Trailer tires

[Hartley]

I am going through a lot of tires on my tri axle stacker. I may possibly have an axle alignment issue. Constantly blowing new tires on right curb side. Carrying anout 14,000 total gross, well within the 21,000 pound range. I have torsion axles and I am told they are a pain to re- align. I have been running Good Year radials with an E rating. Does any one have any ideas? I am pricing F and G rated tires and hoping I can get some reliability back. Also looking for an alignment shop that will do a trailer alignment and looking at a set of tire minders.

[DaveW]

Is it always the same tire location? If so you may have an overloading issue caused by trailer tilt front-to-rear, or a problem with one or more of the axles having a rubber torsion spring issue.

Do you see severe wear on the tire that fails? If not, the issue is probably not the usual unequal alignment angle from trailer center-line issue.

The other thing that causes failures on 3-axle trailers is scrubbing the tires severely in tight turns - that also should be evidenced by severe shoulder wear or peeling off of the tread on the shoulder.

[Nardi]

If the issue is always on the right hand side it might not be the tires fault. Perhaps they are taking abuse by falling off the pavement. That is the ' blind' side of the rig after all.

[Hartley]

Is it always the same tire location? If so you may have an overloading issue caused by trailer tilt front-to-rear, or a problem with one or more of the axles having a rubber torsion spring issue.

Do you see severe wear on the tire that fails? If not, the issue is probably not the usual unequal alignment angle from trailer center-line issue.

The other thing that causes failures on 3-axle trailers is scrubbing the tires severely in tight turns - that also should be evidenced by severe shoulder wear or peeling off of the tread on the shoulder.

Thanks Dave. No severe wear, however the tires are almost new so hard to tell and there is not much left to look at. I just put a straight edge across the 3 tire bad side and there is definitely toe issues on one or more wheels. I just got off the phone with several alignment shops and no one wants to work on Dexter torsion axles. I then phoned Dexter directly and they said it could be a bent axle and there is no fixing them, they just replace them at $800 a pop. At the rate I am going through tires the new axle is not sounding that expensive, just the time and work involved!

[BeerBudgetRacing]

Thanks Dave. No severe wear, however the tires are almost new so hard to tell and there is not much left to look at. I just put a straight edge across the 3 tire bad side and there is definitely toe issues on one or more wheels. I just got off the phone with several alignment shops and no one wants to work on Dexter torsion axles. I then phoned Dexter directly and they said it could be a bent axle and there is no fixing them, they just replace them at $800 a pop. At the rate I am going through tires the new axle is not sounding that expensive, just the time and work involved!

Do all axles have brakes? Is one locking up? or dragging?

Can you drive down the road for 5 minutes and use a pyrometer and check each tire temp?
Check the hub temp too with an infrared meter. Maybe it's doing something weird at speed.

I've seen people pull a pair of tires and run 2 axles when running light...

[J Leonard]

Any scales you could run across and check each axle load? I found that on my 24 foot two axle when absolutely level the front axle had 1000 lbs more load. Torsion axles with consecutive serial numbers. You might also check with just a welding shop for straightening the axles.

[DaveW]

Is it always the same tire location? If so you may have an overloading issue caused by trailer tilt front-to-rear, or a problem with one or more of the axles having a rubber torsion spring issue.

Thanks Dave. No severe wear, however the tires are almost new so hard to tell and there is not much left to look at. I just put a straight edge across the 3 tire bad side and there is definitely toe issues on one or more wheels. I just got off the phone with several alignment shops and no one wants to work on Dexter torsion axles. I then phoned Dexter directly and they said it could be a bent axle and there is no fixing them, they just replace them at $800 a pop. At the rate I am going through tires the new axle is not sounding that expensive, just the time and work involved!

Any scales you could run across and check each axle load? I found that on my 24 foot two axle when absolutely level the front axle had 1000 lbs more load. Torsion axles with consecutive serial numbers. You might also check with just a welding shop for straightening the axles.

