Air Bumps - Worth the $ & effort?

[TWISTY]

Am currently sorting out a order from the USA for my new 40 series build. It has linked suspension and fox 2.5 14" coilovers front/12" rear. Will be running 35" tyres and mainly used as a social rig, with the possibility of some comps down the track.

Looking into some 2.0 fox air bumps for all corners, 2.5" travel. For bumps and mounts its around the $830 plus some freight on top of that too.

Any feedback from people who have run linked suspension with normal rubber type bump stops then gone to air bumps? Are they worth the $ ?

[crankycruiser]

I was going to put air bumps in my Ute, and got talked out of it by Greg at superior. His argument was that the bump cap on the end of the bump wears out then they make a racket when doing high speed stuff.

His explanation was waaay better than mine tho.

[evanstaniland]

why fox bumps? could look at profenders?
cant you replace the ends? plus it would take a fair amount of use to wear them out imo

[TWISTY]

I was going to put air bumps in my Ute, and got talked out of it by Greg at superior. His argument was that the bump cap on the end of the bump wears out then they make a racket when doing high speed stuff.

His explanation was waaay better than mine tho.

Actually I remember reading that on here now I think. I did search before starting the thread, but couldn't find much info.

why fox bumps? could look at profenders?
cant you replace the ends? plus it would take a fair amount of use to wear them out imo

Coilovers are Fox, so was just matching them with that. Profender are only $30 or so cheaper per bump anyway.

[parr]

Im sure hiluxpunisher (Simon) ran them on the front of his old duel cab, made a big difference when flogging around the tracks according to bubs.
Check with buddy he had a set laying around his shop for ages for a good price I looked into them for the lux, might save you freight.

[MikeH]

depends if you jump it, the point of the fancy bumps is they have some damping on the rebound, where rubber just goes BOING and kicks back on the rebound.

[TWISTY]

Well the rest of the suspension will be setup to jump, so will probably be jumping it.

[Havoc Racing]

I recommend them. They are cheap, easy to mount, and you have that piece of mind if you do hit something hard.

[brooksy]

Do it once, do it right !!
I would also be looking at 3-4" stroke for the rear if travel allows.



brooksy

[bru21]

Hey mate I have 4 new black ones with cans. $900. They are from the same batch as your shocks. Give me a bell anytime if you are keen.

[TWISTY]

Hey mate I have 4 new black ones with cans. $900. They are from the same batch as your shocks. Give me a bell anytime if you are keen.

Sounds good to me Bru! SOLD

[brooksy]

Well done, I have cans but Justin has the deal to grab !!


brooksy

[MikeH]

Unless you have more than around 14 inches of travel I wouldn't be running 4 inch bump stops. The 4 inch stroke is designed for serious race cars which often have more than 20 inches of travel.
I'm putting hydro/pneumatic bumps in my GQ for desert racing and I've reduced the stroke to 2.4 inches, my car has limited travel because I'm running vaguely factory suspension design.
these are Foxes which are going in the front with pinch bolt mounts, the rear is getting kings which will fit thru the chassis rails better.

from top to bottom here we have:
Shortened bumpstop.
Standard bumpstop
standard spacer tube
"shortened" stroke spacer tube which stops the piston from extending as far.

[brooksy]

4" stroke are not just for racing. It all comes down to your setup with regard to up travel. 12''s I'd limit to 3" bumps if running 50/50. 14's you can go 4" bumps with 50/50 travel.
If intending to jump you want to run the longest bumps possible as the rear works harder on landing than the front in a majority of circumstances. The shared compression dampening helps.



brooksy

[MikeH]

and constantly hitting your bumpstops upsets the car and prevents you from getting all of the power to the ground. It all depends what the car is for.
Social wheeling and the occasional comp in future the 4 inch will hit all of the time down bumpy tracks and drive him mad unless he's more lift than required and wasting half his travel.

[brooksy]

The setup Dave has will be changed in the rear (probably front too) as it currently has a less than perfect "throw it together to pass eng" arrangement. Like I said in my first post 3-4" rear will be a option but this lies with what I later stated depending on length of coilover (retain 12's or go 14's). If the rear squats more than 3" when burying the boot he has more to worry about with geometry than bumps. It ain't no TT or stripper !!


brooksy

[TWISTY]

Actually I'm pretty happy with the rear setup. Steelart did run it through the calculator off pirate and had Dale at 2dextreme change it a few times to get it exactly how he wanted it.
Rough measurements are 840 long lowers, 600 long uppers, Vert sep @ diff 300mm, Vert sep @ chassis 230, parelell lowers, triangulation of uppers is 120 apart at diff, 700 at chassis.

In the front, I'm not overly keen on having 14" coilovers. I think it is too much travel, as the coilover mounts bind at full droop due to the radius arms rolling the diff forward so much. This could probably be sorted easy enough by getting the lower mount angled just right but. Will see if we can get it to work, but I'd happily replace the front coilovers with 12" travel ones.

Few pics from this arvo. Dropped the right height down to have 5" of shock shaft showing in the rear, and 5.5" in the front. The factory rubber bump stops have been spaced down 100mm from stock. At this height the front is almost on the bumpstop and the rear has 100mm clearance to the bump. Height wise this is pretty close to how my old silver 40 sat but its bumps had only been spaced down 75mm.

[hammey]

Smitty

[brooksy]

That's not what you originally said
Looks heaps better sitting lower, this will change the no's on the calculator too by the way & seperation is excessive at both ends with link lengths but maybe packaging determined this. Why would you setup shocks without even considering bump lengths
What do the fronts bind with, is it the coils fouling on towers ? I suppose we will just Suss it out when you drop it down over a few beers
Plenty of options to look at anyway.




brooksy