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Cymber
United Kingdom
966 Posts |
 Posted - 10/03/2008 : 11:06:28
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What is the reccommended tightening torque for front hubs? There are no torque limits quoted in any of the literature I have seen, did they have torque wrenches 70 years ago?
Now a tip which I was given a long time ago and which works. If you have a shaft such as a stub axle which, after many years of bearings being removed and refitted is a bit too small resulting in insufficient interference to hold the bearing properly, take it to your plating shop an ask them to put .0005" ti .001" 0f copper plate on it. Refit and remove the old bearing and your problem is solved.
With appologies to those of you who already know this.
Maurice Blakey. |
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Peter Scully
United Kingdom
157 Posts |
Posted - 10/03/2008 : 14:01:49
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If you search for 'front hub nuts' this post from 12/05/07 may help.
Peter |
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Cymber
United Kingdom
966 Posts |
Posted - 11/03/2008 : 19:54:07
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Thanks Peter, 50 lb.ft seems about right although the figure quoted on the chart I have for 5/8 BSF is around twice that.
Maurice. |
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David Allison
United Kingdom
665 Posts |
Posted - 13/03/2008 : 08:47:37
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From experience gained over a few years - and the fact that sons seldom agree witht their fathers - I worked on taper roller bearings while doing my apprenticeship.
My tutor at the time was of the same opinion as my Dad - dont fix what aint broke!
Dad had tried to use taper rollers in the late 1960's, however he did not persevere at the time because the only parts available (hub and spindles) were all original and worn out as well.
Peter Cranage used the same set up at the time until he had a rather spectacular front hub failure at Silverstone.
Both he and Dad decided over a pint - that probably the taper roller bearings had caused the failure of the spindle.
My work concentrated on converting my mod sports Midget to run taper roller bearings on the front hubs (the modern Midget and NA hub bearings being the same numbers).
I was at the time running slick tyres, very large amounts of negative camber and thought (not unreasonably) that the taper rollers would give an advantage of some kind.
The standard bearings are a single thrust - pressed in from either end of the hub against a spacer.
The nut on the end of the spindle sets the thrust and the spacer the pre-load.
I fitted taper rollers to the Midget and after one meeting the spindles had stretched.
I talked to my Dad who said it was probably because the spindles were not designed for the task and that they were 20 years old.
What did he know?
I talked to my tutor and he said the same thing!
We set up an experiment running spindles with single thrust ball races and taper rollers.
We made identical spindles and ran the bearings untill they wore out.
The taper rollers were adjusted as they wore.
The bearings lasted a similar amount of time - the only difference was the heat build up in the spindle of the worn taper rollers.
I wrote my paper saying that unless special hubs and spindles were made to suit the taper rollers - the end loadings caused by the taper rollers could cause a shaft fracture in the spindle caused by heat build up.
It was then that Dad told me that it took he and Peter Cranage about ten minutes following the recovery of his car in 1974 to decide exactly the same thing!
There are kits available to convert your MMM car to run taper roller bearings - the best of these recommend new hubs and spindles.
If you fit taper rollers - you must make sure they are adequately set up and installed correctly.
Front hub failure is down right scarry!
I dont know of a standard bearing failure causing a spindle to fracture on a MMM car - those that have had spindles crack with standard bearings the failure was certainly anno dominii.
I do know of several hub bearing and spindle failures using taper rollers - most caused by bad installation or preparation it has to be said.
I go back to my Dad and college tutor - Dont fix what aint broke!
Regards tightening torque.
The hub nut should be done up to around 50 lbs ft.
The thread is very coarse and designed to be done up using a box spanner. I was always told that the bearing should not need to be done up "that tight" - in other words you felt it.
The bearing is set up by the spacer - not the nut.
Overtightening the bearing just reduces the bearing life and increases the load on the spindle.
Just make sure that you always move to the next split pin hole - do not back the nut off.
To set up taper roller bearings it is the exact opposite.
There is no spacer, the bearings set up not only the thrust but also the end float.
You do up the spindle nut until the hub starts to tighten, then back off to the previous split pin hole - then you check the end float using a dial gauge, if the end float is too large the bearings need replacing.
People have been known to "nip" taper rollers tight to get a set of worn bearings through an MOT or as a get you home - but this is a false fix.
Hope all this helps.
Unlike my Dad I am not anti taper roller conversions - I am anti doing it on the cheap.
The NA has plain bearings in all hubs - as does the NO.
Regards David Allison
NA 0307
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Peter Green
United Kingdom
1682 Posts |
Posted - 13/03/2008 : 10:41:25
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DO NOT USE TAPER ROLLER BEARINGS WITHOUT A SPACER BETWEEN THEM.
Peter. |
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kimber
United Kingdom
1529 Posts |
Posted - 13/03/2008 : 10:54:29
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[quote]Originally posted by David Allison
To set up taper roller bearings it is the exact opposite.
There is no spacer, the bearings set up not only the thrust but also the end float.
http://www.triple-mregister.org/forums/topic.asp?TOPIC_ID=362&SearchTerms=taper,roller,bearings
This topic has been covered before and, as Peter rightly points out, if you are using taper rollers on Triple M front hubs which were not designed for them, it IS important to include a spacer. |
Edited by - kimber on 13/03/2008 10:54:51 |
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David Allison
United Kingdom
665 Posts |
Posted - 13/03/2008 : 11:28:35
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That is interesting - the whole reason for using taper rollers on modern cars was to delete the spacer.
By using the spacer the taper roller offers no real advantage over the plain bearings - or am I old fashioned and missing something?
Not disagreeing - just wondering?
Maybe those who have used taper rollers and had spindle failures have deleted the spacer and this has loaded the spindle causing the failure.
Introducing the spacer would make sense of using the taper rollers but you would still need un-worn hubs and spindles to make the best of them.
As I said in my original reply my experience is based on very old news and that the modern kits were indeed designed to be fitted and used in a specific way.
My understanding fromt e last two posts is that the taper rollers therefore offer no advantage over the standard plain bearings?
Regards David
Regards David |
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Peter Green
United Kingdom
1682 Posts |
Posted - 13/03/2008 : 12:26:39
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quote:
I think your comment is correct David, that is why I use standard bearings in my Triple-M cars.
All the stub axle failures I have heard of were on cars with taper roller bearings without spacers. I am not saying that modern cars need spacers, Triple-M stub axles were designed to use them.
Peter.
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Peter Green
United Kingdom
1682 Posts |
Posted - 13/03/2008 : 12:29:38
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David's quote "By using the spacer the taper roller offers no real advantage over the plain bearings" did not appear in my last posting.
Peter. |
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kimber
United Kingdom
1529 Posts |
Posted - 13/03/2008 : 13:14:58
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Personally, I have never used taper roller bearings on a Triple M stub axle. Quite happy to use the original set-up.
Having said that, I notice that the (new) front wheel bearings on my P-special are shagged (I think that is the correct technical term!) after 3 races and one hill-climb. |
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David Allison
United Kingdom
665 Posts |
Posted - 13/03/2008 : 15:43:17
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Andrew
I find that racing does that!
On racing tyres the NO runs a set of front wheel bearings every season - if Tim drives it!
The NA front wheel bearings last about 10 years or so - although I am about to replace them next weekend (these are about 6 years old) I think that has more to do with the cars long lay up after the engine went pop.
I know your P type runs racing tyres - but it does go indecently quickly as well.
They last much longer if you drive as slowly as I do though!
I find road driving much less wearing on the pocket and the car.
Regards David |
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