over hitching and alignment issues

[Roadtoaster]

Brought the AS home this morning. After Thanksgiving activities with the family tomorrow we and another couple are heading for Vicksburg MS for a long weekend. After reading several posts here about high capacity WD bars and stiff truck suspensions I decided to take a link out of tension to see if I could pass the "jump test". Not sure how scientific the test is but hitched the usual way the rear of the truck won't move under my 175 lbs. but it does the way I have it hitched now. Although I'm not having any rivet problems this should take some shock load off of the front of the trailer. This 500 mile round trip should provide some indication.

While checking tire pressures I noted unusual wear on the curbside front tire. No cupping, just way more wear than the rest of the tire. Then it hit me. I use a BAL "between the tires" chock. I always wondered why the chock on one side had to be compressed slightly more than the other to remove. After measuring today, it appears my front axle on the curb side is mounted slightly rearward compared to the street side.

Now, there are a lot of knowledgeable folks on this Forum so I pose these questions. Do I have a positive camber problem? If not and the axle is as I describe, do I have a toe out problem (which seems odd for a trailer)? Is the axle adjustable fore and aft? And, who can reset the camber if that is the issue?

Thanks for any help and Happy Thanksgiving.

Greg

[2airishuman]

Originally Posted by Roadtoaster

...I decided to take a link out of tension to see if I could pass the "jump test"....this should take some shock load off of the front of the trailer...

hi greg

i'll blindly assume u haven't weighed the rig and don't know exactly what the axle loads are?

and might be relying on the factory ESTIMATE of tongue weight?

and don't know (even approximately) how much effect ONE LINK has on these numbers ?

wheel well measurements CAN provide a good approximation if done carefully, has this been done?
_________

the goal of tensioning the w/d bars is to restore steering axle loads to UN hitched values.

so altering the set up WITHOUT baseline numbers is basically just a LOT of WAGn', right ?

jumping UP/down fits that wag process perfectly

and the data in THIS thread suggests there is NO effect on shock/vibration, from altering bar tension...

http://www.airforums.com/forums/f238...tch-53341.html

cheers
2air'

[HiHoAgRV]

Originally Posted by Roadtoaster

...While checking tire pressures I noted unusual wear on the curbside front tire. No cupping, just way more wear than the rest of the tire. Then it hit me. I use a BAL "between the tires" chock. I always wondered why the chock on one side had to be compressed slightly more than the other to remove. After measuring today, it appears my front axle on the curb side is mounted slightly rearward compared to the street side.

Now, there are a lot of knowledgeable folks on this Forum so I pose these questions. Do I have a positive camber problem? If not and the axle is as I describe, do I have a toe out problem (which seems odd for a trailer)? Is the axle adjustable fore and aft? And, who can reset the camber if that is the issue?

Thanks for any help and Happy Thanksgiving.

Greg

Here's what I would do. I would measure the distance between the axle tubes under the belly, street side then curb side to see if the axles are parallel. If the sides are the same then I would measure hub to hub. If the axles are parallel and the hub are different distances it sounds like something got tweeked.

If the gap is bigger on one side as you have described, I'm betting that the axles aren't parallel and one needs to be shifted.

I'm sure you will get some other ideas.

[rluhr]

Originally Posted by Roadtoaster

While checking tire pressures I noted unusual wear on the curbside front tire. No cupping, just way more wear than the rest of the tire. ...
Is the axle adjustable fore and aft? And, who can reset the camber if that is the issue?

Greg, you need an axle alignment. The Airstream factory is where I get 'em done, but you can also find local dealers and alignment shops that can handle a torsion axle. At the factory it's about $235 for tandem axles.

[mutcth]

Rich, I'm curious. How do they do that - does the whole trailer go up in the air and then an alignment jig/machine gets used, like a car?

Tom

[rluhr]

Airstream just runs the trailer up on ramps, and the axles are bent using chain and a lot of leverage. Measuring is done the old fashioned way.

Last year I spoke to a former Airstream dealer who uses an alignment machine. He told me that removal of the gray tank would be required to fit the machine in place. That dealer quoted me $600-700 for an axle alignment. Needless to say, I keep going to Airstream for the low-tech approach.

[2airishuman]

Originally Posted by mutcth

...does the whole trailer go up in the air and then an alignment jig/machine gets used, like a car?

don't we wish!

i think they use a SHOP caliber version of this in-the-field tool...

http://www.airforums.com/forums/f44/...hed-57167.html

their process is reliable and consistent IN the shop but it's far removed from a typical auto alignment gizmo machine.

wahoo posted a good pdf on trayla wheels n axles here...

http://www.airforums.com/forums/246431-post3.html

and there are MANY threads on the issue...

http://www.airforums.com/forums/f437...les-47694.html
___________

this (alignment check) might be exactly what 'toaster needs...

but when one tire on my unit had greatly accelerated EVENLY placed wear...

the conclusion was that the tire was the issue.

here's a basic list of things that could cause 1 tire to vanish...

http://www.airforums.com/forums/421845-post68.html

but i don't recall any obvious asymmetry in the axles and alignment was within specs.

cheers
2air'

[Roadtoaster]

Thanks for the info folks.

