Should wheel bolts be fully tightened by air or by hand?
Discussion
doogz said:
blueg33 said:
This morning, I had the tyres replaced on the Evora, the mobile tyre fitter used a torque wrench to tighten the bolts. Sadly he didnt tighten them in the correct patern, so I will take them off and do it again properly!
You'll take them off? Why?ViperDave said:
doogz said:
blueg33 said:
This morning, I had the tyres replaced on the Evora, the mobile tyre fitter used a torque wrench to tighten the bolts. Sadly he didnt tighten them in the correct patern, so I will take them off and do it again properly!
You'll take them off? Why?I would rather its done right now. I will also re-torque the wheel bolts after 30 miles or so.
I didnt re torque them back in March after having the tyres replaced (Evora eats rear tyres when driven as intended) and one of bolts was loose enough to undo with my fingers.
doogz said:
You don't have to take them off to retorque them properly though. Crack them all, and re-tighten following the appropriate procedure.
Or, is that what you meant? I read it as if you were going to remove the wheels just to re-torque the bolts.
Thats what I meant. Not actually take the wheels off, just loosen them and e-torque. Or, is that what you meant? I read it as if you were going to remove the wheels just to re-torque the bolts.
BritishRacinGrin said:
There is no lubricant known to man which causes friction to cease to exist. I'll volunteer that a bit of copaslip on the flanges to prevent the wheels from welding themselves on will not have a detrimental effect on the fastening provided the fixings are done up right.
Absolutely, no lube reduces friction coefficient to 0. Data from here: linkyCoefficient of static friction between steel and steel:
Dry: 0.74
Lubricated: 0.16
Reduction of 78%
Coefficient of static friction between aluminum and aluminum.
Dry: 1.35
Lubricated: 0.3
Reduction of 78%
Coefficient of static friction between iron and iron.
Dry: 1
Lubricated: 0.15-0.20
Reduction of 85-80%
Feel free to find your own data for aluminum to iron. 0.45 dry is what I've found from here, but no data when lubricated, or with a dab of copaslip, or with enough copaslip to effectively eliminate corrosion but not effect friction (assuming such an amount exists, which it doesn't).
I'm not saying your wheels will fall off, obviously, because they don't in normal use.
However lubrication does make a significant reduction in joint shear capacity.
Whether you want to reduce the shear capacity of your wheel joint is your decision, but I'm professionally bound to recommend that you don't.
[/IMechE-code-of-conduct]
I have got this problem atm, went to a tyre garage, because I would like to think that they know what they are doing, but hell no, seems not, the fact is that wheel bolts are tapered, this is why its important to use a torque wrench when tightening them, especially when you have got alloys too, because the hole for the bolt is precision made for the bolts and if overtight that means its gone in to the point where the bolt is bigger than hole, so even if you get the bolt out afterwards, when you put another one in again it could work loose, overtightening on to an alloy wheel can cause fractures in the metal too, which in my case is what they have done 👍🏼 yeah cheers mate I'm very happy with your work, no I'm fuming right now and I know they are not going to admit fault, the blokes words were, "you must have used the wrong size tool on it, it's started to round off the bolt" lol, my reply, "ok mate I have got the tool in my boot, with the bent bar I used, so I didn't stress the bolt out any more than what it is already" so I got it out, held it up and asked him if he would like a new 17mm manufacturer supplied boomerang for when he bored at work. I then said it was put on too tight because they used air wrench on the maximum setting, it has to be tight said one worker, or it could come loose, it has to be torque wrench tightness or it could do exactly what it has to my wheel I replied, but I'm female, they wouldn't admit that what I have said is right and they are in fact wrong, so I'm going to be left with the bill for their mistake, bet they won't say I'm wrong with this one ☹
BritishRacinGrin said:
Can of worms opened. You'll get mixed opinions on this but in my opinion, unless the handbook specifically mentions it, wheel bolts / studs shouldn't be lubricated. Lubricating them will cause much higher tensile load for a given tightening torque. Personally I lubricate hub flanges but not wheel bolts / studs.
dry threads is the correct techniquexxChrisxx said:
You have loads of fat with wheel bolts, so lubed + torqued correctly
You really don't.100E Anglia, weighs about 700kg. 0-60mph, maybe. Top-speed maybe 60mph. Skinny, high profile crossply tyres. Accelerating, braking, cornering and shock forces commensurate. Wheels held on with 4 x 1/2" Studs.
206 GTi 180, weighs about 1100kg, 0-60mph 7.4s. Top-speed 137mph. 205/40/17 radials. Accelerating, braking, cornering and shock forces commensurate. Wheels held on with 4 12mm Bolts.
You had loads of fat with the former and many of the cars in between, to a gradually reducing extent. This is why you've been doing it for years and never died once. You don't have very much now, at all. Lubed is fine as long as 'torqued correctly' involves using the tightening spec for the prescribed lube. If you're using lube with a tightening spec for clean and dry threads it's 'overtightening'.
