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MG Midget and Sprite Technical - Wheel nut torque settings.

The workshop manual suggests 62n/m for the wheel nuts, should it be the same for Minilites?
Roger D

Yes but----be aware the wheel studs are too short for some alloy wheel sets and the threads pull---You need at least 9-10 engaged threads, minimum

willy
William Revit

Yep, I use the same torque on steel and alloy rims. Be sure to check you have sufficient thread engagement on your nuts, alloys are normally "thicker" than steel wheels.

Malc.
Malcolm

Is there an echo in here? ;-)
Malcolm

An aside on the thread engagement, IIRC Motorsports UK stipulates 1.5 x the thread diameter of nut engagement.

3/8" x 1.5 = 9/16" length of engagement
9/16" x 24 TPI = 13.5 threads

But that is super safety motorsport regs.

Malc.
Malcolm

Roger, I always torque my Minilite clones to 62n/m but I would recommend checking them frequently when you start using them.

I don't have any problems with three wheels but the front N/S wheel nuts will sometimes slacken. Last Saturday I had to re-tighten those nuts after every hill climb run, the other wheels were fine. However, on the Sunday when I repeated the same pattern of runs in similar weather conditions, I didn't have to re-tighten them at all so I wonder whether they find a better grip after a few heat cycles.

I'll echo what Malcolm said about stud length. When I fitted my Minlites, the front studs had enough turns on them but I had to fit longer ones at the back. My Sprite doesn't wear its Minilites all the time and I found that the new threads weren't long enough to clamp the steel wheels as the unthreaded stud shank was too long. I overcame this with spacers made from drilled out and cut down wheel nuts.

Colin


C Mee

Thanks all. I've been using 62 n/m all the time but it just occured to me that that may be incorrect.
Roger D

I use these modified wheel nuts with Minilite wheels on my Sebring rep.




Alan Anstead

Ahh---forgot about the motorsport regs Malc. I was going by the old 1 x diameter min. for a nut, but yes I 'echo' your advice-
William Revit

Colin, I have a similar issue on my rears and use a 5mm (?) wheel spacer.

Although this was only an issue with cast iron brake drums, with the Minifins I have, they are the chunkier casting with a thicker face, so no need for the spacer.

Cheers,
Malc
Malcolm

Good morning gents,

I've just taken delivery of a set of minilite lookalike (JBW's from MGBHive) to fit to my '75 1500 and I didn't give this a thought.
I have Rostyles at the moment.
I haven't put the alloys on the car yet, haven't yet got the tyres (Uniroyal RainExpert 3 165/70x13), but I'll do it this morning and check the stud length.
But just in case I find I need them, does anybody know where I will get longer studs?

Many thanks
take care
Nigel
N Broomfield

Nigel,

Worth checking your studs carefully for bending and cracking. The rostyles were prone to the centre deforming when the nuts were overtightened and the studs bending inwards. When I became aware of the problem I started to check cars fitted with them and found that most were visibly bent as were the ones on my frogeye front disc hubs which came off a later rostyle wheel car. At least one I found visibly cracked so I replaced the lot.
David Billington

Malcolm, that's interesting about the Minifins.

I had considered looking for a pair for my Sprite but won't pursue it as I already have clearance issues with 165 section tyres and the thicker drums would make things worse.
C Mee

Nigel
I believe 1500's with R/style wheels have slightly longer studs than earlier cars but if you need longer studs the old trick used to be fit the longer rear studs to the front and classic mini Cooper-S studs to the rear
Have never done that though, the spigot style nuts as pictured by Alan A is the way to go, much better support further down the thread --The further down the stud you can get the stronger it will be

willy
William Revit

Well,
just tried a bare wheel on the driver side hubs front and back.

I think I'm ok, just, at the front but the rears are too short, only 7 threads. So that's another thing to add to the ever growing list of things to do.

On from what David was saying I think I found that the fronts had pulled inwards making it look like the PCD of the wheel was larger that that of the studs. Although once I'd torqued the wheel on they appear to have pulled back into shape. The rears were ok in this respect.

Cheers all
Nigel
N Broomfield

The minimum required length of thread engagement is dependant on the relative strength of the male and female thread components and whilst the stud is usually good, unfortunately the same cannot be said for the nuts where it is possible that a much reduced strength of material has been used. In the limit, the bolted connection should should fail by tension in the stud and not thread stripping in either component. A further allowance should also be made in respect of thread wear that is far more likely to occur in wheel bolting than any other connection on the ehicle due to their more repeated use however caution must be used as thread lubricants may significantly reduce friction to result in failure due to excessive loading even at the stipulated tightening torque value. Better to only lightly oil threads and to replace, primarily the nuts, every few years or around 10/12 torque tightening operations.
S G KEIL

Ha, as it happens I have just suffered a broken stud, but it wasn't me (honest) it was the tyre fitter who forgot my instructions and put 60 lb/ft on them. Sorry I only do old money. Then yesterday one of the new tyres deflated so it went back for a new valve. I tried to put the spare on, but it's steel and thinner than the alloys, so the nuts bottomed out as the studs are not threaded all the way. For over 10 years I have been running round with a spare I can never use. Where can I get a thin spacer?
Les Rose

This thread was discussed between 20/04/2022 and 22/04/2022

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