Tire alignment

[AeroMcAeroFace]

How much difference to fuel economy, or range/top speed if we discuss solar cars, does tyre alignment make? I know the new mercedes F1 car has alignment that changes on the straights. If you were able to get all four wheels pointing in exactly the same direction, how much difference does that make compared to the tiny toe out/toe in that is usually specified?

Has anyone here used different alignment for better economy?

[Piotrsko]

Toe is compensating for flex in the system. I believe you need more at higher speeds, but I don't profess to be an expert and I am unsure how you could measure the flex at speed. I do know if you stiffen up the system you need less.

[Ecky]

Originally Posted by Piotrsko

Toe is compensating for flex in the system. I believe you need more at higher speeds, but I don't profess to be an expert and I am unsure how you could measure the flex at speed. I do know if you stiffen up the system you need less.

This is my understanding as well. Front tires have slight toe in at rest because they move out at speed.

[freebeard]

The complete package would be caster, camber and toe.

Toe has been covered.* Caster has to do with self centering, witness a Top Fuel dragster — if you don't hold the wheel at low speeds the front wheels will just flop over.

Camber is related to body roll. Drift racers run extreme negative camber.


*Now that I think on it, toe also relates to turn-in. It's generally all about vehicle dynamics.

[CapriRacer]

Here's a link to an old paper (1978) That attempts to answer the question.


https://nepis.epa.gov/Exe/ZyNET.exe/...s=12&ZyEntry=1

[2016 Versa]

I had to put new tie rod ends on one of my cars last spring. I reset the toe in using a string line. I only gave it about 1/8" total toe in. I don't know what the specs are but I'm getting great tire wear on the new tires with about 10K miles on them. The car holds a straight line when letting go of the wheel at highway speed. The tires were replaced at about the same and I did see an increase in gas mileage. I don't know whether the increase was related to the tire rolling resistance, alignment or a combination of the two.

[AeroMcAeroFace]

Thanks everyone who replied, especially Capriracer, that is exactly what I am looking for, I will have a read. So if the tyres are toed in at rest but become parallel when driving due to flex that makes sense. But that would also suggest that harder bushings would need different toe in? 2016 Versa, as long as the toe in/out are equal on both sides the car will go in a straight line, but tread squirm means new tyres are usually worse for gas mileage.

[Piotrsko]

Harder bushings will lessen toe in, however most people abhor having to consciously correct the cars wander these bushings provide. 90% of america cant drive a full blown race car.