How Important is to Have Accurate Tightening Torque?


#1

I’m installing tube steps on a RAV4 and it says to tighten the bolts on the bracket connecting to the frame to 84 lb/in.

Since I don’t have one, is it worth it for me to go and buy a torque wrench or is a snug fit good enough?

I’ve installed side steps on two other trucks and the instructions made no mention of required torque settings. They haven’t fallen off, loosened, cracked or anything else.

I appreciate your input.


#2

Different applications have different sensitivities to correct torque. What you are always trying to do is to get a fastener tight enough to “stay put” but not so tight as to risk snapping a bolt or stud. Obviously engine components are more sensitive - and probably dictate using torque wrenches for factory settings. Ditto for suspension components as some of them need to be torqued to hundreds of foot pounds or risk losing a wheel.

For casual body parts such as the side steps that you mention, unless you’re worried about snapping off bolts because you’re too enthusiastic, there isn’t much risk. If the bolt isn’t tightened enough, the bracket will probably rattle before it falls off and you can tighten it. And if you’ve had no problems with similar installations you’ve done before, I wouldn’t worry.


#3

84 inch/lbs or 84 foot/lbs?


#4

There’s no way that a side step bracket would need 84 ft.lbs. You’d twist off the bolt unless it was a T6 or T8 and then the receiving nut plate would have a problem. This is just “wrench tight” not “suspension tight”.


#5

For this application I think you can safely skip the torque wrench.


#6

Thanks to all who have responded so far.

You have reinforced my opinion, but I’m no expert and defer to those who have more knowledge of these kinds of things.


#7

If you have a common 10 lb. or 25 lb. household or fishing scale, you can do a pretty good job of measuring torque. If your wrench, for example is 7 inches long, then 84/7 = 12 lbs of pull is needed at a right angle to the wrench. If your scale goes to 10 lbs. maximum, then you can tape or wire an extension lever arm to the wrench. Use a piece of wood or metal, a second wrench or whatever else you have available. To use the 10 lb scale capacity, you need a length of 8.4 inches from the wrench end where it engages the bolt or nut to where you will pull with the spring scale. Again, pull at a right angle.


#8

McP gave the best answer…


#9

84 inch-pounds would only be 7 ft-pounds, WAY too little to secure this type of thing. Actually, 84 ft-lbs would be more like what I’d expect for something that has to support a lot of weight. But I’d skip the torque wrench and go ‘tight’ on them, assuming you have a reasonable feel for this kind of thing.


#10

The only thing I ever really worried about getting exact torque measurement to were things like head bolts…Almost every bolt on every car has a torque specification.

Example: When I installed my trailer hitch to my 98 Pathfinder the specs called for 80 ft lbs torque…Did I pull out my torque wrench…NO…I just bolted it down pretty much as tight as I could. Never had a problem ever…

For head bolts…Not only proper torque…but sequence is important.


#11

I agree with McP and Caddyman. You don’t need a torrque wrench for this. Durwin described perfectly the reason.

I do think a torque wrench is a good investment, however. You can get a beam-type for about $25. Bolts the failure of which could cause a catastrophic issue and bolts subjected to vibration, like those on your suspension system and motor, generally have torque values that you’d be well advised to follow. One that everyone forgets is lug nuts. Lug nuts can easily be undertorqued or overtorqued with unacceptable consequences.

In short, while torque isn;t critical for this application, it often is. And when in doubt it’s a good idea to have the torque wrench handy and follow the spec.