Interesting development regarding PDI - U-bolts

[Art-n-Marge]

I would have to agree. The center pint does NOTHING weight bearing but hold the leafs in place and then after the leaf spring pack is installed it's the end points with all the stress. Sure the pin must have some lateral stresses but nowhere near what the ubolts are experiencing.

From IRLP: "Once they are torqued to the proper spec we should not have to worry about them again. Same goes for our lug nuts. I had all new tires put on and although they were torqued to 120 lbs by the dealer when the tires were installed, and I was told to bring the unit back and have them rechecked after I had 100 miles or so on them, I will check them after about 100 miles and I won't likely concern myself with them again unless I have to remove a wheel."

I DO NOT agree all with this. As I've read and heard, the torque MUST be checked on a trailer much more often than your vehicle, which is why there are plenty of notices to check the wheel torque very often. Unlike a vehicle with either very engineered steering methods and differentials, a trailer has NONE Of this. The tires are under extreme streeses on ANY turn. If you have not noticed take a look at your trailer tires on a turn. They are NOT straight up and down any more and those lugs must be going through some pretty good stress. They are at some off-angle than exactly perpendicular to the road. It's these stresses that require us to recheck the torque. I agree the vehicles (TV) do not need to be checked as often and you'll be okay for months. A trailer's ubolt torque should not have to be checked, but I wonder if these same turning stresses warrant it. I do only check every 12 to 18 months and they've remained solid, the trailer lug's too, but I don't tow nearly as often so sitting still shouldn't affect much and they are pretty solid, too and I will check prior to any trip.

When I towed commercially, this was a requirement to check and recheck torque often and some of these trailers had a hard time holding torque.

 

[h2ojocky]

I checked my U-bolts and all of them were not at required torque. Many needed at least a half turn. I feel better knowing that are good now!

 

[Irlpguy]

quote:Originally posted by Art-n-Marge

I would have to agree. The center pint does NOTHING weight bearing but hold the leafs in place and then after the leaf spring pack is installed it's the end points with all the stress. Sure the pin must have some lateral stresses but nowhere near what the ubolts are experiencing.

From IRLP: "Once they are torqued to the proper spec we should not have to worry about them again. Same goes for our lug nuts. I had all new tires put on and although they were torqued to 120 lbs by the dealer when the tires were installed, and I was told to bring the unit back and have them rechecked after I had 100 miles or so on them, I will check them after about 100 miles and I won't likely concern myself with them again unless I have to remove a wheel."

I DO NOT agree all with this. As I've read and heard, the torque MUST be checked on a trailer much more often than your vehicle, which is why there are plenty of notices to check the wheel torque very often. Unlike a vehicle with either very engineered steering methods and differentials, a trailer has NONE Of this. The tires are under extreme streeses on ANY turn. If you have not noticed take a look at your trailer tires on a turn. They are NOT straight up and down any more and those lugs must be going through some pretty good stress. They are at some off-angle than exactly perpendicular to the road. It's these stresses that require us to recheck the torque. I agree the vehicles (TV) do not need to be checked as often and you'll be okay for months. A trailer's ubolt torque should not have to be checked, but I wonder if these same turning stresses warrant it. I do only check every 12 to 18 months and they've remained solid, the trailer lug's too, but I don't tow nearly as often so sitting still shouldn't affect much and they are pretty solid, too and I will check prior to any trip.

When I towed commercially, this was a requirement to check and recheck torque often and some of these trailers had a hard time holding torque.

Art not to argue with you at all but you missed one fairly important part of my original post and that was "I am not recommending anyone do as I do, just saying."

For about 30 years I owned an equipment rental business, we had many pieces of equipment that had their own axles and wheels, we also had two tandem axle trailers that we hauled equipment onto job sites and over thousands of miles on daily deliveries. The "only" time the wheel nuts were torqued on any of these wheels was when a tire was changed. In those 30 years I never had a problem with either the U-bolts or the wheel lugs coming loose. I understand and know all about the stresses our RV wheels are subjected to, they are no greater than on those tandem trailers I had, and I will not loose any sleep over them once they have been properly torqued after being run for a few miles.
I have yet to read in any thread where a wheel has come off of one of these RV's because the nuts were not torqued. What I have seen personally was every wheel lug break off a SOB because they had been over tightened, likely by some over exuberant tire person or delivery driver without a torque wrench.

I will say it again "I am not recommending anyone do as I do, just saying." and add "there is such a thing as overkill".

 

[Tom S.-MOC]

quote:Originally posted by Irlpguy

quote:Originally posted by Art-n-Marge

I would have to agree. The center pint does NOTHING weight bearing but hold the leafs in place and then after the leaf spring pack is installed it's the end points with all the stress. Sure the pin must have some lateral stresses but nowhere near what the ubolts are experiencing.

