CAUTION: Hymotion and all PHEV owners! Tire Treadwear!

[TheForce]

This could be a potential problem with all PHEV owners!

I rotate my tires every 10k miles ( I know I should do it at 5k but I'm lazy ) and I have not rotated my tires since I got my Hymotion battery installed. This is what I found today when rotating the tires.

The outer edges of my tires are getting pretty much bald but the 3 center tread lines are still at least 3.2mm thick. Actually that are about 3.5mm, 5.2mm, 3.7mm

This is a pic of the rear tire.



This is a pic of the front tire to compare. The thickness on these are about 4.0mm, 4.2mm, 4.2mm



I'm not to concerned about this right now because next year I'm going to get new tires anyway.

In the mean time I have inflated my tires opposite of what is recommended. Normally you have 2lbs more in the front. Well I put 2lbs more in the rear to see if that will make a difference.

I'm now running 48psi front and 50psi rear.

Note: I took the pictures after I rotated the tires since I did not have my camera with my when I rotated them.

[fuzzy1]

About how much weight does the Hymotion add to the rear?

[TheForce]

The Hymotion battery is about 200lbs.

[krousdb]

My tires wore that way before installing the PHEV. This is normal wear.

[DonDNH]

Originally Posted by krousdb

My tires wore that way before installing the PHEV. This is normal wear.

I wouldn't consider that normal tire wear; an alignment adjustment is likely due to compensate for the extra weight.

[TheForce]

I did not notice that much wear the last times I rotated the tires.

[mrbigh]

Originally Posted by DonDNH

I wouldn't consider that normal tire wear; an alignment adjustment is likely due to compensate for the extra weight.

I agree, had the same problem and was corrected with front end alignment

[hobbit]

200 pounds is not really an inordinate amount of weight, but
it *is* in the very back and possibly exerts a little more leverage
at the rear axle. But you should definitely check for misalignment,
especially if you feel any treadblock feathering *across* the tire
as shown in my 100k rundown.
.
One should also note that if the weight *is* a cause of increased wear,
the folks who put in beefier springs to accomodate a PHEV rig won't see
any tire-wear benefit from that...
.
_H*

[Fred_H]

From your description, I am fairly certain that the rear axle has excessive toe-in, and too much or close to the limit negative camber. But to be absolutely certain, you would have to have it measured.

The added weight does change the alignment somewhat, but not that much. The increased weight increases wear in general, thereby exaggerating a condition that was probably there already.

The increased rear tire pressure should help, but I wouldn't recommend making it any higher than 2 or 3 psi above the front, for handling and safety reasons. More frequent tire rotating should also help. However, these measures will only reduce the symptoms, and not cure the problem.

If indeed the rear toe-in is excessive, then unfortunately it is difficult to correct, because it is officially not adjustable. According to posts in other threads, the official repair is the replacement of the complete rear axle. Also according to posts in other threads, there is an unofficial adjustment method for do-it-yourselfers, which I consider to be risky unless performed with the proper material, the right tools, and the correct torque.


My rear tires, especially my winter tires, have a similar wear pattern, but to a lesser extent and a bit more wear on the outer side. I rotate about every 8-9k miles. About a month ago I had the alignment checked at the local Toyota shop. I watched the mechanic check the front alignment, which measured near perfect, and then he picked up his equipment and started putting it away. I asked him if he could please also measure the rear alignment, and after thinking a moment, he said yes, that would be possible. Obviously rear alignment is normally not measured there, and would not have been measured if I had not made sure.

The rear alignment turned out to have an excessive total toe-in of 2.75° and camber in spec, but towards the more negative side.

The shop manager spent half an hour trying to find an official remedy from Toyota, but didn't find anything. He sent an email to Toyota, asking what to do, and hasn't heard from them since.

I'm planning to do the do-it-yourself adjustment within the next few weeks, unless Toyota answers before then.

[zcat3]

Although the Hymotion system weighs about 180 lbs I believe, you do lose maybe 20-30 pounds be removing the spare tire and related items. I had new tires installed right after the Hymotion system went in and have 12,000 miles on them now. I will take a look at them when I get a moment to see if I have similar wear. One thing I noticed right away with the Hymotion system is that the car's handling is much more neutral. I did the math and posted it somewhere on Prisuchat - IIRC I determined that although the car still has more weight in front, it is around 55/45 now. With that in mind I adjusted my tire pressure to make the rear almost the same as the front - feels right to me.