Tow vehicle tire cupping

[Connie Estep]

I'm wondering if electric brake problems on my Scamp could possibly have caused cupping on all four tires of my Honda Pilot. I just found out that all four tires on my Pilot are cupped and need to be replaced. Just before my 1st two trips with my Scamp (in Sept) I had the electric brakes hooked up and adjusted (I have a Prodigy controller) and other work done before starting. I did a 60 mile initial overnight, then did a longer camping trip about 460 miles (round trip) to Dash Point.

I had a brake adjustment problem develop sometime during the Dash Point trip. The trailer brakes began grabbing to the point of tires squealing. It was especially bad driving through Federal Way as lots of stop & go. I was trying to use the least pressure possible on my car brakes but still lots of tire squealing from the electric brakes grabbing. I had the brakes readjusted when I returned and took notes on how to do it if I ever need to again. I didn't have the Scamp out again after that.

Before leaving I had the Pilot shocks and struts replaced and tires rotated. Tires were good at that time. Since then I've put about 2500 miles on the Pilot. I was quite shocked that this cupping had happened and that my very expensive All Season tires (with 26,000 miles) need replacing. I've checked on-line about all the things on the Pilot that can cause this problem and will be checking those out, but wanted to check with the Forum to see if the trailer brake problem might be the culprit. My Scamp tires are still covered and haven't looked at them yet but certainly will also do that.
Connie Estep

[RV Doctor]

Hi Connie. What tires and always at spec pressure as per your drivers door jamb placard? Assume the tire shop which did the install was reputable. It isn’t common for a trailer towing behind a suitable vehicle to cause cupping. I’d be interested to know what setting you had on the Prodigy and what boost level, if any.
Also, do you use an Equalizer hitch or just all tongue weight on the Pilot.

[gordon2]

I don't know about the tug tires cupping.. it could be unrelated to the trailer brakes grabbing. As for the trailer brakes grabbing... is it one wheel, both wheels, or you can't tell? (do you leave skid marks on both sides at times?) If it is one wheel, then it sounds very much like a failed inner bearing seal that allowed grease to get on the brake shows and drum. Rather than making them slip, they grab. Both could have failed at the same time but thats less likely.

Improper use of the easy-lub has been known (by me ) to cause inner bearing seal failure.

[Mike Magee]

Connie, I'm no expert on tire cupping but I think I've been told by tire stores that it is caused by alignment problems. So I'm wondering if maybe the shop misaligned your Pilot or something. I can't imagine cupping on the tow vehicle tires being caused by grabbing brakes on the trailer. I'd take it to another tire store that offers free alignment checks, and if they give you a printout of the results showing it's got the wrong caster, wrong camber, or (my guess) wrong toe-in, I'd take that back to the original shop and demand new pro-rated tires and a new alignment.

When you say the trailer brakes squeal, that makes me wonder. Because if my trailer brakes are set too strongly and cause the brake to lock up, the tire makes a rubbing noise as it skids on the pavement... not a squeal! Squeal sounds like maybe the brake shoes got too hot and got glazed, or else they are about worn out (sometimes shoes or pads have a final bit, before wearing through completely to the steel backer, that makes such a noise to let the owner know they're about done for). Can you confirm that either trailer tire is locking up, by observing them in your side mirrors or checking for skid marks? If they are not, I think it's time to look at those brake shoes.

It sounds to me like you have two separate, unrelated problems.

[k0wtz]

my volkswagon beetle did this I finally tracked down bearings were wore out on all 4 wheels!

bob

[stevebaz]

My guess there is an alignment problem with your front end on your pilot. By rotating your tires you moved bad tires to the rear and started a new problem on the tires that were rotated thus ending up with 4 bad tires. I would recheck the total load you are carrying in the car and the actual hitch weight with your trailer fully loaded. If you are over loading the rear of the car you may be inducing an alignment problem as you unload the front wheels. A weight distribution hitch might be required. You might have to get an alignment specialist involved and have the alignment checked with the trailer hitched up and fully loaded. You will probably have problems finding someone willing to take the time and really diagnose the problem. Especially not a tire shop.

[Raz]

Electric brakes use a magnet to grab the side of the brake drum when energized. The magnet is attached to a swing arm that forces the brake shoes into the drum. When you adjust the brakes you are setting the distance between the brake shoe and the drum. If the brakes were properly adjusted then I doubt readjustment will cure grabbing. You need to have the drum removed and the brake mechanism inspected. Rust or a lose magnet would be my guess. When were the bearings last greased? A good technician should lube the brakes when the drum is removed.

Here are some pictures of the brakes with the magnet attached to the swing arm. The magnet is held in place with a little clip. The brake shoes should move in and out freely when the arm is moved from side to side. The springs cause them to return.

[Jon in AZ]

Cupping is usually caused by worn shocks or struts. You said you just replaced struts and shocks. What symptoms led you to do that? Did you buy the tires before or after replacing the struts?

In my research a couple of sources mentioned other uneven wear patterns can sometimes be misdiagnosed as cupping. In particular, feathering, a similar up-and-down wear pattern, is caused by improper toe-in. You did not mention an alignment. Was one done in conjunction with the strut replacement?

