MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - wheel bearing temps. are the new bearins safe???

Im not sure if anyone saw my thread on the gen. side titled...""40 Degree angular W.B. issue solved, IM THE MAN!!""


But I have been reading up on polymide 66 bearing cage (glass fiber plastic) in the 40 degree angular contact wheel bearing...I got to say Im not sure that s a good idea..the operating temp of this plastic bearing cage is only 110 degree Celsius = 230 degree Fahrenheit using genral automotive greases

do the wheel bearings on our cars really run at this teemp. or lower.

By the way the Machined brass cages are rated to 250 degree Celsius = 482 degree Fahrenheit


the SKF code for the polymide bearing cage is becbp,
the SKF code for machined brass bearing cages are becby....which are about the 3rd the price tag$$$$, as you saw in my other thread


anyway I curious what your thoughts are...I should be getting my new 40 degree angular contact bearings with the machined brass cage tomarrow evening.


Thanks

Prop


http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=1_0_59



http://www.skf.com/skf/productcatalogue/jsp/viewers/tableViewer.jsp?tableName=1_0_t47.tab&maincatalogue=1&lang=en
Prop

Bearings should never run this hot. It can happen, if you put too much grease in them. normal operating temp. for a grease lubricated bearing is about 50-60 degrees C, running up to 80 when new but should not be to long. Only thing i can't acount for is heat generated by braking (hard)....
Alex G Matla

For a minute there I thought that Prop had actually gotten his car running... silly me!
David "time to work on the midget!" Lieb
David Lieb

Hey alex

I took that as an avg. and called it 55C that equals 131 degrees F.

thats not a whole lot higher then air temp, what about road heat does that effect bearing temp.

btw thanks for the input, I have no clue what the bearing temp should be, I always assumed it was fairly high...but I see your point, it cant really be higher then that of the grease your using, Id say axle grease is around 150F.

prop
Prop

Brake heat is the main source if using the brakes enthusiastically, much greater than other sources.
Paul Walbran

If the wheel bearings are running in this temp range...IMHO I doublt that braking heat will have much effect of the polymide bearing case of the 40 degree angular bearing, for street driving Id think its rare you will brake this hard so frequently....accoding to the SKF wedsite...it mainly has to do constant temp. that would break down the bearing cage.

then agian perhaps in race only cars this might be an issuue, where hard braking is as common as punching th gas pedal.

prop
Prop

Prop, normal bearing grease has a melting point of about 110 C. If you go above this too long the grease will run out and the bearing goes red hot. I've seen bearings where this has happened.
The polyamide goes brittle if exposed to heat for a prolonged time and then it disintegrates....
Alex G Matla

So, what's the verdict? SKF or KOYO? Plastic or brass?

Andrew
aj robinson

Prop, I think you're wise in going with the brass cage bearings. I just checked the specs on the wheel bearing grease Timken recommends and it's temp range is -40F to +300F or -40C to 149C. The upper end of that range did excede the ratings on the poly cage so just to be sure the brass cage isn't a bad idea. I don't know how hot the wheel bearing area might get but under hard braking there is a lot of heat transfered from the disc into the hub, that's why when disc brakes were first introduced most of the cars required a special high temp grease for the bearings.
Bill Young

I just got my new 40 degree angular contact bearings with the machined brass cage instead of the polymide plastic cage

what a price tag...for both sides with the seals and taxes $126.00 thats $63.00 per side, and the life expectancy is 12,000 hours...or 720,000 miles thats on the Koyos the skf polymide is 10,000 hours

Here is the code #s of what I purchased

these are cross-referanced from SKF to Koyo which is a main supplier to GM.


Koyo 7303BGC3
Koyo 7205BGC3
SKF seals 13649

I got them from
IBT
2401 industrial Dr.
Jefferson city, Mo. 65109
1-800-765-1042 toll free
(573)-635-1042
Prop

This thread was discussed between 01/07/2009 and 02/07/2009

MG Midget and Sprite Technical index

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