Toe Adjust Techniquest

[masraum]

[masraum]

[dhoward]

Beautiful!

[masraum]

[masraum]

There you go.

[KTL]

Rock on Ron and Steve! That's some pretty quick coordination there.

I've read elsewhere that you should do things in the order of corner weighting, caster, camber and finally toe. Strange that weight checking is mentioned last.

[Rot 911]

Most excellent!

[Dutchie]

Thanks a lot Massraum and Ron ! Great stuff to read.

[KTL]

Originally posted by Wil Ferch
Cowtown and others:

Hmmm. ... I thought I knew enough about this to be dangerous !

Anyway, let's go back to the premise that rear toe can't be measured as total toe. If you stop to really think about it...why not? I guess I could understand that if it's done this way, there is the possibility of the car being set up to "crab" ( high thrust angle the angle formed between the true centerline of the car and the steering effect of the two rear wheels), but if your car was never in an accident...why wouldn't total rear toe work? Especially since toe changes rather dramatically with suspension movement ( up and down). At static ride height where all the adjustment is done and where the car spends most of it's life, this should work out reasonably well...no? Help me see this.

--Wil Ferch

Here's my take on it Wil.

Total toe works at the front because your wheels are connected by the steering rack and tie rods. Changing the length of one rod at one wheel affects what happens on the other wheel side because you are changing the overall length of the rod/rack combination. No matter how much you adjust on one rod (while leaving the other alone), the wheels will still have the an equal amount of toe side-to-side. The total toe changes, but each wheel ultimately has the same amount each side.

What gets messed up is how many turns of the steering wheel you have to each side (the pinion is not sitting in the midpoint of the overall length of the rack/rod combo.). That's why it's important to make sure your steering rack is centered and the rods are installed at the same lengths. Otherwise you can end up with more turns, and more importantly, binding on one of the tie rods.

As far as the rear, you don't have the steering rack connection between the two wheels to keep an equal amount of toe on each wheel. If one wheel has more adjustment/toe cranked into it than the other wheel? They stay that way. There's no "balancing" effect with a steering rack and rods to connect them together. If the toe is not equal side-to-side, you then end up with the thrust you mentioned. The only way to make sure the toe is equal side-to-side is to have a common point of reference from which to measure for each wheel.

My descriptions are probably not very clear, but if you draw a picture of how the front works, you'll see what I mean.

Here's what happens when your toe is all messed up:

Sorry dial-up users, it's 14mB

http://fun.from.hell.pl/2003-01-09/malec.wmv

[kstylianos]

Steve and Ron,

Thanks guys......gret stuff.

The home alignment procedures are very thorough and feel like I 'may' be able to tackle this on my own.

[cowtown]

I'll second KTL. To grossly oversimplify, imagine that your right rear wheel is toed out three inches. And your left rear is toed in 3.25 inches. You have a quarter-inch of total toe-in, which may be in spec, but it's obviously totally screwy. The car would handle terribly.

This isn't a factor in front, because the wheels will center themselves and go straight no matter what (though your steering wheel might be cocked to one side).

Anyway, that's my take on it. God knows I've still got a lot to learn!
Colin

[rfix'n]

Nice work gentlemen, thanks much.

[RoninLB]

Originally posted by Kurt V
Most excellent!

yep.. I've been doing the string thing for years.. and I've posted my reaction to it here a few times..
I just did a BigBig Ride.. and started w/brand new S-03s.. like the tires returned worn to the wear bars.. yeah, I flipped the sneakers around every 5k or 6k miles on the 4 similar sneakers.. but they all wore perfectly clean. and there is no driver bias on a cross country ride.
Also .. what I do to confirm my settings with hard numbers is do a temp probe 3 point reading on each sneaker after getting them warm on a straight level highway at 70mph.. then pull over and do only 2 tires at a time/heat lost fast. I guess track guys should do it at the track.. naturally tire psi should be dialed in first.
I also run 3/4 tank of fuel/the settings more radically changes when weight is ADDED to the front than when it's lightened.. and naturally my weight is put on the driver seat.. my fav. settings is another story/screw factory specs. LOL

[Bob D]

Amazing what you can do with an old Fiat and a lot of time on your hands.

I agree with the suggestion of tracking down Ray Scruggs and sending him $10 - this is a really useful brochure.

[RoninLB]

Originally posted by billwagnon
Is this Ray Scruggs guy still around? If he is still making the book available I think I should send him $10.

I'm w/you on sending the bucks.. but to my knowledge/based on old info, he is not around anymore.. someone tried to mail him a few years ago, and it was a "return to sender" thing.. he had it listed in PANO for many moons.. that's all I know about it.. I kinda remember giving the address/info on a thread on this BB a long time ago and it was a no-go.............Ron

[Wil Ferch]

KTL and Cowtown:
Explanation makes perfect sense....
---Wil Ferch

[Wil Ferch]

Hey:
Is it just me ( or my computer settings)?...but I can't seem to print the book in its entirety. Only the "left part" of each scanned image prints. Is there a way around this? Wouldn't mind sending the $10 or so to Scuggs if he's truly around, too.
--Wil Ferch

[rfix'n]

Click on each one and save as a jpeg, you can then use a photo program to manipulate and print. Should be a total of 12 images.

[masraum]

change the "properties," "layout," or "page setup" of the printer to Landscape when you print. That should help. If I was more ambitious I would put it into electronic format, but I'm not.

[JasonAndreas]

Ray Scruggs, Application Developer
DINMAR (U.S.)
755 Baywood Drive, Suite 190
Petaluma, CA 94954
Phone 707.658.5114
Fax 707.658.5155
rscr-@oacis.com