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Old 12-04-2020, 07:00 PM   #1
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Suspension upgrades

After installing the Sailun ST637 tires, I've notice the trailer bounces much more going down the road. It's so bad that I'm worried that the wear will hasten the demise of this stapled together trailer. I'm also thinking about install some 20" wheels and 35x12.5R20 tires to replace the hard riding, poor handling Continential HD2 commercial tires on my F450. I also want to install the Carli Back Country suspension, which is a front levelling lift of 2.5". This lift only affect the front, not the rear. The result will be a bed height increase of about 2". However when the truck is loaded with the trailer, I'll probably be a bit nose high, so some airbags or Timbrens bump stops on the rear axle might be in order.

Right now I have about 8" of clearance between the bedrails of the truck and the underside of the fiver. If I raise the truck 1.5 inches, I'm thinking I can move the bolts on the pinbox higher to make up the difference and still have 6" of clearance to the bedrails, although that makes me kind of nervous.

On the trailer suspension front, it seems like my choices are to either use the Lippert approved and sourced 2" lift kit, or go with a Roadmaster, MorRyde, or Timbren suspension system. The Lippert 2" lift kit is the simplest, but it would do nothing for the harshness of the ride.

The Roadmaster system with the shocks seems like it should do a really good job of dampening the road irregularities. However it does not raise the suspension. I don't know if it can be made to work with the Lippert 2" lift. It's also the best bang for the buck.

The Timbren suspension is about halfway in terms of cost between the Roadmaster and the MorRyde. It also seems like a well thought out system. I removes the axles from the equation entirely which is good for clearance. I have no idea how much dampening it offers relative to the Roadmaster and MorRyde. One bonus of this system is it raises your suspension by 2", which would be perfect for my truck wheels and lift.

The MorRyde system seems to be the Cadillac of suspension systems. It's the most costly at about $7k, and probably requires a trip to Indiana. MorRyde supposedly can set the suspension at whatever lift level I want.

Overall the goal is to soften up both the truck and trailer suspensions and increase the compliance so that I can safely take the truck and trailer down some mild fire roads if we engage in dispersed camping.

So does anyone have experience with these, especially with a very mild truck lift? Recommendations?
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Old 12-04-2020, 07:08 PM   #2
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My 2 cents: I have had the Sailunís on my 5er for the last 3 years. Started of at 110 PSI, but lowered to 100...as you said, they are really stiff. I didnít need the full load capacity with my 5er. Last year I added the Sumo springs to my 5erís axels. That made a huge difference...the ride is night/day different.

For comparison, I have a Ram 3500 DRW with rear air suspension, moryde pin box, and the B&W companion.
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Old 12-04-2020, 07:17 PM   #3
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You are correct. I run my Sailuns at 90-95 psi. They ride much better at that pressure but the ride is still very stiff.

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Originally Posted by bookemdanno View Post
My 2 cents: I have had the Sailunís on my 5er for the last 3 years. Started of at 110 PSI, but lowered to 100...as you said, they are really stiff. I didnít need the full load capacity with my 5er. Last year I added the Sumo springs to my 5erís axels. That made a huge difference...the ride is night/day different.

For comparison, I have a Ram 3500 DRW with rear air suspension, moryde pin box, and the B&W companion.
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Old 12-04-2020, 10:06 PM   #4
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That's a lot of tire for a 10,000# trailer. I toured the Roadmaster manufacturing facility in Vancouver, WA. When speaking to the marketing person I specifically asked if they supplied a lift kit to be used in conjunction with their slipper springs in order to mate older fifth wheels with the newer taller trucks. They weren't aware there were problems fitting fifth wheels to trucks and felt there wasn't a need. Usually 6" of bedrail clearance is sufficient. Raising the front of the truck should have a tendency to lower the tailgate.

One other suggestion is to install a good air hitch. At least, it would eliminate most of the beating your truck is administering to your trailer. The trailer will still bounce around but you won't feel it in the cab. You could air it up further for extra bedrail clearance if needed.

Another issue with adding independent suspension to a fifth wheel is that it eliminates any axle equalization your current suspension has. I feel this causes the trailer to rotate easier and exacerbate chucking forces. I find this to be the case with my 10,000# trailer and independent Torflex suspension.

Maybe installing a shock absorber kit on your existing axles will mitigate some of the bouncing (if not already there). Adding air bags to your truck will only make it stiffer unless you change out your spring packs. I also figure if using the Timbren suspension your frame will benefit from cross bracing reducing the ground clearance advantage.
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Old 12-05-2020, 12:10 AM   #5
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It is a lot of tire for a relatively light trailer (11k lbs GWVR). But one of my oem tires developed a split in its sidewall within a week of my owning the fiver, so I lost all confidence in the tires. I then read a lot of horror stories about similar tires blowing up. So I proactively replaced them. The downside is the 14 ply G rates tires deliver a rather punishing ride, even when aired down somewhat according to the inflation table.

