IHC 3/5 Performance Lowering Kit on 2024 RCSB

[timnohio]

Very nice in depth write up. I'm still needing to do a write up on my IHC ride quality kit.
Very nice looking truck!

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[mdomicolo]

I’ll cross my fingers for you, because that IHC stuff just isn’t it.

 

[Davidwnuc]

I’ll cross my fingers for you, because that IHC stuff just isn’t it.

What is “it” then and why?

 

[1A2A]

What is “it” then and why?

I'd like to know too.

 

[EL5_Zero]

UPDATE!

In the last week, I have driven the truck approximately 600 miles in all kinds of surface streets and highways. I made adjustments to the struts/shocks/ traction bars after every drive until I found what to me is the perfect balance of smooth and performance handling. Compression and rebound settings were set turning clockwise from full soft.

EDIT: 06/03/2025
Front: C-2 / R-6
Rear: C-1/ R7 with 15 psi. in airbags

Comfort: 7
Performance: 8
NVH: 3

Traction Bars were set to contact leaf spring, plus a quarter turn of nut for preload. This setting reduced body roll just right for street driving. Almost acting like an aftermarket sway bar. I also tried going a full turn past contact, and it made the truck feel too stiff to the point of lifting a rear tire when going into driveways. This might be good if you really want to push the truck in the corners to keep body roll to a minimum. Making changes takes about 1 minute per side with an adjustable wrench, and you don't need to raise the truck.

I no longer go by the above statement. The truck rode too rough for daily driving. Go to post #62 for my latest suspension settings for a nice smooth drive.

With the above settings, and with the tire pressure of 35 Front, 32 Rear, the truck handles the road very well! The truck feels very well composed on rolling dips, corners, and rough asphalt. Traction is great when going full throttle from a stop. You can literally feel the rear end lift when you get on it, putting more weight to the rear tires. I get absolutely ZERO-wheel hop with these settings while the truck accelerates fast with minimal wheel spin.

PINION ANGLE!!!
I highly recommend you watch this video. This videos talks about what and why driveline angles matter, and tells you the best setup to run to cancel out vibrations.

THE Driveshaft Video. The Nature of U Joints. Suspension Basics Ep. 06 (youtube.com)

Here's a video showing how to adjust and set pinion angle based on your transmission angle. Pinion angle starts at 3:00 of video

Setting Pinion Angle! Mighty Max Ep. 23 (youtube.com)

I knew going in that I would need to play around with the driveline angles. IHC says the angle is already incorporated into the axle saddles, but I highly doubt the angles are the same on a regular cab compared to a crew-cab, and if you are 4x4/2WD, single drive shaft/ double driveshaft.

I went on ride tech website and downloaded the instructions as well as reviewed what is included in their kit compared to IHC. Ride tech includes a 2.5* shim with very detailed instructions on how to set it up. Little did I know that the orientation of the shim varies depending on your leaf pack setup. My truck has a composite leaf spring, instructions says pinion needs to be set at 1* pinion down.

Today I will attempt to angle both transmission and pinion to be as close as parallel as possible. I have various differential wedge shims, and transmission spacers to try. Once set, I will adjust my traction bars to my settings above to prevent axle from rotating on hard acceleration. I'll report back with the results.

Also, I might not get ALL vibration removed due to the wheel and tire setup I'm running. The 305/40R22 will never absorb road imperfections as well as a 245/70R17 tire will.

 

[Graygoose2021]

What is “it” then and why?

I'd like to know too.

I kinda have heard same, some have issues, vibrations. VAS or Ridetech would be my choice if I were to lower one.
Just my $.02

 

[mdomicolo]

What is “it” then and why?

I'd like to know too.

I kinda have heard same, some have issues, vibrations. VAS or Ridetech would be my choice if I were to lower one.
Just my $.02

when you’ve broken plenty of their control arms, and when you realize they spray paint more of their parts then they actually powder coat, you’ll realize that they’re trash, pure junk. They like to say made in USA, but they’re so close to Mexico… and the quality screams China.. they’re everything but American.

now I know, ride tech is worth the money.

