Anyone have experience with Dobinsons rear coils on Mojave?

[Artidemic13]

Hello all,
'24 Mojave X owner here, stock suspension on 35x12.5x17 tires (Toyo Open Country A/Tiii, E-rated) on Method 701s (-0 offset), finding myself in the same boat as numerous here on the forum: currently running about 500 lbs constant load, mostly in the rear, and seeing considerable sag (as I fully expected w/ the Mojave suspension). I'd estimate that I'm about 1" to 1.5" lower in the rear at my current load.

Deep in the rabbit hole on a short/medium-term solution, basically up-rating the rear coils for now but keeping everything else stock until it's time for a complete suspension overhaul with lift and new shocks (maybe in another 25K miles?). For now, I don't want to lift; I'm just trying to get back some rake, support my current constant load, and hope to ride at or even slightly above level when I'm fully loaded for expeditions (maybe another 300-400 lbs).

Wondering if anyone in a similar situation has experience running Dobinsons rear coils and, if so, how they play with the stock Fox 2.5 IBP shocks. Dobinsons offers various dual rate, 2" lift springs that have different free lengths, wire diameter, and load rating. I realize that no off-the-shelf spring is going to get me all the way there. But I'm thinking that if I can find the right combo to get me in the ballpark--something that, by the time it compresses under current load, has me at just a bit of rake, and then compresses a bit further when loaded for trips--that this will be better than suffering the sag and the compromised ride (on and off road) for the net couple years.

The models I'm looking at, w/corresponding specs:
- C29-233V: 525mm free height (~20 11/16"), wire diameter 17mm, rated for 2" lift @ 200-400 lbs load
- C29-243V: 505mm free height (~19.9"), wire diameter 18mm, rated for 2" lift @ 440-660 lbs load

I've read somewhere on the forums here that the stock Mojave rear coils are about 18.25" free height. No one seems to know anything about either their load rating or spring rate or wire diameter, but we all know they're pretty light springs and spec'd to work with the particular valving of the Mojave shocks (and NOT to be designed to support heavy loads, just like the stock shocks aren't damped to support loads either). What's tripping me up with the above specs is that the heavier duty spring is stiffer but shorter, while the slightly lighter spring is thinner but longer. So there seems to be two different lift philosophies going on there. Not sure which will be right for my use case. I've had ten different people tell me ten different approaches. I've even had different Dobinsons reps each suggest different coils.

I'm leaning towards the lighter/longer spring, thinking I'm already slightly above it's stated load rating for a 2" lift. So that would mean my load would compress the spring somewhat and get me where I want to be? Especially because the lift height is presumably measured off a stock Gladiator and the Mojave sits 1" higher in front?

Any insights or suggestions would be most appreciated. (But please don't tell me I should have bought a Rubicon... that horse has been adequately beaten to death all over this forum.)

Thanks!
GD

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[MRPRmojave]

I have a 2022 Mojave with out steel bumper package. I am ripping out the stock coils and spacers front and rear and installing synergy springs. I have the AEV Lift and it does not handle any weight at all.

From what I have read around the internet is the Synergy coils are the closest to Mojave specs without being overly stiff. If you want stiff - high quality spring I've hear Clayton is the way to go.

 

[Artidemic13]

I have a 2022 Mojave with out steel bumper package. I am ripping out the stock coils and spacers front and rear and installing synergy springs. I have the AEV Lift and it does not handle any weight at all.

From what I have read around the internet is the Synergy coils are the closest to Mojave specs without being overly stiff. If you want stiff - high quality spring I've hear Clayton is the way to go.

Thanks Duke.
I've looked into the Clayton springs as well. Their 1.5" spring could also possibly work, but judging by pics posted by others on here who went that route, doesn't look like those will net me the rake I'm looking for at my current load. But I think their 2.5" coils will be too long. I could do the 1.5" with a spacer if it doesn't give me the height I need, but I'd rather not.

I spoke to someone at Synergy and he suggested I go either with their 3" or even their 4" coils. Just can't get my brain around that concept: 4 in. coils on a non-lifted Mojave? Just doesn't compute for me, even if the springs are supposed to be the closest to the Mojave specs. Essentially what he's suggesting is I just put a super long spring on their and have the weight compress it down to OEM height.

 

[MRPRmojave]

You could always try airbags? That is a cheaper way before changing out coils and doing suspension work.

Yes, putting that long of synergy coils on a non-lifted Mojave sounds a little crazy. I personally would not do that without extensions for the shocks and adjustable control arms ….and so on so forth.

I have friend in town that has a gladiator Rubicon and he did not want to lift it, but wanted to be able to handle weight of camping gear. He ran into the same problem it boiled down to companies really don’t manufacture that much for non-lifted jeeps.

