Carli Pintop with Thuren Install, and still rides harsh?

[Wilder]

Hi, I just finished installing a suspension system on my 2500 Cummins, and I am surprised at how harsh the suspension still is. I installed Thuren +2 front springs and the Thuren stock height mid-rate rear springs, along with Thuren track bar, and Thuren sway bar links. The shocks were Carli King 2.5 Pintop. Running 37x12.5R17 Kenda Klever RT on method HD wheels.

I know this kit is a mixmatch of brands, but the guys at CJC seemed to think it would work. I chose these components based on availability, and the fact that I wanted as minimum lift as possible to clear 37s. The truck tracks really well over the rough stuff at high speed but it's still extremely jarring inside, which I didn't expect given the videos CJC puts out of them slamming whoops and jumping these trucks in the desert. The spring rates really don't feel that much different from stock, and I don't feel like I've lost any carrying capacity over stock.

Is there a common mistake on install that could cause the shocks to bind? I have a couple thoughts:

1. In the instructions that came with the Carli shocks, they said the shocks are often not properly charged with nitrogen from the factory and sometimes need to be reset to 225 psi (can't use compressed air). I have been unable to verify the pressure as I don't have a way to apply 225psi of nitrogen to the shock

2. Sway bar - I still have the stock front sway bar because both Carli and Thuren options are out of stock. I plan to install one of them when I can, hoping this helps. In the meantime should I try disconnecting the front sway bar to see if it makes much a difference?

3. Break in/cold weather - I only have put about 125 miles on the setup, and it's been all in <20F temperatures. Do these shocks need to break in? Do they get really stiff at cold temps due to the oil getting thicker?

4. General incompatibility- is it possible that these kits just can't work together? That seems a bit hard to believe, but did I make a mistake by mixing and matching kits?

5. Alignment - I haven't gotten the truck aligned yet, but I will tomorrow. There are no other strange driving characteristics other than the ride being really stiff still, and not sure how the alignment being off would cause this.

Anyone have a similar experience? Maybe my expectations are off for what is possible in a solid axle HD truck. I just don't feel the amazement at how much better than stock the ride is that others have expressed. I haven't tried any rock crawling or anything, that's more like a summer activity here.

 

[G Mcpherson]

You could message Don at Thuren regarding using Carli Kings with his coils. They are closed until the 4th of Jan I believe. Temps shouldn't have anything to do with operation. I cant imagine them not properly charging the shocks. Have you spoken with CJC? Alignment will help some but shouldn't effect being stiff.

 

[Wilder]

I agree hard to believe, but it says so right here in the installation instructions.

I wanted to get in touch with them at Thuren, but had seen they were closed. I was told at CJC, both companies encourage you to not mix and match, but in truth the spring rates are very close to the same given they are made for the same truck. Would have stuck with Carli but their kit raises the rear by 1in, and the bed of this truck is already high enough...

 

[G Mcpherson]

I have no experience with Carli. My 2.5 Kings were spec for Thuren coils and had no issues. Message Don next week and go over what is going on. Message early.

 

[Wilder]

Called CJC to ask them about this, they said that the system needs to break in. I'll be putting another 200mi on it tomorrow, much of which will be rough roads, will see if there's any improvement

 

[Brewbud]

What tire pressure are you running in the 37s? That will affect small bump compliance a lot. I believe Carli suggests 40 psi front and 35psi rear for Toyo MTs (tire dependent and obviously not while towing).

It already sounds like you are already aware you won't be able to check the nitrogen unless you have a nitrogen setup with a lossless air chuck. You usually set the pressure and not really "check" since checking will lower the shock PSI. The torsion swaybar probably adds the most bang for the buck for ride comfort. Disconnecting the swaybar will give a feel for how it will ride. Some people just stay that way. I prefer the torsion swaybar.

BTW - The Carli 2.5 King system is a step back from the backcountry for an on-road ride. It is a huge step up for offroad performance though. The Dominator actually has the best ride - both on and offroad.

Finally, I don't know why but my truck felt better, more plush, after some dirt time.

 

[G Mcpherson]

Hope it smooths out after a few more miles!

