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Front hub bearings

Posted: Mon Jul 22, 2019 6:19 pm
by Dennis Nicholas
Just fitting new stub axles (from GW) and hub bearings (QRG).
The outer races (cup) of inner and outer bearings are a good press fit in the hubs. But the inner races (cones) are a fairly easy push fit on the stub axle and can be made to turn with my fingers gripping. This will surely mean that the cones are going to be able to turn on the axles and wear both?
I intend to put a small amount of bearing locktite on inner cone which should glue it in place and prevent it ever turning........
BUT the outer bearing cone....
The end float of 0.002" to 0.006" is achieved with bearings dry and using a DTI to measure the in/out movement (or tighten nut till SLIGHT resistance felt then turn back 1/12 of a turn....i.e. 1/2 a hexagon flat.
Thread is 1/2" X 20 threads per inch UNF.
Therefore pitch (distance between threads) = 0.05 inch ....that is one turn of nut;
Therefore 1/12 of a turn (or half a hexagon flat) = 0.05 divided by 1/12 = 0.0041666 which is between the required 0.002" and 0.006" (since there are 2 holes one should be near enough to turn nut very slightly more or less to get pin in and still be within the end float) (half of that twelfth of a turn to align hole would be +/- 0.002" so within tolerance.

Now my thoughts and question.....
The inner and outer bearing's cups are at a fixed distance in the hub. The inner bearing cone is at a fixed position against the vertical link shoulder; so the only movable/adjustable bit is the outer bearing cone on the stub....the position of this will therefore determine the end-float and is adjusted in or out by position of hub nut against the washer with the D shaped hole.......ok so far.....but
Ok tightening up nut to move it in will decrease end-float, but turning back 1/12 turn.....what will make the cone come out to give the end-float? (apart from bashing the hub outwards?????)
I understand that the cones should be a slight interference fit on the stub axles to avoid them turning on it (as has happened on my old stub bearing)
So if I put a dab of locktite on the outer bearing cone that would prevent it turning BUT BUT would not allow setting of end-float :twisted:
In view of my first sentence that cone of outer bearing can be made to twist on axle do I just accept this and hope there is enough friction between cone/axle/washer face compared with rollers running around in grease so that cone stays put while rollers rotate round it????? :?

Dennis' grey cell working overtime.......thank goodness for a PCC meeting tonight to relax a bit (Parochial Church Council )

Front hub bearings

Posted: Mon Jul 22, 2019 8:03 pm
by Joe.
Had this same issue with replacement late type stub axles for the 5a,
The axles stocked by both QRG and GW are from the same re-manufactured batch and appear to be machined undersize, Cant seem to find the post now but I mic'ed them all up and compared them to the original wear limits and they were several thou undersize I seem to remember.
GW sent a replacement set which were exactly the same and eventually after several discussions on the phone "we've sold loads and never had a complaint" we sent them all back and used the early type stub axles which are easily available from triumph suppliers along with some early 5a hubs.

Only referances I can find at the moment are here:
http://scimitarweb.co.uk/sgwrs/viewtopi ... ng#p402594
And here:
viewtopic.php?t=5676&start=165#p375280

Dave

Front hub bearings

Posted: Mon Jul 22, 2019 8:31 pm
by oilrag
I had same issue with gw stub axles ,i returned them and was refunded , i then bought some new ones pt no 115763 from Rimmer Bros at £20 each ,new bearings fit perfectly ,no slop .
All ok now 11k later .
Oilrag.

Front hub bearings

Posted: Mon Jul 22, 2019 8:35 pm
by Roger Pennington
Dave, Is this the other thread you were looking for? (in the members' archive)

Front hub bearings

Posted: Mon Jul 22, 2019 9:04 pm
by Old and Slow
It made sense to me, so you would be to use non-setting loctite?
However, has anyone any experience of using the Revington spacer kit? I believe it uses shims to accurately fill the space between the two bearing inners on the stub axle:
Here it is:
https://www.revingtontr.com/product/rtr ... el-bearing
Looks like a sensible approach to the problem.

Front hub bearings

Posted: Mon Jul 22, 2019 9:45 pm
by David Tew
Old and Slow wrote:
Mon Jul 22, 2019 9:04 pm
However, has anyone any experience of using the Revington spacer kit? I believe it uses shims to accurately fill the space between the two bearing inners on the stub axle:
Here it is:
https://www.revingtontr.com/product/rtr ... el-bearing
Looks like a sensible approach to the problem.
I've used a similar kit from TR Enterprises. The same principle but virtually half the cost.

