Had a change of heart on using a torque wrench for lugnuts after what I heard from the old guy at the shop

I used to just crank lugnuts with my impact gun and call it good. I've been doing that for like 15 years on my own rigs. But last week I was at a TA in Oklahoma and this old diesel mechanic was telling a story about a wheel coming off on the highway because someone overtightened and warped the rotor. He said something about how the rotor acts as a heat sink and if you squeeze it unevenly, it cracks over time. That got me thinking about all the brake jobs I've done and never torqued to spec. So now I grab my torque wrench for every wheel I touch, even on my personal truck. Has anyone else had a rotor crack from overtorquing?

3 comments

3 Comments

the_wendy1mo ago

Man, that "heat sink" thing really got me too. I was the same way for years, just zipping them on with the impact and never thinking twice. I figured if it was tight, it was tight enough. Then I saw a buddy snap a stud on the side of the road and had to wait hours for a tow, and that made me start wondering. That story about the rotor cracking because of uneven pressure is exactly what made me dig out my torque wrench for good. It's such a small extra step but it saves you from a world of headache down the road.

charlescraig1mo ago

Well, I have to say I'm a bit skeptical about all this. I've been turning wrenches for close to 40 years now and I've never had a rotor crack from lug nut torque. I think people get worked up over things that are pretty rare. Frankly, @the_wendy, I've seen more problems from guys who over-torque things with a torque wrench than I've ever seen from someone using an impact carefully. A good impact set to a lower setting and a final snug by hand has always worked fine for me.

spencer7821mo ago

Isn't that how most stuff goes though, one bad experience and you change your whole approach?