Great suggestion from J Leonard - severe overloading will kill tires w/o much in the way of external signs, other than a bit more deflection on the overloaded one.

[Hartley]

Great suggestion from J Leonard - severe overloading will kill tires w/o much in the way of external signs, other than a bit more deflection on the overloaded one.

Great ideas guys! Are commercial scales narrow enough to weigh each axle individually? I think my next move is to string the trailer same as the race car. Using a reference line parallel to the trailer box sides should tell me which tires are out of line in toe. Then with a sketch it should be easy to determine if one of the axles is bent. I currently have 10 ply E rated tires. I am also going to install a Tire Minder system that gives constant temp and pressure read outs and alarms when deviation occurs.

[Jim Edmonds]

CAT Certified Automated Truck Scale(s) typically have three scale pads. I've been told by a CAT traveling maintenance technician that there are 5 load cells per pad (unverified). I've been using them for years on my box and stacker trailer. You can put one trailer axle on one pad and the other two axles on the adjacent pad. Do that twice and you have each axle's load weight. Not worth doing unless the trailer is fully loaded. My experience is that the weights are pretty good. I have changed the relative axle weights by just running the truck air bags up or down. The scales are usually good enough that the off-center load of the axles being on the edge of the scale pad doesn't significantly affect the accuracy.

After you have that data, check the load rating on the tires. I plan on not being over 70% of the maximum rating of the tire on each axle . . . but we tow 75+ in the heat of the Arizona desert. If you are over 80% of the maximum load rating you can expect problems in the long run. My opinion. YMMV. . . but I don't have failures.

The pressure/temperature monitors are a good idea. I had the valve stem type in a prior trailer, that I couldn't get high enough load rating tires for, and they worked.

Almost all trailer manufacturers put on too low load rated tires to meet a price point. If you can't get higher rating tires you'll need to upgrade the axles and wheel sizes. I did that on my current stacker.

Before a long trip I often go to the local scales and check the separate axle loads. At $10.50 per weighing for 3 weights, it's a cheap way to check your load balance.

Failures on only the right side could be road camber moving the high CG weight to the right, but that may be a stretch.

As always, don't believe anything I say. Verify it for yourself, Ha.

Jim

[Purple Frog]

Dual axle trailers with leaf springs have a way of evening out the load because of the "rocker" in the middle shared by the two springs.
With three axles and they being torsion it is a bit trickier.

It may not be alignment at all.

My first question would be which tire is failing first?
I'm guessing it could be a hitch height problem.
If you are towing with the front of the trailer low, you may be overloading the first tire.
If the front is high, you may be overloading the rear (third) tire.
That is why putting the loaded trailer on scales is a good measure.

If you try to do a string alignment check. Make sure you pull the loaded trailer straight for at least 50' before carefully stopping. Then measure. Even a long straight 2x4 up against the tires at axle height will give you a quick view. I would do that even before going to the scales. I found a bent axle on my tandem using that method. ( I still don't know how that tree got out in the middle of the driveway. )

I suspect that with that big of a trailer those right side tires are getting driven off the road more often, bouncing on curbs, and hitting potholes much more than the left side. And with road camber, they are carrying more than 50% of the weight. Just saying.

[Hartley]

Dual axle trailers with leaf springs have a way of evening out the load because of the "rocker" in the middle shared by the two springs.
With three axles and they being torsion it is a bit trickier.

It may not be alignment at all.

My first question would be which tire is failing first?
I'm guessing it could be a hitch height problem.
If you are towing with the front of the trailer low, you may be overloading the first tire.
If the front is high, you may be overloading the rear (third) tire.
That is why putting the loaded trailer on scales is a good measure.

If you try to do a string alignment check. Make sure you pull the loaded trailer straight for at least 50' before carefully stopping. Then measure. Even a long straight 2x4 up against the tires at axle height will give you a quick view. I would do that even before going to the scales. I found a bent axle on my tandem using that method. ( I still don't know how that tree got out in the middle of the driveway. )

I suspect that with that big of a trailer those right side tires are getting driven off the road more often, bouncing on curbs, and hitting potholes much more than the left side. And with road camber, they are carrying more than 50% of the weight. Just saying.

