Rear Hub Tapers have burr lip on outer edge

Both rear hubs have a lip at the small end of the taper, where the washer and nut fit to compress the hub onto the spindle. Should I remove this ridge?
Greg

Are you re-fitting the original hubs or new ones?

I think if there is a lip it might be an indication that the hubs were loose and rocking slightly on the shaft. I think I would remove the lip and then lap in the joints with fine valve grinding paste.

Paddy

That’s a strange one.
The hub should protrude beyond the taper on the shaft; the washer & nut should bear on that part of the hub, pushing it onto the shaft.
Bit of a riddle how that lip can occur unless the shaft protrudes beyond the hub with the washer & nut bearing down on the shaft, which would be seriously wrong.
Is there a possibility that the hubs are cracked?

Cheers
John

The hubs are not cracked nor do the hubs bottom out on the spindles. I think just the compression of the metal with the washer and nut may form a lip on the inside of the hub. When I originally removed them I used some heat as they were tight.
Greg

I am going to clean the lip off with a grinder and file to match the taper.
Gregg

I’d strongly recommend taking Paddy’s advice and lap together with fine paste.
James

Sorry Greg,

I misread your initial post & thought the “lip” was on the shaft which would put my nonsensical reply into context.
I think your solution’s ok but am a bit worried that you may have the wrong washers for that problem to occur.
I don’t know the specific dimensions but the washer should ideally cover the whole of the hub face & from memory the ones I fitted were about 4mm thick, if not more.

I must learn to read posts more carefully :blush:
Cheers
John

Hi Greg

I had a similar problem with the hubs on my Plus 2. I checked all the tapers and they were fine but I found the keys were preventing the hubs pulling up fully. I had to carefully polished the keys and keyways before I coud get the hubs to fit propely.

Andy

The washers are hardened. They fit the spindle and cover the edge of the hub correctly. I think it is the hubs, being mild steel mashed in slightly when the hub nuts were tightend down. As long as the hub retaining nut doesn’t bottom out on the spindle, things will be fine.
Greg

I visited Tony Thompson’s fascinating emporium the other day and learnt that he sells rear hubs and shafts without keys/keyways as well as with. He says the Woodruff key is unnecessary and all the drive is taken by the friction of hub locked against taper. If the key took the drive torque of a vigorous start it would shear instantly. But some people still feel comforted by the presence of a key so he sells both types.

Whether a standard hub and shaft, rather than TTR super-strong ones, would maintain the tightening force required to keep the friction-only drive is no doubt a matter for debate. Interesting idea though.

John

John’s quite correct, the Woodruff key is pretty useless.

The ‘critical’ feature, as mentioned by Paddy, is to make sure there is a full taper contact surface between the hub and spindle. This is achieved by using course grinding paste, and can take some time to achieve.
I don’t think there is a short-cut for this important job.

+1 on that but with exception of using different grades of grinding pastes until the desired all over light grey finish on both parts is achieved.
Makes the job a bit longer but ensures a top quality fit.
Additionally, lots of cleaning of parts & no lubricant prior to final assembly is vital.
The additional round pin is another case of the Lotus “Engineers” bowing to old fashioned “conformity” or accepting that that the quality of their tapered bores needed a “bandage”.
I bet that the guys there didn’t take the time to lap in those bits. :unamused:
I’ve been told that after the O.M. work a re-torque after a few miles is highly recommended.

Cheers
John

Tony Thompson’s instructions for torqueing new hubs say something like:

  • tighten to specified torque;
  • drive 100 yds, torque again;
  • drive 200 yds, torque again;
  • drive 1 lap, torque again;
  • drive 10 laps, torque again;
    etc

Not having a race track to hand :slight_smile: I re-torqued mine every few days for a couple of weeks (driving a few miles each day) and they eventually stopped moving.

Paddy

Sounds just like my Wife,Talk,talk,talk,talk,talk…

John :wink:

Second bottle of Red coming up…

One problem with the woodruff key is that the end of it can create a stress riser in the hub. Instructions for relieving the keyway to eliminate this can be found in the Dave Bean Engineering catalog.

Jerry

I had a rear hub come loose on the taper once - sheared the circular key in half very cleanly, it is sure it won’t carry the load.

I ended up replacing the original cast hubs with billet ones as they kept distoring under racing loads and threatening to coming loose again

cheers
Rohan

I had to smile at what I said about the useless key ? as I still fitted them when I replaced the spindles last year.

John is correct, of course, in saying that fine paste should be used. However, I?m not sure as to the use of fine paste. When I did my car last year I used course paste followed by fine paste (as us old guys automatically would), and when I compared the course finish to the fine finish ? I preferred the course finish as, IMO, it had a potentially better mechanical keying capability.

Now I?m not sure how successfull I was in getting the whole hub up to 150?C before assembly ? as this is probably the most important factor in getting the optimum retention.

I torqued the nuts up to 160lbs.ft as recommended by TTR, and did the six round
the block checks and the 160lbs.ft torque had been retained. I now have to admit that I?ve not checked it since. :blush: I shall do that this afternoon.

Rohan,
Similar happened to me when the axle sheared at the change of profile from thread to taper. Rear wheel arch stopped the wheel coming completely off but the rear wheel steering gave me “one of those moments” as I was doing 75/80 on a busy motorway at the time.

I had been hearing a noise on roundabouts for the previous day or two but hadn’t been able to track down the source.

Checked both nuts this afternoon - no movement at an applied 170lbs.ft.

However, I shall now add this to my annual checklist.

Hi Brian,

in your previous posting you mentioned having heated your hubs just prior to fitting.
I’ve never heard of that being needed on tapered hubs. Where did the information come from?
I would imagine that using that method that the hubs are well & truly seated & could be difficult to remove.
I used the TTR tightening process nearly, I think it’s a tiny bit OTT.
Having done that I can’t imagine the hubs going anywhere & an annual check may be worthwhile but beware, the locking insert in “Nyloc” nuts do take on a “permanent set” after a while & it may be worth while fitting new nuts if you notice any movement during the re-torquing check.

Cheers
John