IMPORTANT SAFETY NOTICE - GROUP BUY REAR HUB

[ccb056]

IMPORTANT SAFETY NOTICE

The Rear Wheel Hubs sold in the second "Group Buy" may be defective.
This requires EVERYONE'S immediate attention to verify they have not installed a potentially dangerous hub.

I was a participant in Jamie's (jeemy) second "Rear Hub Group Buy". I ordered a pair of hubs WITH the bearings included and installed.
One of the wheel hubs I received had an oversized bearing race bore which enabled the bearing race to slide in and out as well as spin in the bore with just my index finger gently pushing on it.
The bearing races are supposed to be an INTERFERENCE FIT and should require a fair amount of pressure to fit them. Some people use a press while others use a drift and a hammer.
Jamie was contacted and was accommodating in sending me a replacement for the defective hub.
Unfortunately, the replacement took five months to reach me.
When I finally received the replacement hub, the replacement hub was also defective with an oversized outer bearing race bore.
Please, see the two photos below of the second replacement hub, showing the race in the outer position and in the inner position with only finger pressure doing the movement.
Please see my previous posts regarding the first hub: viewtopic.php?f=85&t=22935&p=319019#p319019

Some technical details:
Stock hub/disc outer bearing bore: 1.569 inches
Replacement hub outer bearing bore: 1.570 inches
Timken S2 bearing race outside diameter: 1.570 inches
SKF bearing race outside diameter: 1.570 inches
Real interference fit of the race into the hub: 0.000 (NONE!)
Using a caliper for measurements limits accuracy to 0.001 inches.
The interference fit should be .001 inches based on the standard of 0.0005 inches per inch of race diameter.
If the race is allowed to operate in this manner, the race can and (most likely) will spin in the hub rather than the bearing spinning in the race, generating heat beyond its design limit, degrading the bearing integrity to its failure point. Once the bearing fails, the "hub to stub axle connection" will be destroyed (the hub will wobble severely), with potentially fatal consequences even at moderate driving speeds.

I STRONGLY SUGGEST that everyone that got a set of hubs from this Group Buy should carefully examine their hubs, bearings and races.
Please make sure that the inner races are a tight press fit into the hub and the bearings have not overheated.

[dapinky]

Chris,

Thanks for bringing this to the attention of everyone who has purchased from this batch of Hubs.

Just for some clarification, can I ask some questions regarding the situation?

1). When you say "2nd rear hub group buy" could you give the date you ordered the hub? - I was fortunate enough to get mine from BB in the original run, and I want people to know which batch are affected - was it the second batch made, or the second batch made by (or at least, for) Jeemy?....

....even though common sense says that EVERYONE who has a set of hubs measures them, unless they can definitively remember fitting the bearing races themselves and it being an interferance fit... I know some were supplied with bearings already fitted, and some were 'bare'.

2). Have you been in communication with Jeemy? - I know he didn't actually make them, but his company supplied them. I don't know who he used in the end to get them made, and I don't know if they were made from a drawing, CNC file, or measurements taken from another unit.

Whichever way the units were made, there should be very little difference between items made in a batch from the same machine settings - modern CNC machinery should be more than capable of producing 50 identical items.

I know you already understand this, hence why you have brought it to our attention - if 1 is faulty, thats unfortunate, but if 2 are, then it may be indicative of a 'quality control' issue.... what are the chances of the only 2 oversize units ending up in the same garage half way round the world???

************************************************************************************

I believe that this needs attention by everyone who has a set - if they are fitted, then you only need to whip them off the car to check that the inner race is secure - if they aren't fitted, then an even quicker check is possible.

For anyone who is concerned, but doesn't have accurate measuring eqipment, I would urge you to get it checked properly (with digital calipers), but a simple 'push' on the fitted bearing race will show if it is as loose as the one in this post - it should take a fair bit of pressure to move it (press or hammer/drift), so if it moves with less, then it may be indicative of a problem...

