How much toe in are we running?

[Chrisrich]

I'd like to get a sense of what the smart guys (you, that is) are doing for street cars with stock suspensions as far as toe-in settings.

I've got a '70 S4 Elan, and I'm running what I think is about 1/8" toe in. I'd like to find a little more straight-line stability and slightly less sudden turn-in.

Which brings me to my second question: if toe in is the difference between the distance of the forward face of the tires and the rearward face, this would mean that to measure it accurately (using the home measuring method), you'd need to take two measurements 180 degrees apart. How do you do that, considering that you don't really have straight-line access to both tires from either the front OR the back? I figure the best I can do is about 110/120 degrees or so. Doesn't that throw the spec numbers out of whack?

Thanks much (and merry christmas)

Chris

[rgh0]

I run at the top end of the Lotus specification at around 4 to 5 mm toe in.

Toe in is specified at the wheel rim diameter so you can meaure it on the tyres at around 120 degrees apart front and rear as that puts the meausrements at the wheel rim width apart.

Alternatively you can set up parrallel string lines each side of the car and measure of these to the wheels

regards
Rohan

[mr.vman]

You can make a "toe Bar" out of scrap wood. The ends should be at hub hieght. You can scrib the tire using a nail in a piece of scrap wood. Just jack up the wheel on the lower arm, place the srib under the tire and rotate the tire. The nail will leave a line around the tire tread that you use as a reference point. Now roll out the car, measure the distance form the back, using your toe bar (use the lines on the tread you scribed). measure the front, subtract the difference and you have your total toe. Make sure you do this with the steering rack centered. This may be hard to follow but you can find this in automotive text books. I would also check caster camber and toe of the front end and check camber toe and "thrust angle" of the back end. Most Elans have thier caster and camber off on the front,and the rear camber and toe will also be off, which will cause an off set thrust angle. Checking caster camber and thrust angle is more then most home mechanics can do, so you may want to use an understanding alignment shop. Check out some old issues of Lotus ReMarque, I wrote an article on setting up caster and camber on Elans and Europas. Control arms can be spaced for caster and control arms filed for camber. In the rear, Spyder now has some adjustable toe rear arms, but nothing for the street for toe and camber that I know of. I hope this helps, if not I can try again. I have spent a great deal of time making my Lotus cars "track" well, I see no use in having these cars unless they drive.

[gjz30075]

I, too, am running 1/8". Make sure your rear A arm bushings are good or unintended toe changes will happen there and really exacerbate the problem.

Greg Z
'72 Sprint

[Barney]

Chris

The picture shows the tool I think you would need (or something that you could make up along these lines with a bit of minimal "wood welding". using a length of 2x2, a G-clamp and a couple of 4" nails as fine reference points. - One vertical have fixed to the stringer and the movable verticle clamped using the G clamp)

Basically its just a large set of calipers, the exact measurement isn't needed just measure the difference - if any - as stated against the steel rim of the wheel at wheel centre height.

By the way I took this picture off of E-Bay today (.co.uk or .com I'm not too sure)

Cheers
BARNEY

[264889socal]

Chris,

If you have some friends who vintage race, especially those who race formula cars may have a set of Dunlop gauges. These are the easiest to use where access is limited surrounding the tires. They are very accurate and can be adjusted to any size wheel and tire combination. They also work well when trying to center the steering. I currently run 1/16" toe in, in the front, set at the hub center line and the car tracks just fine. However, the car is on radials and not bias ply tires. Bias ply may require a different setting. The rear is pretty much what you get if using stock lower control arms. The gauges will help identify a problem and you can decide if it is within your acceptance level or needs attention. As said, good bushing are essential. Or you can switch to adjustable units. Spherical rod ends, heim joints, rose joints, etc. will cause a deterioration of the ride and transmit significant more noise, but really tighten things up.

Rob

[Foxie]

I have in the past used gauges made from timber battens and nails as described, but have for some time using another system employing the ever useful bits of string.

From the fact that the +2 wheelbase is 96", and the rear track is 1" wider than the front (check this on your car, and if it's a Spyder chassis it's 1.4" !) a string from the front of of the rear tyre at hub height which just contacts both high points of the front tyre will result in a toe in angle of 0.6 degrees (at the first approximation). The Lotus max spec toe-in of 4.76mm (measured at the rim flange, actual dia 14.375") is an angle of 0.75 degrees.

The thread on the steering rod ends have a spacing of almost exactly 1mm, so one complete turn will give an adjustment of 7 3/16" (rim radius) divided by 4.5" (steering arm ball joint radius) or 1.6mm at the rim. So you can dial in a fairly exact adjustment rather than doing lots of trial and error. Of course, a final check should be made.

Has anyone tried experimenting with non-standard toe-in settings ? What was established ?

Sean Murray

[peterako]

I Have no idea what toe in I have...but am guessing 0 to 'very little'.

I use the string method.

