Author Topic: Tracking on a three wheel car  (Read 2053 times)

Peel replica, Steve Fisk

  • Prolific Poster
  • *****
  • Posts: 560
Tracking on a three wheel car
« on: June 01, 2015, 11:12:30 PM »
Right who's got some old skool tips on how to basically track the front wheels in a garage at home

Bob Purton

  • Prolific Poster
  • *****
  • Posts: 5041
    • Inter microcar
Re: Tracking on a three wheel car
« Reply #1 on: June 02, 2015, 08:03:01 AM »
First tip is how to spell school!  ;D
Second, do you know what toe in you want to set it at? If any. As your car is not using Peel running gear the standard set up for a Pell may or may not be beneficial. I guess you will have to experiment.
Basically, it involves measuring the distance between the wheel rims forward edges and the back edges, for a toe in the front measurement will be a little less than the back. Taking the measurement can be tricky if other stuff gets in the way. I use a length of wood with angled point on one end and a sliding piece on the other which I can mark with a pencil. If you have a clear area between the wheels you can use a telescopic camera tripod leg or just about anything that expands that can be marked.
For many small wheeled micro's I would say average toe in is about 4mm. You will have to experiment to see what gives you the best straight line trajectory.
Hope this helps

Big Al

  • Prolific Poster
  • *****
  • Posts: 4578
  • Ranttweiler, biting the breeze block of banter
Re: Tracking on a three wheel car
« Reply #2 on: June 02, 2015, 08:48:59 AM »
I use a high quality car Ariel to measure the front and back of the wheel rim. Its very narrow so normally feeds through. If that is not possible I use some dexion legs I made that reach the ground with two pegs on - to big for a Peel but the method would work on a smaller set of tooling. You measure the two dexion edges. Your looking for the difference between, not the real length between wheels, so it works. The Ariel gives two values and you can work out your toe in from them.

Depending on your design and movement of suspension you might need to set the car up loaded. You might find the value varies as the car moves, it shouldn't if you have got it bung right, but with small wheels and large movement you have a difficult challenge to meet. The steering might pull your adjustment out if its rotation radius is different to the suspension. Clearly to steer, it will be at times, whatever you do. The wheel camber might effect your setting, but only if you have a moving link on the kingpin, as your measuring from the middle of the wheel.

The further removed from the centre pivot of the king pin the centre of your tyre is, the more bump steer effect you might suffer.  However the ride height and suspension loading will make a difference, I expect. It is possible that on hard cornering the steering will squint. These effects are not biggies if the designed speed and use is at lower speeds and demand. What I hope is that you do not get a steering that both self adjusts and tightens up, preventing ease of correction, as in the Tri Tech. Its an unpleasant drive and I fear you might then want to revisit your layout with all the hassle that will create. If your gut feeling and research is correct, it should adjust up and show few compromises. The original Peel is no saint on suspension/steering. Hard on such a small light car.
Messerschmitt set, Goggo Darts, Heinkel 175, Fiat Jolly, Autobianchi, Fairthorpe Electron Minor, Borgward, Isuzu Trooper
Citroen BX 17TZD & GTI 16v
Held - MG Magnette ZB & 4/44
For sale - Vellam Isetta, Bamby, AC Type 70, Velorex, Church Pod, Reliant Mk5, KR200,  Saab 96, Bellemy Trials, Citroen BXs

plas man

  • Quite Chatty
  • ****
  • Posts: 280
Re: Tracking on a three wheel car
« Reply #3 on: June 03, 2015, 01:16:13 PM »
any one done the rear end of a Plas  ?