Power Wagon Registry

I bought a new set of 37x12.50 Cooper STT Pro's from Discount Tire the other month. The are on stock rims. From day 1 these tires have been shaking from about 45-70mph. I have taken it back to discount tire 4 times already which they have tried balancing them every type of way possible including road force balancing. The truck is also pulling to the right pretty hard and I never noticed that before these tires. I got the alignment done and still pulling. I was starting to think I had a bad tire, but Discount said they were not able to find a bad tire. They ended up putting the front right tire to the rear and still pulling right. WTF! Is there anything in the suspension I should check with these issues? Any suggestions what could be wrong?

Did they give you a print out from the alignment? Do you have cross caster?

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I have stock size stt pros, no balance issues but mine do pull to the right. It was very noticeable when I first had them installed but not so much now with 27k.

TankerZak wrote: ↑

Sun Dec 16, 2018 11:39 am

Did they give you a print out from the alignment? Do you have cross caster?

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They did give me a print out. I will have to take a look at that and get back to you.

13powerwagon wrote: ↑

Sun Dec 16, 2018 11:50 am

I have stock size stt pros, no balance issues but mine do pull to the right. It was very noticeable when I first had them installed but not so much now with 27k.

I have read on here that some tires have a right hand pull, but damn it's annoying. My steering wheel is pointing to the left a little just to keep the truck straight.

I feel your pain. When I first got them installed I pulled out of discount and immediately thought something was wrong because of the right hand pull. Went back and had them rotate back to front and left to right with no change. As they have worn the pull has become less noticeable, Thuren’s alignment specs helped as well.

Not surprised, Cooper is a budget tire and gets negative reviews for excessive weight to balance. I'd return them, it's just too much trouble to try to make questionable tires work. For reference, my 40's aren't balanced and are not even close to how your describe your 37's.

I've had zero issues with my 37" Cooper stt pros on stock wheels. I'd push for an exchange.

Steve

Reloaderguy wrote: ↑

Sun Dec 16, 2018 1:35 pm

Not surprised, Cooper is a budget tire and gets negative reviews for excessive weight to balance. I'd return them, it's just too much trouble to try to make questionable tires work. For reference, my 40's aren't balanced and are not even close to how your describe your 37's.

Crazy! I did a ton of research on these tires and didn't come across anything about balance issues.

EasyDoesIt wrote: ↑

Sun Dec 16, 2018 1:45 pm

I've had zero issues with my 37" Cooper stt pros on stock wheels. I'd push for an exchange.

Steve

Did you ever have any pull to the right?

Im surprised Discount even mounted them on the stock wheels. They wouldnt do that for me because the manufacturer recommends a minimum of an 8.5” wide wheel

None the less, if it is something you cant live with, then have them take them back and get something else. My guess is if the truck didnt pull to the right before the tire swap, well, then its the tires causing it most likely.

Cross castor cannot be read on an alignment sheet. Solid axles don’t rotate (the goal of cross caster). You would need to look at the alignment cams on the radius arms to see cross caster.

Discount Tire has their own mounting specs, for whatever reason they don’t care what the manufacturer requires. They mounted my 37’s on 8” wide tires, outside Toyo spec.

If you now have a strong pull and a balance that can’t be fixed, it’s probably a bad tire. You could do some kind of active balancing like centramatics or balance beads but neither of those are a perfect solution.

Have you tried rotating tires to see if pull changes or vibration becomes better or worse?

Discount has mounted both sets of my tires too without issue despite the weight issue.

16PW wrote: ↑

Sun Dec 16, 2018 2:03 pm

Did you ever have any pull to the right?

No pull to the right. I picked up my STT Pros from Discount Tire, no issues mounting or balancing. Assuming the issues came along with the new tire install, it seems like you have a bad tire or two.

EasyDoesIt wrote: ↑

Mon Dec 17, 2018 12:26 pm

16PW wrote: ↑

Sun Dec 16, 2018 2:03 pm

Did you ever have any pull to the right?

No pull to the right. I picked up my STT Pros from Discount Tire, no issues mounting or balancing. Assuming the issues came along with the new tire install, it seems like you have a bad tire or two.

I'm pretty convinced it is a bad tire or 2, but Discount keeps telling me that they can't find a bad tire. Makes no sense why these tires normally shouldn't be riding smooth and/or straight. Discount did snap off a stud on the front right when they initially installed the tires. I'm wondering if the missing stud and and lug nut could be causing the shake. I wouldn't think so, but some one else brought up the idea. Hmmm

So when are they replacing the stud?

KevinABQ wrote: ↑

Mon Dec 17, 2018 1:49 pm

So when are they replacing the stud?

When I have time to. Discount doesn't do those repairs. They sent me to a shop down the street that will do it for free (obviously). I called them up about it and they told me to be prepared to leave my truck there all day.... I haven't had a whole day to waste on that yet, but I think I should probably get that fixed before replacing these tires.