Thanks Frog. I think you might be onto something. It is the front right and I may be slightly low on the tongue height. However the toe is definitely off as well. I bought the trailer almost new but had it towed from Nevada before I got it. No telling how many curbs got clipped along the way. So I could have a bent axle. Is it realistic to straighten the axle? I image it would have to be removed to straighten it. Still looking for the perfect shop that will take on the project. I have a good sized shop with torches etc. I may have to try and fix it myself.

[Purple Frog]

Are not those torsion axles bolted onto the frame of the trailer. Surely they are not welded to the frame.

If welded. You'll have to cut them off. Grind everything flat. Then build jigs to space the new axle correctly. I have cut two pipes the same length and then tacked them to the next axle to keep it all lined up while welding.

If bolted on, it would be as simple as figuring out which is bent, ordering a new one and changing it out.

Basically because of its mechanism you can't straighten a bent torsion axle. Or, maybe i should say, you could, but the juice isn't worth the squeeze.

Be real exact with the measurement of the axle length. You can study up online how to measure. With torsion axles you also need to know the preset angle of the trailing arm. They come set in different angles. You might find that marked on the axle. OBTW, you may not get free shipping on Amazon Prime.

I changed mine myself.

Your situation may be a result of too low a hitch height, and a history of striking "stuff" with the leading tire.

If it is a tag trailer, you can purchase an adjustable hitch to get the ride height closer to optimum. Fifth wheel hitches can be adjusted also.

[BeerBudgetRacing]

If bolted on, it would be as simple as figuring out which is bent, ordering a new one and changing it out.

Can you shim the mount to straighten it out? if the frame is not straight, a new one will be the same.

[Hartley]

Are not those torsion axles bolted onto the frame of the trailer. Surely they are not welded to the frame.

If welded. You'll have to cut them off. Grind everything flat. Then build jigs to space the new axle correctly. I have cut two pipes the same length and then tacked them to the next axle to keep it all lined up while welding.

If bolted on, it would be as simple as figuring out which is bent, ordering a new one and changing it out.

Basically because of its mechanism you can't straighten a bent torsion axle. Or, maybe i should say, you could, but the juice isn't worth the squeeze.

Be real exact with the measurement of the axle length. You can study up online how to measure. With torsion axles you also need to know the preset angle of the trailing arm. They come set in different angles. You might find that marked on the axle. OBTW, you may not get free shipping on Amazon Prime.

I changed mine myself.

Your situation may be a result of too low a hitch height, and a history of striking "stuff" with the leading tire.

If it is a tag trailer, you can purchase an adjustable hitch to get the ride height closer to optimum. Fifth wheel hitches can be adjusted also.

Yes it is a tag and the axles are bolted on. The hitch ball does have adjustable height. I think I will take some good measurements with strings to find the ‘offending’ axle. Then I think a lot can be gained by weighing each axle. It is also possible that I just have too much tongue weight. Do you think higher rated tires such as F or G might help as well?

[Hartley]

Can you shim the mount to straighten it out? if the frame is not straight, a new one will be the same.

Not sure but would it not depend on which direction the axle is bent?

[J Leonard]

If there are three torsion axles. Trailer is level with ground. Total weight of trailer is 7000 lbs. 1000 lbs of tongue weight. How much weight is carried on each axle?

[BeerBudgetRacing]

If there are three torsion axles. Trailer is level with ground. Total weight of trailer is 7000 lbs. 1000 lbs of tongue weight. How much weight is carried on each axle?

Depends on the position of the axles on whether the weight is distributed evenly.

Tire and axle temps will tell you which are loaded and which aren't.