As Chris says, leaving it alone in a loose state WILL cause problems - due to material differences between the hub and the race, they will heat up at different rates (okay, they're both steel - but different types!) - this means that they will either get tighter as the unit wears up, or looser - and the oposite as they cool down... so at some point in the 'use cycle' there may be a point where the race is loose enough in the hub to wobble or spin - either of which could cause problems!!!

[Brit-Car-Nut]

Dave: I believe Chris said it was the OUTER bearing race bore on BOTH hubs but if they can get one bore wrong, then they can get them all wrong, so everyone should check both inners and outers.

I have a set of Bob B. hubs and both of those measure correctly with 0.001" interference fit on the outers and a little bit more on the inners 0.0015".

[dapinky]

Dave: I believe Chris said it was the OUTER bearing race bore on BOTH hubs but if they can get one bore wrong, then they can get them all wrong, so everyone should check both inners and outers.

I have a set of Bob B. hubs and both of those measure correctly with 0.001" interference fit on the outers and a little bit more on the inners 0.0015".

John,

you are correct - it is the outer one which is known to be at fault.... partially my reading, and partially trying to abridge my answer led to a confusing reply....

The outer one can be checked (somewhat) with the whole lot fitted to the car, but if it were me, I'd want to remove the lot and check all relevant measurements.

[lotusflasherman]

Interesting topic prompted me to investigate mine so this afternoon I've been measuring, measuring, measuring ... but only the outer bearings as that seemed to be the contentious one.

Have 2 pairs of hubs:
I bought a pair of hubs in July 2015 from a guy who had just bought an Elan and the previous owner included a set of hubs bought but not fitted and still in the box. I think he was told it's a big job to fit them so put them up for sale. He couldn't tell me where they came from but from the slight surface rust I would guess they had been in the cardboard box quite a while so looking at the delivery dates of Jeemy's Run 2 thread I'd guess they are probably not a Jeemy Run 2 pair but may have been Run 1 or more likely a Bob Brown pair. Then a couple of months ago I bought a S2's HiSpec brake set from DVB that included Elan front discs mounted on some rear hubs. So have 2 sets of hubs of unknown origin, the July '15 pair are in use on the SE in use with HiSpec rear calipers and 10mm thick 264mm diam discs and the DVB pair are in box to go on the SE on SORN.

4 pairs of OE hubs:
First SE I owned from '95 I twice replaced the rear discs when they reached minimum thickness. First time the price of hubs excluded bearings so second time I ordered hubs + bearings and found those hubs had bearings installed, but kept the extra bearing sets in their Lotus bags. Bought another SE in 2000 from Chris Neil with proviso they cleaned the rust off the rear discs. Went to collect it and it had new discs with the rusty pair in the boot so I cleaned them up and drilled and slotted them to see if it would improve performance, particularly for MOT. Also bought a few pairs when they appeared cheap on fleabay, before I went to hubs. So 3 spare pairs of OE hubs plus one with slots on the SE on SORN.

Accuracy of measurements:
I've got several of those cheap carbon fibre digital calipers that I use a lot because they are easy to read (without reading glasses), press a button to zero or to change from mm to inches. Seem reasonably accurate on O.D. but the I.D. blades are 7 thou thick and do not accurately measure small diameters - like the hub bore. There was a significant difference when I used my expensive precision vernier dial gauge caliper with razor sharp I.D. blades to get the true diameters - and then wiped a bit of grease off and nearly sliced my thumb .. The vernier dial gauge is calibrated in 0.02mm segments so can be read to about 0.01mm accuracy (0.4 thou "), though there is the issue of finding the true diameter of the bore and not a chord, and how hard to push the thumbwheel to get a true reading.

At ambient temp of about 14°C all of my 6 spare OE hubs have a bore that measures within a gnat's cock of 39.085mm which seems to convert to 1.5388".
I have 4 spare bearing sets. 2 are Chris Neil Lotus pattern and 2 came with the "July '15" hubs so might well be Chinese. I measure all of those at 39.090mm (1.5389").
Both pairs of hubs have a bore that I measure at 39.084mm (1.5387") so a tad smaller than OE.

