Get it square and straight

[fordsbyjay]

This morning I performed the square and straight procedure posted on the NTBA here.My question is how perfect (or what kind of error) should one allow on your measurements? My car is not square but off approx. 1/8" each way or 1/4" total. I also measured the tire diameter via the markings to compare tire size and there is 1/16 difference on a couple of them. I have a set of toe plates that I used to set my toe in and with the plates my toe out is 1/8" but by the measurements on my sheet it is showing 1/4" so that is why I ask about the amount of acceptable error. Where the A-B lines cross it is 1/16" to the left of the vehicle center line.

If I understand the data I would say I have to shorten the front right and rear left by 1/8".

 

[Corley]

This method relies on the wheels to be absolutely true and the tires to be absolutely true and round. Many are not quite that perfect. I'd want to jack each one up and rotate it as mounted with a pointer near the tread to make sure all is good with that before making any adjustments. JMHO

 

[leg show T]

Hey Corley, --- You're absolutely right on. I owned a major auto repair facility. If the frame wasn't welded in a jig properly, it can also be higher on one end and lower on the other.

For most of the T-bucket guys going from the center of the spindle to the center of the axle, as you already know. Also, this is where 4-bar suspension comes in, as you of course,

have an adjustment. Twenty years ago, we used frame gauges that had a level with a bubble. I'm sure some shops still use them. In my shop, most everything was high-end collision

repair. So, for a couple of decades now, things have gone to computer and laser. If you're a direct repair facility for major insurance companies, you have to have it, in California.

I've read many of the threads on the Forum. If your frame has a twist in it, you will never get it to handle properly. The good news is that you can take your Roadster in to a quality

repair facility. They will put it up on the frame machine, and if they know what they're doing, can chain it down and adjust it. All the bigger body shops also have all the equipment to line

the front-end up. Well worth the couple hundred bucks. Professional chassi shops, like Ted's shop ---- was, already had all this stuff dialed in without all the fancy equipment. He knew his

frames had to be straight. Well worth the extra money for a professional chassi that will be welded properly in a jig. In the end, has to do with safety and a more enjoyable Roadster. Bob

 

[Old Rotor Flap]

Hey Jay,

I showed your drawing to my doctor and she said she'd write me a prescription for Prozac....

By the way, do you recall that video of the rear end coming out of that Camaro at the track? I loved your response about being a Chevy and therefore, not too much horse power......LOL. I'm waiting in the bushes for my chance to ambush you on that one... just kidding.

 

[one finger john]

Granted, the suspension is .125 out on two instances. If you have already corrected these measurements, how does the car handle NOW compared to how it handled with the original measurements?

John

 

[Turbo-T]

I watched an alignment tech check the toe-in on a kenworth truck. The first thing he did was jack the front end up so he could spin the steer wheels. While each wheel was spinning he used a fixture with a sharp point to score a line in the tread. Those lines didn't waver one bit. He then pulled out a long tool and measured the distance between the lines in front and and in back of the tires. Didn't take him very long either.

 

[putz]

I watched an alignment tech check the toe-in on a kenworth truck. The first thing he did was jack the front end up so he could spin the steer wheels. While each wheel was spinning he used a fixture with a sharp point to score a line in the tread. Those lines didn't waver one bit. He then pulled out a long tool and measured the distance between the lines in front and and in back of the tires. Didn't take him very long either.

On a semi out of square can cause excessive dog tracking due to the length that is why they check that first. Dog tracking is when truck is going down the road at an angle in reference to the road on a straight road.

 

[Ted Brown]

As long as you have enough (for and aft) adjustment to both axles, the frame could be as crooked as you build it and still work great! NOW! Race/drag chassis/suspensions are tweaked way out of square, so that under POWER they now run straight down the track, sometimes not the best idea for a street chassis that runs under no real load most of the time... My personal T sits a bit lop-sided because of the chassis LOADING for real quick and straight hole shots, like I said, they only got 1 chance to beat me... Those were the fun Days and nights...

 

[leg show T]

I was involved in many court cases as an expert witness for insurance companies, mainly where people had died, due to

substandard work-- bad work. In every case, the insurance company that represented the shop that did the bad work lost!

Many of the frames were in a twist? So, you buy a new car. Do you want it to be perfect? Yes, you do. If anyone has a frame

that is not square or in a twist, you have a bad frame. I am talking street use only. In California, you can't even get registration

for a T-bucket, because there are no standards or guidelines. Bob

 

[one finger john]

I was involved in many court cases as an expert witness for insurance companies, mainly where people had died, due to

substandard work-- bad work. In every case, the insurance company that represented the shop that did the bad work lost!

Many of the frames were in a twist? So, you buy a new car. Do you want it to be perfect? Yes, you do. If anyone has a frame

that is not square or in a twist, you have a bad frame. I am talking street use only. In California, you can't even get registration

for a T-bucket, because there are no standards or guidelines. Bob

O.K. Bob, i think you are are a little off base with that " in California, you can't get registration for a T bucket, because there are no standards or guidelines". So what you are saying is that if one has a STEEL body, a frame consistent with the year body, and an engine that is the same (because that's where they get the V.I.N. number, off the engine), it can not be registered??? Or if you are one of the 750 people to get a special construction permit ??? Check your facts, in this case you are wrong. Lots of ways to skin this cat.

John

P.S. Still haven't heard how Fordsbyjay's car handles with the suspension out by .125 on two measurements. 1/8 within specs is industry standard (1/16 is a "try for").
And before anyone gets their underwear in knots, I agree that the closer you get the setup in perfect alignment, the better. Each car is different and thats why there are clearances. I wonder what Ted's measurements are what with the different tire loadings and such.

 

[leg show T]

O.K. Bob, i think you are are a little off base with that " in California, you can't get registration for a T bucket, because there are no standards or guidelines". So what you are saying is that if one has a STEEL body, a frame consistent with the year body, and an engine that is the same (because that's where they get the V.I.N. number, off the engine), it can not be registered??? Or if you are one of the 750 people to get a special construction permit ??? Check your facts, in this case you are wrong. Lots of ways to skin this cat.

John

Yes, John, you're right on that. The problem is they're giving people a real hard time. We're talking fiberglass cars. There are thousands of them with fenders.

What they're trying to do is tax the hot rodder. There are a lot of events going on in California all the time, so you have people thinking there is a way to make

money. There's an amnesty period supposedly giving people like me, who have had their pink slips for 50 years a chance to turn them in. Yeah, right, fat chance

that's going to happen!! P.S. They want to smog everything. It's all about the money. Bob

 

[Ted Brown]

I will have to second that motion...

 

[fordsbyjay]

Just to update. We just got back from Cruising the Coast and I never did make any suspension length changes. I did change from 1/8" toe in to 1/8" toe out and that helped some. We drove a few hundred miles last week and the car drove a little better on the roads there (Louisiana roads are terrible) but the car did still wander. I have to go to work so I will try some changes in a couple of weeks and report back.