[Wildcat]

I had to replace somewhat new tires due to cupping wear on the rear. I have just replaced the upper control arms (see the DIY section for my step-by-step), but I'm wondering if I should replace what Honda calls the Rear Knuckle:

I thought it was a Honda-only part until I checked the "Steering" section (yes, I know) on Rock Auto, and found that Mevotech offers a knuckle:

There are no bushings available to press into the rear knuckle. Even if there were, having to press them out and back in is something I don't have the tools for or want to bother with--the extra cost of the knuckle is made up by time saved on the job.

I checked the control arm mounting bushing on the knuckle with a long screwdriver loading it and I found there was no slop or play in it. But under vehicle load, who knows? And I don't know how a new one feels either.

I installed the upper control arm to get some camber adjustability, as I may do a mild lift kit on this CR-V (maybe 1.5 inches), and figured it wouldn't hurt to get at least one bushing changed out in the rear at the same time.

I just wonder if it's worth replacing the knuckle--it's a major undertaking (which isn't a big deal), but I also don't want to go replacing something that might not cure the cupping. I had a new set of tires put on and had the 4-wheel alignment done at the same time. I may take it to another shop on the corner that offers free alignment checks just to double-check that it's OK. I noticed the new set is also getting slightly cupped, yet I rotated a lot sooner (at only 7,000 miles) this time. My old tires weren't cupped at all. Noisy, but not cupped. (Just a lousy tire.)

 

[Scott091981]

How many miles did they take to cup?

 

[Wildcat]

The newer set I just got in early July, so, probably 7,000 miles on them and I was already hearing that slight warbling sound on asphalt. It's so faint that it's just about inaudible most of the time.

The prior set was last year in June, so, maybe 12-15,000 miles on those. (Two long road trips included in there.)

The other '09 had some terribly bad tires when we bought it--they were actually growling in the rear, they were so bad. That was October 2017. Replaced the tires maybe six weeks later and everything was dead quiet. Guessing maybe 20,000+ on those tires, and they are quiet. Same Solus TA11 tires, although I went up a size in the width on mine (235 vs. 225, so the speedometer now reads correctly).

 

[Fortheloveofcar]

I take that rear alignment are all within spec?

 

[Wildcat]

I would hope so--I had the alignment done when the newest tires were mounted back in July. But I am going to have it checked at the tire store a half mile from the house since they offer free alignment checks.

The only thing different is that between my first and second road trips last year, I changed the struts. And that involves unbolting the trailing arm and the upper control arm. I never did have time to get an alignment done after that. I figured this recent alignment would correct it, but, now I'm hearing and seeing some very light cupping on these newest tires. Either they goofed on the alignment (I have used them for decades, so I trust their work), or something else is wrong, like those rear bushings dry-rotting (although they still looked and felt fine to me).

 

[Fortheloveofcar]

When in doubt get it check, since it free. It could be a combination of both you replacing the strut and/or the shop not align correctly. I saw my car get alignment, and it take micro adjustment to get it within spec. Then again it could be from your road trip, travelling over rough terrain that could have caused the alignment to be off.

 

[Wildcat]

One thing I noticed about the rear trailing arm is that the mounting holes are enlarged so that the toe alignment can be set. I wonder if those bolts were not tightened down enough after the alignment.

I did go over some rough road this summer, but I took other unpaved rough roads last summer and didn't have the issue with alignment. (That was prior to the new struts.) So possibly the bolts weren't tight enough, or the bushings took a bit of a beating.

If our dealer ever offers their 50% off alignment special again, I may have them do it.

 

[kloker]

Wildcat - Is your cupping happening on the inside or outside edges of the tires, and does it seem equal on both tires? Also, what does your dealer charge for a full alignment? I definitely need to learn more about IRS. The only possible contribution I might make is that on the front, cupping is a result of toe-in. From my decades of truck driving, I can tell you that big truck tractors have terrible front suspensions, with only relatively crude alignment adjustments. So much, so, in fact, that, even with a brand new tractor, it is impossible to avoid cupping on the steer tires, as even the most accurate possible toe-in settings are not close enough to prevent it. This is mostly due to the fact that the steer axle must be rated at the standard 80k pound load rating, so that the front end parts are too heavy duty in construction to allow for a very fine adjustment, at least as truck makers manufacture them. The consequence of this is that steer tires must be replaced far earlier than their 120k mileage ratings. I've had countless steer tires that couldn't even make it to 50k before they were cupped so badly they shook the whole truck and made it unsafe, not to mention impossible to steer in a straight line. Considering that a steer tire runs about $600, this amounts to a lot of maintenance expense on a vehicle that travels 125k or more per year. It also means the truck is not much fun to drive for about half of that tire life. Also, the two sides never wear the same, so from the driver's seat, the truck is only really pleasant to drive about a third of the time. The rest of the time it shakes. Even the newest models have not improved. And when you take just that one factor and then add all the other different types of wear they are subject to, you can always walk up to any big truck and see the obvious evidence of all this. For the last many years of my career as a linehaul driver, I drove Penske lease trucks, and at their shop, whenever they replace a steer tire, they always have to adjust the toe-in, because it's always off. The only trucks I ever drove that were better in this regard were extended hood Petes, which do not have setback front axles, so the front end geometry is better.

I suspect that there are similar concessions made by carmakers with these IRS suspensions. But my only experience with that came with my '73 Corvette. It was terrible. Interestingly, my '91 Civic Wagon never had the slightest issue, front or rear, all the way to 200k.

Just for fun, here's a picture of the heavy haul truck my youngest son Ryan drives. He's actually out in it this morning. It's a 2000 model, with a '99 converted 3406 and a 13.

 

[Scott091981]

Thats a beast!