Got my car aligned yesterday. Told dealer I was getting very slight inner tire wear (compared to the outer tire wear) on the front and they responded by adjusting the toe-in. I unfortunately had brand new winter tires on the car at the time so they could not see for themselves the tire wear.

Toe-in was 0.05 on all four corners before and is now 0.00 on all four corners.

The dealer printout says that 0.0 to 0.5 is acceptable for the rears as well as the fronts.

I have done a bit of searching and have seen that 0.00 is ok on the fronts but have seen that according to July 2003 specs, 0.02 is the minimum toe for the rears.

Can anybody comment on the 0.00 toe in on the rears?

Thanks,
Elmer.

 

Here's what Paul Frere says about it in "Sport Car and Competitive Driving" " Any toe-in or out will obviously increase the the rolling resistance and tire wear. Consequently, whenever possible the wheels should be kept parallel when the car is driven in a straight line. This is particulary important with ultra-wide and grippy racing tires. Slight front wheel toe-in will sharpen the steering response when the car is driven from a straight line into the bend while toe-out makes the response more progressive. But more important than the toe in or out itself are the toe variations induced by the suspension movements.

If compressing the front suspension causes the wheels to toe-in (bump toe-in), oversteer is induced as the car is turned into the bend because, as the car rolls, the lock angle of the outside wheel (which carries more load than the inside wheel and thus determines the line taken by the car) is increased and the driver must unwind the steering to keep the car on the desired line. Inversely, bump toe out makes the car less responsive, as roll reduces the lock of the outer (leading) wheel. The former makes it very difficult to hold the car on a clean line and will also produce a very strong tuck-in reaction if the accelerator is lifted in the bend, causing weight to be transferred to the front suspension and consequently increasing the toe-in. .......Toe variations of the rear wheels are equally important and amount to passive rear wheel steering. Toe-in on bump which causes toe-in of the outside (leading) rear wheel when the car rolls in a bend, partly compensates for the slip angle and the car behaves as if the slip angle were smaller than it actually is. It consequently promotes understeer, while toe-out promotes oversteer and makes the car difficult to drive."

The change to 0.0 neutral toe-in should reduce tire wear. However, the reduction in toe-in will change handling in bends. The change in the front toe-in should make steering less responsive-more progressive and increase understeer, compared to the way the car handled before you made the change. The change (reduced toe-in) in the rear will make the rear steer more responsive, produce oversteer, and the rear will tend to swing out more and make it more difficult to drive the line. I think I have this right.

Changing your tires (or the supension stiffness) changes the setup too, so you'll have to see how it runs with the new tires and toe. If you don't like the more progressive turn in feel or the rear is breaking loose, get it changed. But make sure you know what the change will do and don't necessarily rely on the guy in the tire shop. I'll check out the tow-in specs in the shop manual when I get a chance, they may be in the owners manual too and may be on this board as well.

 

ok

 

I think that is the best explaination I've ever heard thanks. Is "sport car competitive driving" a book?

 

That was an awesome explanation.

Seeing as I am running my (very expensive) winter tires and I am not doing much hard driving these days, I suppose the 0.00 toe in is good in that it will reduce tire wear.

Once I put the summers back on, I will see how I like the new setup (and see if I even notice a difference) and go from there.

Changing to the summers should affect the alignment a bit as well.

If you could post the shop manual specs, that would be appreciated.

My dealer printout says anything from 0.00 to 0.05 on all 4 corners is within spec but this contradicts much of the information posted on this site.

Thanks,
Elmer.

 

That sounds like a plan Elmer. Not many people drive near the limits of adhesion in the winter anyway, its to dangerous. There reallly isn't a right answer and the toe-in specs are what Nissan believes is best for the car, given the weight, tires, suspension, and tire pressure. Therefore, if you change these, a different set up might be advised. Also, when you tweak one thing to get something, you might have to sacrifice another, like increased tire wear.

Sports Car and Competition Driving, Bentley Publishers, 1992 is a paperback book and I bought it at B&N. Its great, if you want to understand driving and your cars response to forces and changes. It was first printed in 1963 and covers the basics. Its timeless. Paul's style is long sentences, so I had to read some stuff a few times to figure out what he meant. Having some background in physics will help, but it not to bad.

I'll post the specs.

 

From the shop manual, the Wheel Alignment Total Toe-in specs (unladen) are as follows:

Front (A - B)

minimum: 0-mm (0-in)
nominal: 1-mm (0.04-in)
maximum: 2-mm (0.08-in)

tire: 225/50R17
tire: 225/45R18

There are specs for the front caster, camber and kingpin inclination, but these are not adjustable. I'm not sure that you can adjust the front toe-in? The method to check toe-in is a rolling method.

Rear (A - B)

minimum: 0.2-mm (0.008-in) (17-in tire)
minimum: 1.1-mm (0.043-in) (18-in. tire)

nominal: 1.0-mm (0.039-in) (17-in tire)
nominal: 1.9-mm (0.075-in) (18-in tire)

maximum: 1.8-mm (0.071-in) (17-in tire)
maximum: 2.7-mm (0.106-in) (18-in tire)

tire: 235/50R17
tire: 245/45R18

There are specs for the camber. The toe-in is easily adjustable by turning a bolt on the rear lower link. The method to check toe-in is a rolling method.

 

Thanks!