Effort required with a 3/4'' drive torque wrench?

[M.alex]

I need to torque centerlock wheel nuts to 380-400ft-lbs. I'm debating between buying a torque multiplier or a 3/4'' drive tq wrench. the problem w/ the multiplier is I don't think it will be easy to use with the rims, but I have no idea how much effort 400ft-lbs will require.

if a 1/2'' drive torque wrench is 25'' in length and a 3/4'' is 50'', does this mean I should expect 400ft-lbs with the 3/4'' drive to require the same effort as 200ft-lbs with the 1/2''? (i.e., force = torque/length).

[RickDaTuner]

Divide the force by what ever the multiplier ratio is.

I personally do not recomed a multiplier to tighten center nuts for cars, it's very probably that the anchor handle or wrench you will use on it will lift the car.

400 ft/lbs is a lot of force man, it's about the amount torqued required to move a loaded 18 wheeler freely on level ground, heck Maybe even up a slight incline.

[ercchry]

http://easycalculation.com/physics/c...ics/moment.php

you would have to exert 426N (95lbs here on earth) of force with a lever of 50" in length to achieve 400ft lbs and yes, that is half the force compared to a 25" lever.... but you could also toss the handle of your jack on it to extend it even further

[Tik-Tok]

I use 350 ft-lbs of torque on our A/C wheels all the time... it's a lot of force, more difficult part is keeping the head from moving and coming off the nut. Also you have your marth mixed up. You'll need twice the effort to torque 400 ft.lbs on a 25" bar, than a 50" bar.

Edit: I should add, I've tried torquing 350 ft-lbs with our 1/2" bar, and I personally couldn't do it, but you have a much lower center of gravity, so maybe you might be able to.

[M.alex]

Originally posted by RickDaTuner
Divide the force by what ever the multiplier ratio is.

I personally do not recomed a multiplier to tighten center nuts for cars, it's very probably that the anchor handle or wrench you will use on it will lift the car.

400 ft/lbs is a lot of force man, it's about the amount torqued required to move a loaded 18 wheeler freely on level ground, heck Maybe even up a slight incline.

I don't even think a multiplier would work here - the rims are 17'' wide and the nut is recessed deep inside - unless the rim itself held the muliplier in place, lol

Originally posted by Tik-Tok
I use 350 ft-lbs of torque on our A/C wheels all the time... it's a lot of force, more difficult part is keeping the head from moving and coming off the nut. Also you have your marth mixed up. You'll need twice the effort to torque 400 ft.lbs on a 25" bar, than a 50" bar.

Perhaps I was unclear, but what I was trying to say with my math was, in terms of the effort required to achieve the torque spec, Xft-lbs on a 25'' bar would feel the same as 400ft-lbs on a 50'' bar.

[pheoxs]

On a 50" bar you shouldn't have any problem. That's ~90 lbs of force you need to push on the end of the bar so unless your a tiny chick you should be able to do it no problem just leaning into it.

Main things to think about are: Make sure the car isn't going to move, thats a ton of torque, and make sure your socket doesn't come off or strip anything.

Also if you're concerned get a short little pipe to use for a snipe but be careful it doesn't slip off. I've seen lots of guys bust knuckles / knees / elbows etc from snipes letting go.

[ercchry]

is there an echo in here?

[Alak]

3/4" Drive Torque Wrench plus an extension. No problems. 400 ft/lbs is easy on a TQ Wrench that big. I torque 120 wheel nuts to 450 when I service a tractor trailer. If you weigh more than 100 pounds you can pretty much just lean on it.

[RickDaTuner]

If i was in your situation and I had an impact gun with compressor, I would set your gun to max and tighten the nut until the socket won't advance anymore. Most store bought fun only reach 400ft/lbs max. And center lock wheels and nuts don't need equal and specific toque like multi bolt pattern wheels do, they just need to insure the nut holds the wheel in place.

Mind you, doing that would mean you have a good feel for your
Gun, and where metals starts to break when excessive force is applied.

Agreeably not the most elegant way to do it, but that the point of center it wheels, get them on and off the fastest and easiest way possible

[ExtraSlow]

3/4 drive torque wrench from Princess Auto. Easy.
41 inches long, calibrated up to 600 ft-lbs.
EDIT, I also thought I'd do the math for you. If you need 400 ft-lbs, that equals out to 117 pounds of force applied 41 inches away (like with a 41 inch long wrench).

That's a pretty strong pull, depending on your size. You may want a snipe of some kind to lengthen the lever arm, which is fine and doesn't change what you set the wrench to.

Just pull slowly and carefully on that longer lever, as it's easy to overtorque with those. Just pull slowly and listen for that click.

[mr2mike]

I'd have someone helping hold so you're square on. But someone that knows what's going on. Maybe he can use a block of wood to keep the socket on square.


Not sure on your application but I'm with Rick on this one. 400ft/lbs is a lot. Good luck having to get that off too if you ever need to with corrosion, etc.

[ercchry]

Originally posted by mr2mike

... Good luck having to get that off too if you ever need to with corrosion, etc.

like it will ever leave the garage

all he is going to do is sit in it and make engine noises with his mouth

[Darell_n]

Without an impact wrench you will spin the tire on a shop floor with just the vehicle's weight on it. Even on my truck the tire will spin and that's a 4600 lb vehicle and tightening the lugs to 140 ft/lbs. Snow-brush pressing on the brake pedal takes care of that, though.

[mikestypes]

Originally posted by Darell_n
Even on my truck the tire will spin and that's a 4600 lb vehicle and tightening the lugs to 140 ft/lbs. Snow-brush pressing on the brake pedal takes care of that, though.

Not a chance will you spin a weighted wheel with 140 ft lbs! If so, then a honda civic should be able to light up the tires in 6th gear.

[M.alex]

Originally posted by Darell_n
Without an impact wrench you will spin the tire on a shop floor with just the vehicle's weight on it. Even on my truck the tire will spin and that's a 4600 lb vehicle and tightening the lugs to 140 ft/lbs. Snow-brush pressing on the brake pedal takes care of that, though.

911 porsches with centerlock rims don't spin when tightening (I think their torque spec is like 350ft-lbs)

[Darell_n]

Originally posted by mikestypes


Not a chance will you spin a weighted wheel with 140 ft lbs! If so, then a honda civic should be able to light up the tires in 6th gear.

The tire gets more than 140 as the lugs are not on center. It only happens when I pull up on the wrench. Maybe I'm just lifting 1000 lbs off the floor with one hand.

Civics have a 1:1 6th gear? That's awsome, no not really.

[mikestypes]

Originally posted by Darell_n


The tire gets more than 140 as the lugs are not on center. It only happens when I pull up on the wrench. Maybe I'm just lifting 1000 lbs off the floor with one hand.

Civics have a 1:1 6th gear? That's awsome, no not really.

.659 6th but with a 4.76 final drive, so 3.14 overall final gear ratio. With 140 ft-lbs from the engine, a civic would see 440 ft-lbs applied at the hub.

The extra 3-4" of lever you are getting from the bolt center is not going to multiply your 140 ft-lbs any more than 33%.

[mr2mike]

Found you a jdm solution