Another Bump Stop Question...

[LVRockCrawler]

I know I've asked b/4 about removing the bump stops - bad idea from the responses i got - wondering tho if anyone's tried just trimmimng them? i noticed they get alot of contact with the extensions on the axles - btw - its a 4" HellCreek w/33x12.5 BFG M/T's - any feedback???
thanks!

 

[Junkpile]

It depends. If the bumpstops are stopping suspension at a point where you still have alot room to flex, then trim away. But even if the tires aren't hitting, you don't want the spring to be able to reverse arc. Get it all twisted up on a hill or nearby loading dock or anyting else you can jack a tire on(forklifts work good for setting bumpstop height), and see what's happening.

 

[TwistedCU]

If it won't rub, yank 'em. I'd rather have all the flex possible for going over obstacles. Yeah, the springs will sag quicker if you flex them hard and often, but I say use them, abuse them, and replace when needed.

 

[Bounty__Hunter]

Unless your like me and can't afford to be replacing springs every year or two. Nothing wrong with limiting compression to make springs last longer, especially when you've got lockers. Flex isn't everything.

 

[Inspector-Gadget]

Hi-Ya LVRockCrawler,

I would suggest caution as regards modifications of the bump stops of your Jeep.

The purpose of bump stops is to prevent drivetrain damage -- not to prevent tire rub.

Why do we even need bump stops, anyway?

When the rear suspension is under compression from the neutral position, the length of the driveline must decrease. When the rear suspension is under extension (droop) from the neutral position, the length of driveline must increase.

That driveline variable length is achieved by means of the driveshaft slip joint.

As the rear suspension cycles through compression, neutral and extension, the sliding section of the driveshaft is reciprocating: that is, the forward end of the driveshaft is continually approaching and moving away from the transfer case output yoke.

The driveshaft slip joint has limited allowable travel, however.

The bump stops limit how far the drive shaft can slide forward when the rear suspension is under compression by limiting vertical travel of the rear axle.

If the bump stops are removed or shortened, it is entirely possible that the driveshaft will slide too far forward when the suspension is under severe compression. If that happens, the allowable travel of the driveshaft slip joint is exceeded and the drive shaft becomes a fixed length pipe. The front end of the driveshaft then crashes into the transfer case with great force.

That is a bad thing: a bad, bad, bad thing. :roll:

The sound you hear when that happens is the sound of money being sucked out of your bank account to pay for very expensive replacement driveline parts.

So...why bump stops?

Simple: they safeguard your bank account by limiting forward travel of the driveshaft.

:wink:

Regards,

Gadget

 

[TwistedCU]

I was assuming by removing bumpstops you meant removing the bumpstop extensions that came with your lift kit, and not the stock bumpstops. Is this correct?

My BDS kit had a set that came with them and they were recommended with use of 33" tires (it was a 3.5" lift). I was running 32" tires and had an additional 1/2 of lift via shackles. I never installed the bumpstop extenstions.

If your drivetrain is stock and you leave the factory bumpstops on, then you will never have to worry about over-compressing the driveshaft because it will still not be able to compress any more than when you had a stock suspension and tires.

About spring life, if you do alot of offroading that includes obstacles then yes, removing the bumpstop extensions for added flex will probably wear your springs more quickly. It depends on what you're looking to do on whether or not it will be worth it.

As for me, I didn't have lockers and needed all the traction I could get, and the springs I had were warrantied for life so it was a no-brainer.

 

[Inspector-Gadget]

TwistedCopper wrote:

I was assuming by removing bumpstops you meant removing the bumpstop extensions that came with your lift kit, and not the stock bumpstops. Is this correct?

My BDS kit…

Point well-taken, Harry.

When trying to answer posted questions, we often don’t have of all the information we might like. That was the case with LVRockCrawler’s starting post.

My method, when faced with a lack of information, is to imagine the worst-case scenario. That scernario being, in this case, stock bump stops.

Hence, the “cautionary” as opposed to “don’t do this” tone of my reply.

It is in LVRockCrawler's hands now.

Regards,

Gadget

PS: Suspension over-extension/compression also results in broken shocks.

 

[Bounty__Hunter]

IG, the splines on the driveshafts actually compress and entend very little when wheelin unless you're into speed and compress the entire axle at once. Ordinarily one end of the axle is up and the opposite end is down, keeping the pinion in a relatively static position.

I've never seen an issue of an over-compressed driveshaft due to the complete bottoming of an axle. It's possible in theory I guess.

I think bumpstops are more for tire clearance at the fender and to minimize spring fatigue.

BTW, good to have you back with us.

 

[Junkpile]

I don't know how much fender clearance you guys have got.......but my tires are going to have to win a major battle with some sheetmetal if I compress my 4" lift springs and lift shackles enough to hit the factory bumpstops.

 

[redrooster]

Bumpstops? What bumpstops? Pull the stops, cut the fenders and add more spline to the driveshaft. IF you are worried about shackles, make some boomerangs.

 

[TwistedCU]

Bumpstops? What bumpstops? Pull the stops, cut the fenders and add more spline to the driveshaft. IF you are worried about shackles, make some boomerangs.

 

[hi_c]

bob (lvrockcrawler),

don't worry about replacing the springs. Tom Laher, the owner at Hell Creek is real good about replacing them under the warranty. I had to replace my first one since I installed the kit last december. I called him up and told him I bent one wheeling. I had a free replacement (didn't even have to pay shipping) in 5 days. When I bought my Hell Creek kit, I specifically asked about sagging. And he said that it's covered lifetime as long as you are the original owner and it's on the original Jeep it was installed on. So pull those extensions and flex away.

Corey
(ps. I don't get on this board much anymore because it's blocked by our firewall at work now. I guess they started adding up my 'online time' and realized this was my heavily visited site. I only check from home now. And that's not every day. Let me know if you got questions.)

 

[LVRockCrawler]

Thanks...

yea... ive had nothing but great experiences with tom... he answered my questions almost immediately - even on sundays - and when i asked why i got bunches of rough country stickers and no hell creek ones - he sent me my windshield sticker (looks bad-ass at that!) - gonna pull the extensions this weekend and leave the stock rubbers on there - see how she does!

thanks all!