Alignment question

[jaxgt]

Gents-
As I need to replace my rear toe links (see other thread), I was advised to have 4 wheel alignment done afterwards. I have a friend who is a great race mechanic who can replace the suspension bits, however I don't have much faith in my local Ford dealer to do the alignment. The local Porsche dealer's race shop has the specs for the GT alignment in their computer, and they've done lots of race cars, so thinking they might be better?

2 quick questions -

-are the alignment specs same as stock for a car with Bridgestones?

-they asked me to get camber shim kit for front and rear? any idea what to get/and where?

Thanks!

 

[fjpikul]

I have not changed the alignment with the bridgestones and they are fine. In order to affect change in your alignment, there are different colored shims (these are like washers) of different colors to fix the settings. There are threads hereabout this. I have a double set of the shims that I bought from Torrie many years ago. They were very expensive.

 

[BlackICE]

I did a search and found this thread on the shims. I think it wouldn't be to hard to machine some on a lathe from 6061.

http://www.fordgtforum.com/forums/showthread.php/14467-Shim-Kit

 

[ultrasportracing]

I made several different thickness shims( 2mm -5mm) on my lathe and had then hard anodised. There are 2 different sizes, for front and rear. you shouldn't need to alter the shims if the alignment was right from the factory, you only need to do the rear toe, which is a simple undo a lock nut and screw the rod either way.

 

[nota4re]

As stated above, you should not need any shims. The shims space out the legs of the a-arms and all of this should be spot on without having to change them. The links themselves control toe. You should be real close by setting these links precisely to the links of the old ones on a bench before installing them. Note that if you have altered the ride height of the car, the rear camber is likely to be a little aggressive - and technically out of the Ford specs. This fact would lean someone into wanting to add the spacers to the top a-arm to "correct". However, I would argue that this more aggressive camber is mostly goodness all around with possible exception of tire wear... and when it comes to tire wear for most peeps it is largely a "don't care" because they will exceed the date code life before they wear them out. My recommendation is that if you have a race-tech guy doing the toe link replacement, just have him "string it" to set the rear toe and be done.

 

[PL510*Jeff]

Gents-
As I need to replace my rear toe links (see other thread), I was advised to have 4 wheel alignment done afterwards. I have a friend who is a great race mechanic who can replace the suspension bits, however I don't have much faith in my local Ford dealer to do the alignment. The local Porsche dealer's race shop has the specs for the GT alignment in their computer, and they've done lots of race cars, so thinking they might be better?

2 quick questions -

-are the alignment specs same as stock for a car with Bridgestones?

-they asked me to get camber shim kit for front and rear? any idea what to get/and where?

Thanks!

Call GT Guys. Changing sims is not difficult. They alter toe - i.e. handling characteristics . Different result than doing an alignment.

 

[nota4re]

Call GT Guys. Changing sims is not difficult. They alter toe - i.e. handling characteristics . Different result than doing an alignment.

Confused. Don't know the value add of this post - other than having several errors.

No one (I don't think) said changing shims is difficult. I think we're talking about the NECESSITY of changing the shims.

Shims are NOT USED to alter TOE. Front toe is adjusted via the tie-rod. Rear toe is adjusted via the rear track rod.

Caster, camber, and toe are ALL part of of the alignment.

As I referred to in the previous post, shims in the rear are used to adjust camber. PERIOD.

Assuming camber wasn't a problem before the track rod replacement, it won't change with the replacement.

 

[Indy GT]

Kendall is correct.

 

[nota4re]

We (aka Ryan) is doing a lot of racing these days and the NASA season is getting ready to get started. Alignment is EVERYTHING. Reminds me of a provocative question and video. If you take a race car and you want to make it faster - what will yield the best results.... 1) 10% better cornering traction OR 2) DOUBLE the HP/TQ? Of course, it depends on how many straights, etc.... but this video may surprise you.

[video]https://youtu.be/S2S6MJt0998[/video]

 

[PeteK]

I've adjusted the rear suspension on my FGT to get best tire wear, so let me add to the thread. I made these adjustments to bring the camber closer to zero, so the tires would last longer (not wear out on the inside edges first). As others have noted, the TOE is set by the rear track rod. The CAMBER and CASTER are set by changing shims. There's no need to buy the official Ford shims or machine pieces out of unobtanium--a trip to the hardware store to buy some stainless steel or galvanized washers will save you big buck$ and work just as well. I spent all of about $4 for mine. You want to add the same thickness of shims to both upper A-arm mounts, and subtract the same thickness from the bottom mounts. Since the track rod is closer to the lower mount than the upper mount, this will affect the toe setting slightly, so recheck that too.

Use the string method or the sight-along-the-wheels method for setting toe. In either case, you have to account for the difference in width of the tracks from front to rear. If you can't do simple arithmetic, let someone else do it for you. But, it ain't that hard; it's just common sense...

