I've notice a torque table throughout the FSM when it comes to tightening nuts and bolts but have never actually asked how you would go about reading this.

For example the attached table is of the removal and installation of your wheels. Now I always assumed you tightened the nut until it can't go any further and every time I've had my tires changed the person would simply use a impact wrench on the nut until its tight. So is this in fact correct or should you simply tighten the nuts by hand?

I don't own the torque SST so does anyone know a way correctly torquing things on our cars or its not worth worrying about?

 

Since most tools here in the US are using imperial measurements, use the last numbers 66-86 ft/lbs of torque. You really shouldn't be using an impact, you should use a good torque wrench.

 

^ I second that. Impact wrench is for removing only.

Torquing you lug nuts is VERY important. Seriously, it's all that is holding them in place and if they come off or start to wobble, pray you are only backing out of your garage when it happens and you aren't on a freeway going 70+mph.

This should help......

http://www.tirerack.com/wheels/tech/...jsp?techid=107

 

Ever seen that fd at the track that has all four of it's wheels come off as he starts.

 

The reason why I'm asking this question is as it turns out I have the wrong lug nuts on my car and I read on a site which sold lug nuts that something so simple as improper torquing can cause vibration when driving. It so happens that I'm also in the process of changing all my rear bushings as we speak due to clunks so I want to eliminate all the possible causes of vibrations whilst I'm at it.

So what your saying is a good majority of tire shops incorrect fit your wheels by using an impact wrench to tighten them when they should be in fact just be using hand wrench? I've yet to find a shop that does this to be honest.

 

It depends on the wrench. If you know you can get the proper torque with an impact wrench, then its fine. However, if you are using some wrench which delivers 400 ft/lbs of torque and it's not dialed back, then you will over torque the bolts and possibly damage the wheel stud.

 

With OEM lug nuts on OEM wheels, 9 times out of 10 tightening with an impact gun is just fine. If you use a "regular" impact gun and have enough experience to know how long to hit each lug to where it's properly tightened, you're fine. I used my impact gun on my stock wheels for ages, no problems whatsoever.

My aftermarket wheels have special lug nuts that use a key - the key is relatively thin, and an impact gun would just break the tool. So, now I use a breaker bar for removal and a torque wrench to tighten.

Torque wrenches aren't that much - $30-40 at most parts stores for a basic one that clicks when you get to the torque setting. I use mine BIG TIME when it comes to re-assembling a motor - all the mission-critical fasteners are Loctite-d and torqued to spec.

Anyhow, I typically torque lugs to 85 ft-lbs - it's at the top end of the factory spec, but it's quite secure and I've been doing this on many cars for many years, works dandy.

Dale

 

Including Mazda dealers: every time I picked up my FD from the dealer (mostly back when it was still under warranty!), I re-torqued them because they usually were tightened to more than double the FSM max value.

 

What are some of the side effect of over torquing particularly on the wheels?

 

where i work we use a torque wrench on all nuts. there are specs for every vehicle. overtightening can be bad for brakes and all kinds of stuff ive heard it can damage wheels but havnt seen it. we zip them with an impact just till its on then torque when its dropped.

they also have torque sticks which wont allow your impact to exceed that amount of torque. i never use them myself but we have them.

i do mine on and off by hand. my nuts say dont use an impact on them, so i dont.

 

I've heard that overtorquing lugnuts contributes to brake rotor warpage. Considering the massive thermal stresses and dissimilar metals, it doesn't sound unreasonable.

More conventionally, overtorquing can lead to fastener failure. This is not as simple as a bolt snapping. In fact, bolts will permanently stretch before they break, and a bolt that is stretched from overtorquing will not have enough clamping force and will actually loosen and underperform compared to a properly torqued fastener.

I see guys who actually take a torque wrench and tighten them 'extra good' as if it will be more secure. They are sorely mistaken.

Also remember that FSM torques are for unlubricated fasteners. If the fastener has anti-seize on it, torque it *less* or don't use anti-seize at all. So for example exhaust manifold studs might be 35ft-lb per the FSM, but with anti-seize on them I would go no further than 25ft-lb.

Re: impact tools. I use an electric impact for lugnut work but never for final tightening. I spin them on slow with my impact to save time, but when I use my torque wrench there is always 1/4-1/8 turn before the wrench clicks. Impacts by nature are wildly unpredictable compared to a torque wrench.