From IRLP: "Once they are torqued to the proper spec we should not have to worry about them again. Same goes for our lug nuts. I had all new tires put on and although they were torqued to 120 lbs by the dealer when the tires were installed, and I was told to bring the unit back and have them rechecked after I had 100 miles or so on them, I will check them after about 100 miles and I won't likely concern myself with them again unless I have to remove a wheel."

I DO NOT agree all with this. As I've read and heard, the torque MUST be checked on a trailer much more often than your vehicle, which is why there are plenty of notices to check the wheel torque very often. Unlike a vehicle with either very engineered steering methods and differentials, a trailer has NONE Of this. The tires are under extreme streeses on ANY turn. If you have not noticed take a look at your trailer tires on a turn. They are NOT straight up and down any more and those lugs must be going through some pretty good stress. They are at some off-angle than exactly perpendicular to the road. It's these stresses that require us to recheck the torque. I agree the vehicles (TV) do not need to be checked as often and you'll be okay for months. A trailer's ubolt torque should not have to be checked, but I wonder if these same turning stresses warrant it. I do only check every 12 to 18 months and they've remained solid, the trailer lug's too, but I don't tow nearly as often so sitting still shouldn't affect much and they are pretty solid, too and I will check prior to any trip.

When I towed commercially, this was a requirement to check and recheck torque often and some of these trailers had a hard time holding torque.

Art not to argue with you at all but you missed one fairly important part of my original post and that was "I am not recommending anyone do as I do, just saying."

For about 30 years I owned an equipment rental business, we had many pieces of equipment that had their own axles and wheels, we also had two tandem axle trailers that we hauled equipment onto job sites and over thousands of miles on daily deliveries. The "only" time the wheel nuts were torqued on any of these wheels was when a tire was changed. In those 30 years I never had a problem with either the U-bolts or the wheel lugs coming loose. I understand and know all about the stresses our RV wheels are subjected to, they are no greater than on those tandem trailers I had, and I will not loose any sleep over them once they have been properly torqued after being run for a few miles.
I have yet to read in any thread where a wheel has come off of one of these RV's because the nuts were not torqued. What I have seen personally was every wheel lug break off a SOB because they had been over tightened, likely by some over exuberant tire person or delivery driver without a torque wrench.

I will say it again "I am not recommending anyone do as I do, just saying." and add "there is such a thing as overkill".

You are comparing steel wheels with aluminum. When a steel wheel is torqued, it stays torqued. When an aluminum wheel is torqued for the first time, the steel lug nut compresses the aluminum. That is why it is recommended they be re-torqued. However after the first time, the aluminum shouldn't compress anymore, so re-torqueing a wheel that has been changed or removed for maintenance should not be required. However you will still hear from people you should re-torque every time, which I believe is nothing more than CYA.

As for U-bolts, once torqued and the bolts properly stretched, they should never need re-torqueing. If they are loosened for any reason (replacing a spring or axle) they should be replaced.

 

[richfaa]

We have had the experience of changing tires on the 06 3400, Steel wheels and the 2013 3402 Aluminum wheels. On the steel wheels once we did the check as 25,50 and 100 miles they remained at torque and we did check them twice a year after that. One we torqued the U bolts they also remained at torque.

On the 2013 we unfortunately had the experience of changed out tires. We had the same experience and they have remained at torque, same with the U bolts.

 

[Golferdave]

Hey Guys:
Just to add my 2 cents worth. I torgued the lug nuts to 110 lb and the U bolts to 65 lb. I check the lug nuts every trip. I have also checked the U bolts on 2 other MOC trailers and both required tightening. An interesting point also was during a safety check at a dealers the techie torqued the lug nuts to only 90 ( or so it said in his report ) On my check I retorgued them to 110 lb. This is from the information on the forum and according to Keystone.

 

[WaltBennett]

I tend to think along the lines of Tripguy, but with the caveat that I CYA with at least one check after putting miles on a first torque. I think the problem with U bolts (and lots of others people have found) is that they were probably torqued once on assembly - maybe even without the axles and springs being attached to a trailer much less any weight on them - and never checked by a dealer or anyone else afterwards. I also don't trust any tire place to do anything more than running their air gun until the nut stops turning. I've never, ever seen one of those places use a torque wrench.

 

[Recumbent-MOC]

Our Montana U-bolts were torqued to about 45 lbs. It appeared that there had been no movement when I did get around to checking them, and all got torqued to 60 lbs.

 

[scott-pati]

My 3402RL was built on 8/15/13. I just checked and torqued the U-bolts to 60 lbs. Only 3 were correct, the others were way loose.