 

[UglyViking]

One other item to keep in mind is that Thuren rear coils are linear, Carli are progressive. How much is changed for valving between linear and progressive springs is beyond my comprehension but it's likely greater than nothing. Front's you should be fine as CJC noted they should be close spring rates and are both linear.

Also, and I know this is probably obvious, but confirm torque on everything. Any play you get on that suspension is going to come through when trying to push through those thicker 2.5 shocks. If you have loose parts it will not help and even minor you'll have a noticeable degradation in ride.

 

[Wilder]

What tire pressure are you running in the 37s? That will affect small bump compliance a lot. I believe Carli suggests 40 psi front and 35psi rear for Toyo MTs (tire dependent and obviously not while towing).

It already sounds like you are already aware you won't be able to check the nitrogen unless you have a nitrogen setup with a lossless air chuck. You usually set the pressure and not really "check" since checking will lower the shock PSI. The torsion swaybar probably adds the most bang for the buck for ride comfort. Disconnecting the swaybar will give a feel for how it will ride. Some people just stay that way. I prefer the torsion swaybar.

BTW - The Carli 2.5 King system is a step back from the backcountry for an on-road ride. It is a huge step up for offroad performance though. The Dominator actually has the best ride - both on and offroad.

Finally, I don't know why but my truck felt better, more plush, after some dirt time.

I took the truck and hit some speed bumps at an irresponsible speed after work today and I gotta say it eats them up like crazy, but yeah the small bump compliance is not there. I'm running about 50psi cold front and back. I saw that CJC recommends 40psi on the Toyo MT's but are those E rated? These Kenda's are D rated tires, so I was going to start higher. Possibly should let some out of the back though

 

[Wilder]

One other item to keep in mind is that Thuren rear coils are linear, Carli are progressive. How much is changed for valving between linear and progressive springs is beyond my comprehension but it's likely greater than nothing. Front's you should be fine as CJC noted they should be close spring rates and are both linear.

Also, and I know this is probably obvious, but confirm torque on everything. Any play you get on that suspension is going to come through when trying to push through those thicker 2.5 shocks. If you have loose parts it will not help and even minor you'll have a noticeable degradation in ride.

I did test drives with only the front changed over, stock rear coils and shocks, and then the test drive with both front and back upgraded, and there was seemingly little difference between even those two. There may be some difference, gonna try to break it in some more and see if it works in. Gonna go on a long drive tomorrow and put it through the paces on some icy rutted logging roads

 

[Crusty old shellback]

Lower your tire pressure to start.
But it may also be the mix match of Thuren springs and Carli tuned shocks.
Shocks and springs work as a package deal.

 

[UglyViking]

As Crusty said above, shocks and springs are a package deal. Chalk your tires to figure out pressure. D to E rates tires isn't gonna change things that much for unloaded PSI.

 

[G Mcpherson]

Also look at the Toyo Tire Load charts for pressure. That will give you a good starting point for inflation. Chalk testing will help also.

 

[Brewbud]

I took the truck and hit some speed bumps at an irresponsible speed after work today and I gotta say it eats them up like crazy, but yeah the small bump compliance is not there. I'm running about 50psi cold front and back. I saw that CJC recommends 40psi on the Toyo MT's but are those E rated? These Kenda's are D rated tires, so I was going to start higher. Possibly should let some out of the back though

50 is a good start but I would try lower. I am running Yokos which are also D rated. I run around 42 front and 35 rear. Actually, I looked this morning and it's so cold in the mornings now they have dropped almost 4 psi so they are gonna get pumped up a bit. Heck, my 12-mile drive to work doesn't even bring them back up.

 

[Wilder]

I think it's breaking in. Seeming to get better. I let some air out of the tires too, that also seemed to help. Is there anything unsafe about disconnecting the sway bar totally?

 

[AEV_CUMMINS]

All great advice, but I would also re-iterate the fact that you should lower your tire pressure. I am running 45 front and 40 rear cold temps. 100% should not be same all around for pressures. Also, the Pintop will feel more like a ''sports car'' driving experience compared to the Backcountry, Commuter or Dominator on the road. Throw yours around a corner or two at a higher speed versus my truck with the Backcountry and you will notice that you have more confidence in the turn and less lean, but I will not feel the small bumps nearly as much as your ''harder'' small bump valving.

Carli has a interview on Youtube outlining the difference in compliance on road and off road between there systems and what you have found is right in line with everything said, see link:

- jump to Min 8:25. You will notice the difference from stock and over other systems off the pavement. But on road it will be more akin to a stock truck with more travel but still not the ''cushy travel'' that some expect. This is actually the exact reason I went with the Backcountry and have not looked back. At 80,000km's or so, I will get a dominator kit installed or the E-shocks but I am very happy with the ride on road and off. I can tell you however that when I was hitting some pretty big ruts down a popular FSR in my area.. the truck bucked a bit more than I assume it would with the Dominator or Pintop alike.

I find the Carli & Thuren systems so interesting and enjoy learning of the differences and the owner experiences we all have as it is such a custom product for our trucks. Out of curiosity.. if you had got the Thuren King's.. what level valving would you have gone for after reading each valving profiles description (it will help understand your goals and expectations).

 

[Crusty old shellback]

When I talked to Thuren for a set up for my 21 PW, they said their 1/2" front springs, keep the stock rears, level 3 king shocks, their track bars front and rear

 

[Wilder]

All great advice, but I would also re-iterate the fact that you should lower your tire pressure. I am running 45 front and 40 rear cold temps. 100% should not be same all around for pressures. Also, the Pintop will feel more like a ''sports car'' driving experience compared to the Backcountry, Commuter or Dominator on the road. Throw yours around a corner or two at a higher speed versus my truck with the Backcountry and you will notice that you have more confidence in the turn and less lean, but I will not feel the small bumps nearly as much as your ''harder'' small bump valving.

Carli has a interview on Youtube outlining the difference in compliance on road and off road between there systems and what you have found is right in line with everything said, see link:

- jump to Min 8:25. You will notice the difference from stock and over other systems off the pavement. But on road it will be more akin to a stock truck with more travel but still not the ''cushy travel'' that some expect. This is actually the exact reason I went with the Backcountry and have not looked back. At 80,000km's or so, I will get a dominator kit installed or the E-shocks but I am very happy with the ride on road and off. I can tell you however that when I was hitting some pretty big ruts down a popular FSR in my area.. the truck bucked a bit more than I assume it would with the Dominator or Pintop alike.

I find the Carli & Thuren systems so interesting and enjoy learning of the differences and the owner experiences we all have as it is such a custom product for our trucks. Out of curiosity.. if you had got the Thuren King's.. what level valving would you have gone for after reading each valving profiles description (it will help understand your goals and expectations).

If I could have gotten Thuren shocks, I was going to go with level 3 or 4. At the end of the day, control is more important to me than a compliant ride, but I got the impression that the truck would float over the small bumps based on the videos that CJC had put out. I'm coming off a GMC 1/2 ton with a fox 2.5 kit, that truck rode rough for sure but was always in great control. I would say this truck now is still riding rougher than that 1/2 ton, but has equal steering control and probably better traction. The difference is no one said the Fox kit made the 1/2 ton softer, those trucks ride so smooth oem to begin with.

 

[AEV_CUMMINS]

If I could have gotten Thuren shocks, I was going to go with level 3 or 4. At the end of the day, control is more important to me than a compliant ride, but I got the impression that the truck would float over the small bumps based on the videos that CJC had put out. I'm coming off a GMC 1/2 ton with a fox 2.5 kit, that truck rode rough for sure but was always in great control. I would say this truck now is still riding rougher than that 1/2 ton, but has equal steering control and probably better traction. The difference is no one said the Fox kit made the 1/2 ton softer, those trucks ride so smooth oem to begin with.

Yes, you are correct in the CJC videos do give a different impression than what Carli says and what is felt in the real world in regards to the Pintop. With the valving level you would have chosen from Thuren makes the pintop pretty much perfect for you and very good thought process and comparison with your 1/2 ton. I felt my suspension soften up a bit after about 2500km's and I also played with the tire pressure a bit. Best of luck with your system and update us further if anything comes to mind. We need all the user experience available to be looked over, I know when I was buying that it was difficult to find much about each system.

 

[Trail_Wagon]

This thread has been extremely informative. Thank you!