Instruction: Evaluate the answerability of a question by analyzing the related document, outputting yes if the document contains information addressing the question, and no otherwise.

Input:
Question: Will this work for a mtn bike with 8 gear wheels in back and 3 in front?  Previously had a Sram 5.0 derailleur.
Document: Good to have a spare. I bent my original one months past. I was able to straiten it back out and it does work fine, but now i have a backup
I've used the X4 derailleur for commuting for the last three years and in harsh, rainy conditions. The derailleur requires minimal adjusting and is constructed well. I ride to work 5 days per week and I maybe need to adjust this derailleur once every 6 months or so.
Used this on my girl friend's mountain bike that I am building... found some Sram shifters and needed the derailleur to match.
This is a perfect replacement. I removed my damaged 4.0 and installed the one. No issues it works fine. The price under 20.00 was awesome! I'm back on the trails again
I also purchased an 8-speed sram x4 trigger shifter and installed both at the same time. This setup shifts grreat. Quick, crisp shifting.
But I'm not the sharpest knife in the drawer, so off to the LBS I go. The bike mechanics couldn't get it to work either. Oh well, Thank you Amazon for your excellent return policy.In case you're wondering what happened...I ended up keeping the stock Shimano rear derailleur and instead upgraded the shifters to get better, crisper shifting. What a difference! Turns out the shifters are the brains of the operation, the rear derailleur is just following instructions.
SRAM has come a long way in the last 10 years and their bike components are top notch. I run nothing but SRAM drivetrain now (X.5, X.7, and X.4 on my sons bike) and love that I can adjust and forget! Even though this is the bottom of the product line rear derailleur is it reliable and strong.Just an FYI for the reviewer above and for anyone reading. SRAM's rear 1:1 derailleurs DO NOT have a rear cable adjuster like Shimano.
Sofar so good. I installed the Sram X 4 on my bike which is a seven speed casette. After some tweeking it shifts on command. I give it a five star rating for its look  how well it works and ease of ajustment. I'm not a serious MTB rider but I am 300lbs  ( and loosing the weight) I  hit the up hill climbs with a heavy foot. It shifts well under that condition.
This X4 Derailleur exceeded my expectations with smooth shifting(on my 8 speed) and pretty rugged design.overall i like itgood
this item is great, but when/if you need to change the hardware  contact sram any other bolts will strip the holes on the derailleur
Answer: yes