When I got the "July '15" hubs I decided to fit them using the Lotus bearings I already had so drifted out the pre-installed race sets using the slot and a square bar I keep for the purpose. Wasn't too tight, wasn't too slack. (I would never mix a race and bearing from different manufacturers though some might.) Fitting the Lotus race was quite easy as it had been in the freezer a couple of hours so tapped in using a 30mm socket as a drift without a lot of effort. (Just had an outer race in the freezer for 30 mins and it now measures 39.088mm - every little helps. )

I have just tested the fit on the DVB hubs and the race only moves out and back when drifted with a 2lb club hammer so happy with that.

I did post on the other thread that there is a Loctite bearing fit product that works well. My tube that's a couple of decades old is labelled Quick Metal but Loctite now seem to call it 660 www.henkel-adhesives.co.uk/2838_UKE_HTML.htm?nodeid=8797714251777&msdsLanguage=EN_GB&selectedTab=video

Whilst I accept that it should not be necessary to use it to fit bearings to new hubs, if the bearings are slack it's an interim solution to keep the car on the road, unless owners are going to refit the OE hubs.

I've used it as an interim solution when an inner race appeared to be rotating on a stub axle but then couldn't get it off so it ended up a permanent fix..

Edit: P.S. I do have a copy of the drawing that shows the hub outer bearing bore as 39.87mm (1.5697") but thought I'd post what I measured for the guidance of others who might need to try measuring. The slightly smaller dimensions might be temperature related - or measurement error.

[ecb056]

Dave (dapinky)

Thanks for responding to Christian’s ‘Safety Notice’ post.

1) To clarify the "2nd rear hub group buy" (as the string was titled) are the hubs which Jamie (Jeemy) sent in 2015-10. From Jamie’s 2015-10-12 post, eleven (11) folks received the hubs including us. These folks include: johanvanboven, LotusEnthusiast, B_land, Jon , Algirdas (2), ccb056, sheprob, Nick Holland, Rambo, ab2cv and Paul Alexander.
2) Yes, Jamie was notified of the replacement hub defect on 2016-09-30 via email. The email included the two (2) photos Christian posted to LEC and the note below:

Jamie
Thanks for sending the wheel hub, I received it, although it is still defective as the bearing race you had installed in the hub slides in and out with finger effort. Please see the attached photos.
Please refund my PayPal account for the £65 for the one hub.
Thanks for your efforts to provide the quality product advertised.
Cheers,
Eddy

As evidenced by the string, a year after receiving the first pair and subsequent defective replacement attempt, I have only one of three hubs that are acceptable from a safety and reliability perspective.

Putting all the measurements aside, simply put: the race is designed to be an interference fit, not a finger push slop fit. We know and appreciate when equipment is operated beyond its designed limits it will fail prematurely and potentially with catastrophic consequences. My risk tolerance at 70 MPH is microscopic for items such as bearing fit.

Eddy

[B_land]

All
Mine are still in their box /packaging never been fitted, I was waiting to do a front brake upgrade at the same time just not around to it. I've just checked and both hubs are affected the races easily move and do not have an interference fit.

Thanks

Bruce

[Rambo]

I never got mine but I know Alan (AB2CV) did and they were fitted by Craig Moncrieff a couple of months ago. Check now Alan !!!!

Extremely worrying !!

Was the 1st batch ok ? Rambo was sold by me and has now been sold several times since so no way of checking or alerting the current owner

[dapinky]

As there are now 4 known defective items, I have taken the step of sending either an email, (or a PM where email address unknown) to the people who are known to have been involved in this Group Buy.

Those who have already responded on this thread havent got one (Christian, Bruce, Mark), but I have asked the others to provide information on this thread about their current situation...

....in particular,

1. whether you still own the car/hubs,
2. whether they have been fitted,
3. whether you fitted them yourself
4. if you are sure that yours are correct in accordance with the measurements quoted in the thread
5. if the car has been sold on – are you able to bring the matter to the attention of the new owner (or pass the details to me)

My research has suggested that at least one person has ordered them directly via Jeemys' website "SVS", and there may be others - I cannot tell, and hope that Jeemy will respond appropriately and contact them directly.