This Lippert 2" lift kit is Lippert approved, so it will not affect the frame warranty on the trailer. It raises the trailer 2", so it should do the job.

I have no idea if the Roadmaster kit would work with the Lippert 2" lift kit. I'm guessing is the biggest issue would be the shocks and whether 2 extra inches of length would put them "out of stroke" per se. Worse comes to worse, I suppose I could always spec a different shock (I'd love to replace with a Fox but that's big $$$).

The air hitch is a consideration. I'm leaning more towards a MorRyde pinbox rather than a Goosebox simply because I'm worried that when articulating the Goosebox might hit the bedrails. A more expensive alternative would be the Hensley air hitch at more than 2.5x the cost.

Your comment about the Dexter Torflex eliminating equalization between the axles, is interesting. It makes sense. The Roadmaster system advertises itself as having center hanger boxes that isolate leaf springs to prevent shock transfer between axles. But I'm not sure how it does this except through the action of the shocks. I'm going to email eTrailer about using the Lippert 2" lift kit with the Roadmaster system.
https://www.etrailer.com/Trailer-Lea...MaAv-nEALw_wcB

CJC told me that since I'm towing a fiver, that it would be best to keep the stock rear leaf springs and supplement them with Timbren stops or airbags. I suppose I could also do the same thing with softer Deaver leaf springs but I'm worried about how much sag I'll end up with in the back since the front will be levelled and 2.5" higher.

Wow, lots of considerations here to think about! Thanks for taking the time to reply!!!



Quote:
Originally Posted by CecilD View Post
That's a lot of tire for a 10,000# trailer. I toured the Roadmaster manufacturing facility in Vancouver, WA. When speaking to the marketing person I specifically asked if they supplied a lift kit to be used in conjunction with their slipper springs in order to mate older fifth wheels with the newer taller trucks. They weren't aware there were problems fitting fifth wheels to trucks and felt there wasn't a need. Usually 6" of bedrail clearance is sufficient. Raising the front of the truck should have a tendency to lower the tailgate.

One other suggestion is to install a good air hitch. At least, it would eliminate most of the beating your truck is administering to your trailer. The trailer will still bounce around but you won't feel it in the cab. You could air it up further for extra bedrail clearance if needed.

Another issue with adding independent suspension to a fifth wheel is that it eliminates any axle equalization your current suspension has. I feel this causes the trailer to rotate easier and exacerbate chucking forces. I find this to be the case with my 10,000# trailer and independent Torflex suspension.

Maybe installing a shock absorber kit on your existing axles will mitigate some of the bouncing (if not already there). Adding air bags to your truck will only make it stiffer unless you change out your spring packs. I also figure if using the Timbren suspension your frame will benefit from cross bracing reducing the ground clearance advantage.
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Old 12-05-2020, 06:12 AM   #6
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LEX ,

You one of very few owner that has this problem..... You have a truck that's designed to tow way more then your pulling!

Here is my suggestions:
Morryde IS is not a option on your current trailer , the lightest rated IS they sell is 7000 lb rated and would add about 600lbs to your current trailer weight causing you to have to reduce the payload by the same amount to be under your max GVW. There maybe optional rubber block Morryde has to make the 7000 lb IS work better with only 7000lbs sitting on top of the two axles , that is a conversation for them on the phone. FYI morryde IS is is under $4000 for the 7K axles with out a disk brake upgrade.

I think you need to reduce your tire pressure back to 80 PSI assuming you have load range G tires now,you dont need any more air pressure then what you ran before the tire upgrade. Sailun 637 tires are very firm sidewalls compared to most cheap tires and very similar to goodyear 614 load range G .
I would suggest you reduce the air in the truck to suit what the axle is carrying , mostlikey around 65~70 psi is all you need in all your tires on the truck but know your weight and check with the continental tire charts to see how much air you need to carry that weight.

I thing you really should have a air hitch or a hitch like the Hensley trailer saver or the comfort ride hitch. An air pin box would help but doesnt do much to help with the rocking front to back because they only have one shock at best. My Hensley BD5 has 4 shock on the hitch to stop some of that up and down.

The roadmaster shock on the trailer is a good idea but at $500 for the sock and $1000 for the springs I feel its over priced. Its also possible to flip the axles from spring under to spring over to gain about 3" or ride height.

as for the truck Air ride rear supension from Kelderman is the best option , I dont suggest any lifts.
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Old 12-05-2020, 09:36 AM   #7
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I'll probably ruffle some feathers but lifting a truck can have negative consequences for towing and make an unstable and less safe truck. Lift kits might "look cool" but suspension changes are not generally in the best interest in towing. Big ole puffy balloon tires fall in the same category. Maybe ok for rolling around in the mud but not good for towing.
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Old 12-05-2020, 10:38 AM   #8
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Quote:
Originally Posted by xc-mark View Post
LEX ,

You one of very few owner that has this problem..... You have a truck that's designed to tow way more then your pulling!

Here is my suggestions:
Morryde IS is not a option on your current trailer , the lightest rated IS they sell is 7000 lb rated and would add about 600lbs to your current trailer weight causing you to have to reduce the payload by the same amount to be under your max GVW. There maybe optional rubber block Morryde has to make the 7000 lb IS work better with only 7000lbs sitting on top of the two axles , that is a conversation for them on the phone. FYI morryde IS is is under $4000 for the 7K axles with out a disk brake upgrade.

I think you need to reduce your tire pressure back to 80 PSI assuming you have load range G tires now,you dont need any more air pressure then what you ran before the tire upgrade. Sailun 637 tires are very firm sidewalls compared to most cheap tires and very similar to goodyear 614 load range G .
I would suggest you reduce the air in the truck to suit what the axle is carrying , mostlikey around 65~70 psi is all you need in all your tires on the truck but know your weight and check with the continental tire charts to see how much air you need to carry that weight.

I thing you really should have a air hitch or a hitch like the Hensley trailer saver or the comfort ride hitch. An air pin box would help but doesnt do much to help with the rocking front to back because they only have one shock at best. My Hensley BD5 has 4 shock on the hitch to stop some of that up and down.

The roadmaster shock on the trailer is a good idea but at $500 for the sock and $1000 for the springs I feel its over priced. Its also possible to flip the axles from spring under to spring over to gain about 3" or ride height.

as for the truck Air ride rear supension from Kelderman is the best option , I dont suggest any lifts.
Adding suspension parts shouldn't reduce the CCC of the 5er.
The 5er is sitting on those parts not carrying them.

CCC is based on the suspension.
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Old 12-05-2020, 10:42 AM   #9
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Quote:
Originally Posted by chunker View Post
I'll probably ruffle some feathers but lifting a truck can have negative consequences for towing and make an unstable and less safe truck. Lift kits might "look cool" but suspension changes are not generally in the best interest in towing. Big ole puffy balloon tires fall in the same category. Maybe ok for rolling around in the mud but not good for towing.
OP is installing a leveling kit. He's not lifting the whole truck.
I towed for 4-5 years with a 2500 that had a 2.5" front level kit. I towed a 9200 lb 5er. Zero issues.
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Old 12-05-2020, 12:12 PM   #10
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I have 637s on a 14000 lb trailer run at 95 . Need to way your axles then go to a n inflation site to get the right combo . I put the comfort ride shock kit on since my springs were new . It takes much of the bounce out . I also have an air ride hitch (Trailer Saver ) and a moryde 4000 along with a moryde king pin . Itís all about the suspension . You get that right and everything else lasts, including you and your truck !
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Old 12-05-2020, 07:05 PM   #11
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My fiver is a 2014 and weighs 15500 lbs on an average trip. Pin is 3400. MorRyde LRE center equalizer, Sailun S637 17.5 tires installed in May replacing the GY G114 17.5 which I keep at 110 psi. Did the same with the GY. I find the Sailuns run smoother AND cooler.
I tow with a GMC 3500 drw with stock suspension. I have a Trailer Saver air hitch. I don't feel I have any handling issues. I have left items on the bath vanity, the bedroom tv remote on the nightstand and I never secure the dining room chairs. Nothing ever moves. I've a very firm believer in air hitches as they improve the overall ride and certainly help cushion the impact to the pin box area of the fiver.
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Old 12-05-2020, 07:59 PM   #12
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Quote:
Originally Posted by Cumminsfan View Post
Adding suspension parts shouldn't reduce the CCC of the 5er.
The 5er is sitting on those parts not carrying them.

CCC is based on the suspension.
NOT true , 16000 lb GVW if your adding 800lbs you can not carry more then 16000 lbs Cargo or otherwise the max that trailer can weight is 16000lbs (legally ) I will say over 80% of the full time RV's are pulling trailer over the max GVW , is it right no but in the event of a bad accident that maybe getting them self's into a law suit for over weight and that being the cause of the accident.