 

[Davidwnuc]

when you’ve broken plenty of their control arms, and when you realize they spray paint more of their parts then they actually powder coat, you’ll realize that they’re trash, pure junk. They like to say made in USA, but they’re so close to Mexico… and the quality screams China.. they’re everything but American.

now I know, ride tech is worth the money.

This is the type of info that i find useful. Thanks for explaining.

 

[EL5_Zero]

when you’ve broken plenty of their control arms, and when you realize they spray paint more of their parts then they actually powder coat, you’ll realize that they’re trash, pure junk. They like to say made in USA, but they’re so close to Mexico… and the quality screams China.. they’re everything but American.

now I know, ride tech is worth the money.

Thank you for sharing this information! I will definitely be keeping an eye on those control arms. Do you mind sharing how or when the crack happened? Did you hit a large pothole, or was it due to hard cornering? That crack looks to be due to extreme stress at the joint. Looks like the ball joint might have expanded due to heat, and the cup cracked from the pressure due to being brittle material. Is the cup cast iron? If so, that would explain it.

 

[mdomicolo]

It’s a deign flaw, bad cups and bad welds. They are aware of the issue, but they just keep sending out the same shit. One cracked before I even lowered the truck on the lift, we put the UCA in, and torqued the bolts. They’re garbage dude.

 

[EL5_Zero]

UPDATE:

Yesterday I took my brother for a ride to get a second opinion on how the truck drove after installing the kit. He drove it home when I picked it up from the dealership two weeks ago, so he has a good idea of how it drove. He has modified over 20 offroad vehicles (Jeep, Toyota, Ford, and crawlers) these past few years, so I trust him with suspension / wheel issues. As soon as we got up to speed on the highway, he looked over and said, "your wheels are shit" That's not driveline vibration, your wheels are either bent, or unbalanced.

I got off the highway and headed to the shop that mounted and balanced the wheels. I had them go over all four wheels to make sure they were balanced. 3 of the wheels had 2-3 oz of weights, and when checked, they were all perfectly balanced. The fourth wheel had 7 oz of weights, and when checked, it was asking for another 3.5 oz. I had him remove all the weights and check it again. Sure enough, it called for 2.5 oz. I suspect user error when mounting the wheel on the machine caused a bad reading resulting on adding the 7 oz of weights.

With all wheels mounted, we got back on the road to feel the results. I'm happy to say 80% of the vibration was eliminated! This whole time I was chasing driveline vibration, and it ended up being an extremely unbalanced wheel. My brother looked over again and said, "I told you"

We were happy about the results but were not done yet. We headed to the garage and checked driveline angles again. I loosened the rear end and added the 2.5* shims, thick side facing the front of the vehicle. I decided to install them that way in an effort to get both the transmission and pinion angle to be as close as parallel as possible. Once the bolts were torqued to spec, and the truck back on the ground I checked my driveline angles. I used the water pump pulley, and a flat surface on the differential to get my readings and these are the results.

My 2024 F150 RCSB with an IHC 3/5 drop has a final transmission angle of 4.1* angled down, and a differential angle of 4.5* angled up. (Pinion pointing up)

Transmission and driveshaft have a working angle of 1.3*. Pinion to driveshaft has a working angle of 1.7*. In my opinion. 0.4* difference is as good as it gets using an off the shelf 2.5* shim from amazon.

RESULTS!

I'm happy to report that NVH is exactly back to what it was stock, nice and smooth for a truck. I love the way the truck feels and handles when driving spirited. Now that all vibrations have been eliminated, I will back down the compression and rebound settings to find a nice "comfort" setting for daily driving.

If you guys have any questions, feel free to ask and I will help as best as I can.

 

[EL5_Zero]

It’s a deign flaw, bad cups and bad welds. They are aware of the issue, but they just keep sending out the same shit. One cracked before I even lowered the truck on the lift, we put the UCA in, and torqued the bolts. They’re garbage dude.

