tire size vs compound

[1985olds]

I had 225 (cooper cobras) wide tires on my 85 cutlass and they treated me well. They would allow oversteer at there limits, but they were controllable. I switched to a 275 (Sumitomo) wide tire and now the car the car grips well in corners, but oversteer is unpredictable and hard to get back. My questions are is this the nature of a higher grip potential with the wider tires or was it from a harder compound? I am looking to order new tires and was thinking about either stepping down to a 255 wide tire or staying with a 275 with a softer compound (falken azenis) or both. Any thoughts?

[andrewb70]

Did you change the tire aspect ratio? Shorter sidewalls will tend to break free with less warning than taller sidewall tires.

Andrew

[1985olds]

Did you change the tire aspect ratio? Shorter sidewalls will tend to break free with less warning than taller sidewall tires.

Andrew


yes, shorter sidewalls by a very small amount. i was wrong about the previous tire, it was a 235/50/17 goodyear to a 275/40/17 sumitomo. Is there anything I can do to get a little more "forgiveness" and predictability?

[CSG]

Sumitomo's are known for being hard without a lot of grip. I believe you are just finding the limit of the tire.

[1985olds]

Sumitomo's are known for being hard without a lot of grip. I believe you are just finding the limit of the tire.

Thanks, the sumitomos were free to me new, so i couldnt say no at the time. I have been looking at new tires and think I want to try the Falken Azenis R615k any opinion on these tires?

[andrewb70]

Thanks, the sumitomos were free to me new, so i couldnt say no at the time. I have been looking at new tires and think I want to try the Falken Azenis R615k any opinion on these tires?

I used to run them on my GTO and I thought they were excellent. I was doing nice, controlled drifts during a track day event. A lot of people really like them. Matter of fact the picture in my signature was taken at that event.

Andrew

[1985olds]

I used to run them on my GTO and I thought they were excellent. I was doing nice, controlled drifts during a track day event. A lot of people really like them. Matter of fact the picture in my signature was taken at that event.

Andrew


I'm not saying they are a bad tire, I just noticed when I installed them that the predictability and controllability was significantly less than before. With the 235 the car would slip, but would hold it where ever you put it for as long as you wanted it. The sumitomos just lack in my opinion the controllability. I'm not sure it is even the tire itself or the width of the tire vs rim width. I cannot remember of the top of my head the rim width, its either a 8 or 9 inch rim. Im tempted to put 255's on next.

[andrewb70]

I'm not saying they are a bad tire, I just noticed when I installed them that the predictability and controllability was significantly less than before. With the 235 the car would slip, but would hold it where ever you put it for as long as you wanted it. The sumitomos just lack in my opinion the controllability. I'm not sure it is even the tire itself or the width of the tire vs rim width. I cannot remember of the top of my head the rim width, its either a 8 or 9 inch rim. Im tempted to put 255's on next.

I was talking about the R615 tires....That is what I had on the GTO.

Andrew

[1985olds]

I was talking about the R615 tires....That is what I had on the GTO.

Andrew

Ahhhhhhh, got it. Sorry my brain is working at 60 percent, I have been working a weird schedule. Thank you