Shock travel question

[650Hawk]

Getting ready to replace my worn out shocks. Got it narrowed down to either the Fox 2.0 or the Rancho RS9000XL. I've always liked/wanted the Fox 2.0s, but because I spend 90+% of my time on the pavement I'm leaning towards the Rancho for their 9-way adjustability as well as the cost difference (nearly $200). However, one of the specs on the Rancho has me concerned; on the fronts (RS999307) the Rancho lists the travel at just 1.74" (extended length 15.28"/compressed length 13.54") compared to the stock OEM shocks' 4.1" (ext 15.2"/comp 11.1"). So my question is whether or not that is relevant. Knowing that the shocks are mounted inboard from the tire, how much "travel" is actually needed at the shock on the H3? Is the 1.74" (at the shock) sufficient, or will the shock bottom out before the suspension? Anyone know for sure?

 

[jakesz28]

If the Rancho specs are true and not a mistake, there is no way I would buy them.

 

[650Hawk]

It all depends on the geometry of the H3; if there is only 1.74" of actual movement at the shock location, then the Ranchos are fine. If not, then the Ranchos will limit the actual suspension travel of the truck, and I find it hard to imagine that Rancho would spec/recommend a shock that does that. I've inquired to Rancho about the issue. It could be an incorrectly listed spec, or it could be that the H3's suspension only moves that much at the shock location. We'll see what Rancho has to say.

 

[jakesz28]

The H3's shock travels more than 2 inches. You actually can over travel the factory shocks and they have a rubber bump stop inside of them. That is why the bilstien and fox shocks are longer than factory.

 

[650Hawk]

The Bilsteins, while longer than OEM, actually have less travel (3.76" vs 4.1").; the Fox are longer AND have more travel (4.6"). Here's what's interesting; Rancho's RS9000XL that they spec for the H3 with (their) 4" lift, while being longer (19.4" vs 15.28") to account for that lift STILL only has 2.11" of travel. Again, I find it hard to believe that a shock/suspension company that has been around as long as Rancho has would spec shocks that don't have enough travel for the vehicle they are listed for, including for THEIR OWN 4" lift kit. Anyone here with a Rancho lift want to chime in?

With the torsions at stock position, the LCA rests right against the bump stop, so the actual shock compression travel available at that location is minimal, although I don't know how much droop the H3 will allow. With the torsions cranked up, I have about 3/4" gap at the bump stop. Now the shock is a bit outboard from there, but not much, so realistically, the shock can only compress about 1 1/2". I think this weekend I'll dig into it a bit more and see if I can get a clearer answer. Also waiting on a response from Rancho. Thanks for the feedback; I'll make sure to post anything further that I find.

 

[atvspeed4]

We have videos online somewhere where we dug into this showing wheel travel. Cycling the H3 suspension from metal droop stop to about 80% compression of factory foam bump stop you need a 4" travel shock.

 

[650Hawk]

Hmmmm...I have seen other posts on this site that say that there is 4" of wheel travel, not shock travel. Here's one: https://www.hummer4x4offroad.com/fo...(detailed-review)?highlight=suspension+travel

 

[JPaul]

Bebe is saying 4 inches of suspension travel, not wheel travel. 4" of wheel travel does not sound like enough, but I could see the shock mount point measuring at 4" of total travel. A stock FJ Cruiser for example has over 7 inches of wheel travel on the front IFS. I doubt the H3 is over 3 inches less wheel travel than that.

Quote:

[FONT=&quot]Front Shock Comparison[/FONT]

[FONT=&quot]Brand[/FONT][FONT=&quot].........[/FONT][FONT=&quot]Extended Length[/FONT][FONT=&quot]......[/FONT][FONT=&quot]Compressed Length[/FONT][FONT=&quot].......[/FONT][FONT=&quot]Travel[/FONT]

[FONT=&quot]Rancho[/FONT][FONT=&quot]............[/FONT][FONT=&quot]15.77"[/FONT][FONT=&quot]............................[/FONT][FONT=&quot]13.43"[/FONT][FONT=&quot]................[/FONT][FONT=&quot]2.34"[/FONT]
[FONT=&quot]OEM[/FONT][FONT=&quot]................[/FONT][FONT=&quot]15.0"[/FONT][FONT=&quot]..............................[/FONT][FONT=&quot]11.25"[/FONT][FONT=&quot]................[/FONT][FONT=&quot]3.75"[/FONT]
[FONT=&quot]Fox[/FONT][FONT=&quot].................[/FONT][FONT=&quot]16.0"[/FONT][FONT=&quot]..............................[/FONT][FONT=&quot]11.5"[/FONT][FONT=&quot]................. [/FONT][FONT=&quot]4.5"[/FONT]
[FONT=&quot]Bilstein[/FONT][FONT=&quot]............[/FONT][FONT=&quot]18.42"[/FONT][FONT=&quot]............................[/FONT][FONT=&quot]11.77"[/FONT][FONT=&quot]................[/FONT][FONT=&quot]6.65"[/FONT]

