BP-51 help

[1Maverick]

As a counter point I have 2720s that are the same rate as 21s, and they are definitely not too stiff, even when empty with 2nd and 3rd row out.

When I worked with Ben at Filthy for my shocks he was adamant that springs “only determine ride height by holding up the vehicle”, meaning rate wasn’t important for ride quality, damper characteristics were.

I took this to mean there are limits.. but for the vast majority of spring options we have it’s the damper that needs tuning, not the spring, when it comes to ride.

So I wouldn’t chuck those 2721s just yet.





Your side to side sway is most likely caused by excessive panhard rod angle, considering you have 2722s in the rear. I’d keep an eye out for the panhard relocation brackets being developed at the moment.

Dobinson makes panhards.

 

[bloc]

It may help to have a common understanding of what the shocks role is in a suspension. And how various types work. For a vender to say that springs "only determine ride height by holding up the vehicle" is a huge disservice. Yes, suspensions are complicated, and there's a need to simplify some concepts for sales, but that is straight up wrong. The litmus test is easy, keep adding spring rate and what is the logical intuition of how a car will ride? Rate also should not be used to tune free height, i.e. lift.

That's why I took it to mean within reason, or more specifically, the options available to us. Obviously if you replace the springs with solid blocks it is going to ride like hell.

It could also have meant his custom valving can offset changes in spring rate. What I do know is my 2720s have fantastic ride characteristics despite their significant increase over stock rate, even when unloaded.

Dobinson makes panhards.

Very different issue. It's not panhard length, it is how level it sits at ride height. The further away from level, the more the axle moves side to side as it cycles up/down.

Great explanation in the following thread

Panhard drop bracket option?

forum.ih8mud.com

 

[TeCKis300]

That's why I took it to mean within reason, or more specifically, the options available to us. Obviously if you replace the springs with solid blocks it is going to ride like hell.

It could also have meant his custom valving can offset changes in spring rate. What I do know is my 2720s have fantastic ride characteristics despite their significant increase over stock rate, even when unloaded.

I wholly believe you have reasonable subjective ride quality. But it would only be fair to compare apples to apples, because if spring rate is high, compliance is coming from elsewhere.

Namely you have tall sidewall LT-C tires.

For someone else running LT-E, with high spring rate, that may tip the scales to too harsh a ride.

There's no magic in custom valving - the tasks of shocks is to provide control, not compliance. Perhaps to Ben's point, control has a lot to do with ride quality. Damping can increase perceived spring rate but no amount of voodoo valving can reduce spring rate to add that initial compliance.

 

[1Maverick]

That's why I took it to mean within reason, or more specifically, the options available to us. Obviously if you replace the springs with solid blocks it is going to ride like hell.

It could also have meant his custom valving can offset changes in spring rate. What I do know is my 2720s have fantastic ride characteristics despite their significant increase over stock rate, even when unloaded.



Very different issue. It's not panhard length, it is how level it sits at ride height. The further away from level, the more the axle moves side to side as it cycles up/down.

Great explanation in the following thread

Panhard drop bracket option?

forum.ih8mud.com

So I understand correctly, this new lanyard bracket will correct the side it side rear movement when going over bumps?

 

[1Maverick]

It may help to have a common understanding of what the shocks role is in a suspension. And how various types work. For a vender to say that springs "only determine ride height by holding up the vehicle" is a huge disservice. Yes, suspensions are complicated, and there's a need to simplify some concepts for sales, but that is straight up wrong. The litmus test is easy, keep adding spring rate and what is the logical intuition of how a car will ride? Rate also should not be used to tune free height, i.e. lift.

High end shocks don't necessarily provide a better ride, on the contrary has potential impacts of more stiction and NVH due to pressure and use of race components like spherical bearings. Things that's don't last as long on street car. The real benefit of high end shocks is the ability to provide higher damping forces for longer durations. With some having the ability for tuning, which can honestly be a double edged sword, with more ways to get it wrong than right.

Here's a great series

The Ironman sounds like a great every day type of suspension since I’m not doing any Baja. However the lime green coil overs are not for me.

 

[Tex68w]

The Ironman sounds like a great every day type of suspension since I’m not doing any Baja. However the lime green coil overs are not for me.

They used to offer yellow coils, but they should get with the times and offer black as well. I enjoyed the FCP's I had on the GX.

 

[Bighead]

Crazy how I always see more complaints about the BP-51's than I do those praising them. It's enough for me to skip over them altogether when the time comes. I'd love to see some pics of those lifted with 275/70/18's.

That’s just the nature of online forums. Generally speaking you will find more complaints than praise. Other than dealing with the rear lipped washer squeak, my BP-51s have been flawless for 3+ years.

