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  1. #1
    Setting Up Camp
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    Matching Springs to Load Carried

    Paul,

    Doing our de-winterization (finally!). When I pulled our 2015 323BHS into the driveway my wife asked if the driveway sloped... I said no, not that much. That she was seeing the left side lean that I've been talking about all winter.

    Looking at the springs, they are flat on the left, thankfully no frown. Springs are still smiling on the right.

    Doing some weighs at the closest CAT scale I am sitting about 800 lbs heavier on the left side. And that is not fully loaded for a trip.

    I definitely need to replace my springs. After reading over Rob (Cate and Rob), Pat and your posts about springs, leveling and measuring on your units I am thinking about doing something similar.... 3.5k (or I've found 3380lb) springs on the left.... and staying with 3k on the right (new one's of course)

    You have 6k axles on your 337? I see that you have Sailun S637 ST235/85/R16 tires. Other than having to replace with longer U-bolts, did you change anything else out? Are you still using the original 6 bolt wheels?

    I'm wondering if there will be an issue increasing the springs on the left if nothing else changes.
    Kevin and Laura
    Eastern Suburb of Cincinnati, OH
    2015 Reflection 323BHS -
    Steadyfast, RV-CO Steps, LED underbelly Lights, BH Jack knife bed support mod
    2007 GMC Sierra 3500 Classic Duramax CC DRW
    Stock- No Tunes - No deletes
    Power steering fluid cooler

  2. #2
    Long Hauler Paul & Deb's Avatar
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    Quote Originally Posted by KevinP View Post

    You have 6k axles on your 337? I see that you have Sailun S637 ST235/85/R16 tires. Other than having to replace with longer U-bolts, did you change anything else out? Are you still using the original 6 bolt wheels?

    I'm wondering if there will be an issue increasing the springs on the left if nothing else changes.
    Kevin, I'd defer to Rob or Pat regarding different spring packs on left versus right. I went with 3,500 lb packs on both sides.

    A few years ago I resolved my "leaning" 337 by adding 1/2 inch of lift to the drivers side axle.

    Actually it goes deeper than that because I had some rubbing under the trailer by the front DS tire from day 1 (visible by a patch of the black material covering the bottom of the kitchen slide being rubbed away). Then I went up a tire size and it got worse and 3 of 4 tires were rubbing so I added 1" trailer axle blocks on the curb side and 1 1/2" blocks on the drivers side. These resolved my lean and added clearance so that I no longer have any rubbing which remains with the Sailun tires as well.

    Finally I do still have the 6 bolt OEM wheels which, other than being ugly from the clear coat completely broken down, work fine. BTW, per a discussion with Sailun direct, I run my tires at 80 psi which is even higher than they suggested.

    Did that answer your questions? I tend to ramble
    Paul "Poppy" and Deb Cervone
    2022 Imagine XLS 22MLE
    2021 Imagine XLS 17MKE - SOLD ; 2015 Grand Design Reflection 337RLS - SOLD
    2016 GMC Denali 3500HD SRW Duramax/Allison CC 4x4; Tire Minder TPMS

  3. #3
    Site Sponsor Cate&Rob's Avatar
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    Hi Kevin @KevinP,

    I think you have the gist of the discussion/debate from way-back-when . Some summary notes . . .

    LCI was firmly against different strength springs on opposite ends of an axle.
    They never got the F=kX basic engineering of matching the spring strength to the load being carried.
    They tried (and still try) to use "spring natural frequency" as the excuse . . . showing that they know even less about how weight affects natural frequency.
    Several of us now have thousands of miles on suspensions with spring strength matched to load carried . . . with no problems.

    The 337 guys seemed to have enough spring strength so they went with different spacer blocks on each side to get level (Paul's situation)
    The 303 guys did not have enough spring strength on the left side so we went with stronger springs on that side only (Pat, myself and others)

    It is important not to over-strengthen your springs.
    This means a rougher ride for the trailer and the tire sidewalls will be doing more than their fair share of cushioning the bumps.

    I would strongly suggest that you measure your current loaded arch height for each spring. See https://www.mygrandrv.com/fo...ng-Arch-Height This is the only way that you will know for sure that your springs are overloaded (and by how much) or how much your future changes will help. Just "looking at" the springs can be misleading.