[FONT=&quot]Ok, that took a long time LOL[/FONT]

[FONT=&quot]I arranged the measurements to reflect travel from the least to the most.[/FONT]

[FONT=&quot]When we started my H3 project, we removed everything so we could get an accurate travel measurement. Without the shocks, but with OEM bumpstops the H3 OEM suspension travels 4". Down travel is limited by a cast metal stop under your upper A-arm, up travel is limited by the rubber bump and the shock. (Sway bar factors in there too).[/FONT]

I doubt the factory would use 3.75 inches of travel in the shock when it only needs a couple inches of travel. My understanding is the OEM shocks are just shy of 4" of travel so that they can act as limiting straps rather than banging the upper arm against the frame. Up travel is controlled by the bump stops which are also part of the suspension system as designed by the engineers (they're actually more like supplemental springs than strictly bumpstops).

 

[650Hawk]

Hmmmm...I'm interpreting that as suspension travel, not shock travel, but maybe I'm wrong. Here is another link that claims 4" of "suspension" travel: https://www.race-dezert.com/forum/threads/h3-long-travel-build.85789/ I think it's the same person (Beebe vs Bebe?). And here's one that says 5.75", and claims that it was actually measured: https://www.hummer4x4offroad.com/forum/showthread.php/6138-H3-Front-wheel-travel

In any case, I've been off-roading and racing motorcycles for over 5 years, and have never heard the term "suspension travel" to refer to anything other than wheel travel, never "shock" travel. I've seen pics of the H3 with the suspension completely compressed and with it completed extended (tire in the air), and it looks like 4-6" of wheel travel is about right. That would seem to translate into somewhere around 2-3" at the shock.

BEBE says that overall she was happy with the Rancho kit and would do it again. If the shocks cut the suspension travel to 2", I doubt that would be the case. There are also plenty of people running the Rancho 4" lift; those shocks also have the shorter 2" travel, yet I've never heard any of them complain about their suspension travel being reduced because of it (granted, perhaps not all purchasers also got the Rancho shocks, but I assume many did).

The "limiting strap" function would be at the extended length, which is pretty much the same length between the OEM and the Rancho, while the compressed limits are from the bump stop, like you say. Perhaps Chevy may have spec'd the shock with additional compression travel to accommodate for possible loss/deterioration of that bump stop, and Rancho did not?

Later today, I'm going try to go out and see if I can get some measurements; with some basic numbers, I can draw the setup in autocad and see what kind of travel the pivot points and upper/lower stops produce at the shock location vs the wheel location.

 

[bebe]

I have a trash can full of Rancho's you can have cheap!

I liked my Rod Hall Fox shocks. Now I run coilovers.

The Rancho shocks were too short and I pulled the shaft out of at least 3 I can remember. I got the specs from Rancho myself back in the day before I went to the Fox Shocks. We run Fox on both the Bebe Monster and the H3T and love them. I learned quickly to only buy shocks that were rebuildable.

If I were to choose two it would be Bilsteins and Fox, with a preference for Fox.

 

[bebe]

I doubt the factory would use 3.75 inches of travel in the shock when it only needs a couple inches of travel.

They did. It was on all the engineering specs I got from Hummer.

When designing IFS, the shocks always have more travel than the suspension, except Rancho, which is why I ripped them apart on the rock trails.. Usually happened in a full droop situation.

 

[JPaul]

The Queen has spoken.

Thanks Bebe's!

 

[650Hawk]

Thanks for weighing in with your actual experience. I was able to find a pic of someone who did in fact rip the shaft out of a Rancho RS9000 shock. Can you clarify that your spec of 4" refers to the wheel travel, rather than the shock travel?

Looks like I'll be spending the extra on Fox.:cheers: I love this site (although my wallet would sometimes disagree!!)

 

[bebe]

Thanks for weighing in with your actual experience. I was able to find a pic of someone who did in fact rip the shaft out of a Rancho RS9000 shock. Can you clarify that your spec of 4" refers to the wheel travel, rather than the shock travel?

