Tech Topic the week: Front Bumpstops

[steveh]

With the amount of lift a lot of us run, bumpstops area must.

So, how do you figure out how much Bumpstop to use? IE, what should be considered when designing front bumpstops

• What kind of bumpstop?
• How much space for travel?
• Standard vs. air or hydraulic?
• Is it even Important??

A search turns up some info, but not really any process to follow to determine the design.

Results of Title search for "Bumpstops"

Some pics of various designs:

[flecker]

Energy suspension sells a huge variety of bumpstops... I always went by the "stop it where it hits, or binds anything" theory. As for important? Yeah I think so... Helps in all kinds of ways. Just MO.

[derek]

Here's the best way to periodically check them .....

derek

[bursemike]

on full stuff take a measurement from mounting surfaces and then add a 1/2" or so of give on the bump stop. Energy suspension is a great place to find them. Yes they are important and any type that is used is better than none at all.

[montezuma]

Originally Posted by bursemike

on full stuff take a measurement from mounting surfaces and then add a 1/2" or so of give on the bump stop. Energy suspension is a great place to find them. Yes they are important and any type that is used is better than none at all.

This is what I've taken as a general rule of thumb, except I take my measurements from when the spring goes flat. It also depends on what style of bump stop you are using, and how tall it sits. JCA here on the board has done a couple of really nice set-ups on different vehicles. Maybe he will chime in.

[Bones]

You can kinda see mine here. They are energy suspention ones. They collapse a fair amount. As you can see, not much uptravel at all and I am considering lowering it another inch. Shock is ~1/2" from bottoming out. Prerunning I'm sure it just might bottom out.

[4RnrRick]

This is my theories:

Before you can add bumpstops I make sure nothing is binding. How I do this is I flex up each of the 4 corners one at a time slowly and look at the following items while I steer the front tire back and forth. If I seen any major issues I stop and deal with that before I try any farther.

Steering linkage (drag link, tie rod, pitman arm)
Brake lines (enough slack, not rubbing anything)
Tire rubbing (frame, springs, sheetmetal, brakelines)
Shackles (hitting/binding , sideways flex, angle of them)
Springs (kinking, seperating too much, springs gapping, reverse arching)

After I make sure everything is safe and I don't damage anything flexing then I measure for bump stops. Its best to use factory vulconized rubber type bumps instead of they poly bumps. For me teh poly ones are just not strong enough and I end up ripping them off. Also since I sit really low my springs don't have much arch to start with so I do reverse mine a bit. I think my gap to the bumps are about 2 1/2 - 3" up front and 3-4" out back when the vehicle is on level ground. For me most of my flex is from droop and not stuff.

The other thing to take into consideration is that once the axle hits the bump stop the vehicle will then rotate on that bump so it needs to hit what ever surface perpendicular so it doesn't quirt out the side. hence thats why my bumps stops are installed at an angle.

[DRM]

Some good replies so far here

BTW -the stock Toyota front or rear bumpstops are pretty nice actually, and are easily used in a variety of applications... Keep that in mind before you go spend the $$$ on aftermarket ones

[steveh]

Good stuff! Keep it coming, and I bet 4RnrRick will be adding the best of this to the FAQ!

[Bones]

Originally Posted by DRM

Some good replies so far here

BTW -the stock Toyota front or rear bumpstops are pretty nice actually, and are easily used in a variety of applications... Keep that in mind before you go spend the $$$ on aftermarket ones

I run stock ones in the rear, but could not find anymore locally so I nabbed the poly ones off the shelf at the poser shop. Held up great for a couple years. I have a nice 1.5" piece of tube on the flip plate for it to land on so it spreads out the load better.

[ErikB]

I used stock rear bumpstops welded to the frame and trimmed them a tad w/ a sawsall. I set them up so that they keep my drag link off the frame on the passenger's side and my spring off the drag link on the driver's side. I ended up with about 2.5" of vertical travel before the tips hit on flat ground. I'd like more compression travel, but stuff starts hitting...





Oh yeah, in the rear I've never had any bumpstops ever since I put in the Chevy springs. No problems...