[Jon]

I do recall my mechanic saying that he'd had to pack something out - I'm pretty sure it was related to bearings, so that may be indicative of the same issue?

[Paul Alexander]

as i am on this list, i have just checked mine (not fitted yet - they are spares for when needed), and the races in both of mine are tight - they don't move at all, and the bearings spin freely. it looks like my set are not affected.

[dapinky]

Just in the interests of clarity of the situation, I will try to maintain a list of the 'current state of play' so all can see how many units may be problematic.....

johanvanboven - fitted by owner - no problems noted upon instalation - will be rechecked.
LotusEnthusiast - awaiting reply
B_land - not yet fitted, but both hubs showing too much clearance.
Jon - fitted by garage - problems mentioned by mechanic following instalation (resolved at point of instalation) - will be rechecked.
Algirdas (2) - awaiting reply
ccb056 - originator of thread - 2 defective units received from 3 supplied.
sheprob - awaiting reply
Nick Holland - no information known on this customer - purchase made directly via SVS website.
Rambo - no purchase completed - not affected.
ab2cv - when rechecked by garage - found to both be defective
Paul Alexander - not yet fitted - appear fine at this time.

[Jeemy]

See final post on the matter.

[Jeemy]

See final post on the matter.

[Jeemy]

See final post on the matter.

[Jeemy]

See final post on the matter.

[Brit-Car-Nut]

Jamie: Bearings are a critical item and I would be horrified to find that a bearing race for a specific fitment from one manufacturer varied from another by ANY amount. Eddie's races were compared to TIMKEN, the industry leader in bearings and they were exactly the same OD.

There is NO QUESTION that of the first pair of hubs, ONE outer bearing bore is to spec and the bearing race has a healthy interference fit and the other had no interference fit and the race could be inserted and spun in place by finger pressure. The fact that the replacement arrived with your comment that you had measured it and it was GOOD only to be "as bad" as the previous bad hub is upsetting.

You know I have been CC'd all of the correspondence between you, Eddy and Christian, so I don't expect you to be shocked by my reply.

I was of the impression that the manufactured was making the hubs on a CNC mill so every one would be identical. I hope that wasn't the case because it means their very expensive machine is way out of calibration. That leaves me to think the hubs are manufactured one at a time by a human who does not keep tolerances high on the checklist during manufacture.

I have a pair of Bob B. hubs, still brand new in the shipping box, and BOTH outer bearing bores are spot on the same ID as a Factory Lotus hub and .0015" tighter than the OD of both Timken and the aftermarket bearings Bob included with his package. I used an inside micrometer that is accurate to 4 places and compared both of Bob's hubs and two Lotus hub/Disk units.

The fact that one of three hubs Eddie got was on spec and several other buyers have reported good, tight fitting races while at least two others have reported sloppy fitting races should be enough reason to have a serious discussion with the manufacturer.

It is good that you have been able to "see" the issue but to suggest a locking agent to secure the bearing race is offensive and down-right dangerous.

The manufacturer appears to be able to produce both "good" hubs and "bad" hubs, so their manufacturing process should be questioned especially how it is programmed and how well it is maintained. A CNC machine should produce hundreds of identical parts all day long with not a .00001" deviation between any of them.

Regarding your statement: "- a locking compound was used in run 1, and on assembly, they forgot to use the compound" is ludicrous. There is NO WAY a bearing race should EVER be "glued" into place. The bearing manufacturers ALL provide the proper interference fit required to keep the race statically in place so it doesn't start to sympathetically rotate with the bearing. We use bearings with races because the are EXTREMELY HARD, RESISTANT TO DIMENSION VARIATION DUE TO THE HEAT GENERATED DURING ROTATION and the reason the races are fitted is so the DON'T ROTATE inside the cast iron hub which, when it get hot, expands.

The potential of bearing failure due to excessive heat or increasing gap between the bearing and race goes up dramatically when a bearing race "spins". If a wheel bearing "fails" the hub is no longer centered on the stub axle and will wobble dramatically. The only thing that would keep the wheel/hub assembly from coming off the car is the brake caliper and the excess forces put on it would seriously diminish the brake pedal pressure as a lot of the stroke would be wasted just trying to get the pads back in line with the now flailing disc. So you have a car that is wobbling/bouncing down the road and almost no brakes. That is a terrifying position to be in. PLEASE DO NOT COME BACK AND SUGGEST EVERYONE GLUE THEIR RACES INTO THE MISS-MACHINED HUBS. I would expect someone to take legal action to that kind of solution. Hard to do it from the US, but the UK has engineering standards that would seriously frown on a remedial repair for a serious tolerance issue in manufacturing.

I know this probably seems like a direct assault on YOU, Jamie and it really isn't, but since you represent the manufacturer, you are the only person that can resolve the situation safely. The only solution is to recall the hubs and replace them with hubs that meet the specification EXACTLY and CONSISTENTLY.

I grew up in the days of Drum Brakes and horrible engineering and have seen more than a few cars "hauled in" with a wheel missing because a bearing failed and the wheel, tire and hub went a different direction down the road. I have also experienced having a rear tire go flat while doing fast laps on the NASCAR banking at Charlotte Motor Speedway. The flapping carcass produced an effect similar to a bearing failure and it was all I could do to keep the car off the outside wall since I had lost the connection to the race surface due to the tire not running true. It is truly a scary place to be in.

Meanwhile, Eddy and Christian have been running their car on the original Lotus hub/disc units for well over a year while waiting for a solution. What is the chance that you could send them the "good" hub you found so they can finally install the upgrade they paid for last year?

[dapinky]

I have to agree with Johns' post above, and can add the following information.....

.... when Bob did the original run of hubs (or however many 'runs' there ended up to be), they were supplied as 'standard' with no bearings fitted, and he only actually provided them with the races pressed into place if people specifically requested it.

Some were supplied totally 'bare' for purchasers to source and fit their own choice of bearing (by choice, I mean by manufacturer/supplier, not dimension/specification), and with others he supplied a bearing set from his own supplier (can't remember the make/details, but they wern't cheapo Chines copies.)

The set I got were supplied with a set of bearings for me to fit - however, as I had 2 cars at that time, I used the supplied set of bearings on the red car, with OE hubs - they needed to be pressed in.

When I fitted the hubs to the blue car, I sourced a set of bearings (SKF) and they also had to be pressed in (no idea of the force used, by bench press doesn't measure force, but they didn't strike me as being anything different to fitting them in either hub or OE hub/disc units.)

There was never ANY suggestion that the fit should be anything other than a 'standard' interference fit, and NEVER was any glue used (okay, it's a specialist compound, but still glue!).

I don't know how many units/pairs he supplied, but I don't know of any which demonstrated this current issue.

I can only summise that the problem run were either made in 2 small batches, and the CNC machine was out of callibration for one of them, or their tollerances are out, or their QC is lacking.... either way, at least the one good thing to come from this is that the problem was picked up by someone who knew what they were looking at and highlighted accordingly.

As my final submission, i would suggest that the ONLY way to resolve this situation is to have the manufacturer provide replacements for ALL affected units - glue is not the answer.
The only 'safe' engineering solution, other than replacement, is to 'metal spray' and re-bore the items - but with the shipping costs, material work and machining, it isn't really a cost-effective solution - unit costs for the manufacturer should be fairly insignificant, and they need to suck it up - and quickly!

[GeoffSmith]

Jamie, I know you were going to send me a copy of the engineering drawings when I was looking at the issues with the hubs and PNM brakes but I can't find them. I am in Spain at the minute, so haven't got all my historic e-mails, but I was interested to see what tolerance was specified. If one isn't quoted then they may have been manufactured to the standard tolerances of the manufacturers - have you any idea what their bread and butter / basic price tolerances are?

[Jeemy]

See final post on the matter.