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Topic: Riding on rails (Read 1312 times) previous topic - next topic

Riding on rails

I am now satisfied with how my 36' U295 rides.  Constant steering corrections were making driving over a couple hundred miles in a day a draining chore.  I finally took matters in my own hands after two alignments, one at a truck specialty place which checked front and rear alignment, and one at the factory.  She now goes straight down the road and influences from passing semis and road variations are at an acceptable level.  On good pavement with minimal wind you can go straight down the road, no hands.  Here's how I did it. 

I got to checking with some straightedges and spacers, extending lines from the outside of wheel rims back to see how they compared with the body of the coach in general.  Hmmm, somethings not right here, toe in should cause a 10' straightedge to increase in distance along it's length, measured against bulkheads of coach.  So, not having an alignment rack I used the next best thing to check toe in.  Two square edged, straight, pieces of 3/4" square wood material, one about four feet long and one about three feet long.  Exact length doesn't matter, they just need to be long enough to reach from wheel to wheel and overlap at least a foot or more. 

Crawling under coach, I put the end of one stick against the outermost wheel rim, right inside where the tire bead seats.  That's on the metal, not the rubber.  I did the same on the other wheel, letting the sticks overlap and holding them tightly together.  Both sticks were placed about mid height on the wheels at the rear (trailing edge), being careful to be as exact as possible that they're very close to the same location on each rim, parallel to the ground and coach body.  Once satisfied, I made a pencil mark along the end of the shorter stick, marking the longer stick.  This mark was labeled R.  I then repeated the task in the same manner, this time on the forward side of the wheels, once again about half way up the height of the wheel and marked the stick the same way.

So, I took a look at the marks on the sticks and what do you know.  Both marks were in exactly the same place, one on top of the other.  In other words, zero toe in.  Couldn't believe it so I did it again with exactly same results.  Sticks don't lie, the rims are exactly parallel. 

Well, that explains things a bit.  I loosened the clamps on the (track bar or tie bar, not sure the exact terminology but the long bar that ties right and left wheels together, behind the axle.)  Once clamps were loosened I then took a pipe wrench from my position sitting in front of the axle, put it on the bar and rotated it approx 1/2 turn towards me.  Looking at the threads on the ends of  track bar I could see a bit of new metal thread and knew I had turned it the right way.  I then repeated the stick measurement drill on front and rear and noted that the pencil marks now have a bit less than 1/8" gap between them, with the shorter measurement being at the forward edges of rims, the longer measurement at the rear.  Good enough, I'll try that, reclamped the bars and test drove.  Major difference is immediately apparent. 

I had previously installed a Safe T Plus steering stablilizer after being told that alignment was perfect, thinking that maybe it would help.  I didn't see any appreciable difference with it vs without it other than increased turning effort and expect that it's unnecessary though I do like the potential blow out protection and may keep it for that purpose.  I do maintain some reservations about its effect on the steering gear with extra effort required for turns, but also have the pictures of my coach after a blowout with generator shoved back, door askew, lower front cap missing.  If I get extra ambitious I'll pull it off and compare with and without. 

As far as what the actual toe in is now at front and rear of tires, I haven't taken the time to calculate it.  I know this setting works, could be that less would work also but I'm thinking you need a little inward pressure from both front tires to keep steering system tensioned up.  After driving 250 miles I checked the tires to see any signs of scrubbing or abrasive wear on outside edges but none is apparent. 

Sorry about the long winded description but this has been a long and expensive proposition trying to get the steering to work as well as the rest of the coach and the fix was 20 minutes work.  If you're having problems you might try this simple check. I want the 500 bucks I spent on alignments back! 

