Altering alignment for mpg

jdham137 · 04-27-2007, 06:51 PM

Has anyone here changed their toe in, if that's the right term, to get better mileage? Is toe in a standard amount for all vehicles or does it change depending on the type of vehicle? Is it legal to change? Can I go to an alignment shop and have then change my alignment to something more efficient? Any success stories out there? Yes, I do understand that a vehicle becomes less stable with less toe-in.

John David

DRW · 04-27-2007, 09:02 PM

I checked the alignment on my car to see where it was, then made sure the toe was set at zero. The predominant feeling I get with zero toe is that the car feels 'busy' when trying to go straight on the freeway. I'm constantly correcting, the car likes to wander, doesn't want to go straight. It's just a slight tendency, nothing dangerous, only slightly noticeable. I've been driving it that way for about a year or more, it keeps me awake.

Bill in Houston · 04-27-2007, 09:10 PM

Most alignment shops will refuse to go outside the specs. But, if they are willing to tweak all the way to one end of the specs for you, it can make a difference. Back when I was following early Prius stuff, the drivers were on this tightrope of wanting near-zero toe for max mpg, but also wanting some toe-in to keep a reasonable level of stability. A normal level of toe-in could cause big change in gas mileage vs near-zero toe.

jdham137 · 04-28-2007, 08:08 AM

DRW and Bill,
Did you see any improvement in MPG that you can attribute to the alignment change? Changing toe-in seems like some great low hanging fruit.

MetroMPG · 04-28-2007, 09:11 AM

If I'm not mistaken, the Honda Insight spec is 0 for toe in. Several reviews also mentioned its on-center tendency to wander.

I noticed recently my alignment is slightly off - the wheel has to be held about half an inch (measured on the rim) off center to go straight. Must have been a pot hole.

I'd be interested in having it set to zero.

Bill in Houston · 04-28-2007, 02:55 PM

I didn't have a Prius, I just hung out with Prius people. I have never personally seen a mileage decrease or increase attributable to alignment. But, I do think that it is important if you want to squeeze out the last bit of mileage.

trebuchet03 · 04-28-2007, 03:03 PM

Quote:

Originally Posted by MetroMPG

If I'm not mistaken, the Honda Insight spec is 0 for toe in. Several reviews also mentioned its on-center tendency to wander.

Sounds like a characteristic of zero toe

We had that problem with this year's HPV -- if you shifted your mass at high speeds (pedaling really hard), the wheels wanted to catch a new direction

Even crosswinds would take advantage of the wheels searching for "straight" (given our caster and trail angles)

We adjusted for .5-.75 degrees of toe in (hooray adjustable design!) and all of that went away... And our top speed did NOT change

To be honest, I'd take steering stability over fuel economy any day

DRW · 04-28-2007, 06:30 PM

Quote:

Originally Posted by jdham137

DRW and Bill,
Did you see any improvement in MPG that you can attribute to the alignment change? Changing toe-in seems like some great low hanging fruit.

At the time I was playing with different settings, I was doing it for better cornering, so I didn't really look at mpg. I did notice it seemed to roll easier when coasting to a stop or pushing it. It was just a coincidence that I found the best compromise in cornering and stability was with zero toe. I don't consider it unsafe; I've had my car over 110mph and there's no instability.
Of course I was being very attentive at that time too. For those moments when you want to cruise on the freeway and relax, more toe-in works better.

Anyone want to see how I built my own toe gage for $18 worth of parts from the hardware store?

It seems relevent right about now.