W0lfgang

iTrader: (5)

I've been going through the archives a lot to try and answer different questions that I have as I start moding my first RX7. I was in someone elses who had lowered their 7 and put on 17" tires. He consequently KILLED his turning radius. If you took a corner too quick or too tight it rubbed like CRAZY. He also practically bottomed out in potholes and couldn't go up into driveways very easily, but meant it to be a DD. Anyways, I've come to the point where I'm ready to look at replacing the stock tires on my car. Having seen what a bad choice can be for a DD I thought that I would keep the stock 16" wheel size. But then I noticed that everything that I was finding in an aftermarket wheel was only 16X7, but that the stock's were 16X8. Therefore, being narrower, a 16X7 would perform less than stock because it has less "grip" on the road that a 16X8. Correct?

So my question is this: If I go with a 17X8 wheel, what tire size do I need so that I retain the same overall demensions as stock? Also, if I get a 17X8.5 or 17X9 will I have to worry about rubbing and losing my turning radius like the other guy did?

Thanks for your help!

W0lfgang

iTrader: (5)

Ok, I've finally found two good overall diameter calculators!

http://www.1010tires.com/TireSizeCalculator.asp

http://www.miata.net/garage/tirecalc.html


So, I'm set on finding out what size tire I need to have on what diameter rim in order keep the same overall diameter.


HOWEVER, I still could use input on what width I can get and NOT rub when I turn tight corners etc. Also, Can someone please verify for me that stock wheel specs are: 16X8 / 50 / 5-114.3

Thanks again!

W0lfgang

iTrader: (5)

My question could better be asked this way.

What offset do I need in a wider tire (8.5 or 9) in order to not have to worry about rubbing and/or losing turning radius?

Mahjik

iTrader: (1)

Anything between a +45 to +50.

gracer7-rx7

iTrader: (16)

Some of it also depends on your suspension setup and the general geography of where you live. My car has been running 17 x 9 +45 for year with H&R springs on stock and Koni shocks with 255/40/17 tires.

Until recently, I never had a problem with rubbing. I recently moved to an area with more hills and have experienced rubbing of the tires on the fender lip when taking a corner that transitions to an uphill. It seems that the suspension is either a bit too low or the wheel/tire setup or a combination of both cause it to rub when the terrain goes uphill in a corner.

My ride height is around 25.25" to 25.5" up front.

dhays

iTrader: (1)

I've recently been looking at the same thing. If you search in the FD fitment thread, you will find links to a nice Excel spreadsheet that will answer all those questions. According to it, the minimum offsets for 17" wheels would be:
8" - ET 31mm front, 25mm rear
8.5" - ET 38mm front, 31mm rear
9" - ET 44mm front, 38mm rear

Essentially, what Malik already posted. As I understand it, those are minimum offsets to give about a 1/4" minimum clearance. The stock 16x8 have an offset of 50mm.

For a 17" wheel, the tire sizes that will most closely match stock diameter would be:
225/45
235/40
245/40
255/35
265/35
275/35
285/35

Check out the spreadsheet. It is pretty handy. Of course, I'm just hoping my stock 94 hasn't sagged over the years and that the new wheels and tires I ordered will actually fit.

NeoTuri

iTrader: (2)

I used to run 235/40-17's and they would rub the inner liner because my aftermarket springs were too soft.

A new set of Koni shocks helped a bit, but that's not the right way to fix it.

Oh yeah, and the wheels were +45.

dhays

iTrader: (1)

235/40-17 is actually a bit smaller (about 1/2") than the stock diameter. I'm surprised they rubbed.

W0lfgang

iTrader: (5)

Thanks for all the feedback!

I've received very high praise for a set of four Enkei RPF1s in 17x9.0/35/5*114.3 on the FD since I'll be pushing 400HP once I'm done under the hood.

So that would be a 255.40.17 or 255.35.17 tire? They shouldn't hamper steering/acceleration/etc from what I can tell since they're only 15/16 pounds each.


But will these rub???

Thanks again for all the help!

W0lfgang

iTrader: (5)

Oh, 68K original miles. I got the FD at 63K miles. There are a set of Koni shocks on it, but I don't know if it's lowered, etc. How can I tell where it was set in compared to stock height? A ruler I'm sure, but I'm still learning about my car and loving every bit of it too! Thanks again.

Mahjik

iTrader: (1)

Depending on your suspension setup, you'll definitely have to roll the fenders in the least. That's a fairly aggressive offset. If you look here, Rishie ran a special group buy for the +45 as it's a less aggressive fitment for the car (i.e. less things to deal with):

https://www.rx7club.com/showthread.php?t=601552