Uneven rear springs LC200

Joined
Feb 2, 2022
Messages
94
Location
CO
Interesting… mine were installed on the wrong side too ie tall rear spring on (left/driver side). Swapped and more level left/right but my right side is still riding high after 7K miles. Also, took forever to settle and I’ve got the standard weight Dobinsons springs with IMS shocks. One other thing I noticed with the standard weight springs was the amount of sag with not much weight in the back.

I’ve still got front/rear cant… was hoping for it to be more level and it should’ve been based on advertised specs. More on that below.

For anyone interested and wondering why their lift seemed higher than expected, turns out Aussie Cruiser OE heights are higher than the US. My guess due to wind resistance and gas mileage requirements.

Dobinsons advertised measurements are based on Aussie OE specs. After a lot of discussion they said they were going to fix their specs on the website. I think Mike at Exit Offroad has, unsure about Dobinsons. If you’re selling in the US market, marketing materials/measurements/specs should be adjusted to that market.

From Dobinsons…
- US OE ride height is 19.5” front/20.5” rear.
- Aussie OE ride height 20.25” front/23” rear.

So a Dobinson “1” front lift“ spring really 1.75” higher and a OE height spring is really a 2.5” lift.

Im probably going to have Slee take a look since they’re local to me and may look into using OME medium weight springs with the IMS shocks once I get the wife to signoff on Dissent front/rear bumpers and sliders.
 
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Joined
Apr 13, 2022
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78
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Collierville, Tennessee
Open KDSS, roll cruiser‘s high side on 1-2” block of wood then close. Can help sort out imbalances.
So if the KDSS is a closed and sealed system that seems like you're preloading one side and then closing the shutter to seal in the pressure indifference.

I'd imagine that works, but I would think that puts a lot of pressure on the seals to maintain that imbalanced-balancing act.

Also, I'm a couch mechanic so I don't know crap, just speculating.
 

bloc

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Sep 19, 2008
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10,309
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Central Texas
So if the KDSS is a closed and sealed system that seems like you're preloading one side and then closing the shutter to seal in the pressure indifference.

I'd imagine that works, but I would think that puts a lot of pressure on the seals to maintain that imbalanced-balancing act.

Also, I'm a couch mechanic so I don't know crap, just speculating.
You may be a couch mechanic but you better understand the issues with this method than the people actually doing it.
 
Joined
Feb 2, 2022
Messages
94
Location
CO
So if the KDSS is a closed and sealed system that seems like you're preloading one side and then closing the shutter to seal in the pressure indifference.

I'd imagine that works, but I would think that puts a lot of pressure on the seals to maintain that imbalanced-balancing act.

Also, I'm a couch mechanic so I don't know crap, just speculating.
Iirc it re-equalizes once you get it in the road a bit. It’s like a soft reset.
 
Joined
Feb 6, 2020
Messages
103
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Kansas City
I’ve still got front/rear cant… was hoping for it to be more level and it should’ve been based on advertised specs. More on that below.

This has been my experience with Dobinsons and other coil manufacturers as well. The actual lift far exceeds the stated lift numbers. I now have four bonus sets of rear coils knocking around the garage.

On the topic of the left/right offset, I believe the gas tank location is a red herring. The reason for placing the shorter coil on the vehicle’s left is to compensate for the forces exerted by the KDSS ram. The KDSS circuit is pressurized at several hundred PSI. Imagine one of the hydraulic rams in the system. There’s a top chamber and a bottom chamber separated by a piston. Just imagine a floating piston between the two chambers for now. The whole system is pressurized to, say, 400 PSI. The floating piston has equal pressure, equal area and thus equal forces on both sides so it will sit static in the middle of the chamber. Now, let’s add a shaft to the bottom side of the piston that exits the chamber. This shaft connects to the sway bar. If we go back to the piston in the chamber, the top side still has its full area exposed to the pressure in the hydraulic fluid. However, the bottom side has had its area exposed to the hydraulic pressure by the cross section of the shaft. Since the shaft is quite burly and the pressures in the system are high, the delta in forces acting on the piston in the top chamber versus the bottom chamber is hundreds of pounds.

If you’ve ever worked on a KDSS suspension without opening the shutter valves, you’ve probably experienced the KDSS ram slowly forcing its way out. Or maybe you’ve pushed the shaft in on a pressurized shock absorber and the shaft forced its way back out. It’s the unequal forces acting on each side of a piston due to the shaft area in both cases.

On 4Runners, the gas tank is on the left/driver/KDSS side and the left side ends up being the high side (for those KDSS equipped).

On a KDSS vehicle, plan on putting an inch shorter coil on the ram side to be closest to level. Or, as stated earlier, the half inch trim packer will get the rear within half an inch, which Toyota calls “in spec”.

Agreed that the block of wood/lift one side with shutter valves open will only hide the offset for a matter of time.
 
Joined
Feb 2, 2022
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CO
Has anyone tried OME springs with Dobinsons shocks? I like the IMS shocks vs OME for my use case. Rather not swap them out if at all possible.
 
Joined
Feb 6, 2020
Messages
103
Location
Kansas City
Has anyone tried OME springs with Dobinsons shocks? I like the IMS shocks vs OME for my use case. Rather not swap them out if at all possible.
I’ve not tried that particular pairing, but coils are pretty low tech. If you’re liking the IMS shocks, you can pair them with any coil you’d like within reason. Minor changes in the rate will have little effect on ride.
 

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