 

[22EcoDs]

I would get the truck weighed and give Clayton a call. I love ny 2.5 diesel lift but am considering upgrading to HD 2.5 rear with a topper and my heavy rock rails and affinity for towing cars on steel trailers ...

 

[Artidemic13]

Thanks Duke and @22EcoDs for the suggestions. I really don’t want to go the airbags route (I thought about it, but ultimately decided it’s just not what I need). So I’m looking for rear coils. I’m also not looking to lift my truck at the moment, so I need something that will just restore my factory rake with my current load of ~500 lbs. It’s not a perfect solution, but it’s where I’m at for better or worse.

Yes, seems no one really offers any options for folks who don’t want to lift their trucks, and no one can really say how their lift springs will function under load without lifting… because, well, they’re meant for lifting the truck.

But in my mind, it seems like a spring that is meant to lift 2” at stock weight should compress down to the proper height (give or take) under my current load, if I could only get someone to tell me which 2” spring is rated properly (lbs/in, wire diameter, etc.) to achieve that goal. (This is essentially what Metalcloak does for their “Rocklander” lifts: they don’t actually make a specific, heavier duty rear coil for that package, they just swap in the next coil size up and call it “heavy duty”.)

I’ve talked to a gazillion different people and gotten a gazillion different answers. So I’m at a loss. I even spoke to a place that could make me some custom springs for my specific parameters, but that’s way more expensive and complicated (I would need to purchase a set of OEM coils and send them to the company so they could analyze them and calibrate their own springs on that basis, then have them send me back the OEM coils so I could return them for a refund: total PITA).

But what I am going to do is go get my truck weighed and then call Clayton and Dobinsons back and see if I can get some better info.

 

[Bandit’s Lair]

So you want the rake to remain WITH a 500lbs load? I always thought the rake was there to compensate for the extra load and have it ride at similar height to front when loaded. In order for it to take the weight and still have the rake you’ll probably have to run a heavier spring at an increased height. So instead of a 1.5” spring made to give the rake at stock height unloaded, you’ll need to run a 2-2.5” spring in the rear to retain the rake when loaded. Either that or contact someone like Deaver and see if they’ll make you a spring that can handle 760-1000lbs. It’ll be super rough in the rear end though.

 

[CrazyCooter]

The problem here is the MOST manufacturers aren't forthcoming with what they are actually selling you. The spring rate remains mostly a mystery, so no calculations or educated guessing can be done with these brands. The argument is usually made that its proprietary and they don't want anyone to copy it? That's actually pretty easy? Once the spring is in hand, one could measure # of coils, wire diameter, and free length and estimate the rate. I could use my scale and press to do the same and they have spring rating tools for anyone who is really serious about figuring this out.

The reason Synergy is recommending a 3-4+ lift spring is that they are some of the lightest spring rates in the industry. By design, they have a longer free length and will compress under a load more than a higher rate spring like say a Clayton or Metal Cloak.

Say you have a 250lbin spring that measures 20" free. That spring will compress 1" for each 250lbs that is applied to it. In theory the "loaded spring rate" at ride height will be the same regardless of the initial rate, but the loaded spring length will change depending on how much it is compressed. This is what determines your ride height.

Multi rate springs help with ride comfort.....In the case of Clayton triple rate springs, the first rate is mostly just a tender spring rate to keep the spring from falling out at full droop so you get decent travel numbers, while the 2nd and 3rd rates are combined at ride weight unloaded allowing for a comfortable ride while still offering some serious cargo capacity as the vehicle drops compressing the 2nd rate until its fully collapsed leaving the 3rd (firmest)rate. This is why you could run a REALLY long shock with a Synergy (Light) spring, med length shock for Clayton (heavier, but triple rate w/ tender), and a shorter shock for a Metal Cloak (Med rate but only only double rate).

A lower rate spring will not "ramp up" as quickly when adding a load by either adding cargo or just turning a corner that will transfer weight therefore inducing body roll. This is why a light sprung (low ride frequency) vehicle generally has more body roll and a heavier sprung (higher ride frequency)vehicle.

Sometimes watching these threads just cracks me up with all the guessing and mismatching of components. People sooo proud of "Frankenlifts" with components that many times don't work well together.

 

[Artidemic13]

So you want the rake to remain WITH a 500lbs load? I always thought the rake was there to compensate for the extra load and have it ride at similar height to front when loaded. In order for it to take the weight and still have the rake you’ll probably have to run a heavier spring at an increased height. So instead of a 1.5” spring made to give the rake at stock height unloaded, you’ll need to run a 2-2.5” spring in the rear to retain the rake when loaded. Either that or contact someone like Deaver and see if they’ll make you a spring that can handle 760-1000lbs. It’ll be super rough in the rear end though.