It was an easy but fiddly fix as the fitting process (fit bearings and spacers, check hub spins freely, disassemble, re-shim, re-assemble) needs to be done several times before they're correct. Once it's all finally adjusted the hub-nuts are torqued down (no end-float issue). The whole stub axle now seems much more solid.

:D

Front hub bearings

Posted: Tue Jul 23, 2019 1:17 am
by Dennis Nicholas
David Tew wrote:
Mon Jul 22, 2019 9:45 pm
Old and Slow wrote:
Mon Jul 22, 2019 9:04 pm
However, has anyone any experience of using the Revington spacer kit? I believe it uses shims to accurately fill the space between the two bearing inners on the stub axle:
Here it is:
https://www.revingtontr.com/product/rtr ... el-bearing
Looks like a sensible approach to the problem.
I've used a similar kit from TR Enterprises. The same principle but virtually half the cost.

It was an easy but fiddly fix as the fitting process (fit bearings and spacers, check hub spins freely, disassemble, re-shim, re-assemble) needs to be done several times before they're correct. Once it's all finally adjusted the hub-nuts are torqued down (no end-float issue). The whole stub axle now seems much more solid.
That sounds the way to go....much better engineering principle.....wish I had asked earlier as it would have saved me a lot of time and head scratching.
Now I must find if they do it for the bearings and stubs that the GTC (+6a) uses

Dennis

Front hub bearings

Posted: Tue Jul 23, 2019 1:20 am
by Dennis Nicholas
oilrag wrote:
Mon Jul 22, 2019 8:31 pm
I had same issue with gw stub axles ,i returned them and was refunded , i then bought some new ones pt no 115763 from Rimmer Bros at £20 each ,new bearings fit perfectly ,no slop .
All ok now 11k later .
Oilrag.
Was that part number for the 5 stubs or 6a/GTC stubs?
Dennis

Front hub bearings

Posted: Tue Jul 23, 2019 1:54 am
by Dennis Nicholas
REF the stub axles for the 6a/GTC. Is there actually one the same size that is used in a TR and if so does anyone know which model........it still seems to be a best kept secret. (yet again the modern disease of quoting car instead of item dimensions)

Rant...I, like apparently others, am getting a bit fed up with the attitude of "we have sold many and have had no problems".....when there are obviously problems. Damper bushes wrong width so spacers put on WRONG side of brackets, Felt seals, now undersized stub axles......there must be many out there who are running around with unnecessarily rapid wearing parts through no fault of their own just because they did not have the knowledge of some of the engineering but trusted our "specialist suppliers". Rant over but still frustrated at waste of time and money.

Dennis

Front hub bearings

Posted: Tue Jul 23, 2019 5:10 am
by oilrag
Dennis ,

Apologies for not being specific, i was relating to me buying a pair of TR4 Stub axles from Rimmer Bros here in Lincoln to use on my 5a ,(of 72 build year) ,these were/are the later fat /stronger stub axles . ie outer bearing id 3/4 inch ,inner bearing 1 inch.(approx)
Given that our traders sell a front wheel bearing kit for all models (excluding early 5's smaller 5/8th outer bearing) it should be reasonable to expect that the stub axle is same dimensions on 5a to 8b inclusive . i know the wheel bearings that fit my 5a front also fit my 1980 gtc front hubs, but i have never attempted to fit a 5a hub to a gtc vertical link/stub axle. As an aside ,in normal road driving including a trip across the alps into italy in gtc i have never experienced the brake pad knock back caused by stub axle flex,im obviously not driving hard enough ,but im sure the comp boys have and will encounter the problem and explored the solution.
Hope this clarifies .
Oilrag

Front hub bearings

Posted: Tue Jul 23, 2019 11:09 pm
by justfur
When I stripped the front suspension on my SE6 a PO had used a TR verticle link on the left side, this required the stub axle to be machined down to fit the VL, so a TR stub will not fit a 6.

From the left: SE6, machined SE6, TR
Xperia 23 may 19 670.jpg
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Xperia 23 may 19 673.jpg
Xperia 23 may 19 673.jpg (10.85 KiB) Viewed 294 times