 

[BlackICE]

There's no need to buy the official Ford shims or machine pieces out of unobtanium--a trip to the hardware store to buy some stainless steel or galvanized washers will save you big buck$ and work just as well.

Correct but to save weight 6061 bar stock is pretty cheap and if you have a lathe you can make custom sizes so you won't have to use more one shim per bolt. :lol

I wouldn't bother to anodize them through.

I lowered my car with Alex's spring perches and the outside 2" of my Hoosier almost never touch the pavement. Maybe I should make some shims and reduce my negative camber.

 

[ultrasportracing]

just remember that changing the camber will have a relevant effect on the toe, which is always done last, and always toe in on the rear, ( if you want good handling) against a little extra tyre wear.

 

[thegtguy]

alignment

This is not this hard, wow. Sometimes you have to use washers to get within specs, especially if the car is lowered. We used to do string alignments on our road trips and do not recommend that anymore unless you are in a pinch. The toe is way too sensitive on these cars for that. We have a nice Hunter machine that is working great. They must be aligned with a good alignment machine and an even better tech that is familiar with the Ford GT. You MUST settle the suspension before doing the alignment, not just bouncing it on the hoist. Do you want a track alignment? Do you want a street alignment? Do you want a mile car alignment? Do you want a drag strip alignment? Do you care if the tires wear quick? All questions to be asked of the owner to make sure it is set up how they want.

I have spoken with Mitchell offline and hopefully he will take my advice.

 

[Specracer]

^^^^ BOOM!!!!

drop the mic....

Great post Rich! So many forget (or dont know) how many variables and compromises there are in a suspension set up.

 

[nota4re]

Properly done, the ONLY downside of stringing a car for toe adjustment is the consumption of time that it takes. Stating that toe "is way too sensitive for that" doesn't really apply as the granularity of accuracy can be the same or better with stringing as, for one, you do not introduce error-prone wheel attachment devices. There are still many race teams who depend on stringing at the track. If a Hunter machine AND a competent GT mechanic is available, I agree that this would be the preferred method. By the way - the suspension must be "settled" on any car before aligning and if we're talking about a race-oriented alignment, the driver should be in the car as well.

 

[Specracer]

I have slip plates for my scales when corner weighting a race car. Assists greatly to getting the suspension settled.

 

[PeteK]

Well, since Rich just thumped me :wink, let me add the rest of the story: Yes, I drive my car almost exclusively on the street, and I don't do drag racing or 4-wheel drifts around turns on public roads (I hope you don't either!), therefore straight ahead stability and tire wear are my most important considerations. I expect street driving is JaxGT's use, since he's talking about Bridgestones instead of Hoosiers.

Negative camber not only causes uneven tire wear, it also makes a car less stable on public roads because it increases the tendency of the wheels to steer into/out of the ruts in the road and to react to potholes and other objects and irregularities. It also increases those tendencies when braking hard. Zero or negative toe has similar effects. Whereas, on a race car, those settings generally improve cornering. I don't have an alignment rack in my shop (it's on the bucket list :lol) so I use the sight line method. But whether you use a Hunter laser rack or more mundane methods, the real test is what your tires are doing. What's the wear pattern? Are they wearing evenly? Does the car stay pointed where you steer it? Does it pull to one side when braking? Make adjustments accordingly.

Suspension adjustments can get overly complicated in theory or analysis, but it's not magic. Of all the possible suspension designs that have been tried, we have only a few in production, and those have inherent tradeoffs--nothing is perfect--so the alignment consists of compromises too. Suspension adjustments are easy to do and give you pretty direct feedback, so this is a good task for do-it-yourselfers. You may end up with numbers that are not "by the book" but work for your driving style and tires. By all means, experiment, and learn more about your object of passion.

A long time ago when I learned to repair mechanical watches, a book I read about that subject stated, "it didn't grow on a tree," meaning, if someone other than God made it, you can fix it.

 

[nota4re]

Pete - all great points. As racing season is just ramping up for us, we are in the midst of doing a lot of alignments - on our race cars and a few others. In fact, we have a car in the shop right now for a set-up to start the 2017. This is a former IMSA regional champion and he could choose many shops to do the alignment but he has seen the back-end of the cars we have done - and this, as he told us, is the reason he's coming to us. Quite frankly, alignment is literally everything on a (legal) spec race car with a skilled driver. Race drivers all have their own preferences - but the best of them will make the most of whatever you give them. Good slip plates are a must and we have our own secret sauce for those. Regarding the GT, I frankly think it is one of the easier cars to set up - a lot more straightforward than many passenger car. The key, as you point out, is in assessing the use case(s) that the owner may want to use the car for. I wish we had the room (and $$) for a Hunter as I would love to have one - but until then we are "stringers" - but I think damn good at it through lots of practice!