ONLY the OEM can change the GVW rating on a trailer and that is very unlikely once its left the factory. There is a few case that the OEM tag was produced not reflecting the options in the trailer and where corrected once it got to the dealer. Just because I have added 8,000 lbs. axles to my trailer from 7,000 doesn't change my GVW nor does it add any compacity for gear. Some states may want us to register our trailers for weight , all this is for is tax and not getting a overweight fine. My home state doesn't require RV's to be registered for weight. I went to 8K morryde IS (OEM was 7K) because my trailer has 12,900 lbs on the tires, this gave me some room for safety margin and not having bent parts or tire wear issues.
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Old 12-05-2020, 09:25 PM   #13
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Thanks for the detailed reply. Yeah, the truck is overkill, but it's very secure when I'm towing in windy conditions. I actually drove through a dust devil on I-80 east of Reno and our rig barely moved.

It sounds like MorRyde IS is not going to work with my trailer's relatively light GVWR.

Reducing the truck's tire pressure to 70-75 PSI should be ok based on Continental's inflation tables. I do worry because these 19.5" wheels have the shallow commercial bead that requires a minimum of 70 PSI to prevent them from losing their bead seal.

Bringing the trailer pressures down to 80 PSI should be no problem.

The Hensely BD3 or BD5 would be a nice addition. Costly bugger though! I was hoping to actually replace it with a Goosebox so I can have my truck bed back, but I'm worried that articulation on rough trails might result in the Goosebox hitting my bedrails.

The more I look at the Roadmaster suspension, the more I'm liking it. The addition of the shocks should help quite a bit. Unfortunately Grand Design axles are already flipped from the factory. I'm not sure if the Roadmaster suspension is compatible with the Lippert 2" lift. I suppose worse comes to worse I could have a suspension shop fabricate a subchasis, but that's a pretty penny. Oh well, as they say, "you play, you pay" right?

Quote:
Originally Posted by xc-mark View Post
LEX ,

You one of very few owner that has this problem..... You have a truck that's designed to tow way more then your pulling!

Here is my suggestions:
Morryde IS is not a option on your current trailer , the lightest rated IS they sell is 7000 lb rated and would add about 600lbs to your current trailer weight causing you to have to reduce the payload by the same amount to be under your max GVW. There maybe optional rubber block Morryde has to make the 7000 lb IS work better with only 7000lbs sitting on top of the two axles , that is a conversation for them on the phone. FYI morryde IS is is under $4000 for the 7K axles with out a disk brake upgrade.

I think you need to reduce your tire pressure back to 80 PSI assuming you have load range G tires now,you dont need any more air pressure then what you ran before the tire upgrade. Sailun 637 tires are very firm sidewalls compared to most cheap tires and very similar to goodyear 614 load range G .
I would suggest you reduce the air in the truck to suit what the axle is carrying , mostlikey around 65~70 psi is all you need in all your tires on the truck but know your weight and check with the continental tire charts to see how much air you need to carry that weight.

I thing you really should have a air hitch or a hitch like the Hensley trailer saver or the comfort ride hitch. An air pin box would help but doesnt do much to help with the rocking front to back because they only have one shock at best. My Hensley BD5 has 4 shock on the hitch to stop some of that up and down.

The roadmaster shock on the trailer is a good idea but at $500 for the sock and $1000 for the springs I feel its over priced. Its also possible to flip the axles from spring under to spring over to gain about 3" or ride height.

as for the truck Air ride rear supension from Kelderman is the best option , I dont suggest any lifts.
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Old 12-05-2020, 09:44 PM   #14
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Sailun S637 16" load E are rated 4080 lbs or 4400 lbs at 110 psi. Typical example of a severally over tired trailer.
As mention these tires work best on 14k and up trailers with 7k-8k axles.

A 10k trailer probably has 5200 lb axle like my '97 11400 lb 5th wheel trailer. OEM tires were ST225/75-15 D at 2540 lbs per tire. Back then I wouldn't use a ST tire so like my commercial trailers I upgraded to LT215/85-16 E at 2680 lbs per tire.
I could tell the load E at 80 psi vs the OEM 65 psi tire rode a little stiffer but tracking was 100 percent better and I get 50k-55k miles per set. This trailer is on the 3rd set.

I would sell the load G to a hauler and go with another commercial grade all steel ply carcass tire like the Bridgestone R-238 16" LT E in the size of your choice.

The truck.
Those 19.5" tires on later model F450 pickups with 9900 rawr are better suited on a F450 cab/chassis truck with those big 12000 lb rawr.
You might check in on some of the truck camper forums. Those folks carry 5k-6k truck campers out in the boonies on F350 srw/drw and know how to safely mod the truck.
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