Loose wheel causes?

[Rick Kirchner]

At my last event I had a wheel nut come loose and was stopped by the safety pin. the wheel had been torqued, although referring to Van Diemen documentation, my torque spec was a bit low (100 ft lbs vs 130) - although I've run the car this way for years with no issues.

No damage other than the top thread in the nut was buggered. Took it apart at the track and again at home. I can find no damage nor any indication of what went wrong. When I put the wheel on I seated it, ran the nut down with a chatter gun, dropped the car and then torqued it up with a beam wrench. Usually if there's some reason it's not seated properly the end of the nut will look out of place WRT the safety pin.

I also measured the distance from the end of the axle to the hub face - both right and left are within .050 of each other.

Back in February at Willow Springs another guy with a 95 VD had an axle back out of the hat, shearing off all the drive pins. I'm still puzzled over that one. If the axle was properly inserted and the washers were under the bolt heads the axle should have been retained by the washers against the flutes. I don't know all the details though.

Others must have had this happen - what are the usual causes?

[t walgamuth]

I would torque it to the recommended value and keep an eye on it....checking frequently.

[Lotus7]

Check that the drive pin holes in all the wheels are deeper than the longest drive pin. We had a wheel with slightly shallow holes, so wheel seemed seated and when torqued it looked and felt ok. With car vibration the pin tips eventually chewed into the bottom of the holes and it lost nut torque.

[DaveW]

Inadequate chamfer on the ID of the inner edge of the wheel center hole will allow the wheel to rock on the hub radius and come loose. The few loose wheels I've had in 50+ years of racing were due to that.

[EYERACE]

1. I torque to 115 using the handy-dandy regular ol' power drill (not impact wrench/driver) and then the regular ol' Craftsman torque wrench.
2. Time to buy new nuts

[stonebridge20]

Inadequate chamfer on the ID of the inner edge of the wheel center hole will allow the wheel to rock on the hub radius and come loose. The few loose wheels I've had in 50+ years of racing were due to that.

And that sometimes is due to someone machining the mating surface down to try and match offset of another wheel or set of wheels.

[Purple Frog]

Scratches, dirt, rust, or debri on face of hub or wheel can be an issue.

[R. Pare]

Which wheel?

[Rick Kirchner]

Left rear. Right rear seems to have taken the opportunity for a wheel bearing failure too....

There was a small amount of shavings in the drive pin holes and I haven't measured with a gauge yet but you could hardly see the wear.

[Rick Kirchner]

2. Time to buy new nuts

Those were on my list when Brad had his stroke....

[Charles Warner]

Are the wheels powder coated or painted?

[Rick Kirchner]

Are the wheels powder coated or painted?

Near as I can tell these were original OZ.

[DBS Motorsports]

It sounds crazy but check this. When I rebuilt my uprights on my Van Diemen, I replaced the stub axles. I had a wheel that would torque but then come loose. Checked the pins, wheel, wheel nuts, etc. Nothing seemed out of place or order. I disassembled everything and measured everything that I had changed. I found one of the stub axles had its threads cut about a quarter of a rotation shorter than the others. It wasn't obvious just looking at it. Thus it would bottom out when torqued but then wobble on the pins once under load.




Doug

[JHerscher]

Rick,

I had an issue with my 01 where the wheel nuts tightened after torqueing.

Once I replaced the wheel bearings, the problem went away. I suppose it possible that a bad bearing could cause this?

I'm sure smarter people than I will have an opinion that is worth more.

John

[t walgamuth]

Rick,

I had an issue with my 01 where the wheel nuts tightened after torqueing.

Once I replaced the wheel bearings, the problem went away. I suppose it possible that a bad bearing could cause this?

I'm sure smarter people than I will have an opinion that is worth more.

John

What did it do that indicated tightening after torqueing?

[JHerscher]

What did it do that indicated tightening after torqueing?

Required an 800 pound gorilla to loosen!

Exceeded the torque capacity of my 150 ft-lb torque wrench. I ultimately used a breaker bar and jumped on it to loosen the nuts.