Chuck
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Riding on rails

Reply #1 –
Chuck, two years ago when we bought our '89 36' GV the steering was terrible. We went to Nac and had the front end realigned at FOT. Turns out the front end was toed out 3/8 and should have been toed-in 1/16. I found the toe in specification when I opened the glove box. There it was, right there in plain english!!--from the factory!! And yet someone, in their infinite wisdom, thought they knew better than FOT. Our coach now tracks/steers fantastic. Check with FOT and get the exact specification for your coach. Their alignment guy is second to none.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Riding on rails

Reply #2 –
The alignment guy you refer to is who did my second alignment.  What I'm posting is what made the coach drive properly.  As far as the oem spec, it's on a sticker under the dash and was correct 110K miles ago when the coach was new.  It's unlikely any of the components of the coach, engine, drivetrain etc.  will meet original specs but we make accommodations for age and wear, just like the human body.  That said, by my measurement, toe was not what was on the sticker after the alignment. 

 



"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Riding on rails

Reply #3 –
Quote from: nitehawk –
Chuck, two years ago when we bought our '89 36' GV the steering was terrible. We went to Nac and had the front end realigned at FOT. Turns out the front end was toed out 3/8 and should have been toed-in 1/16. I found the toe in specification when I opened the glove box. There it was, right there in plain english!!--from the factory!! And yet someone, in their infinite wisdom, thought they knew better than FOT. Our coach now tracks/steers fantastic. Check with FOT and get the exact specification for your coach. Their alignment guy is second to none.

I asked Oshkosh why they set the caster different left to right which is what I think is what's on your glove box door and lee mentioned that was to compensate for the crown of the road.  Isn't the right side king pin caster different than the left?
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Riding on rails

Reply #4 –
Quote from: Caflashbob –
I asked Oshkosh why they set the caster different left to right which is what I think is what's on your glove box door and lee mentioned that was to compensate for the crown of the road.  Isn't the right side king pin caster different than the left?

Interesting.  Here's the info from the sticker:

Caster  L 5 1/2    R 4 7/8
Camber L 1/8      R 1/16
Toe 1/32
Steering sector centered  (blank)
Road Test                      (blank)
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Riding on rails

Reply #5 –
I don't have my spec sheet in front of me, but my recollection is that right side caster is HIGHER than left by around .75 degrees.  Yes, to compensate for road crown/so coach will track straight on a crowned road. On our solid front axles, caster is adjusted by installing wedge shaped shims between axle and frame rail.

Brett

Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Riding on rails

Reply #6 –
The caster  setting will make the vehicle "pull" to the side with the least amount of caster. Also depening on how it is set it will make the steering want to stay centered.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Riding on rails

Reply #7 –
Caster is king pin inclination, it should never change unless you have wear or bent/broken parts.  Caster determines how your coach handles, pull one way or other, steering wheel return to center after a turn, how vehicle responds to side winds/gusts etc.

Toe in is much understood,  The reason for tow in is to have both wheels with zero            toe at speed, as the vehicle speeds up, the resistance causes the slack/slop in the tie rod linkage to change the tow setting, so when stopped, normal would be 1/16 to 3/8 toe in,  depending on the vehicle.  Solid axle has the least. Toe in at speed equal faster tire wear.
FWIW
Dave M

Re: Riding on rails

Reply #8 –
Your post took me back a lot of years, Chuck, when I used to set toe in on my old Blazer the same way. I took it to an alignment shop and it was perfect! I think I'll do as you did on our 320. I never have been satisfied with the way it handles, too much correction required. (aligned at Foretravel). Thanks.
jor
93 225
95 300
97 270
99 320

Re: Riding on rails

Reply #9 –
I just noticed the sticker under the dash yesterday. I have felt like there is too much steering input also. Thanks for the post I will check mine out.
1999 U320
Mount Dora Fl

Re: Riding on rails

Reply #10 –
Well, based on what Brett Wolfe, Bbeane and Dave M are saying, the caster settings on my coach, from the factory, are opposite what they should be, right to left. Could be it was recorded incorrectly on the tag, could be that the numbers are negative rather than positive, making less=more.  I don't think it was checked at either alignment, one place said they couldn't adjust it anyway as "those  shims are no longer available", the other "it never changes, it's still what it was set at originally."  Thanks for the great descriptions of the various functions,  especially to Dave for his first class explanation of how toe in works.  That was my intuitive feeling, that the additional toe made the steering "tension up" a bit, eliminating a large dead spot in the wheel. 

