Torque wrench

Page 2 - Passionate about caravans & motorhome? Join our community to share that passion with a global audience!
Jun 20, 2005
16,419
3,015
50,935
Thanks Steve
I understand your points.

So is it wrong to check our caravan wheel torques without undoing and starting all over again?
Most tyre shops and dealers say “check” the torque after say 50 miles.
As one who has lost a wheel years ago you will appreciate my caution😉
 
Nov 6, 2005
6,735
1,591
25,935
Thanks Steve
I understand your points.

So is it wrong to check our caravan wheel torques without undoing and starting all over again?
Most tyre shops and dealers say “check” the torque after say 50 miles.
As one who has lost a wheel years ago you will appreciate my caution😉
BUT - if you loosen then tighten again after 50 miles, should you check again after 50 miles - so unless you check every 50 miles, the advice to undo and retighten is logically nonsense.
 
May 2, 2020
249
91
4,635
As far as I am aware you should check the torque of the wheel studs not re-torque, I personally do this after the first 20 or so miles and then again when wheels are cold, as for using a torque wrench to undo bolts I would not do, why risk damaging a torque wrench for the sake of £20ish for a breaker bar, these are my personal opinions.
Gra
 
Aug 5, 2022
114
86
135
BUT - if you loosen then tighten again after 50 miles, should you check again after 50 miles - so unless you check every 50 miles, the advice to undo and retighten is logically nonsense.
It may or may not lead to an accurate torque remaining set I think. Which is where I came in with about alloy engines and their precise needs. But it will likely catch any gross undertorquing. I’m no caravan engineer and maybe absolutely precise torque matters less to caravan manufacturers than it does to alloy engine manufacturers. I think my concern was not so much about people checking once, not sure that minor inaccuracies count here really, you just don’t want them loose, it was more to do with wondering what happens by the time a frequent caravaner has cinched that nut twenty times rechecking the torque for each trip. I’ve been doing that myself like all of us , but am just not sure it’s the ideal. I think the caravan manufacturer clearly has the right to say set and recheck torque once after refitting a wheel and that if they say that we should follow their procedure above all else. It’s maybe that they don’t mind the nuts being within a tolerance that is greater some other engineering situations. I imagine missing gross loosening is their biggest concern above all else.
 
  • Like
Reactions: Dustydog
Mar 14, 2005
1,109
173
19,235
jondogoescaravanning.com
As others have said, You don't use a torque wrench for undoing bolts. It's anyone's guess how much torque is required to undo some bolts. A crankshaft pulley bolt is tightened to 150Nm and since a new bolt is required for each tightening, it's usually already prepared with thread lock. After a few years, they become difficult to shift.
 

Sam Vimes

Moderator
Sep 7, 2020
1,314
913
5,435
My final thoughts on the subject as we all have different opinions.

If my torque wrench is good for tightening both left and right threaded nuts then provided I can undo a nut at less than or equal to the maximum setting I don't see a problem.
 
  • Like
Reactions: Jcloughie
Jun 20, 2005
16,419
3,015
50,935
My final thoughts on the subject as we all have different opinions.

If my torque wrench is good for tightening both left and right threaded nuts then provided I can undo a nut at less than or equal to the maximum setting I don't see a problem.
Yes, But don’t go beyond the click, a no no for me
 
Nov 11, 2009
18,436
5,275
50,935
It may or may not lead to an accurate torque remaining set I think. Which is where I came in with about alloy engines and their precise needs. But it will likely catch any gross undertorquing. I’m no caravan engineer and maybe absolutely precise torque matters less to caravan manufacturers than it does to alloy engine manufacturers. I think my concern was not so much about people checking once, not sure that minor inaccuracies count here really, you just don’t want them loose, it was more to do with wondering what happens by the time a frequent caravaner has cinched that nut twenty times rechecking the torque for each trip. I’ve been doing that myself like all of us , but am just not sure it’s the ideal. I think the caravan manufacturer clearly has the right to say set and recheck torque once after refitting a wheel and that if they say that we should follow their procedure above all else. It’s maybe that they don’t mind the nuts being within a tolerance that is greater some other engineering situations. I imagine missing gross loosening is their biggest concern above all else.
When I had a puncture repaired a couple of weeks back the fitter suggested I can return within 50 miles for a torque check. I’ve had previous tyre dealers have such a suggestion on the issued paperwork. I wonder how many motorists comply?
 
