Measuring Toe

[Rick Iverson]

Gents;

An Apex member replied to a thread that toe measurements are measured at the rim flanges. Since 1972, I have done them from a scribed line at the approximate center of the tire.

So, having a setup sheet with toe measurements from a car circa 1995, what is the recommended procedure?

[CARSHouston]

Depending on the equipment being used either way works

[10rmotor]

I scribe a line on the tire and measure with a trammel bar.

[Ed Womer]

With slicks I have always used a line scribed on the tire and use a toe bar to measure. Since the CC/FV has moved to street radials to substantially reduce costs, the common method is toe plates against the side of the tires. Both work fine.

Ed

[EYERACE]

With the car in a perfectly rectangular box of parallel strings down each side and equal size locking blocks on the steering arms so the car is pointed about as straight ahead as I can get it - I then measure the distance from the string to the front of the rim (if one would be looking at a clock - think 9:00 O'clock) and also measure to the rear of the rim (think 3:00 O'clock). The difference tells me the toe. I do not measure to the tire from the strings.

[David Clubine]

Gents;

An Apex member replied to a thread that toe measurements are measured at the rim flanges. Since 1972, I have done them from a scribed line at the approximate center of the tire.

So, having a setup sheet with toe measurements from a car circa 1995, what is the recommended procedure?

A setup sheet for a 1600 or 2000 from that era will most likely have been done at the wheel with parallel string bars.....

[Rick Iverson]

Thx, Fellas. That is what I surmised.

[john f]

Depending on if you measure at the rim or tire tread do you take into account the difference in diameter and therefore the difference in the amount of toe in?

john f

[Chipv]

When toe is specified in inch/mm it’s based on tire diameter. If you measure from the rims you need to compensate for the diameter difference. If specified in degrees, it doesn’t matter.

[EYERACE]

John f. ......I really don't know how to answer. I do want to throw this thought in the mix about measuring to the tire > remember the tire's sidewall and face undergo deformation under the stress of turning and that deformation varies with the speed, amount of steering input, camber of the road, pressure, temperature, compound etc. So, the only constant that can be known reliably is measure from the rim. After that it would seem to be time to take the car out on track for a test day session and notice how it feels in those corners and your times.

Oh no !! One must go drive the car huh. .......torture.

[problemchild]

If you have a race car with steel wheels, where the wheel edges get all beat up, then it would make sense that people go to all the extra work of scribing tires, etc so they can measure from the tread surface. Measuring toe on a US FF or FC car, with machined aluminum or magnesium wheels is much quicker because you can use the provided machined surfaces. One trick that is very helpful, is that if you measure the difference in toe between "in droop" and "on the ground", then you can measure toe with the car in the air. You can spin the wheel and measure in the same wheel/tire spot, thereby eliminating any tire/wheel irregularities. Also easier on the back.

[Fred Michael]

Echoing what Greg said. We always measure with the valve stems in the 6 o'clock position so that we know we are measuring in the same spot every time to at least try and take one variable out of the equation

[Rick Iverson]

If you have a race car with steel wheels, where the wheel edges get all beat up, then it would make sense that people go to all the extra work of scribing tires, etc so they can measure from the tread surface. Measuring toe on a US FF or FC car, with machined aluminum or magnesium wheels is much quicker because you can use the provided machined surfaces. One trick that is very helpful, is that if you measure the difference in toe between "in droop" and "on the ground", then you can measure toe with the car in the air. You can spin the wheel and measure in the same wheel/tire spot, thereby eliminating any tire/wheel irregularities. Also easier on the back.

Echoing what Greg said. We always measure with the valve stems in the 6 o'clock position so that we know we are measuring in the same spot every time to at least try and take one variable out of the equation

Fellas;

Excellent stuff here.

I have these, allowing all changes to the geometry without rocking the car back and forth. The wide portions abeam the axle nut hole is the precise rim OD. But I am more inclined to sell this setup and stick with your suggestions.

A wealth of knowledge, Gents. Tusen Taak.