[4CrawlR]

Here's what I run (Energy Susp.):



Gives me about 3.5" of up travel, top of stop is about 5.5" off the top of the spring plate. I can change out the aluminum spacer to change the height of the stop if needed, may drop it down another 1/2" or so:

http://www.4crawler.com/4x4/4R_suspe...html#Bumpstops

[Roc Doc]

I run the stockers in front, (run 44044's and 9012's), and the only thing I don't like is they're pretty damn hard. When you blow through the travel, Baja'ing it to the trail head, they slam pretty hard. The Enery Suspension type are a poor-man's air bumps, much more progressive.

I also run the stockers in the rear, spaced down from the frame rail with a 3" box tube, to keep my Chev's, and buggy leaf intact. Although I don't think I've ever actually used up all my up travel.

Doc

Doc

[derek]

STEVE!!!

derek

Originally Posted by derek

Here's the best way to periodically check them .....

derek

[SeaBass44]

Originally Posted by DRM

Some good replies so far here

BTW -the stock Toyota front or rear bumpstops are pretty nice actually, and are easily used in a variety of applications... Keep that in mind before you go spend the $$$ on aftermarket ones

also plentyfull! I bet you and I have more then enough with the trucks we have parted out , that is if we kept them I would like to see the hydro ones, I've never seen them 4sale or a detailed write up of how to brew your own, just remember CAMO havin some, so I justy guess they are BIG$$$$$$$

[4RnrRick]

Originally Posted by 4CrawlR

Here's what I run (Energy Susp.):

I've been running those for the last couple of years and now I consider them a consumable on the front axle! I'm constantly loosing them because they break off. My buddy has the factory ones remounted and has had no problems, and our suspension is almost identical. Heck I even think I've got a couple spares in my tool box! I usually get about 5-10 good trail ride on mine before they pop off. Guess that means I need more lift so the spring can take up more of the force before I bottom out on the bump. Or maybe I should have the 4runner go on a diet!

I think my problem up front is that the axle compresses on against the bump stop and then as the other side keeps drooping down, it actually pivots on the poly bump and puts a side load on the bump and eventually pops it right off the center pin bolt. And thats already with teh bumps installed at an agle to make them hit perpendicluar when I flex. if I go any more of an angle, they pop off if I hit a speed bump to hard!

I'm too lazy to find some factory ones and redo them again!

[4CrawlR]

I have lost one myself and I do carry a spare. Its been about 3 years since I did lose the last one, so I guess I have better luck with them, knock on wood.

[GRMhick]

I run the factory front bumpstops. They are welded to a piece of 2x4 tubing, which is welded to the frame. They contact the spring right when the spring goes flat. Out back I run stiff overloads, and call it good.
I run some rancho poly bushings on my other truck and like them more, as they are more progressive.

Those air bumps that are shown, if I am right, those are off of camo's buggy, and he made them himself.

Any chance you, or anyone else wants to post up about how they are made?

[Brandon]

I use my drag link on one side and my pitman arm on the other - shocks bottom on both sides LOL

curious as to why you say they are a must? One of these days I'll put em en but..

Coming out of the end of the trail saturday on the tahoe end I bottomed out a few times, slammed the drag link into the frame pretty good! Didn't hurt anything though..

[4RnrRick]

IIRC, The air bumps are purchased. The brackets are custom....

[mobil1syn]

Originally Posted by 4RnrRick

IIRC, The air bumps are purchased. The brackets are custom....

nah camo and a friend built them ... cant seem to find the thread right now

[Brandon]

Originally Posted by mobil1syn

nah camo and a friend built them ... cant seem to find the thread right now

Bob Roggy sells em I believe..

[4RnrRick]

Here you go...

Air bumps: http://www.polyperformance.com/air_bumps.htm


They are sweet but out of my price range!

[GRMhick]

Ya, out of my price range too, which is why i would like to see how they are made.

Chris, think with a set of air bumps I can keep up with nebel in the desert

[LouBell]

Originally Posted by Bones

You can kinda see mine here. They are energy suspention ones. They collapse a fair amount. As you can see, not much uptravel at all and I am considering lowering it another inch. Shock is ~1/2" from bottoming out. Prerunning I'm sure it just might bottom out.

I am running the same ones as Bones, but mine are mounted perpendicular to the frame (90* from pictured), which really helps with the side loading during articulation.