I was under the impression you didn't need to replace driveshafts with 2.5" or less lift, but I've read a few comments on here lately that goes against that notion. I realize every JK gets a different amount of lift from springs depending on the weight of bumpers and accessories, but some comments stated a new driveshaft might be needed even with spacers. Can anyone shed some light on this for me?

 

You need to replace it when it starts to fail. This is totally variable on the amount of lift and the use of your rig. On the pentastar equipped jeeps over 2" some people swap them out for extra clearance on the exhaust cross pipe. After market drive shafts use a smaller diameter tubing and therefore give you more clearance.

 

I have a 2011. I guess my question is, how likely is it to fail prematurely with 2-2.5" of lift?

 

2.5'' is the point were your safe. 3'' or more at least exhaust spacers too allow the drive shaft not to come in contact with exhaust but It will wear quicker but not an urgent thing if the funds aren't there.

I also have a rubi and will doing the tera 3'' with tera exhaust spacers with 37's

 

I have a 2011 with 4 inch lift 30000 miles and wheeling pretty often and have not had problems yet. I appear to have adequate clearance for the front.

 

Imo flex/down travel plays just as much a part as lift does.. A 2" lift with 12 inch travel will be hell on it offroading.

 

I have the 2.5" RK max travel lift, and I say about 2-3 months after the install my front DS started slinging grease. I don't think there is any "safe" lift height that prevents you from eventually having to replace the DS. You will eventually need to change it.

 

I'll throw this in. I have a 2012 door with 2.5" Teraflex Budget boost with stock shock extensions (aka it got 2.5", not +/- due to spring rate). Wheel it pretty hard, on 35's. After wheeling it for around 6000 miles like that, I noticed that the front driveshaft slip boot was slightly torn (near exhaust) and that there was some grease up at the transfercase end boot. Now going on 15,000 miles since the lift and still on that driveshaft (36,000 miles total)

 

Id guess thats because rock krawler has longer travel shocks than most...

 

Yep. Lots of variables involved, not just lift height. Make a habit of crawling underneath and checking your joints.