Hello I'm asking for opinions and advice regarding a new unsafe sway/wander following tire replacement and an alignment. It feels like I have a low rear tire when making a steering correction at speeds above 50mph. I have a 2005 Prius with 37K miles and ran the OEM GY Integrities until 2 weeks ago. New tires: 4 - Hankook Optimo H727, 195/65/15 M&B on 4/13/2011 Alignment at Toyota Dealership: 4/20/2011 Inflation: I have experimented with 42F/42R then 34F/32R and settled at 38F/36R for now. Road conditions: same on wet and dry pavements. Cool temps 40F-60F Previously the OEM Integrities were loud but firm at 42F/40R and gave good precise handling in my opinion with a minimal wander on highways. After the alignment I feel like I am correcting and weaving down the road at highway speeds. At higher inflations, the car would almost fishtail! Like running a flat rear tire. I have learned so much from you folks on PriusChat (or as my friend says "your PriusCrack"). I'd like your advice on the following... Should I do (or have done) any of these? - re-align steering wheel angle sensors - reset three steering torque sensors - reset yaw-rate sensor - reset linear valve sensor - zero point calibration (which I believe the dealer should have done during alignment) - calibrate torque sensors - do the rear values indicate shims needed? I see that adding Toe-In has helped correct this sway problem in some 2005's. "Check that the front toe adjustment has them toed-IN slightly. The spec allows zero toe, which will cause wander. Aligning to spec isn't good enough" Any thoughts and advice will be appreciated. Alignment data attached. Thanks, olerox
You had the new tires on for a week before getting the alignment. Did you have the wander/fishtail symptoms for that first week as well? If not, take it back to where you had the alignment done and complain. It looks like you have more a problem with zero front toe, rather than needing to shim the left rear. This was done at a Toyota dealer, so they ought to stand behind their work, sloppy as this was.
The week with new tires and prior to the alignment the car tracked well with no fishtailling sensation. I just called the dealer and have an appt for Monday to re-adjust the alignment. BTW They made a note on my service receipt that my tires are not the recommended size. 195/65/15 Should I insist they recalibrate any of these yaw, or steering sensors? Thanks
The total front toe-in should be slightly positive. Previously it was negative (which means the tires are toe-out), then after adjustment it was less negative. I think that the rear toe-in is excessively positive and could be corrected with shims.
If they say anything about the tire size tell them you are correcting for the widely known 2mph too fast speedometer error
That's a good question. Yaw rate should be zero pointed after making an alignment change. But I think the consequence miscalibration would be having the VSC light come on, due to the reading being below threshold but not zero, rather than a drivability problem.
Today I took the Prius in for an alignment readjust. I have to say Broadway Toyota was very pleasant to deal with today. I spoke with a veteran tech to look at the previous alignment values and tell me what his thoughts were. He liked the zero readings and suggested I rotate tires to compare behaviors before adjusting the alignment. I pushed and he agreed to humor me and adjust as suggested by the wise souls here at PC. The alignment tech called me before starting and double checked what my goal was and did as I asked, he me to report to him my feedback after some time driving. The bottom line is I noticed a HUGE improvement with handling during my 35 mile drive home tonight. The car felt much more centered and 'in control'. Thanks to Patrick, seilerts, cyclopathic and F8L!
-0.05 Degrees of Toe In on each side, for a total of -0.10 Degrees Notice how the remaining values 'wiggled' a bit...who knows why. I know I hit no curbs or big bumps to change the readings in the past 2 weeks since the first alignment yet the values were tweeked.
If I'm reading your charts right, 1st time in your total toe was -0.14 deg before alignment -0.03 deg after alignment 2nd trip to the shop +0.03 deg before alignment -0.10 deg after alignment It look like you are almost back where you started with the 0.10 degrees toe out. ?? I didn't look at all your numbers, but the -0.03 to +0.03 change the car appeared to have made on it's own is nothing to be concerned about. There is rubber in the suspension and the way the car is driven right before the alignment and how it is driven onto the ramp can have an effect. The alignment machine isn't perfect either. A 0.10 degree change in total toe between measurements is approximately nothing in the real world. I am surprised that the car feels stabler with negative front toe.
Crap XS650, Did I do just the opposite of what I should have done? I thought negative Toe-In was making the front more 'pigeon toed'. Making the tires point toward each other more by increasing the negative? Did I really want the front tires to point a bit away from one another? I thought bringing the Toe closer to the original value (prior to 1st align) -0.07 L&R was the direction I wanted since the handling was better at that point. Do you think the improved handling is now at the expense of pointing the front at a detrimental angle that will increase the tire wear too? Sheesh. I can truthfully say I do not 'get it'.
Your front toe is well within spec, it should give good tire life. What surprises me is that the toe out improved your handling. If you like the way it feels, there is nothing wrong with 0.10 front toe out.
Well hells bells. Thanks for the help and feedback guys. I had dropped the tire pressures to 35/33 prior to my dealer visit yesterday because I didn't want (dealer) static about that as a factor for my wandering/sway problems. I just now took the car for a 12 mile highway round trip to get air for the tires to bring the pressures up to 42F - 40R. The drive to gas station was very stable and the return trip was even better with the higher tire pressures...very pleasant...go figure. I appreciate the ski analogy because I grew up in Colorado, was on skis at 7yrs old and even worked at Winter Park for 4 years. So my description before the 2nd alignment was like catching an inner ski edge while guiding a sled with a heavy injured person behind me. This all being said, I should add that the previous owners were elderly and rough on the car, I know of at least one event where the car was driven over the cement divider separating a 4 lane hiway in Maryland. So I may be dealing with an atypical chassis out od whack too. I guess I am good for now but nobody should follow my lead. Thanks.
BTW... you should measure the pressure when the tires are cold... if you drove miles then filled them to your target pressure, then they're probably a bit lower than you thought now. Check them when cold now and adjust as necessary.
