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Discussion Starter #1
I have yet to install any bumpstops since my SAS. I was wondering what everyone here is using? Do the airbumps propose any major advantage over regular bumpstops. I don't jump or race my truck, but occassionaly do a timed run where the front takes a pretty hard beating. The urethanes are certainly more pockebook friendly. I don't know if I can justify 400+ for some air bumps, but we'll see

I don't really have a lot of room to work with on the front. I was thinking of mounting them on the lower links where thay cross under the frame
 

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swank501 said:
I have yet to install any bumpstops since my SAS. I was wondering what everyone here is using? Do the airbumps propose any major advantage over regular bumpstops. I don't jump or race my truck, but occassionaly do a timed run where the front takes a pretty hard beating. The urethanes are certainly more pockebook friendly. I don't know if I can justify 400+ for some air bumps, but we'll see

I don't really have a lot of room to work with on the front. I was thinking of mounting them on the lower links where thay cross under the frame
I put airbumps on mine last year sometime.....and it REALLY helps a lot during braking, no more front end DIVE....same with cornering...seems quite a bit more stable now; but then again, I had NONE beforehand.

 

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Wow. That looks great. . . . But where's your shock?

It's interesting that this topic came up. I just started doing research on this exact topic. I did a snow run yesterday and there were some spots that required a lot of momentum. The front end came down hard several times and really took a beating. . . . I'm switching to air bumps for sure . . .
 

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Discussion Starter #4
Angry Andy said:
I put airbumps on mine last year sometime.....and it REALLY helps a lot during braking, no more front end DIVE....same with cornering...seems quite a bit more stable now; but then again, I had NONE beforehand.

Do those contact the pad the whole time? It's hard to tell from the picture. HOw much travel do they have? I have about 5-6" of up travel on my front shocks.
 

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Revivalist said:
Wow. That looks great. . . . But where's your shock?

It's interesting that this topic came up. I just started doing research on this exact topic. I did a snow run yesterday and there were some spots that required a lot of momentum. The front end came down hard several times and really took a beating. . . . I'm switching to air bumps for sure . . .

Shock was not mounted in that pic...but it sits just to the left of the airbump.
 

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swank501 said:
Do those contact the pad the whole time? It's hard to tell from the picture. HOw much travel do they have? I have about 5-6" of up travel on my front shocks.

No,they dont contact all the time...There is about 1" clearance on the street.

Airbumps only come into play when my axle shifts one way or another....or wants to dive down during braking.....not sure about uptravel, but positioned as they are allows for max uptravel, unless a longer airbump is installed....I did Soupbowl just fine with these airbumps...No PUSHING needed.
 

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Typically air bumps (looks like Andy has Fox's) have 4" stroke of up travel. You can shorten the stroke to 3" or 2" etc if you decide the ride is too soft for you...
 

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Tweeter said:
Typically air bumps (looks like Andy has Fox's) have 4" stroke of up travel. You can shorten the stroke to 3" or 2" etc if you decide the ride is too stiff for you...

Hrm... I might have to go to Air bumps when I wear out another set of poly bumps.
 

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Discussion Starter #9
Tweeter said:
Typically air bumps (looks like Andy has Fox's) have 4" stroke of up travel. You can shorten the stroke to 3" or 2" etc if you decide the ride is too stiff for you...
If the air bumps have a set amount of travel, does that mean it gets progressively stiffer as it compresses? Does it have consistent damping throughout its cycle? I'm still trying to understand how they work exactly.
 

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swank501 said:
If the air bumps have a set amount of travel, does that mean it gets progressively stiffer as it compresses? Does it have consistent damping throughout its cycle? I'm still trying to understand how they work exactly.
They have a "off the shelf" amount of travel at 4" except for Radflo which makes a 2" stroke model.

They get gradually stiffer in compression the further they compress. Furthermore, have a very rapid rebound rate, which is why they're ideal for desert racing, I've never ridden in a rockcrawler with them before so Andy can help you on that.

I'm trying to make as much sense as I can, also if you find them too stiff you can take out 50 psi or so to soften up the damping if you feel it is necessary. What brand were you going to go with?
 

