Overtorqued wheelnuts
Today whilst browsing through the January 2016 CC magazine, I read a chart (page 48) which stated that the recomended torque figure for Coachman alloy wheelnuts should be 115Nm. This is contrary as to the information provided by telephone conversation with
Coachman who stated that the torque figure should be 130Nm. Ealrlier in the year (2015), I acted on thier information and torqued up to 130. If the lower figure is correct then I have overtorqued by 15Nm which = 11.06 foot pounds! Coachman are by no means
easy to communicate with so I need to know the correct figure as 11 foot pounds (132 lbs inches). Surly a vast difference. Comments/help please. Merry Christmas to you all.
Comments
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By the way, the info provided on the telephone was in the mid Summer period (approximately).
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John, I'm no Engineer, so is the difference in torque critical?
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Rocky, small ammounts may be knit picking but I think that 132 lb/inches difference must be concerning. Undertorquing could cost you a wheel and overtorquing will result in stretched threads/studs.
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Why I asked john as over the 3+ years I had my Van I never checked the nuts once, if I had done it would have just been to ensure they were tight & that would've been with a std L spanner, thanks for the reply
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....g but I think that 132 lb/inches difference must be concerning....
It's still only 11lb/ft ..... you could put that amunt of torque on with your little finger. It's so little difference that I wouldn't worry about it. I tighten my wheels up like Rocky
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Rocky look up Hooke's Law on Wiki.It explains what torque critical is all about -the deformation of a material is directly proportional to the force applied to it which is why over tightening is as bad as undertightening a wheel bolt.I had it drilled into
me by my metalwork teacher at school after overtightening the frame bolts on a project car we were made in class.Never forgotten it ,after he made me do it all over again after school.0 -
Bailey very helpfully have stuck a label with tyre pressure and torque on the waste bin attached to the door. I would assume other manufactures would do something similar, or at least put it in the handbook. Incidently ours on our Unicorn 2 are 130 Nm.
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Mollys Mummy, I am talking here about 11 pounds force
feet not inches. You would not achieve that amount with your little finger.0 -
Mollys Mummy, I am talking here about 11 pounds force
feet not inches. You would not achieve that amount with your little finger.I know you were .... I was obviously exaggerating slightly, but 11lb/ft is very very little .... eg the cam cover bolts on my last car were M6 & tightening a plastic cam cover down ... they were 8lb/ft. It's the kind of torque you'd apply with a 1/4" ratchet
set ....11lb/ft is nipping up a bolt by hand0 -
Personally I would change them to the much better design concept WSL caravan bolts that can be torqued up to 130 Nm.
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Thanks to all who replied. My nuts! are set at the higher figure of 130Nm which seems to be prety much standard on caravans. Nobody who replied seemed horrified at the torque difference so I shall have a glass or two tonight and sleep well. If Santa leaves
me a torque wrench tomorrow morning, he will be wasting his time as I already have one. In fact, if he needs one for bolting his sleigh together then he can have one for free!0 -
Rogher. Don't know why alloy wheels require a higher torque. Will Google it but somebody reading your question will hopefully explain.
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The alloys on my Abbey are 115Nm.
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Bailey owners have bigger muscles?
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They were 115 Nm on our Abbey but 130 Nm on our current Bailey. I wonder why the difference?
Write your comments here...About a year ago there were reports of a number of wheels falling off even though they had apparently been torqued correctly! After some research by the companies concerned, some changes were made and the torque raised.
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Mollys Mummy, I am talking here about 11 pounds force
feet not inches. You would not achieve that amount with your little finger.I know you were .... I was obviously exaggerating slightly, but 11lb/ft is very very little .... eg the cam cover bolts on my last car were M6 & tightening a plastic cam cover down ... they were 8lb/ft. It's the kind of torque you'd apply with a 1/4" ratchet
set ....11lb/ft is nipping up a bolt by handWrite your comments here...Molly I have the same make and model caravan as you. About 6 years ago I bought a set of alloys and fitted them. The suggested torque was 86 which I have stuck to. When I changed the tyres back in August 2016 I instructed the
fitter to torque the nuts to 86. I have never had any trouble whatsoever with the wheels...................but I am now wondering if the torque is high enough,given what this thread is suggesting.
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..... When I changed the tyres back in August 2016 I instructed the fitter to torque the nuts to 86. I have never had any trouble whatsoever with the wheels...................but I am now wondering if the torque is high enough,given what this thread is suggesting.
Merry Christmas ..... I think that there's been confusion here in the measuring units used. 86lb/ft is roughly 116Nm which kind of ties in with the torque settings suggested above. I have to admit that I just use a carefully calibrated right elbow when I re-fit wheels
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If you take the trouble to use a torque wrench, I wonder how accurate they are?
This has been covered many times.
IMHO the errors involved in not using a torque wrench are very likely to be major.
Should leave wrench in unloaded condition and don't use it to unscrew bolts etc.
Otherwise don't worry about insignificant small errors of calibration of a tool that is not used (and abused) daily?
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Many years ago the Institute of Road Transport Engineers did a study on loose wheel nuts after many cases of wheels coming off trucks. The eventual conclusion was that maintaining the correct wheel nut torque (680 Nm. on 22.5" rims) is very important. In
the trucking industry it is recommended to check wheel nut torque on a weekly basis. On caravans it is recommended to check before every touring trip.When Bailey had this problem a couple of years ago they were using the industry standard solid forged wheel stud @ 115 Newton metres and the studs were coming loose. They changed to WSL collard washer studs and increased the torque to 130 Nm. & have thus
removed the problem.As a retired road transport engineer I would sugest that all alloy wheel studs be torqued to 130 Nm. regardless of any lower torque setting recomended by the manufacturer. This will not result in any undue bolt stretching.
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What is the purpose of doing them up tight? Mine has split washers that would seem to be there to stop the nuts from coming undone.
Is it necessary to do the near-side tighter than the off-side?
Unless we are talking at cross purposes, wheel securing bolts used on caravans absolutely must not be used with spit washers.
They require seating directly onto either on conical or spherical seats in the wheel.
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