Thank you for the heads up on the control arms. I will definitely post on here if and when my control arms break. If they do, I'll replace them with a pair from Ridetech or better.

 

[MGF150]

UPDATE:

Yesterday I took my brother for a ride to get a second opinion on how the truck drove after installing the kit. He drove it home when I picked it up from the dealership two weeks ago, so he has a good idea of how it drove. He has modified over 20 offroad vehicles (Jeep, Toyota, Ford, and crawlers) these past few years, so I trust him with suspension / wheel issues. As soon as we got up to speed on the highway, he looked over and said, "your wheels are shit" That's not driveline vibration, your wheels are either bent, or unbalanced.

I got off the highway and headed to the shop that mounted and balanced the wheels. I had them go over all four wheels to make sure they were balanced. 3 of the wheels had 2-3 oz of weights, and when checked, they were all perfectly balanced. The fourth wheel had 7 oz of weights, and when checked, it was asking for another 3.5 oz. I had him remove all the weights and check it again. Sure enough, it called for 2.5 oz. I suspect user error when mounting the wheel on the machine caused a bad reading resulting on adding the 7 oz of weights.

With all wheels mounted, we got back on the road to feel the results. I'm happy to say 80% of the vibration was eliminated! This whole time I was chasing driveline vibration, and it ended up being an extremely unbalanced wheel. My brother looked over again and said, "I told you"

We were happy about the results but were not done yet. We headed to the garage and checked driveline angles again. I loosened the rear end and added the 2.5* shims, thick side facing the front of the vehicle. I decided to install them that way in an effort to get both the transmission and pinion angle to be as close as parallel as possible. Once the bolts were torqued to spec, and the truck back on the ground I checked my driveline angles. I used the water pump pulley, and a flat surface on the differential to get my readings and these are the results.

My 2024 F150 RCSB with an IHC 3/5 drop has a final transmission angle of 4.1* angled down, and a differential angle of 4.5* angled up. (Pinion pointing up)

Transmission and driveshaft have a working angle of 1.3*. Pinion to driveshaft has a working angle of 1.7*. In my opinion. 0.4* difference is as good as it gets using an off the shelf 2.5* shim from amazon.

RESULTS!

I'm happy to report that NVH is exactly back to what it was stock, nice and smooth for a truck. I love the way the truck feels and handles when driving spirited. Now that all vibrations have been eliminated, I will back down the compression and rebound settings to find a nice "comfort" setting for daily driving.

If you guys have any questions, feel free to ask and I will help as best as I can.

Thanks for all the info, I am trying to get my truck into my buddies shop this week to do the same thing.
I have another question, does your truck sit level from side to side? Mine is low in the left rear when measure top of tire to the fender with a full tank of fuel. It has been this way with both lowering kits and both composite and steel leaf springs.

 

[EL5_Zero]

Thanks for all the info, I am trying to get my truck into my buddies shop this week to do the same thing.
I have another question, does your truck sit level from side to side? Mine is low in the left rear when measure top of tire to the fender with a full tank of fuel. It has been this way with both lowering kits and both composite and steel leaf springs.

I just went outside and checked. Both sides measure 33 3/4" from ground to fender edge. I have about 1/2" tank of fuel in it. Front is also level side to side. I have about a 1/2" rake front to back. The only thing I can think of that would vary the height is the axle saddle, the drop shackle, or the shackle perch welded to the frame. What is the difference side to side?

 

[MGF150]

I just went outside and checked. Both sides measure 33 3/4" from ground to fender edge. I have about 1/2" tank of fuel in it. Front is also level side to side. I have about a 1/2" rake front to back. The only thing I can think of that would vary the height is the axle saddle, the drop shackle, or the shackle perch welded to the frame. What is the difference side to side?

It is the shackle perch. I am off a good 1/4 inch or maybe a little more. When you put my truck on the lift you can actually see the rear end hangs crooked. I am adding spacers to the left side to lower it a little more to get the rear end even. The bed is also probably and 1/8 lower on the passenger side, so I will shim it first.
Sure is a hell of a lot of work for a cheap truck!

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