I just put on a new set of Kumho SPTs recently and after 3,500 miles, they're starting to cup a good amount on the two front's on the inside, more so on the driver's side. The tires were perfectly balanced, wheels always torqued to spec and alignment is near perfect. I checked the suspension and everything looks tight.

I have 195/55/15 on stock alloys and everything else is stock except for Tokico blues at stock height.

Any ideas on what's causing this, or anyone else have cupping problems with theirs?

 

This website describes the most likely causes of cupping. It's written for truck tires, but it's just as applicable to cars.

 

On my 50 mile commute back home today, I decided to drive slower than usual, and realized that the cupping is probably because I'm an idiot and don't slow down for on/off ramps, and push my tires harder than it can handle.

I guess that means I should stop driving like an idiot.

 

How's the alignment?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chahsiubow &raquo;</TD></TR><TR><TD CLASS="quote">On my 50 mile commute back home today, I decided to drive slower than usual, and realized that the cupping is probably because I'm an idiot and don't slow down for on/off ramps, and push my tires harder than it can handle.

I guess that means I should stop driving like an idiot. </TD></TR></TABLE>

Pushing your car may make the tires wear faster than otherwise, but it shouldn't cause cupping.

 

Actually, after rotating the tires and re-inflating to stock specs, I started getting vibrations in the steering wheel after 70mph and a slight pull to the right. I didn't have any of these problems before the rotation (yes, I did back to front in the proper direction). I'm going to bring my wheels in to get rebalanced today and have them check my alignment. The last time I had the alignment done (a little over half a year ago), the front camber was on the verge of being out of spec in the negative.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">

Pushing your car may make the tires wear faster than otherwise, but it shouldn't cause cupping.
</TD></TR></TABLE>

Even if you make a 90 degree turn too fast so one tire skips sideways? I've done that on occasion.

 

Nope.

When you say that your tires are cupping - do your tires look like the ones in that link?

 

Not as pronounced, since I only ran these for 4k miles, but I can see the scalloping and feel tiny little hills forming on the inside of the front tires.

 

If the scalloping and hills are uniform around the circumference of the tire, that's not cupping. It can just be effects from getting them hot. In which case, it's nothing to worry about.

If you actually have differences in tread depth around the circumference of the tire, as shown in the photo, THAT is cupping.

 

So is it the design of the tire to do that? Now that they're in the rear, even in the morning before I hop in the car, I still see uniform hills around the circumference of the inside of the tires. The rears (now in the front) don't present that problem. So I shouldn't think twice about it?

 

I'm not sure what you mean by "uniform hills".

Do they look like the photo below?

Or, can you take a photo in which it will show up?

 

I had the SPTs and autocrossed with them a bunch of times and drove like an "idiot" sometimes. Never had any issues with them.

 

They don't look that bad. It's not a noticeable pattern of wear from far away, but as i run my hand around the tire, i can feel the inside track isn't smooth and goes a tiny bit up and down. I changed out my front brakes and rotors last night, and found out one of the bolts on the caliper was seized. I hope that was the problem.

 

got SPT for 4 month now and everything is fine!

 

2 Track days and lots of tough street driving on my SPTs, even with a quite aggressive alignment, and I've got no cupping. Alignment issue?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chahsiubow &raquo;</TD></TR><TR><TD CLASS="quote">They don't look that bad. It's not a noticeable pattern of wear from far away, but as i run my hand around the tire, i can feel the inside track isn't smooth and goes a tiny bit up and down. I changed out my front brakes and rotors last night, and found out one of the bolts on the caliper was seized. I hope that was the problem.</TD></TR></TABLE>

that is not the problem. from my experience, cupping is caused by unbalanced tires and/or shock/strut problems. what kind of suspension are you running and is there any signs of leaking? any rubber boots that might be in the way of suspension travel?