Yeah, the reason I was hoping to restore a bit of rake at my current constant load is because I want it there to soak up the added 300-400 lbs. ON TOP OF my current load when I throw in fridge, food, power station, water, fuel, camping/recovery gear and my wife when we go on expeditions.

The problem here is the MOST manufacturers aren't forthcoming with what they are actually selling you. The spring rate remains mostly a mystery, so no calculations or educated guessing can be done with these brands. The argument is usually made that its proprietary and they don't want anyone to copy it? That's actually pretty easy? Once the spring is in hand, one could measure # of coils, wire diameter, and free length and estimate the rate. I could use my scale and press to do the same and they have spring rating tools for anyone who is really serious about figuring this out.

The reason Synergy is recommending a 3-4+ lift spring is that they are some of the lightest spring rates in the industry. By design, they have a longer free length and will compress under a load more than a higher rate spring like say a Clayton or Metal Cloak.

Say you have a 250lbin spring that measures 20" free. That spring will compress 1" for each 250lbs that is applied to it. In theory the "loaded spring rate" at ride height will be the same regardless of the initial rate, but the loaded spring length will change depending on how much it is compressed. This is what determines your ride height.

Multi rate springs help with ride comfort.....In the case of Clayton triple rate springs, the first rate is mostly just a tender spring rate to keep the spring from falling out at full droop so you get decent travel numbers, while the 2nd and 3rd rates are combined at ride weight unloaded allowing for a comfortable ride while still offering some serious cargo capacity as the vehicle drops compressing the 2nd rate until its fully collapsed leaving the 3rd (firmest)rate. This is why you could run a REALLY long shock with a Synergy (Light) spring, med length shock for Clayton (heavier, but triple rate w/ tender), and a shorter shock for a Metal Cloak (Med rate but only only double rate).

A lower rate spring will not "ramp up" as quickly when adding a load by either adding cargo or just turning a corner that will transfer weight therefore inducing body roll. This is why a light sprung (low ride frequency) vehicle generally has more body roll and a heavier sprung (higher ride frequency)vehicle.

Sometimes watching these threads just cracks me up with all the guessing and mismatching of components. People sooo proud of "Frankenlifts" with components that many times don't work well together.

@CrazyCooter (Tony): Thanks as always for your insights: I’ve read everything you’ve written on these forums and it’s always really helpful. (I even thought it could make sense just to call you and talk to you directly.) I’ve actually been able to get some helpful specs from various spring makers and have been trying to go from there. (Of course, the problem is that it’s hard to know exactly what the specs are on the OEM rear coils for the Mojave… unless you have that info? All I know for semi-certain is that their free height is around 18.25”; I think their spring rate is below 200 lbs). Here’s what I have so far:

- Clayton 1.5” triple rate: load=320lbs; free height=21.25” (+/- .25”); wire diameter=?​

- Metalcloak 2.5” dual rate: load=340lbs; free height=20.5”; wire diameter=16.67mm​

- Dobinsons dual rate (C29-233V): load=400 lbs; free height=20 5/8” (approx.); wire diameter=17mm [these are advertised as 3” lift at stock weight, 2” lift at 200-400lbs constant load]​

- Dobinsons dual rate (C29-229V): load=220 lbs; free height=19 7/8” (approx.); wire diameter=17mm [these are advertised as 2” lift at stock weight up to 220 lbs. constant load]​

​

Not sure if any of this information gets me closer to a solution, but I’m listing these specific springs becaause I’ve spoken by phone to reps at each of these companies, and each has told me that all of these springs “could” work for my scenario. (At Dobinsons, I spoke to two different people; one told me to go with the 233V, another told me to go with the 229V).

If any of these data points could lead me to a solution (or not) in your opinion, I’d be grateful for your thoughts!

 

[CrazyCooter]

Yeah, the reason I was hoping to restore a bit of rake at my current constant load is because I want it there to soak up the added 300-400 lbs. ON TOP OF my current load when I throw in fridge, food, power station, water, fuel, camping/recovery gear and my wife when we go on expeditions.


@CrazyCooter (Tony): Thanks as always for your insights: I’ve read everything you’ve written on these forums and it’s always really helpful. (I even thought it could make sense just to call you and talk to you directly.) I’ve actually been able to get some helpful specs from various spring makers and have been trying to go from there. (Of course, the problem is that it’s hard to know exactly what the specs are on the OEM rear coils for the Mojave… unless you have that info? All I know for semi-certain is that their free height is around 18.25”; I think their spring rate is below 200 lbs). Here’s what I have so far:

- Clayton 1.5” triple rate: load=320lbs; free height=21.25” (+/- .25”); wire diameter=?​

- Metalcloak 2.5” dual rate: load=340lbs; free height=20.5”; wire diameter=16.67mm​

- Dobinsons dual rate (C29-233V): load=400 lbs; free height=20 5/8” (approx.); wire diameter=17mm [these are advertised as 3” lift at stock weight, 2” lift at 200-400lbs constant load]​

- Dobinsons dual rate (C29-229V): load=220 lbs; free height=19 7/8” (approx.); wire diameter=17mm [these are advertised as 2” lift at stock weight up to 220 lbs. constant load]​

​

Not sure if any of this information gets me closer to a solution, but I’m listing these specific springs becaause I’ve spoken by phone to reps at each of these companies, and each has told me that all of these springs “could” work for my scenario. (At Dobinsons, I spoke to two different people; one told me to go with the 233V, another told me to go with the 229V).