 

[linuxgod]

The Ironman sounds like a great every day type of suspension since I’m not doing any Baja. However the lime green coil overs are not for me.

Once they get dirty you can hardly tell. Spray them with some fluid film and the dirt will stick right to them. Alternately grab a can of black spray paint and go wild

 

[1Maverick]

Once they get dirty you can hardly tell. Spray them with some fluid film and the dirt will stick right to them. Alternately grab a can of black spray paint and go wild

Not a bad idea! I take it you have these foam cells on your 200? If so, how are they for everyday driving, road trips?

 

[1Maverick]

Interesting that on this tire MT stands for Maximum Traction not Mud Terrain...

 

[bloc]

I wholly believe you have reasonable subjective ride quality. But it would only be fair to compare apples to apples, because if spring rate is high, compliance is coming from elsewhere.

Namely you have tall sidewall LT-C tires.

For someone else running LT-E, with high spring rate, that may tip the scales to too harsh a ride.

There's no magic in custom valving - the tasks of shocks is to provide control, not compliance. Perhaps to Ben's point, control has a lot to do with ride quality. Damping can increase perceived spring rate but no amount of voodoo valving can reduce spring rate to add that initial compliance.

I'm not sure the tire has very much to do with it, as I can raise my pressures to 50psi which would definitely surpass e-load tire stiffness and there will be a notable difference in sharp hits like pavement joints, but the overall ride attitude won't change other than that. Certainly not anything I'd attribute to spring rate.

So I understand correctly, this new lanyard bracket will correct the side it side rear movement when going over bumps?

It may. It depends on how far from level your panhard rod is currently. The 4-minute video in that thread does the best job of explaining it that I've seen.

Keep in mind that for our rigs sometimes ride height changes depending on whether we are loaded or not.. so for some of us we may have to compromise with setting panhard angle to split the difference.

Either way, keep in mind the stock suspension geometry was optimized for stock ride height. Many rigs running 2722s and not super heavy ended up with substantial lift, and the further you get away from stock the more the bar tilts, and the more side-to-side movement you will get with axle up-down movement.

 

[1Maverick]

I'm not sure the tire has very much to do with it, as I can raise my pressures to 50psi which would definitely surpass e-load tire stiffness and there will be a notable difference in sharp hits like pavement joints, but the overall ride attitude won't change other than that. Certainly not anything I'd attribute to spring rate.



It may. It depends on how far from level your panhard rod is currently. The 4-minute video in that thread does the best job of explaining it that I've seen.

Keep in mind that for our rigs sometimes ride height changes depending on whether we are loaded or not.. so for some of us we may have to compromise with setting panhard angle to split the difference.

Either way, keep in mind the stock suspension geometry was optimized for stock ride height. Many rigs running 2722s and not super heavy ended up with substantial lift, and the further you get away from stock the more the bar tilts, and the more side-to-side movement you will get with axle up-down movement.

What would be the ideal springs then, keeping in mind I have a 12.5 LRA tank I keep full Slee slider and generally and want to keep a level 2” lift?

 

[linuxgod]

Not a bad idea! I take it you have these foam cells on your 200? If so, how are they for everyday driving, road trips?

No actually I have the Tough Dog 45mm setup. But I recently swapped the Tough Dog rear springs for Ironman because I added a rear bumper and needed more support, and with their 25% off sale the Ironman coils were half the cost of… pretty much everything else. So I don’t have their shocks but I do have the hideously bright green coils.

 

[bloc]

What would be the ideal springs then, keeping in mind I have a 12.5 LRA tank I keep full Slee slider and generally and want to keep a level 2” lift?

If you are happy with your ride height then the springs are fine. Just look into measuring your panhard angle and consider a bracket if it would help.

 

[Aslantarek]

Rig:
2021 HE 3 Row
BP-51
2721 rear springs
Slee sliders
No extra weight front or rear over stock as of now.

Need some help! I cannot get my ride dialed in. My main issue is in the rear. I can’t seem to get enough rebound dampening to keep the rear from rebound too quickly.

If I push the rear compression up to 4 to keep the spring from compressing as much the ride starts to get a little rigid. If I soften the compression to 2, it feels like the rear is launching after the springs are compressed even when rebound is set to 8, like there is not enough rebound dampening.

OR, maybe I am oversprung with the 2721 at stock weight? Considered switching to the Bilstein rear springs which are rated at 170lb.

I’m tempted to throw in the towel on the BP51 for fox 2.5 dsc.

Please help if you can! Would love to make the BP51 work.

I know its afew years too late but incase anyone else finds these.... when you go into the world of high performance shocks.. you need to always be alittle UNDERsprung not over sprung.. so assuming you need to carry a constant 300kg then go for a 200kg spring and maybe airbags for variable weight... but you need to give these shocks alot od room to work and cycle..