[Eddie Longest]

Just my guess. Do you have a WDH? If not the tongue weight and stuff packed in the rear of the Pilot can cause the rear to squat down. In an independent suspension vehicle this induces positive camber (top tilted out) on your front tires and negative camber (top tilted in) on your rear tires. This can cause irregular tire wear. If the vehicle has AWD this could really cause tire issues. I would think brake issues with the trailer would bee seen as low gas mileage not tire issues in your tow vehicle. Again this is a WAG without seeing the tires, vehicle or hitch set up.
Eddie

[Jon in AZ]

Wouldn't camber issues tend to cause inside or outside wear, not cupping or feathering?

[Eddie Longest]

That is true when you have a straight rear axle and only the front tires with the camber issues. But when the front and rear axles are both out of alignment at different angles who knows what wear pattern you might get. Like I indicated, just a guess. Just something else to look at. With the shocks and struts just being replaced I would take the Pilot somewhere else to have the four wheel alignment checked. OP did not indicate if the vehicle was aligned after a strut change. For me an alignment is follow up maintenance after a strut change.
Eddie

[Mike Magee]

Yeah, it was my assumption that any decent shop would automatically do an alignment after changing shocks & struts because the disassembly/reassembly process and new components can change the alignment. But I am wondering if her shop did one!

[ehoepner]

You have some mechanical problems on your tow vehicle. Bearings going bad, ball joints, tie rod ends. Check around and find a reputable mechanic and take it to him.

[vintageracer]

Tire "Cupping" is caused by incorrect "Toe In" on the alignment. Given the fact that you Pilot has independent suspension in the front and back therefore you will have a "Toe In" adjustment front and rear.

IF your Pilot is properly aligned for driving without a trailer you will have no tire wear/cupping issues. IF this is the situation then the trailer could be the cause of your tire cupping issues IF this occurs after driving for awhile with the trailer attached.

It is possible for the trailer to cause a cupping issue IF you have the trailer too heavily loaded on the tongue/hitch. This will lower/sag the rear suspension of your Pilot therefore causing a mis-alignment in the front-end by raising the front-end of the Pilot UP thereby changing the "Toe-In & Camber" and also the rear suspension by compressing the rear suspension and again causing "Camber & Toe-In" changes in alignment due to the added weight on the rear suspension. You would have drive a lot of miles (3K+) with the trailer connected to the vehicle to develop a "cupping" tire condition caused by the trailer alone. The trailer brakes are NOT a cause of tire cupping on your Pilot.

First things first.

Go and have the alignment on the Pilot re-checked with specific attention to the "Toe-In". IF the "Toe-in" and other alignment parameters are correct for the Pilot then you have situation where you are too heavily tongue loaded with the trailer attached to the Pilot OR your rear suspension cannot properly handle the additional tongue weight when towing the trailer.

I suggest either way you take a look at "Timbren" products as a possible solution to help with this situation AFTER you determine the REAL CAUSE of your tire cupping issues.

http://timbren.com/

[bookernoe]

Lots of different answers here. Here is an article that may help. My experience is with a 2008 Honda Pilot, 2WD towing a 3500 lb, 350 tongue weight Casita. In 6500 miles my rear tires were worn fairly severely on the inside, from splaying outward. This trip was with a lightly adjusted Equalizer hitch.
https://www.popularmechanics.com/car...bout-your-car/

[k0wtz]

of all the answeres ed has the best one. car wheel bearings going bad will cause this and you can check it yourself. Jack the car up on jack stands and lift on the tires if you have play you have bad bearings. bob

[k0wtz]

now saying that you can buy separate bearings but I advise against that those bearings have to be pressed in just buy the whole thing and be done with it


bob

[Jon in AZ]

Originally Posted by bookernoe

Lots of different answers here. Here is an article that may help. My experience is with a 2008 Honda Pilot, 2WD towing a 3500 lb, 350 tongue weight Casita. In 6500 miles my rear tires were worn fairly severely on the inside, from splaying outward. This trip was with a lightly adjusted Equalizer hitch.
https://www.popularmechanics.com/car...bout-your-car/

That agrees with other posts I've read on this forum as well as the Pilot owner's forum. Inside wear on the rear, not cupping, from towing near the tongue weight limit. My recollection is the OP has a 2011 EX-L 4WD with a 450 pound hitch rating. A Scamp 16 should be well below that.

When you review the article, note the distinction between cupping and feathering (heel-toe wear).



If it's cupping, I'm actually wondering if it got started before the struts/shocks were replaced and the wear pattern, once established, continued afterward.

If it's feathering, then it seems like an alignment issue. It could be related to pulling the trailer, but I personally think that unlikely.

Regardless, I feel your pain when it comes to the cost of tires! Just recently had to buy a new set for our 2011 Pilot. Ouch!

[bookernoe]

I should add that the Honda manual specifically prohibits weight distributing hitches on the first generation models like mine. Mine was extremely lightly loaded, at the lowest possible settings. Handling was excellent across the board with the wdh. I just didn't realize it was eating my tires for lunch.

[Mike_L]

Your trailer isn't a likely cause. It's almost always a suspension issue with the tug.