Aug 5, 2022
114
86
135
When I had a puncture repaired a couple of weeks back the fitter suggested I can return within 50 miles for a torque check. I’ve had previous tyre dealers have such a suggestion on the issued paperwork. I wonder how many motorists comply?
I had the same advice after a car puncture repair on holiday. It seems to be a relatively recent change in procedure at tyre centres. Part of me could see why they cover their backsides, I once had a car come from the tyre centre with loose nuts, someone just forgot to…... Anyway no torque wrench while away touring so I just checked them by feel with a tweak of the cars wheel nut wrench. Way that it was done for the previous century I guess,

Steve
 

JTQ

May 7, 2005
3,035
940
20,935
Multiple rechecking our wheel bolts is not going to over load them.
Any repeated torquing is dealing with static friction, whereas initial tightening can invoke kinetic friction.
A bolt's tension, as correctly identified the real aim of torquing up, will always be greater for a set torquing level where kinetic friction is involved, the bolt's mating faces are sliding, than the tension achieved by rechecking a static bolt; unless of course it actually is found lose and moves.
So, forget this nonsense about the dangers of over torquing a bolt by simply retorquing to the correct set value, it will not happen; the danger is it might not achieve correctly tightening a seized up underloaded bolt.
Don't pre loosen them, there is way greater danger the matting thread and face surfaces have over time gained greater friction, [oxidation and loss of the plating metal or coating that itself provides some lubrication], so the achieved tension will be too low.
And definitely don't grease or oil bolts here where the quoted figures are for "dry" torquing; that can massively over tension the bolts.
Torquing up technique involves simply "leaning" on the wrench, not using some inertial flywheel technique!
Other torquing applications, such as with some cylinder heads involves differing techniques some where the bolt is taken into plastic stretch and are very much one shot applications, some involving wet torquing; here it's just a user replaceable road wheel, a potential roadside task, a way different job.
 
Last edited:
Aug 5, 2022
114
86
135
Multiple rechecking our wheel bolts is not going to over load them.
Any repeated torquing is dealing with static friction, whereas initial tightening can invoke kinetic friction.
A bolt's tension, as correctly identified the real aim of torquing up, will always be greater for a set torquing level where kinetic friction is involved, the bolt's mating faces are sliding, than the tension achieved by rechecking a static bolt; unless of course it actually is found lose and moves.
So, forget this nonsense about the dangers of over torquing a bolt by simply retorquing to the correct set value, it will not happen; the danger is it might not achieve correctly tightening a seized up underloaded bolt.
Don't pre loosen them, there is way greater danger the matting thread and face surfaces have over time gained greater friction, [oxidation and loss of the plating metal or coating that itself provides some lubrication], so the achieved tension will be too low.
And definitely don't grease or oil bolts here where the quoted figures are for "dry" torquing; that can massively over tension the bolts.
Torquing up technique involves simply "leaning" on the wrench, not using some inertial flywheel technique!
Other torquing applications, such as with some cylinder heads involves differing techniques some where the bolt is taken into plastic stretch and are very much one shot applications, some involving wet torquing; here it's just a user replaceable road wheel, a potential roadside task, a way different job.
Thanks for the clarification. I did a little reading this evening involving multiple articles dealing with torque and tension in bolts used for everything from cars to helicopters to even the space shuttle. Very interesting. Didnt realise bolt tension can be measured directly using ultrasonics, I digress though. It does seem that the real risk with repeat checks is failing to detect an undertorqued bolt due to static friction locking the rotation, rather than overtorquing. For everything thru to helicopter rotors what came over strongly for me was “ follow the manufacturers procedure” whether it involves re torquing or just straight torque checking as we do for wheels. Either can be required. The procedure is clearly what keeps us safe really and is based on manufacturer experience. Interestingly Land Rover did specify that torques must be checked by slackening and retorquing for all bolts in one manual I found. So clearly there is variation in what is required out there. I will stick with your advice as published here for the van though!

Steve
 
Nov 16, 2015
9,798
2,346
30,935
On some applications of torquing bolts or nuts, do require the torquing up to a specified torque, then releasing the torque and then torquing again to the final torque, then at a specified time interval recheck the torque but not releasing the bolt or nut.
On some helicopter rotors at 5 to 15 hours after instalation the torque of certain bolts are checked but only up to 80% of the original torque.
Carrying this out at 250ft/lbs at 20 feet above the hanger floor whilst balancing a 10 kg torque wrench, is something I miss..
 
  • Like
Reactions: Dustydog and SteveW

JTQ

May 7, 2005
3,035
940
20,935
Indeed, here as elsewhere responsible designers lay out a procedure for the task in hand and we are well advised to follow that.