Since I've opened Pandora's box here, the next thing I want to attempt is to measure caster with a precise digital level.  I will also probably back off the toe a bit, easy enough to do, incrementally, driving between adjustments.  The reasoning here is that  while I don't care about a bit of accelerated tire wear, I suspect it'll take more fuel to push it down the road with excessive toe in.  Also don't want to start developing weird wear patterns on tires, though I'll live with both if thats what it takes to make it drive to my liking. 

I have been told, "second handedly" that Henderson's, along with replacing some components and adding their steering stabilizers, typically adds a fair amount of toe in during one of their tweaking sessions.  They're known for effectively solving problems on other brands, don't know about FTs. 

Getting back to caster, I see the tapered metal shims referred to, one of them is obviously thicker than the other though I didn't note which was which.  Thanks for the help, appreciate all explanations and comments. 
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Riding on rails

Reply #11 –
Chuck.

Most solid front axles have some caster built into them.  So doing just a shim count or comparing thickness of the thick end of the shim will not necessarily tell you total caster.

If your coach is not pulling to one side, I would not be overly concerned about caster.  The only other influence of positive caster is to return the wheels to center after a turn.  Caster does not affect tire wear as long as it is even in the ball park.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Riding on rails

Reply #12 –
Many years ago a company showed me and my foretravel sales men a spring loaded external setup that went over the tie rod ends and pushed the ball into the socket to take the play out.

I had coaches that had feathered and bumpy edges to them that after installing this system would wear back straight.

The tie rod ends wear. Mc allister?  Long time,ago but I still find funny handling and wear may be worn tie rod ends.

My ford f250 superduty I think needs the rod ends replaced at 110k. 

Bob
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Riding on rails

Reply #13 –
Quote from: wolfe10 –
Chuck.

Most solid front axles have some caster built into them.  So doing just a shim count or comparing thickness of the thick end of the shim will not necessarily tell you total caster.

If your coach is not pulling to one side, I would not be overly concerned about caster.  The only other influence of positive caster is to return the wheels to center after a turn.  Caster does not affect tire wear as long as it is even in the ball park.

Brett

Well good enough then, I'll cross caster experiments off the list as my wheels have no problem returning to center after a turn.  It doesn't pull to one side or the other either.  It looks like additional toe in has cured my wandering  woes and I'm going to call it done once I determine the ideal toe setting.    Appreciate everyone's comments and encourage anyone whos been down this same road to give it a try-it fixed mine. 

Chuck
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Riding on rails

Reply #15 –
Chuck,
      My coach tracks better on secondary roads at same as highway speeds, 60-65 mph, than on interstate roads. I suspect the crown is a bit more pronounced on secondary roads. My toe is set 1/16 and it may need a bit more to improve the interstate handling.
Good luck,
Rick

Re: Riding on rails

Reply #16 –
My first impression would be Caster issue and another question would be, does it pull one way or other or is it just a wonder & weave OR is it more a dart & dive issue ?

Wonder & Weave is from worn loose equipment, king pins, tie rod ends, drag link ends, linkage from struts,  loose suspension and/or steering in general.

Dart & Dive would be from rusted, binding, king pins, lack of grease or broken parts, etc type.

Dave M

Re: Riding on rails

Reply #17 –
If interested here is my post on aligning my 1995 U320.  Spec sheet included.

Keith

Alignment. Good place in Belvidere, IL.
Keith, Joyce & Smokey the Australian Cattle Dog
1995 U320 SE Extreme 40' WTBI Build # 4780, with a Honda CR-V hopefully still following behind.
Motorcade # 17030
FMCA # F422159

Re: Riding on rails

Reply #18 –
Quote from: Keith and Joyce –
If interested here is my post on aligning my 1995 U320.  Spec sheet included.

Keith

Alignment. Good place in Belvidere, IL.

Lots of good reading in that spec sheet, it was very helpful to have a known good setup to work towards.  Thanks for posting it.

"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS