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MG Midget and Sprite Technical - front TAPER wheel bearings

Okay I did not add want to add this to the other wheel bearing threads becaus it would get lost in the endless discussion.

This thread is not about the normal angular contact bearings but about the tapered alternative.

I have decided to go to taper bearings because they can be set-up without play, be dismantled without damage and are cheaper that the angle contact alternative.

As can be found here:
http://smithtr6.com/bearings.htm
the 07097&30303 combo is the best suited for the job.
Best because as you can read the bearing pack is a little wider than ideal.

Or so is thought!!!

There are 2 types of 07097!!
the 07097/07196
and the 07097/07204
one is 15,01mm wide and one is 13.5mm wide.
Guess which was used for the study......

If you get the 13.5mm wide 07097/07196 the width difference is minimal and this should only need no or minimal mods to washer and/or castellated nut.

It might cause the disk to be off center in the calliper but that can be solved with a small shim between the hub and caliper.

I hope they will be delivered soon.....
Onno K

Yes the tapers are an alternative however

They do not solve the problem of the inner radius that the Americans are so concerned about

And also they are far less efficient than the angular contact bearings. This is because they do not use the inner stiffening piece plus they have more friction than the angular contact.

Apart from all that they are an option!

:)

Modern vehicles use double row angular contact bearing, they do not use tapers.
Robert (Bob) Midget Turbo

Bob
If you shim them like an MGB front wheel bearing they do use the spacer and the added strength they give.

I am not to concerned about the inner radius as this inner bearing is slightly shallower than the OE bearing and this leaves enough space for a shim if required.

Yes they are slightly less efficient
But a sloppy ill fitting bearing is even worse ;)

But as said they have some benefits to
Onno K

Not looking it up, but there are or were bearings with the correct radius, suffix "X" on the cone number.
And use the spacer/shims.

FRM
FR Millmore

FRM
That one has been discontinued.
And yes shimming with the spacer is preferable
Onno K

I agree the tapers are an alternative to the angular contacts. However, apart from the disadvantages that Rob has mentioned, you will also have to adjust them during their service life, which will also be shorter than the life of the original angular contacts.

The great thing about the original setup, was that it last a huge amount of time, and was fit and forget.

How much are the tapers?

I also think that tapers for Spridgets are likely to become even scarcer than the 40 degree angular contacts.
Lawrence Slater

Taper bearings certainly do not last as long as the original. I had them on a race set up using slicks and they needed replacing almost every other race. I reverted back to the angular contact bearings which lasted a season. (they were the old RHP's though!).
Bob Beaumont

Thinking more on this, I can't see the advantage of the tapers, if you still have to play around with shims.

The major advantage of tapers, is that as play developes, you only need to tighten the hub nut a little to eliminate it, until the bearings are so worn that they have to be replaced. A very simple a quick task.

However as all(most) agree, the spacer is also required for the spridget to retain the strength in the spindle. This then removes the option to simply tighten the hub nut to eliminate play. Instead you will have to deshim, or shorten the spacer, by exactly the right amount each time play developes through the normal wear in the bearings. That seems like more hassle to me than shiming the cheaper angular contacts in the first place.
Lawrence Slater

Somebody tell me how it is that millions of cars, including MGB, run well over a hundred thousand miles with tapers without ever touching them, but some people can't make a Spridget go more than a month from the sound of it?
Think it might have something to do with competence of setup?
Though the ones on my big truck did actually wear out every 500,000 or so.

FRM
FR Millmore

A full set of taper bearings is going to cost me less than €50,-
The Brand is still unknown to me but had I ordered timken's it would have been around the €100,- mark.

But as a proof of principle I am going for cheap as it will be fun to see how long it lasts.
Can't be worse than the 1,5 years the crappy "OE" replacements lasted me....
Onno K

I put tapered bearings on my old race car that my brother now has. 4 seasons old on 6" slicks without a problem.
John Collinson

Sorry, just sticking my nose in here. Feel comfortable to tell me to ping off if you think I should. I've been following this bearing issue re midgets for a while!!

In a purely practical sense, why do I think Fletcher may have hit on something relevant?