[Lotus7]

Required an 800 pound gorilla to loosen!

Exceeded the torque capacity of my 150 ft-lb torque wrench. I ultimately used a breaker bar and jumped on it to loosen the nuts.

were the install torque and removal torque conditions identical?

for instance, torquing up an aluminum wheel to xxx lb-ft when the wheel is say 50 degrees F early in the morning, then trying to untorque it immediately after a session when the aluminum might be close to 200 degrees will produce a much large untorque number given the relative expansion of the aluminum putting more tension in the torque stack.

[JHerscher]

Untorqued and retorqued before each session on a cool wheel. First noticed it after wheels were removed to replace brake pads after reaching ambient temp post session. Also a bear to remove after returning to the shop.

You guys, please stop trying to solve something for me that was resolved 6 years ago after replacing the wheel bearings. Rick is the one with the problem to solve!

[Rick Kirchner]

I'm beginning to think this was wheel bearings.

[Garey Guzman]

I think I had a similar issue on my DB6 when I first got it. IIRC, Doug Learned said it was always the LR wheel. After replacing the drive pins with the correct size and diameter for the wheels and adding steel inserts to the wheels, I've never had the issue again.

[DanW]

Have you checked the drive pins and the pin holes in the wheel for size and ovality? If the wheel can rotate back and forth against the pin, the wheel can "ratchet" against the nut causing it to loosen. Yes, a worn bearing could also be the cause.

[Robins Ken]

were the install torque and removal torque conditions identical?

for instance, torquing up an aluminum wheel to xxx lb-ft when the wheel is say 50 degrees F early in the morning, then trying to untorque it immediately after a session when the aluminum might be close to 200 degrees will produce a much large untorque number given the relative expansion of the aluminum putting more tension in the torque stack.

Good one Ian.
May I add that it could be the (6) SHCS, metric as I recall x 100mm (?). that draw the whole lot together, brgs,stub etc, backing off just a smidge?
Take care all and have a great summer racing.
KR.

[Rick Kirchner]

no. I easily removed the right side brake hat with a brass drift and a light hammer, but the left side is being a bastard. when I get it off I'll start comparing - I have six rear wheels to fool around with.

[Rick Kirchner]

So when I pushed out the left brake hat from the bearing, it decided to take the outer race with it. Other than going after it with a grinder and whacking it with a chisel in hopes it will crack and slide off, what's the best way to go about it?

Dry ice?

There are three holes in the hub that go down to the bearing race. I take it this was designed for some kind of service tool that screws onto the axle and then presses down on the race to remove it?

I've never seen a commercial one. Anybody rig one up and have a picture?

[BeerBudgetRacing]

Had hat happen. Used a dremel to cut down but not through.
Then prying the slot with a screwdriver popped it.

[Mike B]

There are three holes in the hub that go down to the bearing race. I take it this was designed for some kind of service tool that screws onto the axle and then presses down on the race to remove it?

I've never seen a commercial one. Anybody rig one up and have a picture?

I made my own but this is the tool you're looking for:
http://rsport.us/Rsport_VD_Hub_Tool.html

[EYERACE]

Couldn't find the past threads about his accident and all the comments........so I'll post this here for those wondering about how Primus is functioning..............

I need some brake pads the other day........placed the order online at Primus..........two days later UPS delivered 'em !!

[GAC]

Undertorqueing can definitely lead to the nut coming loose. Also, thread lubricant comes into play. Required torque is less with thread lubricant and more with no lubricant it’s important to know how the spec is defined. If you had been using lubricant and it wore off over time, it could be the reason 100 Ft-lb used to work but has stopped.


Sent from my iPhone using Tapatalk

[Rick Kirchner]

strangely enough I had just re-applied it that weekend.