Cheers, Jim
I was at a track day a year or so ago when an MG Midget with non-standard fat wheels shod with semi-slicks was running on the the circuit. Suddenly it was a three wheel wagon because one of its pathetically puny four-skinny-studs-per-hub studs snapped and the remainder came rapidly unzipped under the strain. He'd put wide sticky tyres on a car specced for narrow road tyres and the increased forces due to the much grippier tyres overloaded the studs. He spent the next two hours removing one stud from each of the remaining three wheels and fitting them to his broken studded hub before driving off home! Lesson: increase the grip and beef up the hubs and transmission - diffs will fail if the tyres need double the torque to cause wheelspin, and hub studs and/or bolts will shear.
Quite what this means for greasing hub faces and studs I don't know, but car designers have to build in sufficient safety margin to allow for anything from dry rusty faces and studs, to thoroughly lubricated ones with the nuts given the half-Nelson with a long wheel brace.
Quite what this means for greasing hub faces and studs I don't know, but car designers have to build in sufficient safety margin to allow for anything from dry rusty faces and studs, to thoroughly lubricated ones with the nuts given the half-Nelson with a long wheel brace.
Captain Muppet said:
Absolutely, no lube reduces friction coefficient to 0. Data from here: linky
Coefficient of static friction between steel and steel:
Dry: 0.74
Lubricated: 0.16
Reduction of 78%
Coefficient of static friction between aluminum and aluminum.
Dry: 1.35
Lubricated: 0.3
Reduction of 78%
Coefficient of static friction between iron and iron.
Dry: 1
Lubricated: 0.15-0.20
Reduction of 85-80%
Feel free to find your own data for aluminum to iron. 0.45 dry is what I've found from here, but no data when lubricated, or with a dab of copaslip, or with enough copaslip to effectively eliminate corrosion but not effect friction (assuming such an amount exists, which it doesn't).
I'm not saying your wheels will fall off, obviously, because they don't in normal use.
However lubrication does make a significant reduction in joint shear capacity.
Whether you want to reduce the shear capacity of your wheel joint is your decision, but I'm professionally bound to recommend that you don't.
[/IMechE-code-of-conduct]
In pure theory wheel bolts should be torqued up the manufacturers recommended torques setting DRY .... agreed.Coefficient of static friction between steel and steel:
Dry: 0.74
Lubricated: 0.16
Reduction of 78%
Coefficient of static friction between aluminum and aluminum.
Dry: 1.35
Lubricated: 0.3
Reduction of 78%
Coefficient of static friction between iron and iron.
Dry: 1
Lubricated: 0.15-0.20
Reduction of 85-80%
Feel free to find your own data for aluminum to iron. 0.45 dry is what I've found from here, but no data when lubricated, or with a dab of copaslip, or with enough copaslip to effectively eliminate corrosion but not effect friction (assuming such an amount exists, which it doesn't).
I'm not saying your wheels will fall off, obviously, because they don't in normal use.
However lubrication does make a significant reduction in joint shear capacity.
Whether you want to reduce the shear capacity of your wheel joint is your decision, but I'm professionally bound to recommend that you don't.
[/IMechE-code-of-conduct]
However another common issue which regularly occurs is galvanic corrosion between the wheel/hub. As everyone knows, this means the wheel gets stuck on the hub. Wheels that haven't been off for four or maybe even six years (quite possible when manufacturer services don't remove wheels and intervals of 20,000 miles and 2 years) can be a real bugger to remove .... especially on the roads side in the lashing rain.
Copper slip on the hub/wheel interface is good practice in my book .... yes a small amount accidentally transferred to the wheel bolt thread will have an effect on the shank tension but it's a small affect that's worth the tiny risk in my opinion.
Whilst we're on the subject don't forget that the wheel/hub is designed with a flanged interface so large amounts of shear force due to the mass of the vehicle is transmitted directly from wheel to hub and not via the bolts.
This is for a regular road car ...... A track car which has it's wheels regularly removed and isn't driven much in adverse conditions I'd not bother with any copper slip.
ian in lancs said:
BritishRacinGrin said:
Can of worms opened. You'll get mixed opinions on this but in my opinion, unless the handbook specifically mentions it, wheel bolts / studs shouldn't be lubricated. Lubricating them will cause much higher tensile load for a given tightening torque. Personally I lubricate hub flanges but not wheel bolts / studs.
dry threads is the correct techniqueJohn Laverick said:
Whilst we're on the subject don't forget that the wheel/hub is designed with a flanged interface so large amounts of shear force due to the mass of the vehicle is transmitted directly from wheel to hub and not via the bolts.
I don't think I've ever had a car with a flanged interface - every one of them has taken all the loads through the clamped joint!Gassing Station | General Gassing | Top of Page | What's New | My Stuff