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MG Midget and Sprite Technical - Wheel Bearing Weirdness

Hey everyone. Today while getting ready for my new rotors to arrive I removed my hubs and found that someone had fitted a tapered roller bearing on the right and the car still has regular ball bearings on the left. The rotor was original on the left and aftermarket on the right, so maybe at one time someone did a swap on the one whole stub axle or more. Both bearings seem in fine shape, gave no play prior to disassembly,clean and greased well. Is there any problem with the mismatch? Is there any differences on reassembly for the rollers? Both sides did not seem to be torqued to the specs in my Haynes manual. Thanks in advance. CJ
CJCharvet

Here we go again!

CJ,
There is plenty of reading material in the archives on this topic. I use tapered roller bearings in my Spridgets. It has become rather difficult for me to find good quality of the original ball bearings, since there are no other applications for that bearing other than Spridget front wheels AFAIK, while the tapered bearings I use are a common size frequently stocked by bearing stores.

I do not use the spacer when I use the tapered bearings because they work great without it, even with the stress of autocrossing. Also, the tapered bearings are not engineered for the spacer. There are other, larger, heavier cars using the same diameter of stub axle without spacers.

Without the spacer, you would NOT use the aynes torque figures. You would use the standard adjustment procedure for tapered bearings which tightens them down to the point of dragging, then loosens the nut 1/8 to 1/4 turn and cotter-pin it in place.

If it were my car, I would install fresh roller bearings with new seals on both sides.
David "deja vu" Lieb
David Lieb

Sorry for the deja vu David. When I searched for "tapered wheel bearings" in the archives it returned hundreds of posts with nothing definative as to the subject in the title. I just don't have the time to sort through them. I'm sure the info is in some of the the posts with helpful titles like "I have a question" and "Help". Thank you.
CJCharvet

Thanks again David. I found one of your posts that recommending "Timken" as a search.
CJCharvet

CJ,
Many people have unavailingly begged people to put useful information into threads with relevant titles. Hasn't happened. It would be nice to have an FAQ section with all of these things in them, but, realistically, that represents a lot of work.

BTW, you misunderstood me. I was not complaining that someone was asking this again, I was dreading the eternal conflict we always get between those who maintain that the ball bearings are the only correct way to go, those who use tapered bearings and shim the spacer, and those of us who use the tapered bearings with no spacer. We do this a couple times a year I reckon and no one ever convinces anyone else to convert. This is another reason why the FAQ will never happen ;-)

Another such volatile topic is the removal of the front springs. Some people remove two of the bolts that hold on the spring pan and replace them with very long bolts or pieces of all-thread, then remove the other two stock bolts and use the long bolts to slowly release the spring tension. Others use the technique used in the factory manual for changing the front shocks, which is to use a trolley jack under the sping pan to raise it until the shock arm moves off of the stop. Then remove the shock arm from the upper trunnion, the anti-sway bar connections, the tie rod ends, and the brake line, then slowly release the jack and remove the spring. Both ways work.
David "jack method" Lieb
David Lieb

Should we start a religion thread category as well? haha. I guess until someone posts "wheels came off on I-95" or "Arm came off when removing springs" to each his own right? I'm gonna call Winner's circle after turkey day to get some roller bearings.

Courtney "Ace hardware doesn't carry the right bolts, so I use the jack method and every time I'm disappointed in the amount of energy stored by midget springs" Charvet

CJCharvet

That massive amount of stored spring energy IS a little disappointing, isn't it?
BTW, most bearing suppliers carry the tapered bearings as well as the seals. No idea what the WC (pun intended) charges, but you might want to do a sanity check with mcmaster.com
david "Ace probably doesn't have them" Lieb
David Lieb

Here's the bearing numbers from the set that we put on our race car:

05185
07097
07204
05066

All of the numbers are Timken. I tried to get a set from the local NAPA and they could get all but onee of them, but I have found it on the internet.
BTW, we didn't use spacers when we converted to tapered bearings and it works just fine.
Tim Michnay

Thanks Tim. The bearings that came out were 30303 and 30205 outer and inner respectively. Hopefully I can find a source soon.thanks for the NAPA info too, I was going to check with them first. Ours has a good machine shop attached so maybe they would have some.
CJCharvet

Having had this problem for many years I decided to do something about it.
Fortunately I have a friend who is a director of NSK bearings, a company who bought out the former supplier to British Leyland and BMC group, RHP.

With his help I understood why new bearings do not fit correctly into the spridget hub and always have differing amounts of play when fitted. This was easy to understand as the basic bearing (20 degree angular contact) does not have a tight tollerance on the faces of the inner and outer races.

The way the front hub is constructed is that the hub is machined with a spacer in its edge that sets the 2 outer bearing races a set distance apart. Then the inner races should be held apart by EXACTLY the same amount by the inner spacer that fits between the bearings over the stub axle. This being the case it also means that the bearing inner and outer race faces should be exactly parallel. This is not the case with basic bearings so thus they have too much play or worse too little and fail prematurely.

However if you specify the correct bearing (Face adjusted) then the ones you are supplied with will have these faces parallel and will thus fit perfectly.

The NSK numbers for a new 40 degree angular contact, face adjusted bearings are

7303BEAT85SUN
7205BEAT85SUN

or the SKF numbers for the same bearings are

7303BECBP
7205BECBP

As I said the originals were only 20 degree whilst these bearings are 40 degree. Well 40 degree bearings are far superior and act almost the same as a taper roller without the drawbacks. The main drawback of a taper roller is that it is less efficient (more friction) and thus also has a shorter life.

Before fitting these bearings it is worth checking that the spacer machined into the hub is exactly the same dimension as the loose spacer that fits between the bearings over the stub axle, which it should be. If they are not the same then the face adjusted bearings will not be right
Bob (Robert) Midget Turbo

Thanks everyone, I NAPA will have some new tapered roller bearings for me tomorrow. If anyone is intersted, I can report as to fit to the hubs and any shimming required.
CJCharvet

This thread was discussed between 26/11/2008 and 28/11/2008

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