When I saw some of the ride height tools available, I was wondering how one could use such a tool if measuring ride height from the Lotus frame points to a garage floor.
The attached photos show two options. One I have previously used.
The first photo shows a couple of old FM radio antennae that I pop riveted together. I then clamp Vice Grips around the one I want to use, so it stands vertically with the bottom of the antenna very slightly below the Vice Grip jaws. Extend the antenna to touch the car frame. Sit in the car, then measure the compressed dimension with calipers. You don't even need to add driver ballast using this method. Just sit in the car gently to avoid over compression of the springs. Works fine and showed good repeatability.
The first photo also shows the DIY $10 alternate ride height tool.
Take a small Harbor Freight digital caliper and, using a Dremel or similar tool, cut the overall length to approximately 95 mm.
Then, slip the PVC over for a test fit. You want the overall length when fitted to be 100 mm, so leave it slightly long by a mm or two. Cut the PVC and JB Weld it to the caliper, being careful not to block the access to the battery.
Then CAREFULLY sand down the PVC, so that the overall length of the combined caliper and PVC is as close as possible to 100 mm. Try to keep the unit as vertical as possible when sanding.
In use, the PVC provides a large enough base for the unit to stand vertically easily. Zero the caliper, slide the end up to meet the chassis, take reading and add to 100 (or whatever your final overall unit dimension is).
If you are fussy, you could mask off and paint the PVC.
Then take the money you saved and buy a rear tire.
(While I haven't actually finished the fabrication (new caliper on order), I can't see any issues, but, of course, being human, I might have missed something. Still seems like it should work fine on our cars. I'll post photo of final unit when I get around to it.)
2006 Elise, Graphite Grey/Red leather, Sport Elise Suspension, Cup airbox, ECU ref lash, MonoBalls, etc. etc.
1992 900SS Ducati Race Spec Built by Ferracci
2006 KTM 950 SuperMoto, a work in progress
Old stuff gone: Ferrari 275GTB/4, '69 1275 Cooper S. '72 500 Fiat, old Jags, etc. Never bought a boring car.