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Tweeter said:
Typically air bumps (looks like Andy has Fox's) have 4" stroke of up travel. You can shorten the stroke to 3" or 2" etc if you decide the ride is too stiff for you...
I'm a little confused about this statement. . . . I just ordered the Fox air bumps from offroad-engineering.com and the owner there (Michael) said that the way to stiffen or soften them is by adjusting the nitrogen level inside. He said it comes from the factory with 200PSI but can be adjusted anywhere from 50-500PSI. This can be done by releasing the nitrogen from a valve on it, or putting nitrogen in from a nitrogen tank or at a local welding shop . . .

I asked him about the difference between the 3" and 4" stroke (which I only see on the PolyPerformance website) and he said that Fox only makes them 4" but PolyPerformance modifies them by putting a 1" spacer to make the stroke 3". This requires taking them apart to do that. (That was confirmed from my conversation with Dave at PolyPerformance) . . .

However, I was told that it is better to leave them at 4" if possible because that allows a longer stroke for damping to take place. If you shorten the stroke to 3" but you want it to absorb the same impact, you would actually have to stiffen the air bump by increasing the pressure. That means that a shorter bumpstop stroke would make for a stiffer ride, not a softer ride, provided that you need the same amount of absorption. So the only reason for someone to use a 3" stroke would be due to space limitations, if there isn't enough room to mount the 4" stroke. . .

Now the way I was told to determine the pressure you want in the bumpstop is by taking your rig over an obstacle where you know the front end comes down hard and checking to see how much the bumpstop compressed. I was told there is an o-ring on the bumpstop that will move down when the bumpstop is compressed (which I see in the picture above). As long as the o-ring is not at the bottom then you haven't buttomed out the bumpstop. So you can release a little more pressure, try the obstacle again, and check the height of the o-ring again. Once the o-ring is near the bottom, then you don't want to let out anymore pressure. This will insure that the bumpstop is stiff enough to absorb the hardest impact you give it without buttoming out and yet as soft as possible to provide the best ride. . .

Michael said that for my application (V6 Tacoma with an ARB bumper and winch), I should be able to start at the factory 200PSI setting. He said that with a 4" stroke, that's about 880lbs of pressure from each bumpstop (because the nitrogen provides 1.105lb/in per PSI). So that should be plenty to start with. . . .

Please let me know if anythign stated above is incorrect because I'm still learning how these things work and I would be happy to get input.
 

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if you got the dollars airbumps are nice but not necessary, I have 4.5" competition type poly bump stops and they work fine.
That said I wouldn't mind having some air bumps. :p
 

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Sorry for the confusion that was a my bad on my wiriting skills. You CAN add compression inside air bumps, how? I don't know I'm not a shock guru...that statement I made will be edited to prevent further confusion. I was giving examples on how to stiffen/soften the ride...my bad!
 

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the amt. of Nitrogen is not hte only thing that effects an air shocks compresion and rebound. THey are valved and you can change the valving like a coilover shock.
 

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Correct, I've never seen the inside of a air bump before but I would ASSUME that it would be a shim stack just like a regular shock..
 

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Tweeter said:
Correct, I've never seen the inside of a air bump before but I would ASSUME that it would be a shim stack just like a regular shock..

I've got some Bilstein air bumps that I haven't installed yet. someday I will though. :eek:
 

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Hey angry andy . . . I was looking at the picture you have of your airbumps. Your mounting looks really nice. Did you have to fab a bracket that sits on your axle for the bumpstop to hit?
 

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Hmm . . . ok. Well I guess I'm gonna have to figure out how where to put that. . . . I think my swaybar is in the way and my axle already has a lot of stuff on it (shocks mounts, sway bar mounts, and hydro assist mount). . .

I don't know how I'm gonna pull that off. . . . I know bumpstops would sort of play the roll of a swaybar since they'll keep one side from leaning over too much. . . . But I sort of like the idea of a torsion bar that provides an anti-sway effect even before the bumpstops come in contact . . .
 

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I'll ask the stupid question since I don't know, do you need sway bars on SAS trucks? And also I don't know if it helps but you can mount the strike plate up off the axle like an inch or so, doesn't have to be right FLUSH with the axle housing. If you have a picture that would help too.
 
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