Apexi

I have a set of Volk racing 17" TE-37s with:
Front: Dunlop W-10 235/40/17
Rear: Advan R-compound 225/45/17

I had to put the more narrow Advan R compound tires on the rear, because the car would get twitchy with them in the front and normal tires on the rears. However, today I noticed that the R compounds had worn down right to the belt, but only on the inside of the tire.

Is there any reason why the tire would wear only on the inside? The fronts are fine. My only guess is that having narrower tires in the rear would cause this kind of wear???? Anybody have any clues?

Anyhow, any ideas on what i should put on the rears now?
I'm thinking of 255/40s but not sure if they would fit on a 8.5" rim, OR if they would work well with 235/40s in the front. I calculated the overall diameter and it turns out as follows:

Stock rx-7 tire/wheels: 24.86"
235/40/17s on the front: 24.4"
255/40/17s on the rear: 25.03"

I guess it would be closer with 235/45s on the front with a 25.33", but it's too late to change. Would there be any problems in terms of wear, handling with the larger overall diameter in the rear vs the fronts?

crnchyfrog

Are you rolling with modified suspension? If you are you might want to have you camber checked(might want to have this checked anyways). You probably need to get a camber kit to remedy this problem. The same thing happened to me on my old car (not an FD) when I was rolling on Eibach Springs and had 205/40/ZR17 tires on my Enkei TBS11 17X7 wheels.

Apexi

no suspension upgrades.

Thing I cant figure out is, that with the stock tires/rims, there's no unusual wear.

Just with the 225 R compounds on the rear. I'm thinking it's due to the more narrow width of the tire, and the grippiness of the R compound vs normal tire?

dhg11

Umm... if your car feels twitchy with a wider tire on the back and your narrower R compound tires make that go away, you should go get your alignment checked. Perhaps the reason your car doesn't feel as twitchy with the narrower tires in the rear is a direct result from using stickier R-compound tires. To be frank with you, your alignment sounds fucked. Just because you're still using the stock suspension doesn't mean that your alignment hasn't gone off over the years.

cewrx7r1

iTrader: (2)

Everytime you get new tires, change any major suspension componets, or wheels; it is a MUST to get the suspension re-aligned.

With wider wheels, less negative camber should be used.

Go to the Pettit site for FD alignment values for diff wheels/tires and type of driving.

Apexi

I just checked out the Pettit racing website, and looked at their alignment specs. According to them going from a 16" wheel to a 17" wheel, the rear camber should be adjusted from -1.1 to -0.3
That's a huge difference and alot less negative camber in the rears I'm assuming. Perhaps that's why the R-compounds had such excessive inner edge wear?????

PS. I just realized today, that I probably hold the world's record for running a R compound tire! Almost 19K miles...ran it right down to the belt... eek.

Nobody ever mentioned that the alignment should be adjusted when you get larger wheels...first time I heard it.

Thanks.

kevinmfaust

Thats why your car was twitchy in the first place.......alignement. You can put any kind of tire in the world on you want and if it is pointed in the wrong direction it will make the car twitchy and it ware out unevenly.

DarkKnight

My car did the same thing.....it was the alignment! i would take it and get it checked out. That is most likely the cause