So, at what point do you need to go with L shocks (2 Viewers)

[cruiserdan]

Dan, I think we need to call it down travel, ie, droop. 5" is a very rough estimate.

Agreed, "down travel". Also agreed 5 inches as a rough guess. I still need to check out what a stocker has for this mesurement.

 

[sleeoffroad]

Are you telling me that you are going to compress a suspension 5" cornerning on the highway???? I can't get my front end to compress that much rock crawling

Nay, I think Cdan worded it wrong. We were talking about how much droop you would have. If you do not have enough, you will lift wheels in hard cornering due to the shock being out of travel. Unlikely to happen in the front, but it can happen in the rear. I would not want to drive a 80 with only 3" of rear droop.

 

[sleeoffroad]

See my post above. 35's are clean on a 2.5" - 3" lift. This isn't guesswork or subjecture...it's real measurements. But OME isn't going to design for this, and I think it is purely because of the potential liability issues of relocating the swaybar.

Nay

Nay, how much bumpstop are you running to keep the tires out of the rear mudflap and flares? I agree that you can fit and run 315's with 2.5" of lift, but I also believe it is a compromise since the uptravel is so restricted.

I spoke to a bunch of people at Cruise Moab that ran larger tires (or even 285's) with lots of bumpstops and they all complained that their trucks bottomed out when heavily loaded and doing high speed dirt road driving. I believe one has to add the disclaimer when you say what tire size fits.

 

[Darwood]

Nay, do you have a part number on what shocks those Bilsteins are?

 

[Romer]

Boy this is good. Maybe we should pick a discussion topic now and then

 

[nakman]

Agreed, great stuff!! I'm currently running the setup you're thinking about Ken. 850J/860, non-L shocks, OME castor bushings, 33's. It seems great, no vibration with the stock front driveshaft.

but I've already got the green light to regear, so that's next, along with 35's (hopefully Nay will be ready to run 37's by then.. ). I'm going to see how it goes with the same suspension setup, but after talking with Alvaro & Ali in Moab about Slee's 4" setup I may do the suspension upgrade sooner rather than later.

 

[Gumby]

In my ever so humble opinion I wouldn't go to L shocks unless it was a dedicated, or mostly so trail rig.

I did. I regret it.

 

[Walking Eagle]

Nay, how much bumpstop are you running to keep the tires out of the rear mudflap and flares? I agree that you can fit and run 315's with 2.5" of lift, but I also believe it is a compromise since the uptravel is so restricted. .

I only put 1.375" bump stops and run 315's with no rubbing. If I was lifted 2.5", I'd still have 1.125" more up travel than stock. A 4" lift with 2" bump stop drops gives you 2" more up travel than stock. It's less than an inch compromise / restriction.

I spoke to a bunch of people at Cruise Moab that ran larger tires (or even 285's) with lots of bumpstops and they all complained that their trucks bottomed out when heavily loaded and doing high speed dirt road driving. I believe one has to add the disclaimer when you say what tire size fits.

I'd say that's more an issue of soft shocks. At least if they had lift that was more than what the bump stop drop was. Easy test, find someone with RS9000's, have them run a section w/ them at 1 and re-run at 9, I'll guarantee alot more bottoming at 1 than at 9.

 

[Nay]

Nay, how much bumpstop are you running to keep the tires out of the rear mudflap and flares? I agree that you can fit and run 315's with 2.5" of lift, but I also believe it is a compromise since the uptravel is so restricted.

I spoke to a bunch of people at Cruise Moab that ran larger tires (or even 285's) with lots of bumpstops and they all complained that their trucks bottomed out when heavily loaded and doing high speed dirt road driving. I believe one has to add the disclaimer when you say what tire size fits.

To address a couple of posts:

Having 5" of shock extension makes sense. OME medium I do not believe provides this, though (neither do the stock shocks on your average solid axle Jeep).

The bottoming out issue is interesting. To me...if you can compress the shocks almost 5" driving down a dirt road, then I start to see the issue as not needing more up travel but stiffer springs and shocks geared to compression valving (and probably less speed). But the question does center around tire size and what you do with your rig. It is very difficult to bias a rig to high speed dirt road driving and rock crawling, especially a heavy rig.

Christo makes a good point: I have neither flares nor mud flaps, so that could be a potential issue in clearance. All of this depends on your bias - I am looking for the simplest way to create an extremely high quality suspension to run 35's with the right balance between road use and rock crawling. I avidly avoid the heavy bumpers and accessories to keep my rig as light as possible, and I don't drive fast through rough terrain.

My bumpstop extensions are about 2", which is approximately how much the shocks are compressed by going to eye to eye adapters. The bumpstops are not really the relevant point, though...they are an effect of how you design your shock travel. I personally think that having 6" of up travel and 4" down like OME medium and being subsequently limited to 33" tires is an entire class of performance below being on 35's with 4.5" of up travel and 5.5" down when your focus is on rock crawling performance. How different is this from being on L shocks on a 4" lift?

I think this is a great picture. On straight OME medium, this is the full stuff of the rear tire at the point the 35" tires started to rub. There is approximately 1.25" of travel left to the rigid bumpstop on the frame, and the spring tower stop has made contact. The distance at static ride height to the rigid bumpstop was 5.75".