[xmazdatracy]

I have heard this story a bunch. Put me in for $20 on a bent axle. If it were a overloaded axle it would be two blown tires, if the axle was misaligned it would be two blown tires. Up-ing the belt count will not over come the heating you are putting to that tire. If you are blowing the same position tire then you know which axle it is. If its randomly all three on that side then the trailer might have seen some horrible impact, and all three axles may need to be replaced.

After fixing this situation get yourself fully loaded (truck and trailer (dont drink and drive)) and get yourself weighed. Everyone should. A dry weight is nonsense. Fill your gas tanks, fresh water tanks, extra wheel sets, wife, dogs, kids, ect... you would be amazed at how many people overload and over drive tires. Also dont feel bad replacing a bent axle. Dropping that side of the trailer off the side of the road at high speed is kinda easy to do. Thats why they sell axles. There definitely are trailer repair shops out there that can do this, but it is not a hard job to do.

Good luck!

[Steve Davis]

Hartley,
I spent quite a few years blowing 3 or 4 tires per season .. sometimes 2 at a time. After trying all kinds of things .. including upgrading the axles from 3500 to 5200 and thusly the tires, Court Dowis finally suggested that I try LOWERING my tire pressures, and it WORKED.

Seems the "always check your tire pressures COLD" is totally FALSE! Might be fine for a street car, but NOT on motorhomes or trailers. I installed a tire pressure monitoring system like you have plans for and found that an E rated tire with a specified 85 PSI 'cold tire pressure' rating goes up to something around 100 PSI on the highway.. or higher in the summer heat. That additional pressure is more than enough to cause the 'gator' to delaminate from the carcass and cause blowout after blowout. Although Court suggested 45 PSI, I opted to run 55-60 on my tires and have had ZERO trouble in the last 5 years. The tires get up to around 73 or 75 on the hottest days and usually run around 65-68 on most trips (using TPMS numbers). With TPMS, you will be able to determine exactly (more or less) how high the pressures are going. Adjust your cold pressures to make certain that you do NOT exceed that 'Max Inflation Pressure' number under any type of conditions.

Obviously, you might very well still have a bent axle (or 2) so that takes precedent, but drop those pressures and I think you'll be surprised. The trailer will also ride much softer for what's inside. As a result of all these findings, I have also dropped my pressure on my motorhome about 25 lbs for a much better ride there too. TPMS is WONDERFUL to have.

[Purple Frog]

Hartley,

The adjustable hitch i was refering to is one that fits into your receiver and allows you to raise or lower the ball height.

[Jim Edmonds]

All the above comments are great. First collect data. Scale the separate axle weights fully loaded.

From your 21,000 pound load rating I suspect the trailer has 235/80-16 tires 10ply rating LRE which are about 3500 pounds maximum each. Trailer manufacturers typically assume perfect loading for the rating. If the trailer is loaded perfectly the tires should be OK for your 14,000 pounds.

Collect the load data. Given 235/80-16 tires, and if each axle is under about 7000 pound x .75 = 5200 pounds then the tire size is OK. If not change the load positioning or change the tongue height as suggested above and re-weigh. Like with race cars, scales are your friend.

If the axle loading is in the ball park then look for a different assignable cause with the many good suggestions above.

If you can't find an assignable cause, the final resort is to have 17.5" wheels made for your bolt pattern and go to 215 x 17.5 tires with a 4800 pound load rating per tire. They have very close to the same height and width as the 235/80-16's. Expensive but solves the problem forever, assuming you don't have a geometric problem with the axles.

Tell us what the scales say. 8^)

You have me thinking about side to side weights. I think I'll look at the local Love's truck stop CAT scales and see if the pavement to the side of the scales is level enough to only put one side of the rig on the scales.

Have fun, Jim

[Hartley]

Hartley,

The adjustable hitch i was refering to is one that fits into your receiver and allows you to raise or lower the ball height.

Yes that is what I meant Frog.

Great ideas guys, thanks alot for your decades of experience! I have a 4 point plan:

Determine if axle is bent if so replace.
Scale the trailer
Install tire minders
Definitely drop my cold tire pressure. I was running 70 psi cold.