I used to bring it to one of my many local tyre centres but was never really happy with the feel/responsiveness of the car after adjustments there....

Peter '73 +2S 130/5

[chequeredflagracingjoe]

Hi All, We run 1/8 inch out on all the race and street cars. Triumphs Lotus MGB Morgans and Datsuns. Joe

[john.p.clegg]

Go on then Joe,how come you are running toe-out?

John

[chequeredflagracingjoe]

I have found that the cars turn into a corner better when set up with 1/8 toe out

Joe

[ceejay]

During the last twenty five odd years of elan ownership, plus the odd rebuild or two thrown in here and there, and without offending anyone, the last thing I would dream of doing is stuffing around in the home workshop trying to optimise front suspension settings with string & bits of wood.

If you enjoy lotus fiddling that's Ok, but if you can find a good performance suspension workshop, you will be astounded at just how
much better they can make your car handle when the suspension is adjusted and set up correctly, the cost is not as much as you might expect either.

My elan S2 has been fitted with fully adjustable top wishbones for many years. The one big plus I found was a local bloke who happens to be a motor racing/rally enthusiast who operates a steering and suspension workshop business that truly understands sports suspensions.


At the beginning of 2007 I undertook a total rebuild of the front suspension on the elan S2, the car was out of action for several weeks while fabricating & installing new tubular top wishbones - strengthened bottom wishbones ? new machined red lurethane bushes throughout - new Eibach
coil springs, (Non Standard), and converted the Konis to adjustable platforms.

Quite a bit of work, and all fabrication/machining was carried out in our
own workshop, but it was well worth the time and expense.

After the initial "rough eyeball" set up was done on the suspension, the
elan was driven slowly to the "suspension workshop" so they could work some magic on the front suspension using optical alignment equipment,
after a couple of hours of adjusting and checking, the front end set
up was complete. There's no guess work involved with this specialised gear, just spot on results.

The suspension settings on the S2 are:
Camber 1/4Deg Neg. Caster: 7Deg. Toe In: 1/8"
So, how does the car track and turn into the corners, fantastic,
note that this elan is a road car, competition settings may require
something quite different.
Learn More>> http://www.elantrikbits.com/front-suspension.html

[Foxie]

The suspension settings on the S2 are:
Camber 1/4Deg Neg. Caster: 7Deg. Toe In: 1/8"
So, how does the car track and turn into the corners, fantastic,
note that this elan is a road car, competition settings may require
something quite different.

I won't argue that "magic" will not give a more precise setting than fiddling with string and bits of wood, but how were these settings actually determined as 'optimum' in the workshop ? What were the rear settings ?How did variations in the settings effect turn-in and straight line stability ? Don't these characteristics adversely effect each other ? In what way would these be different for competition ?':?'

[ceejay]

Q: But how were these settings actually determined as 'optimum' in the workshop?

Colin Chapman gave Lotus enthusiasts brilliant cars to drive, he also had many financial constraints within his sports car production business, he was a genius at solving problems and finding workable production solutions, perhaps not all of them were correct, the implementation of non adjustable suspension on a performance car like the elan is a poor choice. To allow the luxury of "optimum" settings in the workshop is to have a fully adjustable suspension system to work with in the first place. The benchmark for elan suspension settings is detailed in the Lotus workshop manual, by utilizing a fully adjustable front suspension you are then able to try different set ups and compare them on the road or track, whichever is your preference.

Q: What were the rear settings?
The rear wheels are set almost parallel with only 1/16" toe in; the rear struts have narrow wound 80LB springs on adjustable spring platforms.

Q: How did variations in the settings effect turn-in and straight
line stability?

After the modifications were completed on the front end early in 2007,
The end result was quite dramatic, when driving the ?lan it just felt so much more stable in the corners and it tracked better than it had ever done previously, the wheels are 14 X 6? bolt on Simmonds Alloy, tyres are Yokohama A539 195/60R14. Front Anti sway bar is 19mm Dia (??)


Q: Don't these characteristics adversely effect each other?

Each modification that has been done to my elan S2 has been one of gradual improvement, if something did not feel right, or it upset the car in some way, then it was modified or reverted back to standard specs until another solution was found.

Q: In what way would these be different for competition?

Suspension settings for track competition usually differ to what is generally use on the road; spring rates, anti roll bar stiffness, camber, caster, even the toe in settings may need to be different, quite often, race cars have different set-ups for each track they compete at.

To learn more about the mystery & black art of suspension tuning, try to get hold of the book called: "How to Make your Car Handle" By: Fred Puhn. This book covers all you need to know about suspension tuning for any car. ISBN: 0-912656-46-8. Published By HP Books. USA.

[Foxie]

Thanks, that's a lot of information.

I've Yoko A539s fitted myself, best road tyre I've used (so far !)

I heard Chapman been quoted in defense of the non-adjustable suspension system he used: "If it's adjustable, they'll adjust it wrong !"