Lotus Elan

Lotus Alloy Wheels fit to Hub

PostPost by: david.g.chapman » Mon Feb 23, 2009 7:27 pm

I have just made some measurements to my new +2 alloy front wheels (as fitted to S130 versions).
When placed on each hub with no centre nut fitted there is no detectable play from the 5 dogs in the hub and the holes in the wheel. I then looked at the gap between the threaded centre shaft of the hub and the inside hole edge of the wheel.

I measures a worst case difference of 9 thou on the NS hub and 14 thou on the OS hub (UK RHD) :shock:

A wheel/tyre combination weighs 12 kg. For each thou of centre offset you get an out of balance moment of 0.001 x 6,000 each side. This is roughly equivalent to a 2 gram balance weight at 6.5 inches from the centre. As the centre wheel nut is tightened up when the wheel is fitted, the dogs will prevent the wheel from centreing.

So as tyres are balanced on the centre hole, there is a likely 18 gram out of balance condition on the NS, and a whopping 28 grams on the OS!

My solution is to bore out the 5 holes in the wheels by 10 thou, giving me a float of 20 thou. If you have balance problems, measure that centre gap with feeler gauges and see for yourself.

Dave Chapman
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PostPost by: rocket » Mon Feb 23, 2009 9:44 pm

Thats interesting and may well have explained why iv a very slight vibe after removing my wheels before christmas..was going to switch them around but maybe your explaination is the answer.

Ian
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PostPost by: ppnelan » Mon Feb 23, 2009 10:22 pm

david.g.chapman wrote:I have just made some measurements to my new +2 alloy front wheels (as fitted to S130 versions).

Dave, is that 'new' as in brand new from a supplier, or 'new' as in refurbished original ones?

Thanks,
:arrow: Matthew
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PostPost by: david.g.chapman » Mon Feb 23, 2009 10:35 pm

The alloys are new from Sue Miller at ?98 each. I believe from the year stamps that they were manufactured around 2000, but I consider them new and without any hole wear. Note that I am note blaming the wheels for this - just the fit with my hubs.

There was a deliberate mistake in my original E-mail - 10 thou oversize on the holes only gives you 10 thou float.

People with older alloy wheels may have elongated holes, but could still experience this problem - the holes will only wear circumferently (is that a word?), not radially to give the float.

If hole wear becomes a issue in the future, I will think about sleeving the holes with a steel tube section.

Dave Chapman.
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PostPost by: Galwaylotus » Tue Feb 24, 2009 7:06 pm

david.g.chapman wrote: - the holes will only wear circumferently (is that a word?), Dave Chapman.


Circumferentially
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PostPost by: david.g.chapman » Tue Feb 24, 2009 7:41 pm

Thanks for that - you're never too old to learn!

I have now been out in the car, and the previous out of balance condition is much improved - just a buzzing at 70-80 mph though the steering wheel - 1mm deflection - not bad. :)

The centre nuts on my car have some sideways play on their threads - a few thou. As you tighten up this nut, where does it finish up? Does it centre on the thread, or sit to one side?

If it sits to one side, a possible fix would be a thin circle of PTFE tape - but will this cause the nuts to come off? Hmmmmm.

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PostPost by: Foxie » Tue Feb 24, 2009 8:00 pm

I'd try to find a place with an on-vehicle wheel balancer. This will balance the complete assembly; hub, brake disc, wheel and tyre. And then mark the relative position of each wheel on hub :)
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PostPost by: david.g.chapman » Wed Feb 25, 2009 12:16 pm

My nearest on the car balancing facility seems to be up the M40 - see www.vibrationfree.co.uk.

Now I have got rid of my Fred Flintsone wheel fit, I might try them out for the icing on the cake.

Dave Chapman.
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PostPost by: Foxie » Wed Feb 25, 2009 12:40 pm

david.g.chapman wrote:My nearest on the car balancing facility seems to be up the M40 - see www.vibrationfree.co.uk.

Now I have got rid of my Fred Flintsone wheel fit, I might try them out for the icing on the cake.

Dave Chapman.


Hi Dave,

There's something wrong with your link above, but I found them on Google.

You lucky lucky b******, I haven't found one yet here in Ireland :cry:
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PostPost by: paddy » Wed Feb 25, 2009 12:46 pm

1963 Elan S1
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PostPost by: worzel » Wed Feb 25, 2009 1:30 pm

Hi All

Couldn't help but notice the input about wheel balance.

For years I put up with at times pretty severe steering wheel shake and general driveline roughness- until- I fitted a set of Minilites (this is to a sprint).

Amazing transformation- 70-80- absolutely no steering wheel flutter and somehow the driveline seems much smoother. These are 5 inch by 13 rims with the 155/80 tyres stretched across the wider rim. The steering is very slightly heavier (presumably caused by the stiffening effect on the sidewalls).

Maybe the way I've modified the column fixing arrangement has something to do with it as even with the dash clamp not fitted (no I don't drive it like that) the steering wheel is held very securely- even with quite a lot of deliberate strain being fed into it.

The original steel wheels seem to be pretty variable in quality- two of mine (the problem ones) had centres that were not true to the outer rims.

John
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PostPost by: david.g.chapman » Thu Feb 26, 2009 12:11 pm

I am in the middle of firming up my +2 steering column (it felt rather loose before) but I do not know about a dashboard clamp - just the clamp further down that secures the steering column tube (early type) to the engine bulkhead bracket.

I have stuck a rubber strip on the column shroud to give a tight fit on the dash cutout. The steering wheel feel much firmer now. I will try it out on the road tomorrow.

Is there a dash clamp for a +2?

Dave Chapman.
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PostPost by: david.g.chapman » Thu Feb 26, 2009 12:13 pm

I am in the middle of firming up my +2 steering column (it felt rather loose before) but I do not know about a dashboard clamp - just the clamp further down that secures the steering column tube (early type) to the engine bulkhead bracket.

I have stuck a rubber strip on the column shroud to give a tight fit on the dash cutout. The steering wheel feel much firmer now. I will try it out on the road tomorrow.

Is there a dash clamp for a +2?

Dave Chapman.
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PostPost by: Foxie » Thu Feb 26, 2009 12:59 pm

david.g.chapman wrote:Is there a dash clamp for a +2?
Dave Chapman.


Hi Dave,

I posted details of a steering column/brake box reinforcement arrangement on this site a few times already, have a search, get back to me if you can't find it.

Sean

(Thought I submitted this already :shock: )
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PostPost by: david.g.chapman » Thu Feb 26, 2009 1:51 pm

You certainly did Sean, and I might use it. I just wondered of there was an original bracket missing from my car.

Thanks everyone.

Dave Chapman.
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