Wheel bolts torque settings.

[television]

Finally got around to reading this very informative thread and it brings 2 thoughts to mind:

1. Got to get myself a torque wrench as I have always used all my strength to tighten bolts thinking that is the correct approach (Worse, in the last few years I've been doing that while using an extending bar wrench!!!)

2. In the past I have used spacers on wheels (to stop rubbing on the inner arch). I thought they would be fine as I used extended length bolts when I fitted them. From what I have read on here they must be a really bad idea as they would stop\reduce the intended clutch effect between hub and wheel and place more reliance on the bolts to transfer the load. Especially as I used to liberally apply copper slip!

It just shows how a little knowledge can be dangerous.

Dave

Very difficult Dave,, it is instinct to apply a little some thing on a wheel bolt that is very tight or rusty, I think that the makers have allowed a fair tolerance on these things

 

[Number_Cruncher]

One thing I forgot to mention above when I talked about how bolts are stretched as they are tightened - I didn't mention the distances involved.

A typical wheel bolt will become about 50 microns longer after it has been tightened up - and the material around the wheel hole will be compressed by about 10 microns.

For most short bolts, this type of extension is quite typical, and it's only on cylinder head bolts for engines like the Rover K Series where you can get bolt elongations during installation of the order of 1mm (1000 microns).

So, dirt or foreign material in the joint which can compress and become embedded in the mating surfaces can easily squash by these amounts - which would relax the tension in the bolt. For this reason, it's very important to recheck your wheel bolts some time and distance after remounting a wheel - tyre depots typically stipulate something like 30 or 50 miles.

I would go so far as to argue that this re-checking of the bolts is actually more important than if you set them to 100Nm or 110Nm.

 

[Number_Cruncher]

I think that the makers have allowed a fair tolerance on these things

Yes, I concurr - manufacturers know that car wheel bolts will be abused.

The wheel bolts oin trucks should ever be handled by professionals, and so, the need to include a bodge factor in the design is (or should be!) diminished.

 

[nick73]

Would it make any difference in torque settings if a 210 was fitted with wheels off a 211?? Different bolts are used, so just thought perhaps different torque settings would be used too?

 

[television]

Would it make any difference in torque settings if a 210 was fitted with wheels off a 211?? Different bolts are used, so just thought perhaps different torque settings would be used too?

A 210 uses 12mm bolts and a 211 14mm, so you are still using the 12mm so the settings stay the same

 

[Kompressor]

Is there an app for that?

 

[Kompressor]

Is there an app for that?

Actually there is and I had it all along on my iPhone. This app is the best converter I have seen in the app store so far and it converts among many things Ft-lb to N-m visa versa among many others.

The app is called Convertbot.
Actually all the bot series are very good!!
List of things it converts - scroll to the bottom of the list

 

[alc250d]

The torque setting of wheel bolts provide even distribution of force spread across the five bolts and the surfaces of the wheel/hub,the centre of the wheel provides location. We all use loctite on our caliper bolts but have to clean the old loctite out before fitting new bolts. If there was a concern over the tonnage applied to wheel bolts to keep the wheel on then the hubs on our mercs would be at least 20mm.thick to stop threads pulling.Hence the warnings about using wheel spacers.

 

[ALFIEBEARD]

They should be dry.

The root of the problem is that, despite using a fancy piece of kit, tightening a fastener to a specified torque is a truly awful installation method.

The purpose of tightening a bolt is to elastically (and in some cases plastically) deform the bolt, to stretch it. For equilibrium, the stretch in the bolt is matched by the compression across the faces of the joint.

In the case of a gasket joint, this compression is needed to make the gasket seal.

In the case of a wheel to hub joint, this compression is needed to transmit the drive and brake torque. In this respect, the hub face and inner face of the wheel are acting as the two faces of a clutch. The bolts themselves should not be transmitting the drive and brake torque.

So, applying torque to stretch and preload the fastener is how it tends to be done, but, it's a rubbish method. It's poor because there is so much variation in the levels of inter-thread friction, and friction between the bolt head and clamped part (in our case on the radius under the bolt head).