2air, I did weigh when I originally set up the hitch and achieved the correct weight transfer I was looking for. You are correct that I did not re-weigh after today's adjustment which is a good point. I'll have to work that into the schedule.

HiHo, you gave me something to ponder so I went out tonight with light in hand (actually on head) and measured and sure enough the front tube is 1/4 of an inch closer to the rear tube on the curb side. This compares well with the 3/8 of an inch I measured between wheel centers. Looking at the mounting, I don't see any fore/aft adjustment so I'm guessing an alignment is the answer.

Rich, appreciate the info on the factory alignment. For now, I think I'll swap the curbside front and rear tires and plan on a trip to the factory, maybe in the spring. We've never been so it kills two birds so to speak.

Thanks again

Greg

[SteveH]

Greg,

Our current trailer had a simular problem when we got it....the curb side front tire was wearing more than the others, and from the wear pattern appeared to be toed in too much.

I took the trailer to North Dallas RV for allignment. They use an elevated rack, and a devise that stretches strings on each side for reference and measurment, and then a large hydraulic press type of thing that goes under the trailer and bends the axle as necessary.

Just so happened the problem was not the front axle, but the rear. All wheels are supposed to be toed in a little, and our curb side rear was toed out, which with the road side being toed in properly, caused the curb side front to be scrubbing all the time.

[Lumatic]

RT, Where is the wear on the tire? Inside, outside, middle of the tire? Does the trailer track properly when towing or is it crabbing?

[Roadtoaster]

SteveH, thanks for the Dallas tip. Dallas or Jackson, both about 8 hours from here.

Lumatic, I'm getting wear on the outside edge of the tire with no cupping. Tires are pumped to 65 lbs at each trip. Although the running gear has never been balanced, all tires/wheels were balanced late last year after valve stem replacement.

[Roadtoaster]

And I forgot to mention it tows great. Straight with no wandering.

[Lumatic]

Go over any big bumps? I had a bent spindle which I think was from running over a curb. I could not find anyone willing to bend it straight for liability reasons. Time for new axles anyway.

[SteveH]

Originally Posted by Roadtoaster

And I forgot to mention it tows great. Straight with no wandering.

Greg, So did ours. Go figure.

[Roadtoaster]

Originally Posted by Lumatic

Go over any big bumps? I had a bent spindle which I think was from running over a curb. I could not find anyone willing to bend it straight for liability reasons. Time for new axles anyway.

No curbs but we have driven on our share of rough roads that could have created this issue. So goes the life of an RV'er, always something to fix.

[Roadtoaster]

Finally going to JC to get the alignment done. I'm scheduled for August 9 so we will roll in sometime Sunday. New GYM's all around. Going to catch the tour while we are there.

[HiHoAgRV]

Originally Posted by Roadtoaster

Finally going to JC to get the alignment done. I'm scheduled for August 9 so we will roll in sometime Sunday. New GYM's all around. Going to catch the tour while we are there.

good luck and keep us posted!

[Roadtoaster]

All 4 wheels were out but only one tire showed wear. Not unusual according to the AS tech, JIm. I registered with the service desk at 7:00 AM, they picked up the trailer at 7:15 and returned it at 10:00 AM. Really nice experience. Taking the tour this afternoon.

The brake recall was a non event for us. Although the manufacture date was within the dates listed, our actuator was the older model and was not affected. Great news as far as I'm concerned.

[2airishuman]

greg since u are STILL THERE and this opportunity only comes rarely...

you might wanna ASK THEM to INDIVIDUALLY WEIGH each tire/wheel load.

they've got the gear to do this and it only takes a bit of time for them to tow it over.

they will give you a PRINTOUT of each tire/axle load,

which would be valuable for wear, rotation, loading and so on....

my unit (6 wheels) had SIGNIFICANT differences, with one tire carrying several 100 lbs more....

Originally Posted by Roadtoaster

...The brake recall was a non event for us.
Although the manufacture date was within the dates listed, our actuator was the older model and was not affected.
Great news as far as I'm concerned.

goog info, since my unit has the 1st generation actuator also, there is no need to RUSH in for an inspection.

u might wanna post this info in the recall thread too.

cheers
2air'

[Roadtoaster]

Thanks for the suggestion. They say too late to get me in today and I"m leaving early in the morning. So it goes.