Shocks as bump stops?

[Bud125]

I have seen this mentioned by some knowledgeable people here. I am currently working on my rear axle clearance and after cycling it looks like I need 3" inches plus to keep my JKS trackbar from hitting the rear cross support. Should I build up my bump stops or just measure and select shocks that will limit its travel? I may have misunderstood their intentions in saying this, just looking for some clarification,

 

[jjvw]

Build up the bump stops so that the jounces do their job of slowing the shock down before it reaches full hard compression.

Also, if the track bar is needlessly limiting the up travel, then fix the track bar so it doesn't limit travel.

 

[pagrey]

I have blown shocks with a single impact on a setup that didn't have properly setup hard stops. By blown I mean the shock no longer worked and fluid was everywhere. I don't know the details of what happens or what shock types are vulnerable but generally the shock and shock mounts aren't really designed for hard impacts like bottoming out and that's why you need the bump stops set to protect the shock. It would be interesting to hear if there were shocks that were more or less vulnerable to this sort of abuse, I've always assumed they all would crap out if they weren't protected and you bottomed out at speed.

 

[Bud125]

Build up the bump stops so that the jounces do their job of slowing the shock down before it reaches full hard compression.

Also, if the track bar is needlessly limiting the up travel, then fix the track bar so it doesn't limit travel.

Thanks, will do.
On the track bar I assume it would take a custom bend or trim the cross support.

 

[imahnu]

Thanks, will do.
On the track bar I assume it would take a custom bend or trim the cross support.

What part of the track bar is hitting the rear cross member? Is it the bend upward on the frame side?

If you have the JKS track bar raised bracket installed on the axle side mount that came with your rear track bar, you‘ll want to remove that as that will bottom out too soon as well if you still have the 2” of lift in your profile.

 

[IPerkWVU]

Build up the bump stops so that the jounces do their job of slowing the shock down before it reaches full hard compression.

Also, if the track bar is needlessly limiting the up travel, then fix the track bar so it doesn't limit travel.

Does the quality of shock matter for this application?

Basically asking is your above method OK for all shocks or just for those that are rebuilt on a certain interval (fox smoothies)

 

[jjvw]

Does the quality of shock matter for this application?

Basically asking is your above method OK for all shocks or just for those that are rebuilt on a certain interval (fox smoothies)

I did this way with cheap Rancho 5000x and not cheap Fox 2.0.

 

[Blackjack]

Does the quality of shock matter for this application?

Basically asking is your above method OK for all shocks or just for those that are rebuilt on a certain interval (fox smoothies)

Not necessarily. What you are trying to achieve is making sure the bumpstop does what it needs to do without leaving shock travel on the table. That said if you are more into the go fast thing then you want to bias towards the bumpstop being the hard stop with the understanding that some sacrifice of total articulation may come with it.

 

[eastbloc]

I have blown shocks with a single impact on a setup that didn't have properly setup hard stops. By blown I mean the shock no longer worked and fluid was everywhere.

Same thing happened to my front Fox 2.0, one invisible speed bump at night and fluid started coming out.

 

[pagrey]

Same thing happened to my front Fox 2.0, one invisible speed bump at night and fluid started coming out.

Good to know, I think you have to be realistic about how you drive. For me I think it's best I set mine 100% protected metal to metal.

 

[jjvw]

Good to know, I think you have to be realistic about how you drive. For me I think it's best I set mine 100% protected metal to metal.

If you are going to do that, how much shaft do you leave exposed? 1"? 1/16"?

FWiW, Currie/RockJock bumps do not allow for a metal to metal stop. Nor do they specify what kind of shock or what kind of driving they are intended for.

 

[pagrey]

If you are going to do that, how much shaft do you leave exposed? 1"? 1/16"?

When I checked I just made sure at full stuff the bushings didn't start to compress. I didn't really pay much attention to the exposed shock shaft. Like I said before, I don't really know if it matters but with metal to metal I didn't think I needed any margin. I've hit pretty hard on my current setup and they haven't exploded yet. I'm running aftermarket Sachs that are 12.5" and they aren't great but it's not like I have many options at that length.

Edit: I did see your little tower extensions, those are great

 

[jjvw]

When I checked I just made sure at full stuff the bushings didn't start to compress. I didn't really pay much attention to the exposed shock shaft. Like I said before, I don't really know if it matters but with metal to metal I didn't think I needed any margin. I've hit pretty hard on my current setup and they haven't exploded yet. I'm running aftermarket Sachs that are 12.5" and they aren't great but it's not like I have many options at that length.

Edit: I did see your little tower extensions, those are great

I've been saying for a long time to make the factory bumps match the compressed shock. That allows for full shock travel and metal to metal contact at the bumps.

 

[freedom_in_4low]

Before I had Currie bumps I let the shock bushings do a little bit of the work, like 1/8" between the bumps with the shock fully bottomed out. Not that I necessarily did that on purpose... I just didn't want to mess with adding 1/8" of bump stop and figured that would be good enough.

Now the curries touch with about half to 3/4" of shock shaft exposed.

 

[Bud125]

What part of the track bar is hitting the rear cross member? Is it the bend upward on the frame side?

If you have the JKS track bar raised bracket installed on the axle side mount that came with your rear track bar, you‘ll want to remove that as that will bottom out too soon as well if you still have the 2” of lift in your profile.

The track bar is hitting where the gas tank skid plate bolts to the cross member, the bolt towards the center of the vehicle.
I am in the process of installing 4" lift springs and yes I have the JKS relocation bracket installed.

 

[Bud125]

I have been looking at the Currie rear bump stops and cannot seem to find how tall they are. Any info appreciated.

 

[Rescue6]

Before I had Currie bumps I let the shock bushings do a little bit of the work, like 1/8" between the bumps with the shock fully bottomed out. Not that I necessarily did that on purpose... I just didn't want to mess with adding 1/8" of bump stop and figured that would be good enough.

Now the curries touch with about half to 3/4" of shock shaft exposed.

How much will the Currie bump compress under full hard compression. I’m guessing it’s less than your stated 1/2”-3/4”

 

[freedom_in_4low]

How much will the Currie bump compress under full hard compression. I’m guessing it’s less than your stated 1/2”-3/4”

No idea. It's like 3-4" of all polyurethane, no steel. At speed I can see it compressing that much, probably not crawling though. I will admit to pretty much just copying what jjvw did.

 

[jjvw]

How much will the Currie bump compress under full hard compression. I’m guessing it’s less than your stated 1/2”-3/4”

Mine compress about 3/4" when the shocks reach full compression. There is no reason to doubt they can do more.

 

[jjvw]

The track bar is hitting where the gas tank skid plate bolts to the cross member, the bolt towards the center of the vehicle.
I am in the process of installing 4" lift springs and yes I have the JKS relocation bracket installed.

The rears are about 3". Just understand that isn't a hard number. Currie bumps are more of a jounce to slow the travel speed, not a hard limit to travel. The shock is the hard limit.