Lost a Wheel at Freeway Speed Last Night

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Devil Frog

Devil Frog

10 Year 15 Year
Joined
Aug 3, 2007
Threads
47
Messages
619
Location
Albuquerque
No, it was not on the pickup or 40, (I would have likely rolled, and the 40 still 5 years from being drivable). It was in my MR2 commuter car, which only has 4x100mm lugs. I had changed the clutch this weekend and even though I had cross torqued these lugs with an impact wrench to about 170 ft-lb with this: http://pdf.lowes.com/useandcareguides/879686002796_use.pdf, two adjacent lug nuts came loose, and within seconds the other two lugs failed and the wheel was gone. It was the rear drivers side wheel, I was able to steer on to the shoulder, the car dragged on the lower A-arm/lower ball joint and came to a stop rather quick, I did not even have to break.

My suspicion is that I did not wipe the lugs clean, and oil/grease on my hand could have been transfered to the threads and caused them to slip? Either way it scared the :censor: out of me. I am now going to wipe lugs completely clean with asetone, add a few drops of blue locktite, and torque them to exact factory specs. This is especially important on a 4 lug wheel, I think the 6 lug on the Cruisers and Pickups have enough redundancy to prevent this, but I guess it is really needed, because a 4x4 would have probably rolled with the high CG.

Anyway I am just glad to be alive.


lost wheel.webp
 
Last edited:
Wow doggy, glad you're ok. Did you say 170 ft-lb? That seems like twice the normal torque spec. Are you sure? that kind of torque should have pulled out the studs. Also, how do you know what is the torque put out by your impact gun? I have yet to clean any lugs with Acetone or even use blue loctite. If you indeed used 170 ft-lb then you stretched the studs and they loosened up on you. New studs and factory torque setting with a torque wrench should do ya.
 
Last edited:
alia176 said:
Wow doggy, glad you're ok. Did you say 170 ft-lb? That seems like twice the normal torque spec. Are you sure? that kind of torque should have pulled out the studs. Also, how do you know what is the torque put out by your impact gun? I have yet to clean any lugs with Acetone or even use blue loctite. If you indeed used 170 ft-lb then you stretched the studs and they loosened up on you. New studs and factory torque setting with a torque wrench should do ya.
Click to expand...

Well the lowest setting on my impact gun coresponds to 170ft-lb @90psi I looked that up after the incident, but I have used it on lugs for years with no issues. About every shop I have been to seems put tires on uses an impact wrench, but then again maybe they have a special impact gun calibrated to a lower spec just for wheel lugs? I would like to think that toyota used a factor of saftey that is greater than 2, but regardless after this I am doing it by the book! Cleaning the lugs and blue locktite may not be nessary, but will make my feel better and ease my parnoia after an incident like this.
 
Last edited:
the tire shops I've seen put the nut on loosely with a impact, then torque with a proper torque wrench. glad you are Ok and the car isn't damaged to bad.
 
irbrito said:
Well the lowest setting on my impact gun coresponds to 170ft-lb @90psi I looked that up after the incident, but I have used it on lugs for years with no issues. About every shop I have been to seems put tires on uses an impact wrench, but then again maybe they have a special impact gun calibrated to a lower spec just for wheel lugs? I would like to think that toyota used a factor of saftey that is greater than 2, but regardless after this I am doing it by the book! Cleaning the lugs and blue locktite may not be nessary, but will make my feel better and ease my parnoia after an incident like this.
Click to expand...

Most tire stores, even Discount Tires, use torque sticks http://www.torquestick.com/ at the end of their rattle gun.

Discount typically does at Bionic stated, start off with a rattle gun then finish off with torque wrench. In fact, they have a torque wrench calibrator in their shop that I've used in the past several times to check my torque wrench :D

In any case, I'd find out what exactly is your rattler putting out because if it is indeed 170 ft-lb, odds are that your studs are stretched and you're on borrowed time on all of your cars. You just happen to find this out on a smaller car with lighter gauge lug studs that couldn't take that kind of tightening torque, consequently, suffered a catastrophic failure. I have a beam style torque wrench that can be used to find what torque your rattler is putting out.

