dual axle trailer wearing one tire excessively

bob johnson

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Feb 25, 2009
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I rebuilt my dual axle trailer.. I bought two new axles , two new sets of hubs and new springs, and bushings and bolts. ought 2 new tires and used a pair od oldies that were lying around...just to get it set up... I have taken only two trips with the boat and trailer rigged up. about 300 miles max..... I am getting scupping on my new tires and one of the older tires that had very little tread is just about completely bald in just 300 miles.... the spring mounts are on a sliding bracket that allows you to adjust the axle placement to set up tounge weight. so there is ONLY the few holes to choose from and you can easily tell if one side is off a complete set of holes!! (that's like 12" or more). the only thing that is different is the equalizer... the originals were shot and the parts place didn't have the exact style....so I replaced with something close. On the last trip I specifically made sure the tire pressure was equal all around......so why am I shaving rubber off the tires so fast???

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bob
 

oldjeep

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Do your equalizers sit like that at ride height with trailer attached to truck? If so then your hitch is too high or too low and you are putting a lot of load on one set of the tires.
 

bob johnson

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ok to answer Bad dog..... there doesn't seem to be a way to ADJUST alignment... the axles bolt to the bracket and the bracket slides only to be in place when the bracket aligns with holes in the frame...UNLESS the frame is twisted or bent!!

OLDJEEP:....so you might be saying that my receiver ball is al the wrong height?.........when I installed those springs and hangers... they would flip upside down in either direction ON THEIR OWN.....with no boat on the trailer... if that is what you are saying.... you suggest I lower the receiver ball height??

bob
 

Silvertip

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The purpose of using equalizers is two-fold. 1) One axle does not unload or load more or less with raising or lowering the hitch ball. The entire load is placed at the pivot on the equalizer. 2) The equalizer lets each wheel step over bumps and go through dips without excessive one-wheel loading. This is very different than tandem torsion suspensions where you can actually overload an axle on depressions, driveway entrances and running tongue high or tongue low for example. It's all geometry and physics to you need to wrap your head around it a bit. I agree with others through -- alignment is likely one issue while excessive skidding when turning is another.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Question #1 what is the load on the trailer, and what are the axles rated at?

Question #2 - to you do a lot of turning, or backing and turning?

Question #3 - step back about 30' and take a picture of the boat, trailer, and truck so we can get some perspective. the photos are basically of the bark of the tree, we cant see the forest.
 

MH Hawker

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to eliminate alignment measure from the ball goes into the receiver to the front of the front set of tires
 

bruceb58

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Unless the equilizers hit their limits, the load on each wheel will be identical. Still should try to get the trailer level but that is not your tire wear issue.

I would be measuring alignment as well. There may be a bent axle involved here.
 

StarTed

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Measure from center of hub to center of hub on each side. They should be the same.

If the distance from the ball to the center of the front hub on each side is not the same the trailer will travel down the road to one side. A bigger problem will be the axles not being parallel. A bent axle is also a possibility. A camber check can show that for a bend up or down. A bend front to back can be checked with a straight edge on the hubs with the bearing covers off.

Good luck.
 

bob johnson

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ill check....I don't do much turning over normal....boat ramps require lots of turning and backing... I do know that the trailer probably does sit unlevel when hooked to the truck.. it is slightly pointing upwards in the front.....ill try and take a picture of it set up after work today..i can use another receiver adapter...

ill also measure... the axles are new...everything is new!

BOB
 

Silvertip

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Axles are cambered, meaning they have a slight upward bend in the middle. This is why one needs to pay attention to over-slung or under-slung mounting of the axle. If an axle is ordered for installation on top of the spring but the axle ordered is for mounting below the spring, it would be possible to have the camber bend facing down rather than up. If the axle has the spring center bolt holes both on top and bottom of the axle then this wouldn't be a problem because the axle can be installed either way. However, if the axle is drilled for only one installation, it would be possible to flip the axle and end up with incorrect camber. You can check this by standing well back of the trailer, squat down and look carefully at the very center of the axle. If the bend is upward you are good to go. If it is facing down, the axle is flipped. I still feel however, that alignment or bent spinidle is the issue. Measure very carefully between the centers of the front and rear wheels for the same dimension on both sides. Then measure from the front wheel to the center of the coupler on both sides. Any significant differences between sides indicates alignment issues. For most accurate measurements, remove the wheels and hub covers so you can measure at the very center of the spindle. If a different length spring(s) were installed at some point, that could create an alignment issue. You might even check for a broken spring leaf or two. A broken main leaf can certainly affect axle position yet be hard to see because they usually break at the center bolt hole.
 
