what is your budget? there's a ton a stuff you can do to pollish a D30. but the weakest link, as Martin pointed out, are the ujoints. when I went to 35's, I upgraded to new stock '95 shafts w/x760 ujoints... carry the old joints/shafts as spares. I also have a locker and I wheel it purdy hard. has worked fine to date. if you're looking to not spend a ton of $$$, then you could swap in a new YJ driver side and a TJ pass side, and get rid of the vac/2 piece and gain the big ujoints all at the same time. a little more $$ and upgrade to chromos. also, good quality R&P is not a bad idea, either.
Also what are Chromos? I know there axle shafts but what make them great?
Good call on a quality R&P. I always used Dana gears and never had issues.
As I said, keep your eye open for some lightly used quality parts. I got a set of chromo shafts c/w CTM u joints for my current JK Rubicon axles for 1/2 price from a vendor on another forum that was going out of business. Otherwise my axles would still be stock.
Keep your eyes peeled on the XJ and Wrangler forums, there are others besides this one (although OBVIOUSLY not as good).
1998 XJ on 37's.JK Rubi axles with chromo shafts and ctm's, 4:1 transfer case, etc etc etc.
2003 Range Rover HSE, 4.4 Quad Cam.
1998 Range Rover with a 6.0 LSx
1994 YJ, 4.3/700R4/OME SOA, etc
Western Star 4900EX 4 axle.
4.3/700r4/new frame buildup (YJ).... http://www.jeepforum.com/forum/f12/swap-offically-underway-324622/
The problem with CTM's and RCV's is you are wasting money... not you are taking all the stress from your u joint and putting that into the ring gear/pinion which will not tolerate that much of it.... I'd rather snap a $15 u joint that destroy my internals... Even when i switch to Chromo's I will not be going with CTM's.... Now if your rocking a Dana 44, 60 or bigger up front, the ring gear and pinions are able to handle more so the CTMs or RCV's are a great purchase.
I suppose it depends on the big picture. I'll explain.
Lets say I got F&R ARB's & Spicer 4.56 gears installed for free as a gift. After a while decided to step up in trail difficulty so went with a Warn hub conversion with Warn inners at ~1/2 price (this was loooooong ago, way before the prices went up on them). I also decided to go with a set of CTM's since a friend of mine is the guy who designed them & gave me 2 for ~ 1/6th the regular price.
So now I've got an ARB'd, Spicer geared (both for free including install), Warn hubs & inners with CTM's, homebrew truss and sleeved long side axle tube which I designed & built myself, HPD30 all for less than the cost of a set of chromo's alone.
Is this still a waste of $ ? It certainly is not for me and several others I know who did almost the same exact thing & spent about the same $ doing almost all the work ourselves.
The hubs almost ensure that they will go before other items do if/when it grenades.
And like Martin mentioned - I push my POS with an Atlas 5.0, so the stress going to those axle components is quite high along with hand grooved 35" MT/R's. I generally play in the big rocks (think Johnson Valley/Hammers trails).
What I'm getting at is - its not always a waste of money to put CTM's in a HPD30 knowing the big picture of a build.
Now that I'm stepping up to 37's an HPD60 is going in.
more then anything you simply have to determine for yourself how much money you are willing to put into a 30. this is the larger issue. some have no desire to put anything else under their jeep so they will spend more on every possible upgrade. this includes breaks, which people tend to forget. you have to add it all up and put it side-by-side to a drop-in aftermarket setup. you might be surprised at how much people spend polishing a "turdy."
in my case for how much i was willing to dump into it, nothing really, 35" is too big for what i do. an important factor is "what i do" unlike many i dont think limping painfully slow over rocks is the end-all test to component durability. so for those that i read who run 37s on a stock 30 in the hardcore arena of 'rock crawling.' thats fine im just not going to follow that guy all day. if coaxing your tires along one inch at a time is not your thing then take a hard look at how much its going to cost you with a dana 30 to wheel in the style you enjoy. there is a reason why KOH vehicles dont run 30s but wheel in the same areas where people are successful with them. my point is it has little to do with the terrain itself.
i will say without a doubt that driving on a stock dana 30 with anything over 35" tires is absolutely unsafe and shows a complete lack of common sense and respect for other drivers. you might be fine on your way to the store but load you down for the trail with spare everything (dana 30) tools, friends, food, etc and run down a windy road into the desert and you are knowingly setting yourself up for disaster. my avatar pic shows 36" bias iroks. what you dont see is the stock dana 30 they are mounted to so i have direct experience with this issue. those tires and driver destroyed the 30.
-insert meaningless out-of-place political diatribe-