PROTHANE FRONT BUMPSTOP WRITEUP

[travisk]

OK. So I need about 6.5" of hard bump stop. If I get the 10.5" Prothanes, I will have almost no air gap. That doesn't seem optimal.

What if I used a 7.5" Prothane on top of something harder, like a hockey puck?

 

[dukie564]

best option seems to be to leave about 1" air gap (you can cut the prothanes), and use UHMW solid rod inside as a hard stop.

You could use pucks too though

 

[Lurch]

Would a 3" round plate welded to the upper bump tower be small enough to clear the spring?

I *think* the plate diameter I am using is 3", but I welded a 1/2" bolt to the top side of the plate then drilled and tapped a hole in the bump tower so that the plate could be unscrewed and removed. I wasn't able to get the spring on/off with it attached.

I think that this is the company that I order the disks from but I couldn't find the e-receipt so I'm not sure.

http://www.wagnercompanies.com/disks_and_plates.aspx

They are definitely DIY-able but I was living in an apartment at the time so this was easier.

 

[zachandandy]

I used a 3" hole saw on a piece of 3/8" plate. Drilled it with a cordless drill to avoid breaking parts when the saw would catch. Bolted in for easy removal.

 

[dukie564]

3/8? holy shit

 

[rockclimber]

my bumpstop plates are 3/8" as well. got them from ruffstuff.

not sure if they have any more to sell, but they are still listed on the site.

http://www.ruffstuffspecialties.com...arch_Begin_Only=&sort=&range_low=&range_high=

 

[ert01]

I just used a hole saw to cut some discs out of 1/4" and welded them onto the stock tower (with the stock bump removed of course).

 

[yossarian19]

Hardware didn't have the right hole saw, but the welding / metal shop had 1/8" steel discs. Bought four, doubled them up, through-bolted them to poly bump stop inserts. Might have to open up the air gap and weld them to the towers, though.

 

[Vanimal]

i put these in front and rear into my zj, and i don't really like them so far. they definitely don't seem to compress much, if i flex the jeep out with the forklift they barely budge. I have 12" shocks front and rear, and about 50/50 droop/uptravel. My air gap is about 1.5".... thinking of cutting one rib off on each one. Any thoughts? I definitely feel them rebound on the road when i hit big dips... WAY more than it did before.

 

[cal]

You have too much bumpstop.

4643 has like a 3.5" airgap and 1.75" of prothane until we hit the hard bump.

 

[Vanimal]

thats what i thought but figured i'd ask. i saw mixed responses in this thread. i'll cut rib one off tomorrow and see where it goes. Do you notice that it helps at all with stability with that much gap? my whole reasoning for getting them was that the zj has rather soft springs and it didnt seem to be all that stable. I know my roll center is screwed because i still have stock steering and track bar locations (for now), but still...

 

[SteveMongr]

The Prothanes will not compress much from the static weight of jeep. That would defeat their purpose. They perform at speed, in whoops and jumps, or dropping off ledges/obstacles, and anywhere you would normally bottom out the suspension.
Also will not make up for soft springs or low damped shocks.
If you feel rebound from the Prothanes, it is likely because the shocks do not have enough rebound dampening.
I have experimented a lot with these and settled on 2" air gap, 5 ring Prothanes on 4.5" lift. Rubber stop inside of prothane. Daystar hard-rubber jounce bumpers to contact plate on top of Prothanes.

 

[cal]

thats what i thought but figured i'd ask. i saw mixed responses in this thread. i'll cut rib one off tomorrow and see where it goes. Do you notice that it helps at all with stability with that much gap? my whole reasoning for getting them was that the zj has rather soft springs and it didnt seem to be all that stable. I know my roll center is screwed because i still have stock steering and track bar locations (for now), but still...

No. You're trying to use an orange to make applesauce.

You need a sway bar, and or firmer coils, and or real shocks.

 

[Vanimal]

No. You're trying to use an orange to make applesauce.

You need a sway bar, and or firmer coils, and or real shocks.

i plan on an antirock at some point, but i was just hoping this would help a tad so i could get through SCF this weekend. I have 7100 remote res shocks all around with decently slow valving, I would not want any more rebound valving. It is almost too much right now.

 

[cal]

sounds like time to call up PAC and order some firmer coils then.

 

[$700later]

I ordered the longest ones and initially installed them without cutting them, which was zero air gap but they didn't have any actual weight on them. I tested, cut a "ring" off, tested again and cut another ring off. So that's around 3" or 4" air gap now? I like where it is. Works well keeping my 39s out of my lap. Some day I hope to go down to a 37" tire and may cut another ring off at that time. This stuff varies from application to application. What works well for me at windrock might not be so good somewhere else. Happy trails!

 

[cracker]

sounds like time to call up PAC and order some firmer coils then.

And spend money for Wayne to tune.....but wait, he won't do that and then tell everyone how much the prothanes suck :doh:

 

[Vanimal]

And spend money for Wayne to tune.....but wait, he won't do that and then tell everyone how much the prothanes suck :doh:

cool story, douche.

 

[Vanimal]

I ended up cutting a rib off each one and it was definitely much better. It worked pretty well up in big bear. I think i'll throw a zip tie on my shocks next time i go out and see how close i get to bottoming out and trim them a little more if i can get away with it.

 

[zoomy97acr]

After 20 miles of severe use the prothane bumps are toast. Don't waste your money if you are looking to save your suspension. Yes they do work, for a short time, but they crack down the sides and flake off. Better to save money and get hydraulic bumps.

- 1711 Jeepspeed