I have been thinking about it, and I can't figure out why the bumpstop extenders matter.

Anyone try running without them?

Seems like there will be a little more flex... I think i bottom out on the stops before the spring fully compresses.

I've seen it discussed in the threads but nobody seems to have tried it...

 

When you put in spacers, you effectively increase the gap of the bumpstops. Since your spring is the same length as before (just moved down lower), you want to have the same gap in the bumpstops, thereby allowing the same amount of uptravel and spring compression. The spacers you put in are non-compressable, so all compression is applied to the spring. This assumes that Jeep knew what they were doing in sizing that gap. The extended bumpstops bring that gap back to the stock amount (or close to it) to save you from overcompressing the spring.

You could try without the extenders and see, but you will compress the spring more than it was designed for. If you really want greater flex and wheel uptravel, you should go with longer springs instead of spacers.

 

what he said...

You will get more flex without the bump stops, but it’s not a flex you want. The springs are only designed to compress down to a certain height, and any more than that will warp it and cause it to be over compressed which in turn will make the jeep sag. Longer springs don't have this problem, but they still have their limits which is why all lift kits will come with some sort of bump stop extender.

a buddy of mine had a small lift (2-3") installed on his TJ but the shop that did it forgot the new bumpstops. we got off the trail one day and his jeep was leaning something aweful to one side. We had to use a highlift to raise the one side of his jeep just to reconnect the swaybar. That leveled it out enough to get him home. He had over compressed the springs with all the flexing we did. Luckly the shop admited there mistake and replaced his springs for him, and put the new bumpstops in.

 

Not all kits have bumpstop extenders.....for example OME and Rusty's both have longer springs and are designed for longer compression, they don't have and don't need the bumpstop extenders.

 

That makes a lot of sense, I came to a theoretical answer like that, but I wanted to hear about what *actually* happens.

Summary for me: 1) bumpstops good. sag bad. 2) More flex needs longer springs.

Thanks

 

ah. i knew longer spring lift kits usally came with new bumpstops, guess not all of them. thanks for correcting me.