    Lots of experience with this, on this forum . . . don't hesitate to ask, if you have any questions.

    Rob
    Cate & Rob
    2015 Reflection 303RLS

  4. #4
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    Quote Originally Posted by Cate&Rob View Post
    Hi Kevin @KevinP,

    I think you have the gist of the discussion/debate from way-back-when . Some summary notes . . .

    LCI was firmly against different strength springs on opposite ends of an axle.
    They never got the F=kX basic engineering of matching the spring strength to the load being carried.
    They tried (and still try) to use "spring natural frequency" as the excuse . . . showing that they know even less about how weight affects natural frequency.
    Several of us now have thousands of miles on suspensions with spring strength matched to load carried . . . with no problems.

    The 337 guys seemed to have enough spring strength so they went with different spacer blocks on each side to get level (Paul's situation)
    The 303 guys did not have enough spring strength on the left side so we went with stronger springs on that side only (Pat, myself and others)

    It is important not to over-strengthen your springs.
    This means a rougher ride for the trailer and the tire sidewalls will be doing more than their fair share of cushioning the bumps.

    I would strongly suggest that you measure your current loaded arch height for each spring. See https://www.mygrandrv.com/fo...ng-Arch-Height This is the only way that you will know for sure that your springs are overloaded (and by how much) or how much your future changes will help. Just "looking at" the springs can be misleading.

    Lots of experience with this, on this forum . . . don't hesitate to ask, if you have any questions.

    Rob
    I followed the link and plan on measuring my 303 soon. What are the specs so you can tell if they're overloaded?
    Steve & Ann Ellis
    2018 Reflection 303RLS
    2019 Ram 3500 6.7 Cummins

  5. #5
    Setting Up Camp
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    Thank you both.

    Reading the past posts have had great information. I have read them several times to learn from the experience.

    My 323 has a similar layout as the 303 (and 337 kitchen) and same issue... heavy left side especially with the third slide in the bunk room.

    I will be doing the Load Arch measurements tonight.

    Yesterday I was able to visit a CAT Scale to get individual wheel weights to see what the differences are between them and side to side. Thankfully on a Sunday the location isn't busy, but it did raise some concerns from some drivers there when my unit was halfway off the scale.

    We are at 5320 lb(2740 lb LF, 2580 lb LR)on the left and 4420 lb (2080 lb RF, 2340 lb RR). Not stocked for a trip (no food, no clothes). So already 900 lbs heavier on left. Not maxed out or over, but getting there.

    A possible way to help decrease the dynamic shocks transferring to the frame or by pounding tire and wheels, was to also replace the LCI Equa-flex with the MorRyde SRE4000, providing some vertical movement at the center point.

    Should this get moved to another thread (new or existing) so it isn't buried at on page 5 of broken spring?
    Kevin and Laura
    Eastern Suburb of Cincinnati, OH
    2015 Reflection 323BHS -
    Steadyfast, RV-CO Steps, LED underbelly Lights, BH Jack knife bed support mod
    2007 GMC Sierra 3500 Classic Duramax CC DRW
    Stock- No Tunes - No deletes
    Power steering fluid cooler

  6. #6
    Seasoned Camper webpilot's Avatar
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    I opted for 3500 # American Steel springs on both sides of our 337. Clearance was much better, ride was better, and it took our almost all of the street side droop. I do not have any rubbing of the tires now on the kitchen side. I don't remember exactly, but it went from like 1 1/2 inch clearance to almost 4 inches of clearance. I latter changed to the Mohryde SRE4000 and that added another 1/2 to 3/4 clearance. I think I have 4" total clearance now, but I have slept since last measuring and do't remember exactly. I still have to level street side up once in a while in a campground.

    George
    George and Connie
    Commerce City, CO
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    Solitude 380FL
    2014 Ram 3500 Dually
    [SIGPIC][/SIGPIC]

  7. #7
    Site Sponsor Cate&Rob's Avatar
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    Quote Originally Posted by sellis1053 View Post
    I followed the link and plan on measuring my 303 soon. What are the specs so you can tell if they're overloaded?
    Hi Steve,

    All these springs have a "free" arch height of about 3". They should reach their "design load" at about half that, or about 1.5" of compression.
    They should be running at less than design load so should have an in-use static compressed arch height of about 1.8".
    If you look at my data sheet which is the last page of the Arch Height attachment, you will see that the right side was running at about 1.8" and the original left side was running at about 1.4". (with 2600 lb springs on both sides). My goal was to change the left side springs to match that 1.8" loaded arch height.