During some tests I did on a rail vehicle, with instrumented M16 bolts, after torquing using a calibrated torque wrench, wielded by a highly trained fitter, there was of the order of 25% scatter between the bolt which was stretched the most, and the bolt which was stretched the least.

Using grease anywhere on the bolt is a bad idea, becasue you then get more stretch of the bolt for your torque, and you are over-stressing the bolt. However, as the under head (or radius) section is at a larger radius from the centre line of the bolt, changing the friction here has a larger effect on the torque to preload conversion.

Using grease on the wheel to hub joint face is also a bad idea, because this face transmits the drive and braking torque. Some calculations I did demonstrate that you would get slip across such a grease joint under hard braking conditions.

Slip across the wheel and hub interface is bad because this loads the bolts in a way they were not designed for.

If you are concerned about alloy to hub corrosion, it's better to remove wheels frequently, perhaps as part of a rotation regime, and clean thoroughly.

It happens that manufacturers have long known about the abuse meted out to wheel bolts, and they tend to be designed with a large margin of safety or margin for bodging!, and so people tend to get away with it.

On commercial vehicles, the design margins are not so large, and wheel loss is much more common.

Very Interesting info,
it should be noted most commercial wheels have left handed wheel nut threads on one side and right handed threads on the other, this system is also used on Rolls Royces, who incidentally used brass nuts on the Shadow 1.

Alfie

 

[Wingnuts]

Wheel torques

On this subject my A150 owners book says 130nm can I assume that this also includes the specified alloys? sadly no more info on this in book other than spec for steel & alloy wheels themselves and I am about to fit alloys.

Thanks

 

[Silver_Star]

On this subject my A150 owners book says 130nm can I assume that this also includes the specified alloys? sadly no more info on this in book other than spec for steel & alloy wheels themselves and I am about to fit alloys.

Thanks

Usually on Mercedes the torque setting for the road wheel bolts is the same for steel and alloy wheels.

 

[Wingnuts]

Thanks for reply, asking because other cars I have owned have had different torques.
This car is a pain as there is no Haynes for 2005 onward, until I found this forum it was a battle to find out anything.

 

[Silver_Star]

I guess part of the reason some other cars have different torque settings for steel and alloy is that they use bolts with a collar washer on them. I know this is true for some Renault's.

 

[brigbeale]

Actually there is and I had it all along on my iPhone. This app is the best converter I have seen in the app store so far and it converts among many things Ft-lb to N-m visa versa among many others.

The app is called Convertbot.
Actually all the bot series are very good!!
List of things it converts - scroll to the bottom of the list

I found a very useful web page a while ago, but due to my laptop giving out, I lost it.
I found this one though.
http://www.cleavebooks.co.uk/scol/cctorq.htm

 

[AlunG]

Not sure what usual price of torque wrenches are but I bought mine today from Aldi for £14.99. Will be using it when I switch from summer to winter wheels. All other gear I've had from Aldi has lasted well & been pretty well made too.

 

[syncropaddy]

Ashtray on a motorbike, Aldi Torque Wrench, chocolate teapot, tits on a nun ....... all about as useless as each other Im afraid !!

 

[AlunG]

yep...I've got another for you...about as useless as your Freelander. Thanks for your positivity.

 

[syncropaddy]

...about as useless as your Freelander. Thanks for your positivity.

Actually the Freelander 2 is a very useful tool for my line of work and has never let me down or broken anything. It cruises happily all day at motorway speeds, gets 40 to the gallon, is equally as happy plugging its way around an open cast mine or a drill site. In short it does exactly what Land Rover say it can do!

You cant say that about an Aldi Click styleTorque wrench ......

Have a look at post number 20 and 21 from this thread

http://forums.mercedesclub.org.uk/showthread.php?t=85891&highlight=torque+wrench&page=2

 

[Bxstar]

Locking Wheel bolt size

Hey hope you can help, I need to know what type and length of locking bolts for R15 alloys wheels on a SLK 200 2003, currently using hollow head 12mm x 20mm conical/radius bolts and are looking for some locking bolts.

 

[television]

Hello and welcome,,, do get in touch with this firm and they will look after you very well with the correct bolts

http://www.alloywheelsdirect.net/information/fitting_chart/mercedes-benz