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MG Midget and Sprite Technical - Stub Axle question

Does anyone out there know what the correct diameters are for the bearing seat parts of a midget stub axle, please ? The exchange units I bought recently seem to be incorrectly machined, in that the inner bearings will not slide on at all - they immediately get stuck fast. I am using the very nice but expensive face-adjusted bearings from Ransome & Marles ( Orinoco ) but the inners will not go on. The outers will but seem a bit tight as well.
Also, the stubs are dull, matt grey. Should they not be at least a bit ' shiny ' where the bearings sit ?
Thanks.
M W Sutherland

Hi, I fitted my bearings into my wire wheel hubs this afternoon! As the o/s bearings had worn (due to being fitted incorrectly by a PO).
Like you, prior to fitting the bearings, I tried them on the stubs. What I found was that there was a very slight machining difference between the diameters of the stubs, (about 1/2 a thou) this small difference made one bearing not appear to fit at all, with the other one sliding on after a lot of fiddling about. What you will find is once the bearing are in the hubs, this keeps them straight and make things easier to slide on.

If you want the dia's of my stubs, I can measure these in the morning for you.

regards Tony
Tony G

Yes please Tony - can you measure your stubs and let me have the numbers, as I have a contact in the trade coming around tomorrow to measure mine, and I can then compare. I don't have the necessary gauge to do this.

In my case, neither of the two inner bearings even remotely want to slide over the widest part of the stubs, whereas the outer ones aren't too bad.

Many thanks.

Myles
M W Sutherland

The larger diameter is 25mm whilst the smaller is 17mm not sure of the tollerances? I would expect these diameters to be an absolute maximum

Robert (Bob) Midget Turbo

c'mon Bob, they aren't exact metric sizes, nothing is on our cars, Imperial leads the way...
David Smith

David,

Actually they are metric and so are the rear hub bearings, probably the diff bearings also. It's all down to cost and it was explained to me that as rolling element bearings were invented and standardised in Europe that metric bearings predominate in the world so making them cheaper.

A mate was doing some research on a Scammell truck gearbox designed around 1935 and he was surprised to see metric bearings in an otherwise inch designed gearbox, he was curious and tracked the designer down, as he was still alive at the time, and when asked why the response was metric was cheaper.
David Billington

Hi, the original RHP engineering drawings for the bearings are metric!

Outer - 47mm (outside) & 17mm (inside)
original part no. 3MJT 17

Inner - 52mm (outside) & 25mm (inside)
original part no. 34LJT 25

My stubs were mearsured this morning as follows:-

NS inner 24.97mm & 16.95mm outer

OS inner 24.95mm & 16.95mm outer

The .02mm (1/2 a thou) difference between the diameters, when trying a push fit by hand, is enough to make one appear not to fit and the other fit with difficulty.

Both will slide on once bearing are fitted in the hubs and lightly driffed into place.

Regards, Tony
Tony G

Thanks very much all, particularly Tony G.

We'll see shortly how my stubs compare !!

Myles
M W Sutherland

well, apologies, learn summat new every day, the tricky bit is remembering it!
thanks Tony & David
David Smith

Flippin heck??
So let me get this right?

I note the bearing dimensions are metric
I also supply the original bearing drawings to the group

Yet I don't get a mention LOL.

I will go away and sulk now!! LOL.
Robert (Bob) Midget Turbo

Yea, and the meek shall inherit the earth...
LOL
David Smith

Hi, is this Uni? do we have to reference every bit of info. now?

The bearing info. came from :-

http://www.mgexperience.net/article/mg-midget-wheel-bearings.html

Should royalties be paid?

Have I infringed copyright?

Just trying to help!! (had a bad day, sorry)

Tony
Tony G

Everyone want's to be loved. :)
Lawrence Slater

Don't we just

Steady on Tony I have known folks go bananas on here simply because someone copied one of their photos.

I wasn't aware however that Norm had used my drawings to add to an article on another webite, so perhaps he will explain?

An occassional thankyou is all that matters although in this case ????????????

I just feel left out. LOL

Do I really care? NO!!!!!
Robert (Bob) Midget Turbo

Hi Bob, you are a saint, those images were a key part of solving the mystery of the front bearings, and I struggled about including them in the article, because I just could not remember who had sent them to me, in order to give proper credit where due!

It was (has been) a team effort, there were so many who had done so much. Think of me as the "Linus" in your Ocean's Eleven, Danny (I mean Bob).

Norm


Norm Kerr

This thread was discussed between 08/10/2011 and 10/10/2011

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.