Lug studs should not need to be loctited, ever. All the texts that I've read say that proper torque is critical, the studs need to be DRY and re-checking torque after 100 miles is also critical. Discount has this printed in their invoices for customers to read. Since the studs are now stretched, you'll not be able to maintain proper torque after few revolutions of the wheels.

copy/paste:

Torque values are based on fastener stretch. Fastener stretch is based on the Young's modulus of the material used for the lug. In the case of rod bolts, the ideal way to install is to measure the bolt unloaded, then tighten until the specified stretch is reached. Some torque values are based on elastic range, others on plastic range (torque to yield). They're all based on the fastener's material and treatment.

Oiling the threads lowers the torque required to achieve the same stretch. Anti-seize is a lubricant on threads. All wheel specs are for dry threads. I don't trust dry threads, so I use anti-seize, even though I know it will stretch the fasteners more than Toyota expected.
 
Last edited:
My father was an auto machanic and he taught me to always tighten the lugs with a torque wrench to the factory spec. I still put anti-seize on mine too.

Really glad to hear that you survived relatively unscathed, other than needing to buy some new underwear.
 
irbrito said:
... I had cross torqued these lugs with an impact wrench to about 170 ft-lb
Click to expand...

Isaac,
As others have pointed out, you over-torqued your lug nuts. The 80-Series has some substantial diameter wheel studs and the spec is 76 ft/lb for alloy wheels and 90 ft/lb for steelies.

The documentation on your impact says 170 +/- 10% at 90psi. If your regulator is off a little and your impact is on the high side, you would be in the 200 ft/lb range. At best you are probably double the factory lug nut torque specification.

I'm with Ali on the suggestion that you should plan to replace all the studs for safety. I have a recently calibrated click-type if you want to borrow one.
-Mike-
 
Always good fun. I lost the left rear wheel on my fj40 a few years back going 60mph and the wheel nearly hit a couple walking their dog on the side of the road. These things are really scary but it's always the 'could'a beens' which are the most scary. I still shudder when I think about what my life would have become if my wheel had hit that couple at 60mph.....brrr
 
Got new wheels studs for MR2 and Taco going to replace this weekend. I have a toque wrench and checked, the breaking torque was 100-120 ft-lb on the lugs on the Taco and MR2, and 80-90 ft-lb on my wife's Lexus (I have never used the impact gun on this or the 40). My regulator was about 85 PSI and I have a filter, and about 50 ft of hose in between.
 
Last edited:
Sounds like a busy weekend up ahead!!! Did you check the breaking torque on all the lugnuts to see what the average loosening torque was? I'm just curious if you had similar numbers on a random sample.
 
alia176 said:
Sounds like a busy weekend up ahead!!! Did you check the breaking torque on all the lugnuts to see what the average loosening torque was? I'm just curious if you had similar numbers on a random sample.
Click to expand...

Checked em all 100-120ft-lb
 
well, it's consistent!

Make sure you're done in time to make it to the meeting tomorrow in Sandia park! :-)
 
Resurected! After new rear rotors, lower ball joint, wheel studs, and wheels.

BTW found the root cause of the lugs coming off. PO used the wrong lug nuts, there was virtually no seating area between the nut and wheel.

My gasoline bill doubled this month with the Taco. :-(

image-2249091683.webp
 
Very nice dude!!!
 
holy crap, well done, at least from now with new studs and lugs all around and the knowledge of don't overtorque on sake of principle... you should be good for a while now!
 
Did the tire that came off do any body damage to the fender arch? I don't see any from this side shot.
 
marcfj60 said:
Did the tire that came off do any body damage to the fender arch? I don't see any from this side shot.
Click to expand...

No body damage, the lower ball joint got ground off from the asphalt, the rotor took a decent grinding too.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom