Front wheel bearings

[Mknight702]

Westfield 129 wrote:
> Don't worry about the radius at the back end of the spindle. Any shims you put there moves the hub, and that is not a good idea.

I have to disagree here. The hub has already moved because the bearing thrust face doesn't sit flush to the face of the upright, all the shim does is fill this gap and give the axle back the strength that it was designed to have. The slight gap between the bearing and axle face is equivalent to filing a notch in a glass rod, it gives a weak spot where failure is more likely. Yes, given the lightness of the car and the strength of the stub axle failure is extremely unlikely, however for the price of a 0.020" shim it makes sense to me to eliminate this (allbeit) small risk, especially given my luck.

As for shimming the spacer, my problem was that the spacer was already oversize so shimming would have made this worse, I could have shimmed the bearing seat, but machining the spacer was the simplest solution and also enabled me to correct for non face adjusted bearings.

BTW I was specifically advised by Peter May that the taper bearing kit he has would move the hub and cause potential problems with the brake caliper so no work around solution is ideal.

[Westfield 129]

Don't use the Peter May bearings. They are incorrect for the application. Wrong combination of bearings and races.

Specifically, here in the US, I have installed 6 sets of the Speedwell TIMKEN bearings and races. They don't move the rotor at all. The discs are centered in the calipers, and in most cases only two shims (one thick, one thin) are required to achieve the free rotation without play at 40 lb.ft. of torque. The setup is a DIRECT REPLACEMENT for the ball bearings, and includes the proper spacers to complete the setup. They fit perfectly, with no modifications at all. These are the preferred bearings for the last few years here in the US. Also available from Huffaker Engineering. Perfect fit. The last set that I fit to the car went on my new RHD XI, with brand new wire wheel hubs from Moss US. The fit was perfect. Everything was centered as it is supposed to be.

I have yet to find a spacer that required no spacers. I suppose that it's possible. I just have not seen one. If I did, I would just hand it to the machinist to shave a few thou off. Shims or no shims, the wheel has to rotate freely, without any wobble or play, at the specific spindle nut torque. One does what ever has to be done to achieve that. However, with the ball bearing set having to be pressed into position, making changes is a little involved. Setup is a LOT easier with the taper bearings. More accurate, too.

Obviously, the Peter May bearing set is not the same as the Timken pieces we get here in the US. Contact Speedwell Engineering, US. They can send you parts that fit, and don't cause any problems at all.

Besides the fact that the bearings will last far longer, the brake feel and modulation improves about 1000%. It is an amazing modification.

I still would not shim the backside of the bearing against the hub. Perhaps you could have a piece machined that would provide the flat face that the bearings require, or better, get the bearing that fits. Otherwise, the bearing gets moved outward, and that puts more stress on the spindle.

I have over 45000 miles on my XI. Who knows how many miles were on the original spindles prior to their mounting on the XI. I have not broken a spindle yet. Lots of races, lots of long trips. Lots of driving. I even drove it today about 50 miles. It's quite a bit lighter than the Spridget donor. I suppose that the parts were over designed to start with. There is no history of spontaneous spindle failure here, other than when the cars are running wide slicks at the races, or run without the spacer. If the parts have not been abused,, and are properly installed, I don't think that there is a problem. BTW, the radius fits the Speedwell taper bearings perfectly.

Note: Prior to the installation of the Speedwell/Timken bearings, I was replacing the front wheel bearings more than once a year as they loosened. The main reason for this was the problem with "knock back" with the brake pads, and the resulting erratic brake pedal. You know, "Soft,with hard bits, like stepping on a dead amimal". This made me nutz when driving in the local canyons. Always having to double pump the brakes. Changing the bearings fixed this, permanently.

I do recommend installation of the strengthened 4340 spindles when renewing the king pins. These fix all the problems when fitted with the taper bearings by Timken.

The BP is high now. Good time to buy from US suppliers.

[Mknight702]

The taper bearing solution is very tempting, had Peter May sold me a set i would be running them now. Maybe next time I replace my set I'll give Speedwell a call, unfortunately, although the exchange rate may be good at the moment, by the time I've paid freight, duty and VAT I'll be looking at £200 which is somewhat expensive. If you knew the part number of the bearings I might be able to source them locally.

When you next have your bearings apart, could you measure your spacer for me, the specs say it should be 1.500", mine being oversize was pushing the thrust face out making the bearings loose no matter what I did, a shorter spacer would have been better as then I would have had to shim to get the correct fit although, as you say, shimming with a pressed in ball bearing is difficult to say the least, another way in which taper bearings are better.

I think that a lot of the loose fitting problems that the Midget and XI owners have at the moment come down to the fact that non face adjusted bearings (and potentially oversize replacement spacers) are not giving the bearings the preload that they require for a good fit, meaning that often you have more play in the wheel after fitting new bearings than before. Now I know the dimensions that we should have, I can machine the spacer or shim to suit whereas before that I was fitting the bearings blind assuming, as do the manuals, that the new spacer was correct and that the bearings were to original specification.

[11admire]

I have just had a look at the Timken catalog and they list a Roller bearing conversion for the front wheel.
link to catalog http://www.timken.com/en-us/products/Do ... _older.pdf
on page 16
is that the roller bearing solution you are discussing ?

[Mknight702]

Having looked at the 30205M/30303 bearing configuration it looks like some machining is required to fit the inner bearing so I don't think this is the Speedwell solution.

http://smithtr6.com/bearings.htm

Has a load of information on the various options.

http://www.mgexperience.net/article/mg- ... rings.html

Is a more detailed look.

Have fun!

[Westfield 129]

The Speedwell bearings are Timken items, and are unmodified. There are unlimited options with the Timken bearings, with different bearings fitting a number of outer races. Tom Colby at Speedwell did the research. The parts fit, and include the necessary shims to get the proper pre load at the standard spindle nut torque setting.

Contact Speedwell directly. The price is probably better for those in the UK now, as the exchange rate is favorable.

[jonclancy]

Short story: loose front bearing = lots of research and a missed opportunity to buy a NOS set on eBay because I was faffing about with eBay offers.

Didn't want to fit generic parts listed in a few places as it's known they are of a variable spec - quality might be fine but are not face-adjusted. Can't afford Speedwell's offering.

Found out that SFK Bearings 7303BECBP and 7205BECBP are what I need. Plus a Payen NA301 seal.

Got that lot on the way now.

BTW, I called SFK Technical (01582 496534) and can confirm that the brass-race version is suffixed BECBM. But they are nearly twice the price. The plastic races are good for 100 dec C plus before wearing, and are used in rail applications, so probably fine for me!

[Westfield 129]

The prices on the taper bearings have dropped by about 20% or more. The best part is that they don't wear out.

The best way to make sure that the conventional ball bearings last is to properly shim them and torque the nut to specifications. However, I never was able to get more than 5K miles out of mine (plastic race or brass race) before the brakes started to go off from the play.

Use a high quality synthetic grease. Probably the best thing you can do to extend the bearing life. However, ball bearings are really not designed for side loads...

[erictharg]

The only problem with the original angular contact ball bearings is that they need to have the correct face location tolerance to suit the factory fixed length spacer. Both Peter May and MGB Hive stock the correct bearings. I have bought replacement bearings from Unipart (who you'd think would get it right...) to find they were not face located spec, and were loose when installed. If you just buy bearings to the "right" reference number for type and size they'll not give the required fit. I've run factory spec ball bearings for two race seasons now with absolutely no problems. The Peter May taper rollers work just fine, but only with their bigger disc brake set up, as they move the position of the hub relative to the spindle. Are taper rollers a better solution? Yes - if correctly engineered for the application, as the one's Jan recommends clearly are. Are the stock bearings perfectly fine form 99% of users as long as face located? Yes. As ever, you pay your money and take your choice.

[jonclancy]

Yep. The indicated part numbers I used are for face adjusted bearings. I didn't call MGB Hive, but did so another supplier chasing QH parts.

I'll bear MGB Hive in mind if I need another set - probably cheaper than I have just shelled out (and I did quite a bit of searching around for the best price!).

BTW: I ended up using www.engineersmate.com