Roger T

Roger
Read FRM's comment carefully.
He says some can't get them to work.
And as John has indicated his old racer is doing fine on them.

This all has to do with the diversity of taper bearings and the fact you do need to set them up properly (easy)

If you have the correct bearings and set them up right they should last a long time.

On my old mini I switched from ball to taper and the difference was night and day!
The tapers did not have play nor did they develop it in the next 4 years of hard use.
Onno K

Of course each person needs to do what they believe is right

However to set up the taper bearing is no different to setting up normal angular contact bearings. You can perchase very good quality 40 degree bearings that are not face adjusted for next to nothing (cheaper in fact than tapers) so I would rather install them and do the shimming than do it for tapers.

As I said all modern wheel bearings are twinn row angular contact, why? because they are mfar more efficient than tapers can ever be.

So tell me why a taper installation is better?
Bob Turbo Midget England

Hi Bob,

I guess that the appeal of tapered would be the ease with which one can perform the shimming process.

However, if one has decided that separating the angular contact assembly is of no concern to them, then the difference is almost nothing. In that case, the ball bearing's rolling efficiency is a winner.

However, bearing makers recommend against separating their angular contact ball bearing assemblies, because damage is done to the balls and the races when that happens. The amount of damage is hard to predict, and it may be small enough to not matter, or it may be enough to lead to premature wear.

However, with the low miles put on most Midgets, the life/wear question may not be the priority that it would be on a daily driver.

The number of "howevers" above indicates why this topic (tapered vs. angular contact) is almost just one of personal preference. Both tapered and angular contact should work, if shimmed properly, and the center distance piece is retained (like on an MGB).


Angular contact: more effort is necessary to do the shimming process (difficult to press out and in to the hub for each shimming trial), but after that is done, the life and the rolling resistance are best.

Tapered: easiest to do the shimming, but shorter life and higher rolling resistance.


Norm "tastes great, less filling" Kerr

Norm Kerr

Shorter life should be put in to the correct frame.
Shorter life is still a lot of years of hard use!!

And that is not acomplished with the cheap "OE" bearings fitted the original way.
And I am no fan of splitting ball bearings which happens when setting them up correctly
Onno K

I was wondering why tapers have higher friction, and found this about taper roller bearings.

"The downsides to this bearing is that due to manufacturing complexities, tapered roller bearings are usually more expensive than ball bearings; and additionally under heavy loads the tapered roller is like a wedge and bearing loads tend to try to eject the roller; the force from the collar which keeps the roller in the bearing adds to bearing friction compared to ball bearings."

Would a Spridget be considered a heavy load? I suppose that depends on the size of the taper bearing selected to carry it. Tapers have been around for a long time, I wonder why BMC elected for angular contact balls, as opposed to taper cylindrical rollers. Was it just the cost factor?
Lawrence Slater

Pleased my limited knowledge is correct and I have not lied. :)

I suspect the reason that BMC used the wheel bearings that they did is because it is far superior in every way to tapers so why would they not choose it on their vehicles?
Robert (Bob) Midget Turbo

And why did the mini's change to tapers with their switch to disk brakes?

And why did the B have tapers from the begining?
Onno K

Not sure but they soon learned their lessons and quickly changed to double row balls as are most vehicles today.

From our point of view I think tapers are acceptable. Whilst they will sap a little power and cause a bit of drag they will function well enough for what we require.
Robert (Bob) Midget Turbo

