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MG Midget and Sprite Technical - Front wheel bearing - wobbly spacer?

Hi all


Sorry but after checking the archives loads I can't find the answer.

I managed to buy some decent bearings last year with the correct 2mm radius, after a recommendation on here. I think it was mgbhive but not sure.

I have just fitted them, in the correct orientation I think, but have ended up with a gap between the spacer and the bearings, of what seems to be about 5mm.

Does anyone have a hub or bearings lying about? Or shed some light on my problem? Both bearings have been pushed fully home.

I can't check the other side as I removed both sets at the same time! Should have just done one side at once doh.

Many thanks all
Matt






Tarquin

Is it possible that your spacers have been shortened in the past to compensate for incorrect bearings?
I've forgotten how long they should be but I have one somewhere I can measure tomorrow.
Greybeard

Your bearings look like they are fitted the right way round. Difficult to tell, but the inner one doesn’t look as though it’s all the way home.

Spacers are exactly 2.0” IIRC. I doubt that they would have been shortened by more than a couple of thou.
Dave O'Neill 2

Dave O'Neill,

From memory the spacers are 1.5" long but just to be sure I checked the archive and found various entries saying 1.5"
David Billington

Tarquin

Spacer length should be 1.500”.

Link below to an article by Norman Kerr gives a very detailed description of midget/Sprite front wheel bearings.

https://www.mgexp.com/article/mg-midget-and-sprite-front-wheel-bearings.271

Simon
S Holt

Matt
Are all the bearings fully home??. The later type resin caged outer bearing has a very thin outer ring compared with the earlier brass caged ones. I recall it goes quite a way in to fully seat. Looking at the image I think the hub nut may foul the grease cap if the bearing remained in that position.
Bob Beaumont

Just to expand on this thread, if you fit tapered bearnings it is ESSENTIAL the spacer is shimmed so that the clamping force goes from nut to inner bearing, to spacer, to inner bearing and to stub axle face. The spacer should be just long enough to provide very slight play in the bearings. I have seen owners tighten tapered bearings until the wheel locks and then baked off the nut to allow rotation. The bearings won't last very long.

Jan T
J Targosz

As many a B owner has fopund, when the inners spin and weld themselves to the stub axle. Expensive.
Paul Walbran

"From memory the spacers are 1.5" long"

David

You are correct. I did say "IIRC", which I obviously didn't. ;o)

Dave O'Neill 2

Hi all
After a lot more looking I have noticed that the new outer bearings have a shallower outer race than the old ones. By about 0.2", so they should push further in and close up the gap.

But I need to remove them first so I can check whether the spacer needs reducing or shimming. Bugger!

As an aside, does anyone have any spare shims for the spacer?

Thanks again
Matt
Tarquin

It may be better to fit the outer bearing fully into the hub and see if you have any movement on the spacer. Removing the bearings could result in damage. In my experience if they are the genuine old stock bearings it should be fine.
The need for spacers and shims is really only required with the modern aftermarket bearings.
Bob Beaumont

There has been a huge debate over the years as to whether the spacer, when firmly clamped between the two bearing inner races, adds to the strength of the stub axle.

Consensus AFAIR, was that it does, providing additional radial support to the weak point at the root of the axle.
GuyW

It doesn't increase the strength, but does reduce the bending stress. The interface between spacer and upright will take compressive loads, so the distance from the bottom of the stub axle (under tension from the vehicle weight) to the top of where compression occurs is increased and overall bending stress reduced accordingly.
Paul Walbran

Okay, so I've had a go at the other side. Pushed the inner bearing fully home, and checked the depth fron the inner race to the seat of the outer bearing. Its 1.508". The spacer is 1.5" exactly.

So I need a 10 thou shim to reduce the gas to 1.498"? According to Norms article.

Then repeat on the other side.
Tarquin

Jaguar IRS shims are a perfect fit, C16626 (.003") and C166262 (.007")
Paul Walbran

Tarquin,

Did you take that measurement with load on the inner race as it would be in use, if not loaded then the inner race may move due to clearance in the bearing. I find it odd that if your bearings are the correct face adjusted bearings and the spacer is the right length that you have that 0.008" discrepancy.
David Billington

Hi David, I did push onto the inner race with my hand. Maybe I need to put it on to the stub axle and apply some weight?

Paul, thanks for that info.
Tarquin

I agree David.

The measurement needed, even without much preassure seems a bit far out.

Just to confirm, because some of the previous wording isn't precise/correct.

" -- checked the depth fron the inner race to the seat of the outer bearing.- "

The spacer, sits between and separates the **INNER** races of the outer and inner bearings.

Hence the measurement needed is, inner face of inner race of outer bearing, to inner face of inner race or inner bearing.
anamnesis

I would also check the seat faces for burrs. If you do have that much slack it will be obvious when you tighten it all up as the bearings will bind.

Trev
T Mason

This thread was discussed between 23/04/2023 and 30/04/2023

MG Midget and Sprite Technical index

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