Retorquing wheels

[canoetrpr]

It is very possible that my lack of mechanical knowledge is hiding an obvious answer here.

I've been thinking about adding a torque wrench to my arsenal to retorque wheels and such. Most of the torque wrenches I've seen are reasonably long - for the necessary leverage I imagine.

However, when I took a look at the rear wheels on my Kubota L3400 today, I realised that the tire is about a foot wide which means the spot where the bolts hook onto the wheel is about a foot in. I'd imagine I couldn't get a wrench longer than about a foot into there to tighten the bolt.

Am I missing something obvious here? or should I just be looking for a short torque wrench (under a foot) and expect that I will be able to tighten to the required torque without the leverage a great big wrench would give me.?

 

[deerhunterf350]

Thats what Socket extensions are for, however whenever using extensions on a Torque wrench , you "loose" some torque in the Extension. The Longer the extension the more torque lost. I don' know what the % of loss is, maybe someone else can chime in .

Dan

 

[RoyJackson]

I've always added a few ft-lbs (or whatever value I'm using) if using an extention longer then 3". Ballpark it about 5% of the value.
Although I've looked, I've never found a specific formula for this.

Just remember the torque is to provide a specific tension on mating fasteners. That means tight enough, yet not too tight.

 

[crbr]

I've always added a few ft-lbs (or whatever value I'm using) if using an extention longer then 3". Ballpark it about 5% of the value.
Although I've looked, I've never found a specific formula for this.

Just remember the torque is to provide a specific tension on mating fasteners. That means tight enough, yet not too tight.

We encounter this upon torquing anchor bolts on pipe supports (within the nuclear powered electric generating plants) with a specified amount of torque. There is a specific formula that is used. I'll look in a procedure on Monday if I don't forget.

As for RoyJ's explanation on torque and tensioning onto the mating surface, that is a true statement indeed. On very large bolts (over 2" in diameter) used for replacing the reactor's vessel head, torque goes by the way-side. We actually elongated the bolts (tighten) with a hydraulic system and measure the elongation in 1/1000ths. Interesting that RoyJ would mention this.


RoyJackson never ceases to amaze me....

 

[pat32rf]

My dad, who used to teach auto mechanics taught me that when a torque value is given it should be specified weither it is a dry torque or wet( lubricated with grease, oil etc). You must then start with a loose nut(on a stud) or bolt and tighten it to that torque value. Unless it is one of a series of clamping nuts or bolts such as wheel nuts or head bolts, in which case you tighten them in increments in a certain specified order.
To sum it up, unless you are just checking wheel nuts that were torqued previously you must first loosen all the nuts so they are below the specified torque value then retighten them. This all applies more to fancy rims on high speed road vehicles than 15mph tractors...

 

[cp1969]

I guess I'm missing something. Where does the torque disappear in an extension?

I can see it if you're using an impact, in fact they make things called 'torque sticks' to limit the amount of torque an impact can deliver to a fastener. But that results because the impact is of shorter duration than the extension can respond to.

But tightening with a torque wrench is essentially a static operation. If I hold 100 ft-lb on my end, why isn't 100 ft-lb coming out the other end? The extension twists, but it's acting like a spring.

 

[crbr]

I guess I'm missing something. Where does the torque disappear in an extension?

I can see it if you're using an impact, in fact they make things called 'torque sticks' to limit the amount of torque an impact can deliver to a fastener. But that results because the impact is of shorter duration than the extension can respond to.

But tightening with a torque wrench is essentially a static operation. If I hold 100 ft-lb on my end, why isn't 100 ft-lb coming out the other end? The extension twists, but it's acting like a spring.

A straight extension is a moment about the same axis. Where I got side-tracked in collective thinking was just what you pointed out. We have a formula for using a crow's foot and various extensions at an angle other than 90 degrees to the axis.

 

[hitekcountry]

I guess I'm missing something. Where does the torque disappear in an extension?

I can see it if you're using an impact, in fact they make things called 'torque sticks' to limit the amount of torque an impact can deliver to a fastener. But that results because the impact is of shorter duration than the extension can respond to.

But tightening with a torque wrench is essentially a static operation. If I hold 100 ft-lb on my end, why isn't 100 ft-lb coming out the other end? The extension twists, but it's acting like a spring.

Sure looks that way to me also.

Imagine you have one of those hanging scales that are in the vegetable section at the store. And lets say you took the basket off and placed a spring between the scale and the basket. Set the scale at 0 then add onions until the scale reads 10 pounds. Now do you have a true 10 pounds (I think so) or do you add onions until you get to 10.5?