The sole justification for the modern double row ball bearings is space/weight saving. In order to use them, they must be heavily preloaded AND high contact angle, to provide the "overturning " resistance that a well spaced set of either angular contact ball or taper rollers gives. It is probable that the high preload causes enough drag to match the tapers in-built inefficiency. From a bearing design standpoint, it is a horrible thing, but it is compact, allowing smaller & lighter mating parts. In order to make it work at all, assembly MUST be extremely precise, as the combination of high contact angle plus high preload makes spacing a matter of tenths if not hundredths of thousandths of an inch, rather than the thou or two of the old ones. That is why they are always made as cartridge bearings, or integrated into the hubs. It works sometimes - Mazda seem to last 200,000+ most of the time, though I've seen a few fail around 100,000. NOT having enough preload WILL kill them - the Mazda axles are torqued to 205lbft. With all this, the idiots have made failures common where they were formerly unheard of - Ford trucks/SUVs and many other vehicles (which formerly commonly went the entire vehicle life on original bearings) are loosing bearings at under 50,000 miles, repeatedly. I was getting my car inspected (MOT) and he had a pile of failed bearings on the floor that had 20 times as many junk bearings as I have seen in my whole 50 years of fixing cars. It was about two weeks of replacements in a small 2 man country shop. And I can tell you those suckers were fried, many failing on the road, can't move the car/truck - call Paul because he is the towtruck/tiltbed guy. He now says failed bearings and the resulting eaten hubs and brake discs are the biggest part of his business.

FRM
FR Millmore

FR,
Does that imply that the modern 40deg' tighter tolerance angular bearing would last less time than the original 20deg' that BMC specified?
Lawrence Slater

Are we seriously debating that BMC did anything for reasons other than cost-saving? And if so, I want whatever pills you're taking!
Growler

Does ANYTHING get seriously debated on here? I always think it's just a bunch of people on drugs putting in their penniworth. :)
Lawrence Slater

Lawrence-
Not necessarily, but certainly possible or probable. The relatively wide spacing between the bearings lessens the loads a huge amount - it is at least a "square of separation" deal", maybe even higher order. But the tolerance of 40 degree bearings for either under or over preload is much more fussy. Tolerance for low preload = clearance could vary by precise ball track configuration, but once preload is established, any tiny reduction in spacing will put the loads off the chart.
The limits for these things is the old original New Departure separable bearings, as used in steering heads of bicycles and motorcycles - and bicycle and Chevrolet wheel bearings for about 75 years. The ball tracks were a full 90 degrees of a circle, and would work OK from not even finger tight to heavily preloaded - but they were very widely spaced.

BTW, I suspect that most taper failures are the result of bearings set too loose - you cannot feel .002 in a greased bearing, and .002-.005 is the generally accepted minimum for most humans to feel. Some people cannot feel .005 in an oiled bearing, by my personal testing; I can feel .001 on a very good day, but I'd not swear to it! This is why you set up MGB with an indicator and dry or very light oil in the bearings, and grease after shimming.

In that case, when the side load on the tyre tilts the hub, the rollers contact at the ends, rather than on the roller surface, killing the rollers and races in short order, as metallic debris fills the bearing, The correct .001-.002 does not allow this, and in fact you can preload tapers as well, although small clearance is more common on hubs, This gives room for hub growth with brake heating, and cuts unnecessary drag.

FRM
FR Millmore

Thanks FR, things are always more complicated than they appear.
Lawrence Slater

I asked my mate from RHP why he thought BMC used tapers in the MGB he answered immediately without even thinking.

He said they would have wanted to spread the work out!!

So in reality they didn't are one way or the other simply wanted a set up that would get the car running for a year or 2!!

Great. :)
Robert (Bob) Midget Turbo

May as well continue this bearing school.

OT rant: The Spridget bearings were R&M, which was et in the merger that produced RHP out of three old line bearings producers. I consider RHP to be the first definite sign of the continuing collapse of integrity in parts identity, which has led to today's infuriating impossibility of finding decent parts by brand. And, their boxes are astonishingly ugly! I remember the day I walked into Bearings Inc, and the sinking feeling I had when I was given that baby s**t box and the takeover/merger story.
OT rant 2: Timken originally was the patent holder and sole manufacturer/supplier of taper rollers, and they sold NOTHING else. That is why taper roller numbers ARE Timken numbers, and why anybody talking about "genuine Timken" anything but rollers is smoking bad dope.

If you consider the load on a ball or roller bearing, you will see that the majority of the load is carried by the two rolling elements at the bottom of the bearing, in a wheel bearing configuration. The creates a spreading load, trying to push the two (balls) apart, as the inner race tries to fall down between them. Nobody is happy when his balls are forcibly spread. This load creates large frictional forces between the balls and cage, which attempts to contain the spread. That creates friction, hence the machined bronze retainers in the old R&M bearings.

If the clearance in the bearing is zero, then the load will be spread to adjacent balls, balancing the loads on the retainer, and decreasing the loads on the two bottom balls; the load is shared across all balls in the lower half of the bearing, typically 4-5, but high load bearings commonly have as many as 20 balls per track, so 10 carry the load. With close clearance, cage loads are spread all around the cage.

If there are large clearances in a bearing, because of wear or bad setup, or loose preload settings, then the tensile tangent load in the cage breaks it, the common failure in the old bearings (before they just fall apart). Hence the reason (other than cost) to use the modern injected plastic cages.

Angular contact bearings, ball or roller, continue this; the contact angle causes thrust loads to be translated into the same kind of forces. BUT: if they are correctly preloaded, both thrust and radial loads are spread across ALL the elements, and the cage loading is nearly eliminated.

The extreme example is a double row angular contact ball race with preload. This is used as a precise locating device, capable of carrying very heavy loads, both radial and overturning. The classic example is the transverse A series third notion shaft bearing. The ball track separation is about 1/2" with a ball set diameter around 1 3/4", it has more balls than standard, very heavy preloasd, very compact, and precise enough to carry the gear and overturning loads loads without deflecting enough to bother things. These can last for 100,000 miles, but if the big nut is left at less than spec, or unscrews itself (both very common) the bearing will disintegrate in a few hundred miles, maybe taking the entire gearbox with it. The bronze cages are ALWAYS broken by the time the gearbox has enough wear to dismantle, but function as spacers until the pieces get small enough to fall out = end of movie.

You might notice that the bronze cages are usually broken in the 20 degree bearings, in Spridgets or 1100/1300 rear hubs.
If these had been precisely set at some preload, this would not happen, and the bearings might last forever. The problem is assembly costs, so the OE specs were designed for nominal assembly with top quality parts, at a reasonable amount of track separation, to give acceptable life.

The cartridge wheel bearings are exactly the same. except they are bigger, carry relatively smaller loads, have less critical location requirements, and appear to have somewhat greater track separation - Mazda ones are about 1" separation with a ball set diameter around 2.5". (The Fubared Ford trucks are not much bigger!). The high preload/high angle requires assembly beyond any reasonable shop procedure, hence the cartridge designs. A transition phase was the mini front hub, which started as plain Conrad bearings with fair separation on 803/850 minis, but proved dubious by the time we got Cooper S with fat rubber. So, they engineered the preloaded taper rollers, with factory supplied spacer sets, to achieve the same thing as the modern bearings, in the space available. These still had far greater track separation than the cartridge do.

Old designs, like the TD/TF/MGA, used Conrad bearings with wide separation and no preload. The bearings may or may not have acted as angular contact, depending on assembly tolerance stack-up.

Taper rollers are angular contact, most common ones nominally designated as 25 degree I think, but that varies by application. Things with high thrust loads use higher angles. But, there is NO surface in a taper roller that measures as the designated angle; it is the angle perpendicular to the roller axis.
Typical RAX pinion bearing tapers require huge thrust capability, and absolute position accuracy; they are high angle (~40) heavy preload, and should last forever - if you don't leave them loose!

In applications like MGB front hubs, precise positioning is of little consequence, but heat and drag are, so .001-.002 is a way to assure as near zero as possible, without giving preload, which could get excessive quickly. An expedient and acceptable recognition of field service reality. I have never seen a failed taper roller hub bearing that could not be traced to contamination, or gross incompetence by the assembler. Never a worn out one, except on my big truck at some believed mileage on the order of 1,000,000. I got to examine them regularly, since you have to dismantle the hubs to replace brakes, none that I replaced ever showed serious wear at 500,000 miles after replacement.

End class/

FRM
FR Millmore

Hate this "EDIT" thing!

Edit: Re Bob's pal: MGB hubs were the direct result of Twin Can development. The design allows heavier loads with more precise positioning of the disc, leading to less knock=back of pads, and also a shorter lighter hub and spindle.
FR Millmore

Why?
Robert (Bob) Midget Turbo

Bob-
Why what exactly?