Dave

 

After a local tire shop had a customer throw a tire on the freeway because of improper torquing, they ALL carry them on their hips everywhere they go...it's now part of their uniform to have a torque wrench because some dumbass wound them too tight and it snapped.

I always torque mine, and then even after doing so I still never trust myself so I double check.

 

Correct. When I do my tires ill zip them on with the gun and check then to 85lbs with a torque wrench.

 

If your going to work on your car you need to simply make proper torquing of nuts/bolts a matter of routine. I would never hand tighten any wheel/suspension nut/bolt. That can kill you! If you don't torque and engine bolt, maybe you blow your engine, but you don't die! I use a high quality, i.e., NOT Harbor Freight, torque wrench and torque my lugs nuts twice (once to tightness, second just to be sure I did it right.)

 

Sorry for bumping an old thread but im about to install my new wheels this weekend (my 3rd set of aftermarket wheels) and all of a sudden, torque the lug nuts has dawned on me.

I also have some rays engineering anodized lightweight lug nuts to spice things up.

Anyway my question is why would mazda recommend 66-86 ft lbs??

Do they give you a wide range just because of aftermarket wheel reason?

And would a high torque value cause a problem to my lightweight lugnuts?

I was gonna go half way and do 75 ft lbs.

 

With most torque wrenches, the accuracy is +/- 15%. Hence the 76+/- 10ft-lb. Aim for that mid range.

Your aftermarket lug nuts should handle the stress of 86 ft-lb no problem. It's the lug studs that would stretch first if the nuts were overtorqued.

Overtorquing results in a looser connection because the bolts stretch. Never do it.

Dave

 

I don't know anything about the Rays lug nuts but I did notice something in the OPs post (from a couple years ago) where he mentioned that the lugs didn't fit his wheels. There are two things to be sure of about your lugs nuts.
1) They obviously have to be threaded correctly for your lugs. This is pretty easy.
2) The lug nuts must fit the wheels. I don't know what it is called, but the head of the nut must fit perfectly with the depression in the wheel to receive the nut or you won't have a safe and secure fit.

Finally, centering rings don't hurt either.

 

Yes all my wheels came with preinstalled centering rings.

I also checked my lug nuts and the lug holes in my wheels. They match up, both with matching tapered ends to accept each other.

Not to mention my wheels are made by rays engineering so i would HOPE the lugs i bought from their company will work with their wheels lol

dgeesaman, that makes alot of sense. I never really worried about torque specs on my wheels but now with these light weight lug nuts (and they really are LIGHT, it feels like paper lol), i am concerned so i need to take all precautions.

So i guess ill do the halfway with like 75ft lbs.

Thanks

 

This might have been mentioned already....but over-tightening wheels can warp rotors. Most frequently done when using an impact to drill them on. Under-torquing can allow the wheel to loosen over time. Also not a good thing.

 

Nah i knew that. What i meant was the high torque value in general (75,80,90ft lbs) will cause any problem with a lightweight lugnut.

I mean i doubt it otherwise they wont sell them but this is the first time i actually held and will actually USE lightweight lugnuts on my car. So im a bit nervous. They are so light, you will be a bit nervous trusting only 5 of these little suckers holding your wheel on. I mean its like holding a lottery ticket haha.

 

Hey, sorry to bumps this thread again.

I've got a 2 part question. I'm swapping my water pump, so obviously want it to seal right the first time.

Part 1) Some bolts and nuts in the FSM, have numbers followed by units. Obviously I understand this to be the torque specs, newton meter, kg's f per centimter, and in pounds force. HOWEVER, other fasteners have 3 sets of number on them, but no units, and the numbers don't look right to be torque specs. What are these numbers?

Part 2) I'm unable to find a small enough torque wrench. I can find the large wheels ones, that start at like 30 ft lbs. For engine work, i'm looking for something that starts at 40 inch pounds, or something like that. Can someone point me to a good wrench?

 

----> http://www.sears.com/shc/s/p_10153_12605_00944593000P

 

I use a cross wrench. My arm doubles as a torque wrench.

 

Also note that some of the Units of measure that are in the FSM are NOT LB/FT but are instead INCH/FEET - much lower value that totally screwed me up when I was installing the water pump.