How to correct uneven "Bump Clearance" ?
I have a slight sag on the passenger side of our travel trailer. After extensive measurements, I find the bump clearance is actually less on the right side. Bump clearance is the space between the top of the tire and whatever stationary part of the trailer it will hit above it.
Unloaded, unhooked, and as level a spot as I can find, I measure:
LF 2.9"
LR 2.7"
RF 2.6"
RR 2.5"
Dexter and E-trailer recommend a minimum of 3". This is a Lippert suspension system, double 3,500# axles, but could not find their minimum.
I am actually starting to see signs of scuffing where that RR tire is periodically brushing against the bottom of the trailer. Ironically this condition existed to some extent even before we had the rear axle/springs replaced 1 year ago (we bent it somewhere on a 3,500 mile trip).
The right side is the kitchen and the left side has an extra large slide. I attempted a crude method of weighing side to side using a tongue scale and although far from absolute, the relative difference was only 100 lbs or so heavier on the right side.
Spring hangers look OK and measuring centerline of the bolts to trailer frame shows no appreciable difference. Measuring leaf spring to frame shows the same differences as the bump clearances.
I found a dealer nearby willing to help, and they contacted Forest River and Lippert and took dozens of pictures and additional measurements at their request. That was just before the holidays and we are still waiting for their reply/recommendation.
Since we are out of warranty, I am a bit concerned they will come back and say this is essentially normal.
If there is no silver bullet finding from the OEM's, I am seriously considering building shims to mount between the spring pack and the spring perch on top of the axle to level the rig. At a minimum this could involve 1/4" flat stock on the RF and 1/2" flat stock on the RR. It would not be hard to customize the shims on 3 wheels and get it exactly level.
I've done this on Tahoe's several times after lifting the front a bit with the torsion bars. Not terribly complicated.
1. Suspension work is almost always done symmetrically. Anyone see a problem in having 2 different size shims on 2 wheels and none on the other two ??
2. I have considered changing springs. They offer a 2000 lb spring that has the same centerline spacing as my 1750 springs, but they are only 3 leafs instead of my current 4 leafs and the bump clearance spec would be 1/2" LESS than a new 1750 spring, so they would still require shimming. Just wondering if there is an appreciable difference in QUALITY of springs? Mine are marked made in China - would it be worth the trouble to consider replacing all 4 springs with a better quality, and what would that be??
Would welcome any other any other suggestions you might have.
Unloaded, unhooked, and as level a spot as I can find, I measure:
LF 2.9"
LR 2.7"
RF 2.6"
RR 2.5"
Dexter and E-trailer recommend a minimum of 3". This is a Lippert suspension system, double 3,500# axles, but could not find their minimum.
I am actually starting to see signs of scuffing where that RR tire is periodically brushing against the bottom of the trailer. Ironically this condition existed to some extent even before we had the rear axle/springs replaced 1 year ago (we bent it somewhere on a 3,500 mile trip).
The right side is the kitchen and the left side has an extra large slide. I attempted a crude method of weighing side to side using a tongue scale and although far from absolute, the relative difference was only 100 lbs or so heavier on the right side.
Spring hangers look OK and measuring centerline of the bolts to trailer frame shows no appreciable difference. Measuring leaf spring to frame shows the same differences as the bump clearances.
I found a dealer nearby willing to help, and they contacted Forest River and Lippert and took dozens of pictures and additional measurements at their request. That was just before the holidays and we are still waiting for their reply/recommendation.
Since we are out of warranty, I am a bit concerned they will come back and say this is essentially normal.
If there is no silver bullet finding from the OEM's, I am seriously considering building shims to mount between the spring pack and the spring perch on top of the axle to level the rig. At a minimum this could involve 1/4" flat stock on the RF and 1/2" flat stock on the RR. It would not be hard to customize the shims on 3 wheels and get it exactly level.
I've done this on Tahoe's several times after lifting the front a bit with the torsion bars. Not terribly complicated.
1. Suspension work is almost always done symmetrically. Anyone see a problem in having 2 different size shims on 2 wheels and none on the other two ??
2. I have considered changing springs. They offer a 2000 lb spring that has the same centerline spacing as my 1750 springs, but they are only 3 leafs instead of my current 4 leafs and the bump clearance spec would be 1/2" LESS than a new 1750 spring, so they would still require shimming. Just wondering if there is an appreciable difference in QUALITY of springs? Mine are marked made in China - would it be worth the trouble to consider replacing all 4 springs with a better quality, and what would that be??
Would welcome any other any other suggestions you might have.
