Sunday.

[Leon]

Best I could do with the way the car is parked:

 

I looked back at the alignment numbers and the rear actually has +0.5deg of camber. That's the reason why I got those camber plates! When I ran the green car, it used the orange car's wheels. I've not actually driven it as it sits now.

[thedarkie]

Thanks, I appreciate the photo. They look pretty good, I wonder how much they'll tuck back inside when going from +.5 to something like -1.5 camber. Not sure how many mm those 2 degrees will translate to. I'm still tossed up on whether it will give a much beefier look or if I should be looking at new wheels with 235-245mm rear tires.