 

[john_bud]

I just torque them to the spec. Extension or no.

Also, on retorqueing wheel nuts, I just slap on the wrench and have at it.

If you buy a torque wrench a clicker is easier to use than a pointer. Especially when in tight areas or with high torques. Holding 150# with one hand behind a wheel in an awkward position and craning you neck to see a pointer is just plain silly.

Remember too, that a torque wrench is one of the most important tools in the chest. You can snafu a good repair faster than a rat jumping on a cheeto with a junk TW. Buy quality otherwise you may as well just tighten until it feels right. Or like my high school buddy Mike, he tightened until the studs broke then backed off a 1/4 turn.

 

[RoyJackson]

My dad, who used to teach auto mechanics taught me that when a torque value is given it should be specified whether it is a dry torque or wet( lubricated with grease, oil etc). You must then start with a loose nut(on a stud) or bolt and tighten it to that torque value. Unless it is one of a series of clamping nuts or bolts such as wheel nuts or head bolts, in which case you tighten them in increments in a certain specified order.
To sum it up, unless you are just checking wheel nuts that were torqued previously you must first loosen all the nuts so they are below the specified torque value then re tighten them. This all applies more to fancy rims on high speed road vehicles than 15 MPH tractors...

It's called progressive torquing. I've used it in almost every application in which more then one fastener is used to hold components together such as an engine head (to the block), split wheel assemblies (aerospace) and automotive wheels (especially aluminum wheels) to the hub or axle.
The intent is to ensure an even setting of the components.


As far as cp1969's question "Where does the torque disappear in an extension?", the extension itself will twist (due to the fasteners' resistance to movement and the force applied by the wrench) and absorb a small percentage of the torquing force. The force is converted into heat.
How applicable is this in torquing a tractor tire? Not very, in my opinion, although it is in high stress components. For tractor wheel torque, I apply a modicum of Yankee common sense.

Crbr, thanks for the compliment. By profession, I'm a Quality Engineer and have worked aerospace, among other industries. Even an old dog like me picks up some information along the way...

Here's another tip: Never let anyone airgun your wheels on your car or truck. Odds are, they'll over torque and you'll have a heck on a time breaking them loose at 2:00 AM when you're trying to change a flat tire. Airgunning a cast aluminum wheel (to completion) can also result in cracking the wheel.

 

[Redbug]

Hi Canoe,

I would go ahead and get a torque wrench to add in the toolbox. It is an underutilized tool but an important one. For example, I do most of my own vehicle work...tire rotations, etc. In the past, I would occasionally have problems with brake disks warping, (the brake pedal would pulse when brakes applied). That problem can be caused by improper lug nut torques. After I started torquing them, no more warped disks! I don't think many of the tire places worry much about the torque values, (like Roy Jackson said), because they don't care. They want to get you in and out.

Now that I am torque educated, I use my torque wrench more often for most critical bolts.

 

[crbr]

Holding 150# with one hand behind a wheel in an awkward position and craning you neck to see a pointer is just plain silly.

Listen for the click. Dial indicators are like an 8-track player....
Actually where the concern for an additional setting of torque values (with regards to the crow's foot extension piece) is mainly when working in instrumentation and small applications dealing with inch-pounds.


Foot-lbs are minimal concern for verification of + / - specs unless required by a procedure or standard for a QA / QC program (as I know life and nothing to brag about at all).

 

[EdC]

Definitely want to go with a breakaway (clicks when torques is reached) then a dial indicator. They are much easier to use.

I worked on munitions for the AF, including nuclear weapons so we were really pick about torque We torque everything from 3 inch ounces to 800 ft lbs.

Roy is certainly right in that there is some torque lost in an extension used at 90 degrees to the wrench and that it is converted to heat. We were always told though that it was so small that the accuracy of the actual torque wrench was a bigger factor. So was the technique using the wrench. This was when we had our torque wrenches recalibrated on an average of every 90 days. I would not worry about it. Buy a good quality torque wrench and aim for the given torque value or the middle of the torque range and you should be good to go.

 

[California]

If we're talking tractor-grade precision and not nuclear industry:

I've found HF's cheap click torque wrench gives torques that are verified precisely by my Craftsman beam torque wrench (I purchased it new in 1960) and another name-brand beam wrench that shows identical readings. I 're-certify' the HF one a couple of times a year by this comparison (never trust HF stuff for critical applications) but I've never seen a change. Close enough for tractor work. Or as an old carpenter buddy used to say: "Good enough for the girls I go with."

