Lotus Elan

My laser wheel alignment tool ...

PostPost by: crypto » Mon Aug 08, 2016 9:47 pm

After two years of restoration and conversion from RHD to LHD I had to align my front wheels for 4.8 ... 1.6mm toe in (according manual). Unfortunately this was not specified in degrees, so it was a little guesswork and with the help of the forum I found out (0.8 ... 0.25 degrees).

However, I did it the same way as I always used to do it with all the cars I had before. My most expensive tool is a string with a wire hook :D. So I hooked it into the rear rubber and pulled it around and up to the front tyre and adjusted the track rods on both sides to be inline with the rear tyres. Needless to say the steering and the handling of the car was awful. So I checked the manual and ohh, front and rear have different track (only 1mm ? I have a Sprint). I added a 0.5mm metal sheet at the rear tyre and did the adjustments again. Steering and handling was as bad as before.

So I started measuring the track width front and rear. The difference was about 30mm more at the rear ! Either the manual is wrong or I have a Series 1 or 2 rear end ?

To get to the point, I bought 2 cheap laser pointers on bay. Placed at the rear of the car, they project a vertical surface on each side of the car. Make sure the two vertical surfaces are parallel and symmetric to the car axis.
img_20160716_174749b.jpg
img_20160716_174749b.jpg (49.09 KiB) Viewed 716 times

I did this by measuring the distance from the lasers vertical surface to the rear hub so they are equal on both sides. Then equalising the distance between the surfaces near the lasers and at the front of the car (or the garage wall). With a little luck, the laser surface should be equally far apart at the front hub on both sides. If not, rotate/move both lasers by the same amount. Once they are parallel, the car is centred between the two laser surfaces (re-check at the rear hubs).
img_20160716_174357a.jpg and

Now measure the distance from the laser surface and the rims (at 3 and 9 o'clock) and enter the values in the Excel sheet below (only yellow fields). Do it for all wheels, if necessary measure also on 12 and 6 o'clock and you get camber angle. Finally, enter the diameter of the rim (to be precise the distance between the 3 and 9 o'clock measurement point, the default value is for Sprint steel rims).

PS: the idea is of course not new and has been "borrowed" with some modification from the internet.
Peter
wheel-alignment.xls
(11 KiB) Downloaded 279 times
Last edited by crypto on Thu Apr 27, 2017 6:24 pm, edited 1 time in total.
The really good drivers have the bugs on the side windows (cit. Walter Röhrl)
User avatar
crypto
Second Gear
Second Gear
 
Posts: 103
Joined: 20 Apr 2014
Location: Switzerland

PostPost by: Jentwistle3 » Wed Aug 10, 2016 12:42 pm

Peter, I've done it this way with strings in lieu of lasers way back when... 8-). Adding the lasers is brilliant! Thanks for posting!
John
Jentwistle3
Second Gear
Second Gear
 
Posts: 98
Joined: 03 Dec 2011

PostPost by: bill308 » Fri Aug 12, 2016 3:17 pm

Hi Peter.

Good job, but I have a concern about using the knock on spinner surfaces as reference points. I think there are too many places where errors can creep in to assume this reference point is the same side to side.

I would think the outside surface of the wheel, in close proximity to the inner seating surface with the hub, might be a better reference for centering purposes.

Bill
bill308
Fourth Gear
Fourth Gear
 
Posts: 775
Joined: 27 May 2004
Location: Windsor, CT USA

Total Online:

Users browsing this forum: No registered users and 3 guests