There are way more accurate bolt tensioning techniques and some applications need them, but here the focus is on a viable roadside, user employable technique, where we don't have loads of specialist kit and "fresh treated bolts" to hand.
The results here are pretty rough but typically adequate, with one important proviso, they need rechecking after a few miles of initial loading. During that settling time there are real risks that far outweigh precision in the initial torquing up.
Not an artisan covering their rear end, but one correctly understanding the risks.

In my car and caravanning experience, once past that first in use check, then the road wheel retention systems we have are very reliable.
 
Aug 5, 2022
114
86
135
Indeed, here as elsewhere responsible designers lay out a procedure for the task in hand and we are well advised to follow that.

There are way more accurate bolt tensioning techniques and some applications need them, but here the focus is on a viable roadside, user employable technique, where we don't have loads of specialist kit and "fresh treated bolts" to hand.
The results here are pretty rough but typically adequate, with one important proviso, they need rechecking after a few miles of initial loading. During that settling time there are real risks that far outweigh precision in the initial torquing up.
Not an artisan covering their rear end, but one correctly understanding the risks.

In my car and caravanning experience, once past that first in use check, then the road wheel retention systems we have are very reliable.

I think it was Bailey wheels that at one point were falling off and triggered the modern caution about torque though? Focuses the mind as that is what I have,

Steve
 
Nov 16, 2015
9,798
2,346
30,935
I think it was Bailey wheels that at one point were falling off and triggered the modern caution about torque though? Focuses the mind as that is what I have,

Steve
Steve, I have just read up on the ultra sonics method of checking torques, I had never heard of that before. Thanks.
I have now thought about using the WSL bolts for my wheels on my caravan, after reading about the technology.
 
  • Like
Reactions: SteveW
Aug 5, 2022
114
86
135
Steve, I have just read up on the ultra sonics method of checking torques, I had never heard of that before. Thanks.
I have now thought about using the WSL bolts for my wheels on my caravan, after reading about the technology.

I read about that in context of some of the space shuttle bolts. It seems they were monitored for tension for some time after torquing on a planned program. I had no idea that spanner work got that sophisticated,

Steve
 
  • Like
Reactions: Hutch
Feb 13, 2022
553
407
1,135
I had the same advice after a car puncture repair on holiday. It seems to be a relatively recent change in procedure at tyre centres. Part of me could see why they cover their backsides, I once had a car come from the tyre centre with loose nuts, someone just forgot to…... Anyway no torque wrench while away touring so I just checked them by feel with a tweak of the cars wheel nut wrench. Way that it was done for the previous century I guess,

Steve

I thought most tyre centres had only one torque setting on the windy gun, “tight as a knat’s ****”.
 
Aug 5, 2022
114
86
135
They eat healthy salads for lunch and are seen carrying torque wrenches these days ;)

Steve
 
Mar 14, 2005
16,949
2,631
50,935
We have been through the issue of caravan wheel fasteners many times, and firstly it is not just related to one make of van, it has been advised to recheck the the wheel fasteners a few miles after a wheel fitting, but it was highlighted when one manufacture issued a technical notice following a number of problems had been reported in the media and forums.

It's good advice, and it really is advisable for all road wheels including cars.

It's a reasonable conclusion to suggest a combination of forces acting on the wheels when being used caused the wheels fasteners to relieve, but we never found what the detail reasons were.

However, we did find some instances where alloy wheels were fitted and either the wrong fastner's or torque settings had been used. But this was not the case in every instance of loss of fastner tension or wheel.
 
  • Like
Reactions: SteveW

JTQ

May 7, 2005
3,035
940
20,935
It's a reasonable conclusion to suggest a combination of forces acting on the wheels when being used caused the wheels fasteners to relieve, but we never found what the detail reasons were.

However, as seems often the assumed case, don't necessarily associate this with bolts coming undone, ie rotating; the bolts can and do "relieve" their required level of tension before they ever rotate.
A wheel comes "loose" long before the bolts rotate. It only comes "off", if they subsequently rotate or break.
But when "loose", a wheel here is very shortly destined to lead to bolt rotation or destruction, ultimately, typically the wheel coming off.

Thus, bolt rotation indicators use here are far from ideal, the more so with it being just a five bolt system. The wheel not being adequately secured happens long before these indicators show anything; at best they give a pre hint the wheel has not yet come off.
 

TRENDING THREADS

Latest posts