As for losing torque in an extension bar - after you've held the torque for a moment I can't imagine heat loss being significant or even measurable. I don't think truck springs are shedding measurable heat while they are under tension after the truck is parked, so why should this bar under tension have different physics? Has anyone observed a heated extension bar, after testing wheel lugs with the torque wrench?

 

[RoyJackson]

May as well get some terminology squared away...

Types of torque wrenches:
Micrometer Setting: The "Click" or Break Away type most frequently used. It is suggested these be returned to zero of a bit below when not in use. Don't leave them at a torque setting as this can affect their accuracy (got this from a calibration lab).

Dial Indicating: Has a dial which one must read the torque. I've heard these were the most accurate but have no data to back that up. Normally has a setting marker on the bezel of the dial to make it easier to read. Once the torque indicating needle reaches the setting marker, you've reached the proper torque.

Deflecting Beam: The indicating needle is inline with the axis of the wrench and one reads the scale as the wrench deflects from the indicating needle.

Of course, these are not wrenches. It's better to use a standard combination wrench or socket to approach the torque value (lightly snugged, in my experience), then use the torque wrench to complete the operation. Also, handle with the same care one would use for any precision measuring device.

 

[BillyP]

I guess I must be in the minority because I've never in my life torqued a wheel lug nut/bolt. I just snug them up a little at a time using a crisscross pattern until they are tight. Never had one come loose, strip or break. I'm not saying this is the right way to do it, just the way I've always done it.

Clicker type torque wrench is the best way to go.

 

[RoyJackson]

I guess I must be in the minority because I've never in my life torqued a wheel lug nut/bolt. I just snug them up a little at a time using a crisscross pattern until they are tight. Never had one come loose, strip or break. I'm not saying this is the right way to do it, just the way I've always done it.

Clicker type torque wrench is the best way to go.

I never did until two things happened to me. One, I bought an old Porsche with aluminum wheels (cast, in my case, but most Porsche wheels are forged). I always torqued those, but never steel wheels.
Two; in an earlier post, I wrote about changing a tire at 2:00 AM...well, that was me. I did all kinds of dancing, beating, cursing and such, but I couldn't get those nuts broke loose. A longer wrench would have helped (or maybe more heft on my skinny butt)...and a helper bar on the tire iron did, in fact, do the deed...the next day.
I torque 'em to make sure the nuts are tight, but not too tight. I always use anti-seize too, BTW.

I prefer the micrometer setting ("ClicK" type) wrenches too.

 

[patrick_g]

It sure makes a difference whether the threads are lubed, clean, or dirty (or rusty) and if you are not square to the wheel with the tool you can get erroneous readings but no torque is lost or "stored" in the extension, if any, unless their is angular acceleration in your wrench motion. If the nut is stopped or turning at a constant (or nearly so) rate then the torque wrench will give an accurate reading irrespective of the length or number of extensions.

A swivel extension or a "wobble" socket can introduce errors but a straight extension concentric (collinear?) with the fastener being tightened will have no effect on torque wrench accuracy no matter what style you have, clicker, pointer and dial, or digital readout or whatever.

Pat

 

[RoyJackson]

It sure makes a difference whether the threads are lubed, clean, or dirty (or rusty) and if you are not square to the wheel with the tool you can get erroneous readings but no torque is lost or "stored" in the extension, if any, unless their is angular acceleration in your wrench motion. If the nut is stopped or turning at a constant (or nearly so) rate then the torque wrench will give an accurate reading irrespective of the length or number of extensions.

A swivel extension or a "wobble" socket can introduce errors but a straight extension concentric (collinear?) with the fastener being tightened will have no effect on torque wrench accuracy no matter what style you have, clicker, pointer and dial, or digital readout or whatever.

Pat

Coaxial...

Yeah, using a swivel or those wobble type extensions isn't good practice.

 

[prosperity]

I also cringe at the sight of an auto shop using an air impact gun on wheel lugs/nuts.

Over tightening can cause stretched bolts and problems with the wheel holes.

Our tractor wheels need special care when talking about torque on the wheel bolts.

Case and point - here's a couple photos of a brand new JCB backhoe with about 30 hours on it. The wheels had never been re-torqued after delivery.

I recently had an issue with my new 2520 JD, and brought it back to the dealer - had to do some adjusting to the ROPS, and had to remove the rear wheels also.
When the mechanic started putting things back together, he reached for is air impact gun. I asked if he was going to torque the bolts.....says "I never use a torque wrench on anything here". I'm sorry, but we are talking the ROPS and rear wheels here.
Had my salesman look up the appropriate torque values, as the mechanic got out his torque wrench - which sure looked like it had never been used.