Mounting out of spec is kind of at the Managers discretion. Obviously discouraged by Corporate, but...

If the pull remains regardless of tire position, seems difficult to blame the tires. Is there another DT in your area? BTW, where are you?

FWIW, I just put a set of Grabber X3's on a couple of weeks ago, went from zero pull to slight right. I have not rotated them yet to see if it goes away.

Oilbrnr wrote: ↑

Tue Dec 18, 2018 6:17 pm

Mounting out of spec is kind of at the Managers discretion. Obviously discouraged by Corporate, but...

If the pull remains regardless of tire position, seems difficult to blame the tires. Is there another DT in your area? BTW, where are you?

FWIW, I just put a set of Grabber X3's on a couple of weeks ago, went from zero pull to slight right. I have not rotated them yet to see if it goes away.

I am in NW Peoria, AZ. Plenty of Discounts to choose from.

I got my 315 70 17 STT Pros at Sam's club and they balanced just fine. They are not the 37's but I would agree to have them look at replacing the tires. Did they try mounting them on different wheels?

Finally got around to get the broken stud repaired as well as the front end checked out. Alignment was good. Steering wheel was a little off, but they said nothing to cause the shaking and right pull. I still have the shake and pull to the right so back to Discount I go for new tires. Now the decision of just getting a new set of these or going with a different tire. I just don't want to fork out another chunk of money for a different tire.

The pull didn’t bother me that much as a lot of big mud tires cause a very slight pull. Had the same problems with 37’s and 35’s on my Jeeps. I don’t think there is anything inherently wrong with the Coopers. You might just have a couple of problem cases. If you like them, have them put a different set of STTs on it and try again.

I'm on my second set of STT Pro 37" tires. I like them and will stick with them.

The first set was 37X13.50R17LT on 17" AEV Katlas.
I purchased the tires from Discount Tire.
I never had an issue with balance on them. The only issue I did have with them was quite a bit of sidewall flex and bounce on the road.
It was pretty noticeable after they broke in around 8k-10k miles.
It wasn't so bad though that I would have changed tires had there not been a recall on the wheels.

When AEV recalled the wheels, I went back to my factory wheels/tires temporarily, since I had them already.

I eventually ended up going with a second set of STT Pros, but on a 20" wheel, as I wanted to cut down on the sidewall flex and bounce.
I went with 37X12.50R20LT on 20"x9" +18 Raceline wheels. My front tires extend out about 1/2 inch on each side.
The rears are completely under the body. If the front of the truck didn't have a slope, the front wheels would be pretty much underneath the body as well.

I did buy some aluminum hub centric rings for the 20" wheels to make sure everything matched perfectly. They were roughly $100.
The tires required minimal weights for a perfect balance and they are smooth as glass on the highway. I really like them, except I want to get more sidewall.

With that said, when these wear out, I will be changing wheel size again and going to the STT Pro 37X13.50R18LT and an 18" wheel with a +25 offset. I like to try to keep the tires under the truck. I'm sure I will see more sidewall flex and bounce again, but I think it will be worth the compromise.

16PW wrote: ↑

Mon Jan 07, 2019 8:31 am

Finally got around to get the broken stud repaired as well as the front end checked out. Alignment was good. Steering wheel was a little off, but they said nothing to cause the shaking and right pull. I still have the shake and pull to the right so back to Discount I go for new tires. Now the decision of just getting a new set of these or going with a different tire. I just don't want to fork out another chunk of money for a different tire.

Just a thought... but do you have another Discount Tire nearby? You could always go there and have them do a free balance assuming you have the free lifetime balancing. That takes both the balance machine and tech from the existing Discount Tire out of the equation. If they also come back and show all is good, it might give you some piece of mind with regards to the wheels/tires themselves.

Thanks for the input guys. I went to Discount this afternoon and had them order me up some BFG KM3's. I've been hearing that coopers are a hit or miss as far as having issues with them so I didnt feel like taking that chance again. Plus I'm only having to pay an additional $160 for the KM3's when normally it would be an additional $400 or so over these coopers. I almost went with Nitto Trail Grapplers as I've had a set in 35s on my 1500 Ram and loved them. They were about the same price as KM3's but I figured I would try something different. I've heard good things about the new KM3 and that they have made some good improvements over the KM2 especially with reducing the road noise quite a bit. I was going to go with the Toyo MT but they said those tires are a bit hard to come by and can take a while to get in. Plus I've heard that they don't have the best life compared to other MT's and the guy helping me confirmed that his 40" Toyo MT's wear out crazy fast. I should have them by Monday. Wish me luck!

16PW - are you in a snow belt? I'd be interested in hearing your thoughts on the KM3 if you are.