Bilstein 5150 - can they be revalved?

[Michael Slade]

Hey gang,

Just put some Bilstein 5150's on the Serious One. The front feels really good...the back feels really bad. VERY hoppy, so much so that the rear end bounced off the ground after going over a speed-bump in the neighborhood tonight.

Can I re-valve them? I got them from JKS as a partial trade for some work, so I don't know if I can send them back.

I have some other shocks I can run instead, but I wanted to use these Bilstein's if I could.

Any advice?

[ntsqd]

Could you post a picture of the dampers? In specific a quartering view of the bottom of the main body where the shaft comes out would be good.

[Michael Slade]

Could you post a picture of the dampers? In specific a quartering view of the bottom of the main body where the shaft comes out would be good.

Yeah, but I won't be able to post until tonight.

[SeaRubi]

the 5150 shares much of the same internals as it's rebuildable 7100 brethren. They can be revalved, yes, but the issue is getting it recharged. I think someone on Pirate had welded a shraeder valve onto their 51** body and got 'er done, but i kinda doubt this is worth the hassle.

If you haven't dealt with Shaffers before in NV it's worth a call. I ordered the 7100's for my rangie from them, and they were very helpful. They also work directly with Bilstein out of LA.

http://www.shaffersoffroad.com/shop/


If I remember correctly, they were able to get custom valving done direct from Bilstein for the 5100 series. You might be tempted to buy 7100's and revalve them yourself - the process is straight forward, but there's more equipment you need to buy to do it right, and it's a PITA. If you can get the Serious I down to a good scale and get corner weights loaded up, take those numbers back to Shaffer and they should be able to get you fixed up with the right shocks.

my two bits -

cheers
-isaac / searover

[Maine 110]

Mike not sure about the revalveing, it sounds like isaac is correct. I cannot say enough good things about the 7100 though, a great shock for the money. E-Shock.com is a good source and they stock several valving configurations for Rovers. Paul is the guy to talk with there.

[ntsqd]

It's not a big deal to change the valving in a 7100. Requires a rather simple special disassembly tool that is available from Bils as well as some of the off road vendors. Most motorcycle shops can do the nitrogen re-charge.

The issue, for me anyway, is that I've not seen a 5150 up close so I've no idea if it is built similar to the 5100's or the 7100's. The lack of a Schrader valve is a hindrance. Surmountable, but I wonder at the amount of effort paying off?

Lee at raceshock.com is another good source for Bils parts and rebuilds.

[RonL]

Which valving did you get, 255/70 or 170/60? Some of the shorter travel (below 10") version don't have the 170/60 option.

I have the 8.3" travel version with the 255/70 valving and they are also "very hoppy" on large bumps but great on wash board roads. I was told (after I bought them) that the valving was not stiff enough for the weight of my Disco. It seems to me that Series 1 would wieght a lot less that my Disco.

[ntsqd]

How to approach this?
It's a common misconception that the valving of the dampers (shocks) relates to the weight of the vehicle. Not true since it is the suspension that is moving relative to the whole vehicle and not the other way around. Damper valving relates to the spring type (and more minorly to rate) and is indirectly related to the unsprung mass. It is the spring and axle/suspension mass that needs damping, not the body mass.

In a Bilstein the standard single damper per spring leaf spring valving is 255/70, for coil springs their standard valving is 360/80. The difference is because of the internal friction inherent to most leaf springs. That friction makes them slightly self-damping, reducing the damping required of the 'shocks'. This 'feature' of leaf springs is often exploited on trailers with no dampers.

The lighter valve stack offered is intended for dual damper per tire applications though they are frequently used for exclusively slow speed applications.

Some leaf springs have been designed to have lower internal friction. As supplied the fabled GM 63" springs are like this. So are the various "Parabolic" springs that I've seen. The standard Bilstein leaf spring valve stack doesn't work as well with these leaves. I've gone to the 275/78 valve stack on the set of 63's that I have under the rear of Patch. I should note that I am not entirely convinced that the 7100's actually had the reported 255/70 stack in them (got them used) as the seemingly minor difference in damping made a huge difference in how the truck behaves. The "hoppiness" described above is completely gone. The rear suspension is now best described as "compliant, but firm."

[Oilburner]

That's what I was told as well, the 5150 255/70 valving was for leaf springs. That's whan is on the front of my pile, and they are very nice on the road. I believe the stiff compression damping helps with cornering stability with leaf springs.