Dunlop Alignment Optic Set UP

[veeracer98]

I've got an opportunity to buy an old school Dunlop optical alignment set up for $750. Is that a good price? Any thoughts on the practicality of one? TIA

[kevskisps]

Old skwl fishing line is a better option. I have both and measuring against two parallel lines of taught fishing line is the best and easiest option IMHO

[Richard Hybels]

Old skwl fishing line is a better option. I have both and measuring against two parallel lines of taught fishing line is the best and easiest option IMHO

Thats what I’ve seen being used on Indycars.

[Bob Wright]

you can make a set of toe bars for next to nothing but a couple of alu angle bars and some ingenuity; and yes, some fishing line.

[Lotus7]

Adding nothing but emphasis to the previous posts:
4 jack stands, 2 eight-foot aluminum angles/tubes, fishing line, and a tape measure ...

Spend the $730 you save on go-faster stuff :-)

[Roland V. Johnson]

Do not use jack stands. If you attach the bars to the car they will always stay on centerline (if you put them there) even if you move the car around...a good idea after you make an adjustment.

[Lotus7]

Do not use jack stands. If you attach the bars to the car they will always stay on centerline (if you put them there) even if you move the car around...a good idea after you make an adjustment.

agreed, but I was going for minimum cost emphasis.

[kea]

With all the different class and models of race cars I've aligned since the early 70's, the Dunlop optical (and other gauges) solve this issue the best.
If you only have one car/type, yes you can make a string setup and it will do a good job. But for me, starting when I changed race cars every 4-5 years, this has been the most versatile.

[Michael Rand]

I agree with Keith Averill, I have always used my faithful Dunlop gauges, I figure by now I have gotten my moneys worth !
No concern about inadvertently bumping the string as I clumsily make my way around the ar....

[Fmracerbob]

This is not as simple as it appears. Two different ways to approach it.

1) Toe bars attached to the chassis : Allows each wheel to be aligned to the center line of the chassis. But requires a well thought out attachment to guarantee they are in fact parallel to the center of the chassis, as defined by the suspension mounting points. Relatively easy to do in back of chassis, can be very hard to do in front where the chassis doesn't really stick out far enough.
Unless one has reasonable fabrication ability and equipment can end up having a different "center Line" to the chassis every time installed.

2) Total Toe gauges. The Dunlop system, the ART Laser system and others like the simple stock car boards that lean against the side of each tire and measure the difference of the front and back edge are all measuring total toe. What they don't guarantee is the toe is equally centered on the chassis, it may be more to one side than another. This can cause the car to "Crab" at one end or the other. Sometime so little it isn't important other times it is. Can even effect bump steer depending how much different relevant links are in length side to side.

Both systems have their advantages. If I have a car that I run a lot I prefer a dedicated set of toe bars. I have one set that I have adapters for several cars which makes it pretty quick and easy and most importantly repeatable.

For cars that I do one time I use gauges but I make sure that my suspension arms are as close to equal length from side to side and in the case of the front I have repeatable rack locks. Then toe adjustments require I keep getting the toe links equal both sides. This of course supposes the chassis is square and the same both sides, which in old formula cars is anything but assured.

It's worth taking the effort to have a repeatable system, it's amazing how often toe is found to be changed from the last time. And key is making sure suspension links/settings are as close to equal from side to side

[RussMcB]

I like my Dunlop toe gauges a lot. I've had them for decades. You can get a toe reading pretty damn fast.

On edit (a minor point) - Over the years I've become much more comfortable measuring toe in degrees and minutes rather than inches. It just seems "cleaner".

But, I've experienced two issues with them (somewhat minor, depending on your situation) :

1) If you have a conventional front wing, the Dunlop gauges probably won't work (without removing the front nose box).

2) They measure total toe, so you still need to do additional measurements if you don't want to be crabbing down the track.

Oh, and they probably take up a little more space in the garage or toe vehicle, although they do break down, if needed. Heck, for $750, maybe they come with a carrying case? Some do.

Thanks, Phil, for this:

<snip> We made some tubular extensions to get over the nosebox vision problem.

[Phil Creighton]

Echo what Keith said - We have a set in each trailer and use them all the time. We made some tubular extensions to get over the nosebox vision problem. We have done toe changes easily in pitlane during testing with them - if they are preset to the wheels it takes a minute to get a toe reading.

Strings and fixture bars are great if you do one car in the shop.

750 seems a bit high for used - paid 500 for the last used set.
Phil

[problemchild]

As noted, the old-timers like them.

But ..... whether you like them or not, I don't think FV wheels are "regular" enough for them. The outer "gutter" edge on a FV wheel can easily have 1/8" of run-out when the wheel is relatively straight. You really want a machined surface on the wheel for the Dunlop gauges, or atleast a solid regular edge,. I always set my FV toes in the air, so I could rotate the wheel/tire and measure from the same spot on the tire or wheel.

[tstrong]

One additional advantage of measuring total toe (like the Dunlop gauge) is the tolerance Of your measurement is cut in half as opposed to using strings and tape measure or caliper on each side of the car. Depending on your techniques this can be significant as well as ensuring your lines are actually parallel and centered. My technique is to use strings to set toe roughly in the shop to get things parallel to centerline and then use a trammel bar with scribed lines on the tire to fine tune and/or at the track. Checking the toe with the trammel bar literally takes less than 5 mins at most. Todd

[Lee Follansbee]

First off, Todd is a master and has been doing this for ages. You can do well to heed his advice.

I bought my Dunlop gauges in 1975, been using them forever. I too like to be sure that my centerlines are verifed, a "must" in my opinion. I get it all close and then finalize with the Dunlop stuff. About the string thing - I had the problem of running into the string all the time as I worked around the car as well. My solution was to buy two 10 foot (maybe 12 foot, I would have to go measure) long pieces of aluminum channel, 1 x 3 x 1 that I set on jackstands to measure from to get centerline to wheel rim close - so that I know I am good side-to-side. Are they a bit bulky? Yes but straight and true and they don't need to be used all the time unless you have bent something. Once you have it all aligned once they don't need to be used every time. Plus being aluminum they are fairly light and store easily.

I have a Dunlop Camber gauge, a work of art. I also have one of Wayne Mitchell's camber/caster tools (also very nice and utilitarian), guess you keep gathering tools forever. I am not fond of the digital stuff, but some say it is better. I also have (either fabricated or ended up with) the alignment bars that use string and go on the car - for Crossle's, Lotus 69, Titans and maybe a couple others, but don't use them much, so they sit in the rafters unless I have to use them. They are good to take to the track sometimes.

The keys are:
1. find centerline and make sure you are good side-to-side
2. dunlop or string to final-set measurements
3. check and reset if necessary after each event
4. be sure the weight of the driver is in the car during the process
5. anti-swaybars disconnected
6. correct tire pressures

Last, I also have a set of Sherline wheel alignment jigs that are by far my favorite. They bolt on to where the wheel would go and have load cells in each so you don't need scales and they change as you make spring adjustments, including a bearing at the bottom to allow movement of the hubs perpendicular to the centerline. They also have a flat plane (the plate itself) where you set your camber gauge against for very accurate readings. And they have "wings" for reading toe-in and toe-out with various wheel diameters. Doesn't get much better than this in a small compact package. Alas, these have been off the market for many, many years. They were not cheap but rugged, accurate and compact. See the photos.

Happy aligning!

Lee