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PROTHANE FRONT BUMPSTOP WRITEUP

slcpunk74

NAXJA Forum User
Location
UTAH
So I know that I am among a few that are doing this but I thought I would get this up so we can all build ideas.

You need to make a cap for the prothanes so that the stock bump does not kill it. I opted to do the cap out of 2.5"x2.5"x.180 welded to the top of a 2" piece of 1.5"tube. The 1.5" tube fits snugg inside the prothane with no mods.
Here is the cap

DSC00985.jpg


I also made a base so that the bump would not be free. Some say that it being free is ok but I just figured why not. One thing to note is that after welding the base on my coil bucket I now have to unbolt my trac bar to get my coils out.

Here is the base that is also a 1.5" tube.

DSC00982.jpg


Now just paint your junk and install the coils with the prothane loose in them and when the coil is on you can slide the prothane onto the base.

DSC00986.jpg


I have not tested these and I do not know how much they compress. I would highly recomend thinking about how long of a bumpstop you need and if anything make it bigger then you expect to need. Keep in mind your stock bumpstop will compress aswell as the prothanes. I bought the 10.5" prothanes but ended up using about 6.5".

Link to where I got mine. http://www.jegs.com/p/Prothane/762170/10002/-1

I hope to have a review by tomorrow and maybe a video too.:party:
Have fun guys
Chadwick
 
Goatman indicated that with a 12" travel shock, with 6" of up/down travel, he's runnning a 2.5" airgap. My measurements are nearly identical.

Had a similar thought about keeping them centered on the base plate instead of letting them float in the coil, only my plan is to use a 1.5" OD piece of tube, with the top capped and a welded in bolt protruding from the bottom, secured with a nut below the spring baseplate. This way they can simply unbolt, if the coil needs to come off.

I didn't get mine installed in time, so we'll see how yours work today.......see you at Sand Mtn.
 
My only worry about this is: If the Prothanes compress enough to make the two pieces of tubing at both ends hit each other you might have a problem. I think I read somewhere (goatman or cracker) said they compress quite a bit, I'd just be worried about the tubes hitting each other before it really compresses enough to slow the suspension down.
 
My only worry about this is: If the Prothanes compress enough to make the two pieces of tubing at both ends hit each other you might have a problem. I think I read somewhere (goatman or cracker) said they compress quite a bit, I'd just be worried about the tubes hitting each other before it really compresses enough to slow the suspension down.
There is a bit of room between them(like 3"+). Im not really worried.
 
Have you thought about drilling a hole in the top plate there, so the air can escape when it compresses?
The air can escape out the bottom of the stock coil bucket.
 
So I treid them out today and wow they work great! Very progressive and not harsh at all. I have hit two small jumps on these and my rear poly setup and they perform very good. I also have to add that my FOA's work very well. No video yet because my camera was being a douche.
 
i also have concerns about the 2 pieces of tubing hitting eachother.

and on a side note, do you really need to have each of your threads start in ALL CAPS? stop yelling man we're all friends here ;)
 
So I treid them out today and wow they work great! Very progressive and not harsh at all. I have hit two small jumps on these and my rear poly setup and they perform very good. I also have to add that my FOA's work very well. No video yet because my camera was being a douche.

Glad to hear their working good. Which FOA's do you have?
 
i also have concerns about the 2 pieces of tubing hitting eachother.

and on a side note, do you really need to have each of your threads start in ALL CAPS? stop yelling man we're all friends here ;)
I guess if I make them all look like every other thread good tech could fade away. Didnt mean to piss you off there. If nobody wants me posting I will stop but I am only trying to help and I dont think knocking on me is very productive.
 
Goatman indicated that with a 12" travel shock, with 6" of up/down travel, he's runnning a 2.5" airgap. My measurements are nearly identical.

Had a similar thought about keeping them centered on the base plate instead of letting them float in the coil, only my plan is to use a 1.5" OD piece of tube, with the top capped and a welded in bolt protruding from the bottom, secured with a nut below the spring baseplate. This way they can simply unbolt, if the coil needs to come off.

I didn't get mine installed in time, so we'll see how yours work today.......see you at Sand Mtn.

Make sure you add pics and what not. I started this thread in the hopes that it could be a general prothane tech article. Hey plus most people dont seam to like the way I did it so maybe they will like your way better.:cheers:
 
I picked up a set of the 10.5"s so I could have two sets, one for trails(3 ribs) and one for jumping(4 ribs). I had to drill about 20 1/2 holes in them to soften them up, before they where way to hard, now it's like landing on a cloud. I'm running 3.5"RE zj coils with f-250 front shocks in front(shocks work great for a set of free longer shocks). I have not made a 'landing' plate for them yet and not sure if I will, have not had an issue getting speared on the bump tower.

I feel they are money well spent, sorry for the poor post details, fighting a cold...andy miobi.org
 
How do you figure out the compressed height of these things so that you're not wasting travel?
Thanks,
Billy

make them longer then you need and run a zip tie on your shock, go jump it and do the math. I just guessed and it seems pretty close so far.
 
doh2.gif
Thanks!
Billy

Yeah SWAG is a great system. I really just guessed and watched what my shock shafts did. I really dont know how much they compress because I have not done the math yet.
 
"UPDATE"

I was hitting some whoops about 50mph and it was doing great. After hitting the whoops super hard I went home and flexed out in my driveway to inspect my suspension. Long story short I need to add an inch or so to the prothanes because I bottomed my shock and bent one of the mounts "OUCH!". It wil be an easy fix and I will post up my lengths in 5 mins so we all know ho much they compress.
 
1.5" gap between the prothane and the stock foam bump. I think the stock bump could compress somewhere around 1.5" and I bottomed all 5" (at ride hight)of my shock shaft so we can figure that my prothanes can compress around 2.5-3.5".
So I guess I can add another 1.5" to my prothanes(which is easy due to my tube design) or get some poly bumps that replace the stock weiners. I will just add some prothane for now but maybe later on get poly weiner replacers.

Also a good not is that I found nice foam bumpstops off of a 96ish blazer rear. I looked at them and they could sit inside a coil and you could cap the top just like a prothane. I might do a blazer bump writeup just for fun and good tech.

crappy pic
n1478550133_30046409_6906.jpg
 
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