Lotus Elan

What is an acceptable run out for the wheel rim?

PostPost by: Keith Scarfe » Wed Mar 14, 2018 12:48 pm

As title. What do people think is an acceptable run out of a wheel rim before it is noticeable while driving? and thus when the rim is therefore not usable.
Thanks.
Keith.
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PostPost by: ericbushby » Wed Mar 14, 2018 5:04 pm

Hi Keith,
In the workshop manual there is a section on wheel shape tolerances.
It states that the rim has to be within 0.050" Radial run out and the same ( 50 thou`) axial run out.
It also says that it may not be possible to balance the wheel sufficiently.
So, at about 50 thou` you would notice vibration from the wheel and could not correct it.
As we have said before you can balance weight errors, but not shape errors.
I had a wheel which had a 120 thou` axial run out and was only good enough for a spare.
It is sometimes possible to correct axial errors (sometimes better understood as a buckled wheel).
I have done that, but some people do not like the idea.
I would not know how to tackle a radial error.
Eric in Burnley
1967 S3SE DHC
Edited for a missing word.
Last edited by ericbushby on Thu Mar 15, 2018 9:02 am, edited 1 time in total.
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PostPost by: StressCraxx » Wed Mar 14, 2018 5:46 pm

I had three steel wheels with lateral runout, one as much as 3/16". I had the tires removed and the wheels straightened by a local shop. They came out with less than 1/32" runout. I remounted the tires, balanced them and reinstalled on the car. The lateral runout returned on two of the three wheels.

YMMV.

The right rear wheel was the worst one. It caused a fatigue failure of the lower wishbone forward pickup point on the chassis. The rear wheel steering was exciting.

I gave up and bought a set of Panasports.
There is no cure for Lotus, only treatment.
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PostPost by: MarkDa » Wed Mar 14, 2018 8:11 pm

I don't it's easy to define an irregularity that won't be noticeable.
Put them in and see/feel!!
Obviously the least bad wheels go on front and if you dont notice wheel wobble then you carry on don't you? The steering is so full of feel that anything untoward would be uncomfortable.
If there's noticeable vibration at the rear then you'll probably want to replace the wheel before it shakes something (itself?) loose.
Worst to spare.
In my experience I reckon that you can get away with more run out than you might think.
Or just go out and buy some alloys and keep the steel wheels for when you sell the car!
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PostPost by: Gray » Thu Mar 15, 2018 8:32 am

Whilst it cannot eliminate all causes of out of balance, such as excessive run out, Road Force Balancing can help reduce the effects. I've had it done on a car (non-Lotus) with good results. It is not commonly available in the UK, but there are a few places, mine was only ?10 per wheel.
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PostPost by: ericbushby » Thu Mar 15, 2018 8:59 am

Hi Gray
Thank you, I have never heard of that. We learn something on here every day.
However, I have looked it up and watched the video, and every one shows an alloy wheel.
Alloy wheel straightening and repairing is quite common now. A fellow near me does it in a shed in the garden.
The problem is that none of them will tackle our steel wheels and it is not easy to get the required result.
Eric.
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PostPost by: Keith Scarfe » Thu Mar 15, 2018 12:57 pm

Hmmm thanks all. I have 50 and 70 thou on the worst 2 with the other 3 OK. Up till now, I have been running on the 50 one and this is not good giving a horrid wobble at speed so I am in the process of swapping over to the other one. Didn't know it was 70 thou out till I measured it recently. I thus expect it to be worse :( but you never know. I think the 50 one is also out radially but this is difficult to measure with the tyre on. Will see.
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