So what this says is that on a 2.5" lift (OME medium) with a true 35" tire and no plastic, you have a clean 4.5" of up travel to contact. If you go up to a 3" lift (net of any extra weight), then you have 5" of up travel. So you can space down the travel of your shock and bumpstop accordingly, and on a 10" travel suspension you are well balanced between the concerns of providing enough up travel for a heavy truck and enough down travel for the trail you are barrelling towards at high speed.

Nay

 

[Walking Eagle]

That is correct. If you keep the same shocks mounted in the same position and lift your vehicle, then you have simply extended the shock at static ride height, and shifted available shock travel upwards. You have also maintained the exact same limitations you had on tire size. L shocks will shift travel back down (as will eye to eye adapters).

To use a real world example, the OME shocks for the stock replacement suspension are the exact same shocks as the 2.5" lift. So you can run 33" tires either way, and you simply have more up travel with the lift and less down travel.

Another real world example is Slee's 4" and 6" lift. Both use L shocks. Both have same bump stops, both have same limitations on tire size.

 

[Nay]

I'd say that's more an issue of soft shocks. At least if they had lift that was more than what the bump stop drop was. Easy test, find someone with RS9000's, have them run a section w/ them at 1 and re-run at 9, I'll guarantee alot more bottoming at 1 than at 9.

That is actually a major reason I love Bilstein on lifted applications. The 5100's are heavily geared to compression valving. The adjustability of RS9000's as I understood a few years ago was in rebound valving. I've gone from RS9's to Bilstein 5100's in the past, and I would never go back.

I am getting out of my range of direct knowledge here, but I think there is a good reason why Bilstein has made a name in offroad racing shocks. If you really want to run hard and fast to the trail, and crawl when you get there...you probably need a remote reservoir setup and I would not be one bit surprised if people are overheating their OME shocks in this kind of usage.

Nay

 

[Romer]

Relative to bump stops. I think the following section can be completed now.

Here is what I am getting, please correct it as you see fit.

Bumpstop modifications are required for two issues: 10 To prevent tire rubbing on lifts and 2) to keep the shock from fully compressing potentially damaging the shock. The Bump stop limits the axle movement.

Please correct or expand as you see fit so we can complete this FAQ item.

Thanks for the great discussion!

 

[Walking Eagle]

from another thread:

I can think of 3 reasons for lowering bump stops.

1. Longer springs that would over compress.

2. Longer shocks that would bottom out.

3. Larger tires that you want to keep from rubbing.

 

[Trunk Monkey]

In my ever so humble opinion I wouldn't go to L shocks unless it was a dedicated, or mostly so trail rig.

I did. I regret it.

It's funny that you say this. Right after I put the J's and L's on, I took a freeway corner that's on my way to work that I'd taken every day at 60mph. Well, different springs and shocks and the truck was leaning WAY over. With the std. OMEs and the LTRs the 80 actually cornered decently. For a brick.

 

[Walking Eagle]

. The adjustability of RS9000's as I understood a few years ago was in rebound valving.

from their site

"The RS9000X is fully adjustable while mounted on the vehicle which allows drivers to easily "dial in" their ride for precise control in any condition, tuning the compression and rebound damping is easily metered by manually changing the setting on the dial at the the bottom of each shock."

I just used it as an example, cause then all other things are equal.

 

[Romer]

Thanks for everyones help. I have cleaned up and re-issued the OME FAQ. The link can be found in the modifications section of the FAQ.

I have closed it for now, but we could open it up if someone has a post that would add to the FAQ. PM me or reffug and we can temporarly open it.

PM us with any corrections, modifications or additional links that you think are pertinent.

Thanks for all your help, especially Christo Slee for contributing as this was generated.

The 80's section rocks because of the members here!

 

[Nay]

from another thread:

I can think of 3 reasons for lowering bump stops.

1. Longer springs that would over compress.

2. Longer shocks that would bottom out.

3. Larger tires that you want to keep from rubbing.

This gets to the heart of suspension design. All three of these parameters can flow from the same design element. They don't have to, but they can if you have a goal to minimize your lift.

1) You choose your tire size for the trails you want to run
2) You then create your lift requirements by designing shock travel to accomodate those tires within the constraints of your suspension design and willingness to trim for clearance
3) Bumpstops should then be designed to stop up travel slightly before the shock runs out of travel which is just when the tires would hit the body.

You don't have to be this precise, but that is what I am getting at with using a 3" lift for 35's. By designing the suspension around 35" tires, the necessary shock travel and lift amount follows. If you put all of these elements together, then you have minimized the amount of lift required for your suspension design, or to put it another way, you have chosen your spring length and rate and the lift amount is the minimum effect of this design (unless you change mounts in which case all bets are off).

So in my case, the shocks will prevent serious rubbing...or full compression will occur at about the same time as rubbing, so the stops are lowered to protect the shocks that are protecting the body.

I still have to play out the millimeters in a variety of offroad situations, but this is the design premise and where bumpstops fit in. If you disconnect tire size and shock travel in suspension design, then bumpstops might have nothing to do with protecting shocks as the body will stop the tires before the shocks run out of travel.

Nay