If any of these data points could lead me to a solution (or not) in your opinion, I’d be grateful for your thoughts!

So you have currently no lift or spacers?

Do you like the way the truck feels currently and just desire some more ride height and intermittent load carrying capacity?

 

[Artidemic13]

I currently have no lift whatsoever. With the constant load of approx. 500 lbs, I’m sagging I’d say about an inch (maybe more) in the back. Ride is compromised and sub-par but tolerable at this load and the stock Mojave suspension, but is severely compromised with any added weight beyond the 500 lb. constant load. When fully loaded, steering is especially out of whack in town and on highways at speed (needless to stay, since the front is somewhat unweighted from the sag in back), and off road, the thing is just all over the place.

So ideally, I’d find an uprated spring that would get me back into compliance with the constant load and be also reasonably compliant on and off road once I add additional weight on trips.

But on the daily, I’ve got a canopy, rtt, bedslide and molles in the bed, and steel fender flares on all four corners. I’m on heavy 35s (Toyo Open Country ATiii, E-rated) but no lift for now.

 

[Artidemic13]

My gut is pushing me towards the Metalcloak coils, based on free height, load rating, and wire diameter… but not entirely trusting my gut.

Worth remembering that both Clayton and Metalcloak (not sure about Dobinsons) are calculating lift heights based on JT Rubicon. The Mojave, however, is lifted 1” in the FRONT over the Rubicon. And I think Metalcloak measures lift off the front, while Clayton measures off the rear. Could be wrong there, but that’s what I recall.

 

[Zachanadandy]

Thanks Duke.
I've looked into the Clayton springs as well. Their 1.5" spring could also possibly work, but judging by pics posted by others on here who went that route, doesn't look like those will net me the rake I'm looking for at my current load. But I think their 2.5" coils will be too long. I could do the 1.5" with a spacer if it doesn't give me the height I need, but I'd rather not.

I spoke to someone at Synergy and he suggested I go either with their 3" or even their 4" coils. Just can't get my brain around that concept: 4 in. coils on a non-lifted Mojave? Just doesn't compute for me, even if the springs are supposed to be the closest to the Mojave specs. Essentially what he's suggesting is I just put a super long spring on their and have the weight compress it down to OEM height.

The stock Mojave rear coils are 170lbs/inch. Load up 500lbs constantly (250lbs per side) and you're down ~1.5" from stock. Add another 400 lbs as you mentioned and you're down another 1.2". By that math alone if you get a longer spring with similar spring rate you'd need a 3" spring to look like a stock mojave (which don't have much rake). If you want more rake than that fully loaded, you're looking at a 4" spring as they suggested. The problem there is with your normal ~500lb load you'd be 2.5" taller than stock in the rear.

 

[CrazyCooter]

I wouldn't say your front axle has been unloaded just based on sag in the rear. The angle of the frame/body transfers minimal weight.....like probably only a few lb! Now if you put 750lb behind the rear axle like on the trailer hitch, that will unload the front.

I think you probably know the answer to this problem, just don't want to confirm it because it's painful to the wallet.

Your springs and shocks need to hit the dumpster, be replaced with springs to match your loads, and then shocks to match the ride frequency.

If your answer was that you liked the overall ride, but the rear was just a little soft and low with your loads.....I'd slam a 3/4" spacer and a set of in coil airbags for a Ram 1500 in the rear.

If you step up to a heavier rear spring to support the loads, I would predict that you will have a rebound damping issue and things will be wobbly and then unsettled on the small chop. Overseer might become a thing as well.

 

[CrazyCooter]

The stock Mojave rear coils are 170lbs/inch. Load up 500lbs constantly (250lbs per side) and you're down ~1.5" from stock. Add another 400 lbs as you mentioned and you're down another 1.2". By that math alone if you get a longer spring with similar spring rate you'd need a 3" spring to look like a stock mojave (which don't have much rake). If you want more rake than that fully loaded, you're looking at a 4" spring as they suggested. The problem there is with your normal ~500lb load you'd be 2.5" taller than stock in the rear.

Which rate is 170? 1st, 2nd, or combined? The set of Mojave coils I have are double rate.

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