Mountain Biking - What's the difference between the Deore/LX/XT cranksets?

I test-rode a few bikes with these cranksets and truly could not tell any difference. I personally think it is impossible to tell the difference between a Deore and an XTR crankset in a blind test.

How do i decide which one i need?

It depends on how much $$$ you want to spend.

the difference is weight, less weight on each higher level crankset, and less weight in your pocket. That being said, I have XT cranks and rear cassette

ah, found it. off the trek website

someone needs to make this chart for sram too.

Component Comparison
http://www2.trekbikes.com/images/bikes_my07/shimano_logo_specs.gif

Shimano
Best
XTR
Deore XT
Deore LX

Better
Deore
Alivio

Good
Acera
Altus
C-Series
T-Series

Bontrager (http://www.bontrager.com/)
Best
Race XXX Lite
Race X Lite
King Earl

Better
Race Lite
Race
Big Earl

Good
Select
Superstock
Earl

RockShox (http://sram.com/index.php?lchange=1)
Best
Reba
SID

Better
Duke
Pilot

Good
Judy

It's more than just a weight diff...the higher end cranksets are stiffer so you don't have as much flex-to-front derailleur rub issues. If you're a lightweight, you won't notice this. The other difference is the improved shifting performance due to higher precision. Sure, a Deore can shift well on a brand new build, but what about when you get 1000 miles on it? Will it still shift crisply compared to the XT or even LX? Nope.

I think the Hollowtech II crankset is a good "blue collar" set. It's not as light as the XT, but it performs well and won't break you.

I believe the Deore's middle ring is steel vice Al. alloy like the others. At least the older ones were that way.

Al

i'd say the LX is one of the best/buck ratios around. lighter than allot of parts that cost more, and proven to be durable and reliable.

Yup, it really comes down to how much you want to spend. Certainly XT, and XTR are better than LX, but not by leaps and bounds. Therefore, your "bang for buck" ratio comes WAY down. All are good components for sure though.

... Brad

In my experience, the cost differential between LX and XT is not that great, but the leap from XT to XTR is tremendous. I'm an XT kind of guy.

So is there any gain in strength and durability in the higher end parts? Or is it only weight savings? I can already see durability is going to be a major issue for me, these things just don't seem to be built for my tonnage and leg strength. My rear sprockets were shifting all by themselves on a uphill today and making some very nasty noises doing it. The lbs already replaced my rear cassette under warranty with a supposedly stronger one after my first three rides.
Also when I raise the back wheel and turn the crank by hand to lube the chain it doen't exactly feel all that smoothe, I can definitely feel a lot of roughness in the bearings in the bb.

i have LX, shifts good enough for me, i can swap gears when i need to on steeps, im no vet but i dont really see why you need anything much better.