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bob johnson

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Axles are cambered, meaning they have a slight upward bend in the middle. This is why one needs to pay attention to over-slung or under-slung mounting of the axle. If an axle is ordered for installation on top of the spring but the axle ordered is for mounting below the spring, it would be possible to have the camber bend facing down rather than up. If the axle has the spring center bolt holes both on top and bottom of the axle then this wouldn't be a problem because the axle can be installed either way. However, if the axle is drilled for only one installation, it would be possible to flip the axle and end up with incorrect camber. You can check this by standing well back of the trailer, squat down and look carefully at the very center of the axle. If the bend is upward you are good to go. If it is facing down, the axle is flipped. I still feel however, that alignment or bent spinidle is the issue. Measure very carefully between the centers of the front and rear wheels for the same dimension on both sides. Then measure from the front wheel to the center of the coupler on both sides. Any significant differences between sides indicates alignment issues. For most accurate measurements, remove the wheels and hub covers so you can measure at the very center of the spindle. If a different length spring(s) were installed at some point, that could create an alignment issue. You might even check for a broken spring leaf or two. A broken main leaf can certainly affect axle position yet be hard to see because they usually break at the center bolt hole.

well both axles have the same part #, but were ordered about a year apart. The first one sat under the trailer in the yard until I started to work on the boat.. then eventually I bought the second axle... they were drilled by me to clear the bolt head on the springs..... I cant remember exactly how that went down...but I do know that most axles have a camber..... so I am thinking I would have thought about that...but now in recollection... I cant remember going through that thought proicess when I was installing the second axle... ill check for that as well and remove the tires and hubs and do some measurements to the ball receiver....

this would be an easy fix...and simple...I am hoping for it to me my issue!!!


bob
 

bob johnson

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so I got home today and pulled the trailer onto level ground and went about checking...as it turned out the frame along the span over the axles was just about perfectly levelwhen the receiver was on the ball of the truck!! so then I pulled the wheels to have a look... the axles have NO CAMBER...flat and straight as can be just sitting on the springs.

BUT I could see that the springs were not mounted the same on both sides! there is a clasp that holds the leafs together on one side of the springs... and the mount bolt that's also holds the leafs together is NOT in the center...well I see that the clasps are close to each other on one side IE the clasp are both close to the equalizer...on the other side both clasp were towards the front!!! thus there is a 3/8th" difference in the center to center dimensions of the axles from one side to the other.....

is 3/8ths " enough to cause a lot of issues??

aslo the equalizer can pivot...but not freely...I can move it with a blow of a 20 oz hammer....(with no tires on the hubs and axles hanging in the air)


bob
 

StarTed

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3/8" is too much.

I have a flat bed equipment trailer that had that problem and was wearing out tires. I flipped it over with my backhoe and cut off two spring mounts and welded them back on much better. Now the difference is less than 1/16" and the tires wear much better.

By the way, new tires don't wear as fast because the tread is deeper and will flex more to compensate. As they wear down they'll begin wearing faster.

I think you found your biggest problem.
 

bob johnson

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here is each side , you can see the clasp should be going the same way for the spring to be mounted the same front and back axle......on one side they are close to each other!!! don't know how I missed that....I think I had asked here is it matter if the short end was on the front or the back, when the springs are mounted.... since the spring is not symmetrical!!!!!

anyway its good to find an obvious problem....


PS.... should the short ends of each spring face each other, face the same way or face away from each other???

bob
 
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Idlespeedonly

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The clasp that you are referring to is there just to keep the spring leafs aligned, nothing more.
The fact you said you had to drill the axle for the locating pin can be a problem if not centered properly.
The first measurement i would take is the distance from the grease fittings on the spindle. and compare that with the other side.
This will tell you if the axle is parallel.
The equalizer will need to be level also.
 

Thalasso

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If your referring to the clamp on the spring package, all mine face to the rear of trailer. (i have a triple axle)
Your first picture is like mine. Maybe change the springs around in second picture to be the same as the first pic

The spring half lengths will be diff if there mounted opposite then the other side. here is a video that gives you an idea

https://youtu.be/uUepz7MDdqk

this will will tell you if the axle is parallel.

 
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bob johnson

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update. I found a few things out of whack for sure once I delved into troubleshooting. I guess I got a little lazy and complacent when I assembled this trailer. I assuemed it was clear cut because the axles mount to a sub frame with fixed hole spaceing.... but it is possible the tounge might be crooked...because the eyebolt for the front spring mount was off in length to the ball from one side to the other about 1/4". Plus I drilled the holes in one axle poorly....one hole was off center by about a 1/6th ( 1/8th total difference ) PLUS it was about 1" closer to the end of the axle than the other three holes !!!!!!!!!!!!!!!( both axles)....don't know what happened there!!!...so since the axles are flat with no camber..i just flipped and redrilled mount holes.... with care... I originally used 1/2" galvanized bolts to hold the subframe to the frame, which didn't fit, because all the holes were about 7/16th dia...so I opened them up....resulting in zero adjustability at each setting... to solve the side to side mount difference I used 3/8th galvanized bolts instead and forced one side upwards and the other side backwards to get an even measure...then I bolted up tight and then drilled a pair of tight fitting holes on each subframe and bolted them up tight...so they wont move if the trailer gets bumped one way or the other!!!........I mounted the axles and I haven't check axle to axles distance, because of the variablility of the equalizers....but the front axle is extremely close to equal from side to side to the ball!!..id say less than 1/16th"......... there is no way to adjust axle to axle spacing , other than drilling custom holes in the axle for the clearance of the spring bolt....

it was raining all day yesterday so the final assembly of hubs and tires happens another day!!

thanks for all your help

PS NY law is trailers over 3,000 lbs laden require brakes...or trailers weighing 1,000 or more unladened......my rig weighs 2700 lbs total, boat trailer and gear...so legally I am fine.... although I have a set of disc brakes I have that I plan on installing.... the boat-trailer has only been on the road twice since it was rebuilt!!!!!

bob


bob
 
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