Sheared Lugs
New to this forum. It is winter but in a few months it will be time to go get the camper out of storage. My last camping outing was ended abruptly and I can't stop thinking about it. I was towing i...
Forum Discussion
Our son works for the state and pulls a 30ft v nose. A few years ago another co worker was towing it after the motor pool repaired a tire with a slow leak nand He lost the wheel they had removed and reinstalled somewhere. When he stopped for gas and was missing a wheel and all the lugs were sheared off.
Motor pool analysis: They did NOT tighten the lug nuts to enough torque. course co worked hadn't checked torque after a few hundre miles. Coupled with lug centric wheels, not hub centric= likelyhood of sheared lugs. Hubcentric wheels only require the studs to take lateral (side-side) load, the hub takes all the vertical load. with lug centric wheels the lugs must support vertical and lateral loads, so if a stud is the least bit loose as the tire rotates the lugs get hammered every revolution. there is always a slight amount of clearance around the lug in the wheel. And if it is a steel wheel, which his were, all the force against the stud is in a very concentrated narrow area on the stud.
BTW motor pool confirmed that virtually all trailers have lug centric wheels. And all the cars and light trucks are hub centric. Virtually no lug centric wheels on cars and light trucks anymore.
One clue for lug centric wheels is center caps that go through the hub and are a loose fit. Therefore the lugs take all the load.
Hub centric wheel center caps, if they are used, attach from the outside. they can't go through the hub since it is (a) very tight tolerance and (b) the load bearing surface
Motor pool analysis: They did NOT tighten the lug nuts to enough torque. course co worked hadn't checked torque after a few hundre miles. Coupled with lug centric wheels, not hub centric= likelyhood of sheared lugs. Hubcentric wheels only require the studs to take lateral (side-side) load, the hub takes all the vertical load. with lug centric wheels the lugs must support vertical and lateral loads, so if a stud is the least bit loose as the tire rotates the lugs get hammered every revolution. there is always a slight amount of clearance around the lug in the wheel. And if it is a steel wheel, which his were, all the force against the stud is in a very concentrated narrow area on the stud.
BTW motor pool confirmed that virtually all trailers have lug centric wheels. And all the cars and light trucks are hub centric. Virtually no lug centric wheels on cars and light trucks anymore.
One clue for lug centric wheels is center caps that go through the hub and are a loose fit. Therefore the lugs take all the load.
Hub centric wheel center caps, if they are used, attach from the outside. they can't go through the hub since it is (a) very tight tolerance and (b) the load bearing surface