Looks like I'll be spending the extra on Fox.:cheers: I love this site (although my wallet would sometimes disagree!!)

You won't regret it, I've had the truck now since 2005....I've never had to replace the Fox shocks because they never broke or failed and both times I took them in for a freshen up, they said the oil looked brand new.

The numbers above I posted nearly a century ago but it feels like it was yesterday :giggle: I said

"[FONT=&amp]Suspension Travel - stock being around 4.0"[/FONT]

= suspension travel, and 3.75" OEM is the shock travel E-C = T.

IIRC somewhere in the Engineers specs that travel was 3.5".

Honestly, we didn't cycle it for exact measurements because we were cutting it all off. :horns:

 

[jakesz28]

The h3 has about 8" of wheel travel in the front. The front bump stop is not a bump stop it is an active part of the spring rate designed to compress or a jounce bumper.

 

[jakesz28]

If you look at the position of the shock on the A arm it is approximately in the center so wheel travel will be twice what the shock travel is.

 

[jakesz28]

If you look at the position of the shock on the A arm it is approximately in the center so wheel travel will be twice what the shock travel is.

 

[atvspeed4]

If you look at the position of the shock on the A arm it is approximately in the center so wheel travel will be twice what the shock travel is.

If you go to our facebook page "outfitter design llc" there is a post from may 6 2019 where we took the torsionbars out and measured wheel travel. We posted the pictures of the tape measure from floor to center of hub while truck was on lift. 8.6" of wheel travel. Funny enough same wheel travel on a new colorado zr2.

 

[jakesz28]

If you go to our facebook page "outfitter design llc" there is a post from may 6 2019 where we took the torsionbars out and measured wheel travel. We posted the pictures of the tape measure from floor to center of hub while truck was on lift. 8.6" of wheel travel. Funny enough same wheel travel on a new colorado zr2.

Thanks, I knew 4" was not correct. Funny than the H3 has the same travel as my ZR2. BUT most of the parts are similar. The ZR2 CV axle is only 3/8" longer then a AC Delco H3 replacement. The tie rods are the same length too. Sucks the ZR2 has a larger taper on the outside tie rod. If they had the same taper I was going to put H3 tie rods on My ZR2. Sucks GM went back to 14 mm on the ZR2.

 

[atvspeed4]

Thanks, I knew 4" was not correct. Funny than the H3 has the same travel as my ZR2. BUT most of the parts are similar. The ZR2 CV axle is only 3/8" longer then a AC Delco H3 replacement. The tie rods are the same length too. Sucks the ZR2 has a larger taper on the outside tie rod. If they had the same taper I was going to put H3 tie rods on My ZR2. Sucks GM went back to 14 mm on the ZR2.

Wow! I didnt know they went back to 14mm thats crazy after what they went through with H3 snapping them. We havent gotten around to building parts for the new zr2 yet but I have a feeling there is going to be a few repeats on requested parts.

 

[jakesz28]

Wow! I didnt know they went back to 14mm thats crazy after what they went through with H3 snapping them. We havent gotten around to building parts for the new zr2 yet but I have a feeling there is going to be a few repeats on requested parts.

The inside tie rod is the same thread/design. So part of that can be used on the ZR2 if you start looking at them. The outside tie rod is larger, so there is a bigger taper in the spindle. I am running a sleeve on the ZR2 to help from breaking tie rods.

The ZR2 tie rods break pretty easily. Unfortunately the people running the sleeve to increase strength risk breaking the electric steering rack.

An out of balance tire can make the rack go crazy.

 

[bebe]

The h3 has about 8" of wheel travel in the front. The front bump stop is not a bump stop it is an active part of the spring rate designed to compress or a jounce bumper.

Sorry - I meant suspension travel.

 

[atvspeed4]

The inside tie rod is the same thread/design. So part of that can be used on the ZR2 if you start looking at them. The outside tie rod is larger, so there is a bigger taper in the spindle. I am running a sleeve on the ZR2 to help from breaking tie rods.

The ZR2 tie rods break pretty easily. Unfortunately the people running the sleeve to increase strength risk breaking the electric steering rack.

An out of balance tire can make the rack go crazy.

What part of the electric rack breaks? Is it the electric assist motor?

 

[jakesz28]

What part of the electric rack breaks? Is it the electric assist motor?

The aluminum housing will snap in two.

 

[JPaul]

Sounds familiar...