Bilstein Shocks Info

[transio]

Ok, so I've been on the phone with Bilstein for the last two days due to a mixup in some shocks that I got from a Bilstein reseller.

Here's the deal. For the VehiCross, Bilstein suggests the following setup:

Front: B46-1738-H2
Rear: B46-1739-H1

However, I was accidentally shipped 1738-H1's for the front. The length and travel is exactly the same on the H1 and H2, however, the H1 has a more aggressive valving, making it about 25% stiffer than the suggested H2.

This is great news for those of us looking for a stiffer ride for better performance! The H1's are about $20 more per shock than the H2's, but they should provide a much closer-to-stock ride! Here's what I am going to install:

Front: B46-1738-H1
Rear: B46-1739-H1

I'll let you all know how it all works out.

[Dallas4u]

Good info Steve. Definitely let us know how the stiffer Bilstein's compare to the OEM ride. I think many of us would like to keep as close to the stock stiffness as possible if we have to purchase new shocks at some point.

[t2p]

transio:

Sounds good ......
.
I would definitely go with the H1 in the front ......... more so than the rear if I had to choose ..................
.
the front - probably due to the weight of the engine, etc ....... appears to require the additional damping .........

[joe-yamma]

transio, thanks for the info... please keep us posted.

i will be replacing the shocks on my Vx as soon as i can (read: afford it) and bilstein's are one of my choices.

[t2p]

JY:
.
We should get together so you can try my VX with the KYB MonoMax's.
.
I like the MonoMax's ........ but I don't really have any 'baseline' to offer a comparison ..............
.
I would like to try a VX with the Rancho 9000's set at the stiff settings .......... and also would like to try a VX with Billsteins ........
.
I was tempted to go with the 9000's ...... heard good things ....... but could not get the 'Monroe' out of my head .........

[joe-yamma]

t2p, we definitely need to get together.
you can feel the "see-saw bouncy yo-yo effect" in my VX

[transio]

Ok, I finally had a chance to get the Bilsteins on. And the verdict is... The ride is absolutely FANTASTIC !! The VX feels like a BMW M5 with them on. Very little roll, very good road feedback. If you're going for street performance, these are definitely the way to go. I haven't had a chance to test them out on rougher terrain yet, but I'll update you guys once I do. Again, the setup is:

Front: 1738-H1
Rear: 1739-H1

H1's are about 25-30% stiffer than H2's up front.

While changing out the rear shocks, I had a little bit of a revelation. I was looking at the extreme angle of attack that they are mounted at, and thought that this could very well be the reason they go so quickly. They're mounted at an angle about 30 degrees off vertical. This means that they endure about 150% of the load that they would if they were mounted vertically. I don't really see why Isuzu set them up the way they did (they're not even mounted directly to the frame rails). Anyhow, food for thought.

[thedutchguy]

how much did you pay for these shocks?

[angrylittleman]

http://www.eshocks.com/bil_veh.asp?M...Isuzu&Manf=All

[thedutchguy]

they're $200.00 alround at shox.com

[transio]

They cost me about $280 + shipping for all 4.

The 1738-H1's cost about $20 more per shock than the 1738-H2's

IMO, it's worth the extra $$$, though!

[transio]

Originally posted by thedutchguy
they're $200.00 alround at shox.com

Those are not the same shocks.

[t2p]

While changing out the rear shocks, I had a little bit of a revelation. I was looking at the extreme angle of attack that they are mounted at, and thought that this could very well be the reason they go so quickly. They're mounted at an angle about 30 degrees off vertical. This means that they endure about 150% of the load that they would if they were mounted vertically. I don't really see why Isuzu set them up the way they did (they're not even mounted directly to the frame rails). Anyhow, food for thought

.
??? .......... shock absorbers are sometimes mounted in a 'canted' position to allow for more suspension 'travel' ...... given the length and 'movement' of the shock absorber ........ this allows for more suspension movement given the movement at the shock absorber ........ just a guess .......

[transio]

Originally posted by t2p
.this allows for more suspension movement given the movement at the shock absorber

I understand, but at the same time, applying the load at an angle multiplies the load to the shock absorber, because of basic trigonometry. If it's "canted" at a 45° angle (off vertical) for example, the load is approximately 141% what it would be if it were vertically mounted. The formula is something like this:

L = 1/cos(A) * F

Where A is the angle the shock is mounted at, F is the force applied to the wheel hub from the road, and L is the resultant load applied to the shock absorber.

At angle (A) = 0° your load (L) equals the force (F) applied to the wheel. As A approaches 90° your load (L) approaches infinity.

At 30° (like the VX is mounted at) the load (L) is something like 115% the force (F). If the suspension compresses a few inches, the shocks are canted even more, and could likely be enduring a load of 150% or more of the force applied to the hub, which is already significant to have compressed the suspension that much. I may be wrong, but I believe the load on the shocks increases exponentially as they are compressed.

This would explain why my rear shocks were leaking BADLY and my fronts were 100% fine when I replaced them all. Or am I missing something?

[SlowPro48]

Originally posted by transio

Or am I missing something?

Could be...

I'm no expert but it seems like all that load/vector/cosine stuff is for force transferred by solid rods, beams, etc.

The shock is not solid unless it's bottomed out, therefore the "load" experienced by the shock in most cases is limited to whatever damping force it's providing at the moment. The shock doesn't care if it's straight up or canted - all it cares about is squishing oil through that orifice. Thick oil and small opening at high speed? Lotsa damping going on. Shock feels high load. Old oil, thin and cut up from too many passes through the hole? Not much damping force there my friend. And of course no oil = no damping = no load. (other than friction)

I don't know if the VX shock's compression damping is position sensitive (fixed orifice, a nasty velocity squared situation) or is speed sensitive with shim stacks or something of that ilk - but either way you'll have to bust out a lot more complicated math to figure out the loads involved...