Tire repair; TPS; and alignment

Friday afternoon, the tire pressure light came on. I couldn't tell which one so that evening, I bought a pressure gauge and found the right-side, rear tire was at ~24 psi while the others were at 44 psi. Late, I simply pumped the low tire back to 44 psi, the tire pressure sensor indicator went out and I and decided to check it Saturday.

Saturday about 12 hours later, it was down to 38 psi and I knew we had a slow leak. So I took it to Firestone for repair and they found a small nail, dead center, an easy fix. At the same time, I bought a life time alignment service:

Front : Left
-0.1 - Camber (-1.3 to 0.2)
5.7 - Caster (2.4 to 3.9 normal)
0.0 - Toe

Front : Right
-0.5 - Camber
5.5 - Caster (2.4 to 3.9 normal)
0.0 - Toe

Rear : Left
-1.4 - Camber (-2.0 to -1.0)
0.12 - Toe (0.03 to 0.28)

Rear : Right
-1.4 - Camber (-2.0 to -1.0)
0.23 - Toe (0.03 to 0.28)

Well it looks like time to order some EZ-shims and a camber adjustment bolt. I'd like to get the right front camber closer to neutral and bring the rear toe and camber closer to vertical and neutral. The time for perfect alignment is while the tires are new.

As for the tires, I've got to double check the pressure and then reset the tire pressure sensor:

The owner's manual has a sketch but the photo really identifies the switch location.

Bob Wilson

What does that service include -- and what is the cost?

That photo is so much better than the info in the manual. For those with the SKS system, it is easier to do by feel. If you find one button, then feel for the ridge (either right or left of the button). The button to the left is the TPMS button, the one on the right is the SKS button.

Not sure how much different the 2010 front suspension is, but you may be able to correct the front camber without a camber bolt - there is a small amount of movement available even with the stock bolt(s).

I know what the TPMS reset button is (I used it when I first got my car and adjusted all the tires to the correct pressure), but what is the SKS button for?

It cost $150 but it means every time I get the tires rotated, twice a year, I get a free alignment check. Since it is a 2010 Prius, I also get free belt checks and changes. <grins>

Bob Wilson

The SKS button is for turning on/off the Smart Key System.

I don't know that YOU are missing anything, but it sure looks like Bob is! I thought the III came with they SKS, so I'll need to check my now, for certain.

hmmm... pkg 3 comes with SKS for driver door only . i dont see the button either

AND, my car does not have it. i have SKS for all 3 doors (well 2 doors and the hatch)

in fact, where is the SKS switch at?

My car doesn't have a SKS button--at least not near the TPMS button.

:caked:

Curious that the front caster is that far off for both sides. Is it possible that Firestone does not have the correct ranges, since the 2010 is do new?

Oops...sorry for the typo. Last line should have said "2010 is so new"...

FYI--you can edit your posts--click on the edit button on the lower right corner.

Nope. Not when posting from a Blackberry using the mobile version of the PC forum. Which I was when I left the post. Otherwise I would have fixed the error.

On my laptop....of course.

Hello Bob, Rick:

What's the possibility that Firestone has the wrong ranges for caster? It's just strange (I think) that the caster on both left and right front are about the same, and also that they are so far off from normal.

I'd definitely verify the allowable caster ranges for the 2010. After all, Toyota had the wrong octance listed in the owner's manual originally (88 vs. 87 octane). What's to say that the wrong information could not have been provided on alignment caster? So maybe 5.5 is actually correct.

Just a thought.

I'm not worried about caster and suspect the higher angle contributes to the better road-following of the 2010. It is camber and toe that I want to fix before more rubber is lost. I agree, they probably only had the NHW20 model specs to use but they should be close enough.

You do bring up an interesting thought, after market caster change. My NHW11, 2003 Prius, still has the road-neutral feel. I'm now wondering if I could figure out a shim setup to increase the caster angle, perhaps the highway tracking would be improved. ... hummmm.

For good friend HTMLspinnr, I understand the vehicle stability control (VSC) systems rely on an angular rate sensor as well as wheel and operator inputs. I doubt the mechanical angles, other than caster, are that important as long as they are within the manufacturer's limits.

Bob Wilson

Duh! Sorry, Bob. You wrote "camber", but my brain saw "caster". My apologies. That's what I get for reading too fast!

But I guess that brings up another question. If I'm reading this correctly, the range you show is "-1.3 to 0.2". I'm assuming that is a "positive" 0.2? That, then, would be the same exact range that I see for the G2 cars: +0.2 to -1.3 for the left, and -1.3 to + 0.2 for the right.

If so, then your values of -0.1 and -0.5 would be in spec, would they not? Maybe not in the middle of the range, but still within spec. Is there then any real value in trying to improve them?

My G2 is -0.7 on both sides.

Best wishes,

I was working at NASA HQ when I learned Mike Newell would soon join the team with a lot of enthusiasm from some of my fellow engineers. I asked one,"Tell me about Mike?"

Don replied,"Oh you'll like him. He is just as anal retentive as you are."

I burst out laughing and sure enough, Mike actually taught me a few tricks about 'details.' <GRINS>

So I go back to first principles ... perfect alignment when the tires have less than 1,000 miles is a good thing ... it means I should be able to run them for a long, long time. <GRINS>

But this brings up a new subject.

Bob Wilson