    I strengthened the left side (3000 lb springs) to match the compressed spring arch height of the right side, but found that the left side of the trailer was still running a little low. Then I realized that this was because of additional compression of the tires on that side. The tires on the left side are still carrying 800 lbs more than the tires on the right . . . changing springs won't change this. So . . . I went from a 4 leaf spring to a 5 leaf spring of the same 3000 lb load rating on the left side. The extra spring pack height of the 5th leaf (1/4") compensates for the extra tire compression on that side and has brought the trailer to almost exactly level.

    Thats the "short version" of a very long story .

    Rob
    Cate & Rob
    2015 Reflection 303RLS

  8. #8
    Site Sponsor Cate&Rob's Avatar
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    Quote Originally Posted by webpilot View Post
    I opted for 3500 # American Steel springs on both sides of our 337. Clearance was much better, ride was better, and it took our almost all of the street side droop. I do not have any rubbing of the tires now on the kitchen side. I don't remember exactly, but it went from like 1 1/2 inch clearance to almost 4 inches of clearance. I latter changed to the Mohryde SRE4000 and that added another 1/2 to 3/4 clearance. I think I have 4" total clearance now, but I have slept since last measuring and do't remember exactly. I still have to level street side up once in a while in a campground.

    George
    Hi George . . . good to hear from you!

    Something else must have been going on for a change from 3000 lb springs to 3500 lb springs to have increased your tire clearance by 2.5" (from 1.5" to 4"). Even if your original springs we flat, the difference between completely flat and normal loaded arch height is only 1.5". Typically, going up one size in springs is about 1/4" to 1/2" increase in ride height. If there is enough lean to the trailer that weight from the right side is being shifted to the left. that could be part of it. Strengthening the springs on both sides of the trailer should have lifted it straight up without changing the left/right difference .

    Rob
    Cate & Rob
    2015 Reflection 303RLS

  9. #9
    Seasoned Camper webpilot's Avatar
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    Hi Rob,

    We are going a ways back in the memory banks here, about 4 years, so memory is probably clouded. The left side springs were really weak and the lean to that side was pretty signifiacant. The tires rubbed just going down the road, not even on bumpy roads. The new springs have I believe two more leafs in them than the original. It did lift it to almost straight up, but there is still a little lean to the left. The SRE4000 added another probably3/4" according to their website, so that would probably be where it got to 4 ". Rides and tows much smoother on the new (4 years old now) springs. A small investment to make with excellent results.

    Thanks,
    George
    George and Connie
    Commerce City, CO
    Webpilot
    Solitude 380FL
    2014 Ram 3500 Dually
    [SIGPIC][/SIGPIC]

  10. #10
    Site Sponsor
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    Quote Originally Posted by Cate&Rob View Post
    Hi Steve,

    All these springs have a "free" arch height of about 3". They should reach their "design load" at about half that, or about 1.5" of compression.
    They should be running at less than design load so should have an in-use static compressed arch height of about 1.8".
    If you look at my data sheet which is the last page of the Arch Height attachment, you will see that the right side was running at about 1.8" and the original left side was running at about 1.4". (with 2600 lb springs on both sides). My goal was to change the left side springs to match that 1.8" loaded arch height.

    I strengthened the left side (3000 lb springs) to match the compressed spring arch height of the right side, but found that the left side of the trailer was still running a little low. Then I realized that this was because of additional compression of the tires on that side. The tires on the left side are still carrying 800 lbs more than the tires on the right . . . changing springs won't change this. So . . . I went from a 4 leaf spring to a 5 leaf spring of the same 3000 lb load rating on the left side. The extra spring pack height of the 5th leaf (1/4") compensates for the extra tire compression on that side and has brought the trailer to almost exactly level.

    Thats the "short version" of a very long story .

    Rob
    Thank you..
    Steve & Ann Ellis
    2018 Reflection 303RLS
    2019 Ram 3500 6.7 Cummins

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