[stownsen914]

I've posted here a few times while chasing a recurring issue of wheel nut loosening. March 87C 2.25" spindles and hardware in my case, on a GT car.
Hogged out locating/drive pin holes in the wheels can allow back and forth movement on drive wheels, causing loosening action.
Inner face of wheels mildly deformed near hogged out holes, causing reduced contact area where it mounts to car.
Ensure clean mating surfaces of course.
Watch for physical interference for older / swapped / non-matching parts. A couple examples mentioned in above posts. Take nothing for granted.
Ensure clean, completely flat mating surfaces for all parts in the stack. Notably brake rotors/hats. I had an issue with a nut loosen once after replacing a rotor hat. There was galvanic corrosion on the hub that I hadn't noticed. Wheel nut loosened as new rotor hat seated itself (ground itself) on the hub, leaving a few thou clearance.

I now put shims between the wheel nuts and safety pins to take up the slack to minimize the amount they can turn in case they start to come loose.

[Phil Creighton]

Just a quick observation but the Left Rear with a normal RH nut will tend to loosen with any play from the diff to the nut. Sometimes its very small or the torque stops the rotation. Years ago Tiga s2000 cars would lose the outer hub nut on the LR - bolt on wheels!
Always surprised no manufacturers went LH thread on that side of the car.

We had an issue on wheel nut material on one small formula car - made new nuts out of better material and problem went away
Phil

[DaveW]

...Hogged out locating/drive pin holes in the wheels can allow back and forth movement on drive wheels, causing loosening action...
I now put shims between the wheel nuts and safety pins to take up the slack to minimize the amount they can turn in case they start to come loose.

Just a note from a nerdy engineer - if there is enough clearance between the drive pins and the pin holes to be able to assemble one to the other, there WILL be some play. There is no way to avoid it. But if the compressive force between the 2 faces is high enough, the wheel will move in the highest torque direction until pin contact is made and will not rotate back the other way. So, since repetitive rotation back and forth is what causes loosening, it can be avoided even with some play if the wheel is attached tight enough. My wheels always have some play on the pins, and I have not had a wheel loosen (center-lock) in the last 30+ years.

My safety pins, which I always use, are set up as you say - hardly any room for loosening before they make contact.

[Rick Kirchner]

makes me wonder if a washer/spacer between the pin and the nut would be helpful - at least limit the amount of loosening. I may go back to thicker pins. the thin one bent and was a pain to get off.

I have everything apart now and sent the uprights off to be re-blacked. Just need to sit down wiht the hats and the wheels that came loose and see if I can find anything obvious on the bench.

[ejsprint30]

I just went through replacing a RR broken bearing and hub on an Elan F2000 DP08...after reading this, it was strange to me that my wheel nut never came loose, and was tight before I disassembled.

I checked the LR, and nothing broken, but decided to replace the hub, bearing and hardware anyway. After removing the rotor hub/hat with the tool Brad sells, I put the upright in an oven at 350 for about an hour. The bearing fell out with no force, no tools required.

What disturbed me, was that I found the threaded holes for the camber shims/attachment were stripped out and helicoiled by previous owner. So what should be over inch or so of thread was repaired to only have a little less than half. I bit the bullet and ordered a new upright...just not comfortable with this on the LR. Without disassembly and shims in place, its tough to tell just exactly where the threads started in the upright.

I like the idea of taking up the space between the wheel nut and pin.

The thought just occurred to me...I also replaced my tripods and housings, as I am sure these were probably original to the car, or had been used beyond their life and not serviced regularly . The tripods did have (in my opinion) excessive play in the housings...could this contribute to any of the above?

[DaveW]

...The thought just occurred to me...I also replaced my tripods and housings, as I am sure these were probably original to the car, or had been used beyond their life and not serviced regularly . The tripods did have (in my opinion) excessive play in the housings...could this contribute to any of the above?

Excessive play, assuming it was loose enough, could create a "hammer" effect as the slop was used up in opposing directions. So your thought that this could be at least part of the reason for the damage you found makes sense.

This idea is particularly applicable to shifting imperfectly w/o use of the clutch. When I tried to learn to shift my Staffs clutchless (for sure not smoothly), I wound up breaking one of my old style Lobro CV's. That's one of the reasons I use the clutch for every shift - less impact load on the drivetrain. I also have a lot of (excessive?) mechanical sympathy - any time I feel something jerk or shudder, I immediately have visions of stuff fatiguing or breaking.