BP-51 Compression/Rebound set up (1 Viewer)

[MEGT369]

So I have a local shop installed the BP-51 suspension on my 200 series with REAR COIL SPRINGS ARB2722. I love the stance when I got the truck. Rear Compression was set on 10 and Rebound on 8. I have told this is the setup comes from factory. Unfortunely, it was too rough of a ride for me and my lower back could not take it after 2 weeks. I had to bring down the compression from 10 to 3 and I could not be happier with right quality. but I lost the stance now the rear sits 1 inch lower than the front. Is there anyway that i keep the same ride quality and the right stance?

 

[daneo]

The settings on the shocks have no impact on the ride height. Remove weight from the back, get a stiffer rear coil, or my personal suggestion would be to get a 1” coil trim packer. Expensive route would be to add rear air bags to allow dynamic adjustments to the rear ride height.

FWIW, weight behind the rear wheel has an increased effect on front:rear rake because the rear axle acts as a fulcrum, and the front end will lift while the rear is compressed. I see you have a substantial looking bike carrier and bike combo that could be affecting the stance more than one might think.

 

[bloc]

I agree with Daneo. The only shock adjustment that should impact ride height is nitrogen charge pressure, if you didn't mess with that the height change is something else. Including sticking the bike and carrier on back.

I will say that 2722 yes is taller but is still a fairly soft spring (same rate as 2720/2721), and ride height will be impacted significantly by load in the rear. A firmer spring will keep the height more static with load, but your back probably wouldn't like it.

 

[TeCKis300]

Trim packers/coil spacers are the answer if you're looking to tune ride height. Spacers achieve that without changing spring rate which is important for ride quality, articulation, and off-road performance.

 

[MEGT369]

The settings on the shocks have no impact on the ride height. Remove weight from the back, get a stiffer rear coil, or my personal suggestion would be to get a 1” coil trim packer. Expensive route would be to add rear air bags to allow dynamic adjustments to the rear ride height.

FWIW, weight behind the rear wheel has an increased effect on front: rear rake because the rear axle acts as a fulcrum, and the front end will lift while the rear is compressed. I see you have a substantial looking bike carrier and bike combo that could be affecting the stance more than one might think.

thank you for the clarification. why would they design a suspension that sits 1 inch lower on rear? is the installation correct?

 

[MEGT369]

I agree with Daneo. The only shock adjustment that should impact ride height is nitrogen charge pressure, if you didn't mess with that the height change is something else. Including sticking the bike and carrier on back.

I will say that 2722 yes is taller but is still a fairly soft spring (same rate as 2720/2721), and ride height will be impacted significantly by load in the rear. A firmer spring will keep the height more static with load, but your back probably wouldn't like it.

even without the bike rack installed, rear sits 1 inch lower than front. I do not understand why they would design a suspension from factory that sits like this.

 

[bloc]

even without the bike rack installed, rear sits 1 inch lower than front. I do not understand why they would design a suspension from factory that sits like this.

It's most likely just the suspension breaking in. Short answer, your front preload is too high for the rear springs you have. Take some front lift out and it will sit level. Or run trim packers as Teckis suggested. But note that as your rear ride height goes up, you increase the need for panhard correction to reduce rear end sway over compression/rebound.

 

[linuxgod]

Check the front coilover preload. With a factory front end you should be set low, like 0-5mm. I think the default is 10mm which is for vehicles with some weight up front, and if you have a full on winch bumper and battery it can go up to 20mm.

Compression around 2-3 and rebound in the 4-6 range is what I'd expect. I run C2/R6 and I have a bunch of extra weight, which leaves me a bit floatier than some might like but for driving around the city I prefer it. If I was driving mostly on fresh asphalt highways I might want to go a little higher; however since you look like factory weight you definitely want to be on the low side.

 

[daneo]

even without the bike rack installed, rear sits 1 inch lower than front. I do not understand why they would design a suspension from factory that sits like this.

Given how different every vehicle is with its accessories (most vehicles that are getting their suspension swapped out probably have other accessories… look at your vehicle for example!) and people’s preferences for ride height, rake, etc., suspension fitting should be viewed as an iterative process.

I like linuxgod’s suggestion to reduce the preload to help level things out. OME designs their stuff in Australia, and it’s likely they had the heavier diesel engine as well as front bumper in mind when they set the preload. Much easier to reduce the preload than increase it, but still requires the front shocks to come out.

On the flip side, adding trim packers is a much easier job and may still be necessary after decreasing preload.

I’ve swapped out the rear coils on my 4Runner more times than I can count at this point with changing loads and changing preferences.

 

[bloc]

BP51s have to come out to change preload?

 

[linuxgod]

BP51s have to come out to change preload?

Yes. One of those things I dislike about their design (also adjustment is a pita compared to the dials on a Dobinson’s MRR or King).

It might be possible to reduce preload while still installed, perhaps by strapping the coils while the vehicle is on the ground and then raising it up just enough to take the load off the collar, but it’s not the method they include in the installation instructions.