[Fred Michael]

That setup is designed to measure toe from the flat outer surface to strings. Use it. It is as repeatable as it gets

[Ed Womer]

Those are cool looking pieces. Just remember that if you want to use the string system you need a way to attach a bar at the front and rear to hold the string so you can measure off of it. Also you need the exact center of the chassis and exact spot on the bars to be able to reliably measure everything and it must be repeatable. Using the scribe method or toe plates against the sidewalls is a simple and doesn't need a lot of equipment. You also need to have the driver weight in the car so you are at ride height or the alignment will not be accurate.

Ed

[CARSHouston]

Could be interested in your fixtures, but they are for center lock hubs, can't tell in the photo if the center is made into the fixture or bolts in. If it would be possible to change it for a four-bolt hub.
Thanks

[jkeller]

MK Technologies - Setup Wheels

call Marty

[Rick Iverson]

My system:

[Rick Iverson]

Could be interested in your fixtures, but they are for center lock hubs, can't tell in the photo if the center is made into the fixture or bolts in. If it would be possible to change it for a four-bolt hub.
Thanks

They are center lock, matching the Van Diemen pattern. And yes, there is a removable insert to change to any configuration.

[ejsprint30]

Made a tire scribe tool...works great on new tires...not so great on used ones, so I made 2 sets of bars same length as diameter of tires. Etched measuring sales on both ends, and use an adjustable/locking trammel. When bars are vertical, can measure camber. Made sure hub flange is true to wheel mounting surface. Under $50.00 in materials.

[problemchild]

It is very important for casual racers to understand that some people like spending large amounts of money building fancy tools, but that is certainly not required. $5 worth of fishing line, some surplus tubing or pipe, even broomsticks, and a ruler ..... are all you need for checking toe on most modern cars. FVs and some older cars with poor bumpsteer, may need some extra stuff, but please do not let anyone convince you that you need to spend entry fee or tire budget resources on fancy alignment tools.

The best toe bars that I ever had were some aluminum bars I cut off of an old truck cap roof rack. They were 3 ft long and went inside the tires so I could check toe in the trailer or a cramped garage. Wheels were truer on the inside too. Add a cheap camber gauge and some floor shims and you have all you need for a starter alignment kit. Spend your resources going racing.

[Rick Iverson]

Gents;

Just my opinion, but it is OK to stand in the corner and think/engineer your race car. I derive a great deal of pleasure in simply thinking about how to improve the performance of my race cars. Out of the box, what will it take, a labor of love.

I designed this parallelogram to determine toe probably twenty (20) years ago. I bought some surplus 8020 on eBay for a fraction of the cost, and although the mounting plate was expensive (say $65.00), I have $120.00 into it.

I will be working with my manufacturing partner to bring this well engineered, REPEATABLE, and exceptional product, either in pieces, or complete. And my surmise, less than $120.00.

And it ain’t going to be $5 worth of fishing line, some surplus tubing or pipe, broomsticks, and a ruler.

[Robins Ken]

Gents;

Just my opinion, but it is OK to stand in the corner and think/engineer your race car. I derive a great deal of pleasure in simply thinking about how to improve the performance of my race cars. Out of the box, what will it take, a labor of love.

I designed this parallelogram to determine toe probably twenty (20) years ago. I bought some surplus 8020 on eBay for a fraction of the cost, and although the mounting plate was expensive (say $65.00), I have $120.00 into it.

I will be working with my manufacturing partner to bring this well engineered, REPEATABLE, and exceptional product, either in pieces, or complete. And my surmise, less than $120.00.

And it ain’t going to be $5 worth of fishing line, some surplus tubing or pipe, broomsticks, and a ruler.

Why drive yourself nuts with minuatae? Turn in? Good. Straight line? Quick. No weird snap oversteer? Near the top of the grid sheet? String and broom handles it is.
KR.

[Rick Iverson]

Why drive yourself nuts with minuatae? Turn in? Good. Straight line? Quick. No weird snap oversteer? Near the top of the grid sheet? String and broom handles it is.
KR.

Ken, can we agree to disagree? I respect your opinion, but again, I enjoy the thought process of the engineering.

[Robins Ken]

Ken, can we agree to disagree? I respect your opinion, but again, I enjoy the thought process of the engineering.

Certainly Rick. Life is all about different solutions to challenges. Keeps the grey matter between the ears active.
KR.