FRM
FR Millmore

Why go to that kind of detail for no gain?

I suspect those of us who have engineering knowledge know exactly how bearings function and those that don't will not care?
Robert (Bob) Midget Turbo

Bob
For once shut up!
For once accept that someone has more knowledge of a subject and/or is willing to explane it to others
For once have the dignity to not have to have the last word.
Onno K

Sorry
Read on. :)
Robert (Bob) Midget Turbo

By the way I accept I do not know too much about bearing design but I get my info from a application engineer who started life with Rand M then RHP finishing in a month or 2 time with NSK.

So I will gladly shut it!! (said in an essex accent) :)
Robert (Bob) Midget Turbo

Is it relevant that the Spridget hub design predates the MGB one by 11 years, and the MGA (if that was the origin of the MGB design) by 4 years. Cost, materials and availability were all still extremely limited in the UK in 1951 and the chosen design must surely have been very much controlled by these things.
Guy Weller

Was there an 803 Mini?
Dave O'Neill2

Nop 850 was the smallest.
Why?
Onno K

FRM mentioned 803/850 Minis
Dave O'Neill2

There was an 803 something, and I couldn't recall exactly what, and I didn't feel like looking it up, and I don't care.
But you stirred me up so Wiki:
The original A-Series engine displaced just 803 cc and was used in the A30 and Morris Minor. It had an undersquare 58 mm (2.3 in) bore and 76.2 mm (3.00 in) stroke. This engine was produced from 1952-1956.

Applications:

1952-1956 Austin A30, 28 hp (21 kW) at 4400 rpm and 40 lb·ft (54 N·m) (54 N·m) at 2200 rpm
1952-1956 Morris Minor Series II, 30 hp (22 kW) at 4800 rpm and 40 lb·ft (54 N·m) at 2400 rpm

I had said Morris, so the number is in me noggin.
Then to 948, then destroked to 848 for mini.

The A series hubs were very much of the time, with the nicety of the angular contact rigid spaced bearings to increase load capacity of smaller than usual bearings. The MGA ball bearing hub design is identical internally to 1950 T/Y series and maybe earlier ones, and first appeared, to my knowledge, in identical form on the Magnette 1954, and probably other BMC larger vehicles of the early 50s. The TC hub uses identical bearings/geometry to MGB.

FRM


FR Millmore

Nice history that FRM. Always good to read a bit of history IMO. :)
Lawrence Slater

FRM: thank you for the neat treatise on bearings, (I may not represent the average punter but) I actually enjoy learning more about the technical inner workings of things.

I'm especially happy to learn more about things which keep the wheels on my car.

Carry on...
Growler

All welcome, and I love stuff that keeps the wheels attached!
Should I write the treatise on basic bearing loading in vehicles?

FRM
FR Millmore

I save all threads like these, as they contain some great knowledge. You just know that the subject will come up again, and searching the archive is a bit of a chore.

So go for it FRM, I'm looking forward to the next installment.
Lawrence Slater

So..... I got the bearings in today.
Guess what the inner radius is?
Huge!
I'll be fitting them tomorrow an I will let you know how it goes
Onno K

Well if the do fit properly and (fairly)easily Onno, then I suspect there will now be 4/5 viable and cheap options for renewing Spridget/Minor front wheel bearings when worn to the point of wheel play.

In no particular order:

Tapers.

NOS for as long as you can get a decent deal somewhere.

New cheap moderns. I think Moss will come up trumps, and I think Firstlines, Sussex, and BullMotif specials will fit, but are still not fully confirmed.

New cheap moderns that require shimming, but perhaps are not so easily installed as the tapers.

Re-use existing RHPs. Grind a little of the face and reinstall. Admitedly still in the early testing stage, but seem to be fine.
Lawrence Slater

whoops!
Made a small mistake!!!
The 07097/07196 is wrong in outer diameter.
instead of 52mm it is 50mm.
So either a 1mm ring is needed or I need to co for an other bearing.

Ah well if all victory was achieved easy there would be no fun in it!
Onno K

This thread was discussed between 12/07/2012 and 21/07/2012

MG Midget and Sprite Technical index

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