There are so many factors in problems with bicycle drivetrains that I have to read some of the less-favorable reviews for these and other similar cassettes with a grain of salt.
Skipping, bad/slow/missed shifts, noises, and other problems can come from many sources.
Often just replacing one part like this and expecting a magic bullet to fix all your ills is a bit short-sighted. If your old cassette was bad it's almost a certainty that the chain was bad too. Chains wear out faster than cassettes -but a worn out chain will grind away the favorite cogs of a cassette in short order. Replacing a worn out cassette and not replacing the chain will cause the problem to come back in short order. A worn-out cassette will also chew up a new chain in short order too!
It's a good idea, if you are not an experienced bicycle mechanic to review Sheldon Brown's excellent articles on bicycle drivetrains and derailleur adjustments. Do a websearch for "Sheldon Brown Derailleur Adjustment" and just keep reading that page and other linked pages on the Harris Cyclery Website until you have more of the big picture of what you are up against here with modern indexed-shifting systems.
If you are getting a cassette with a bigger largest cog for a lower low gear be aware that you may need to adjust your B-tension screw to keep the derailleur off of the cassette. This is a mistake a lot of people make and can cause serious damage to the chain, cassette and derailleur -even bend the derailleur hanger on the frame if it jams up and/or do serious damage to your wheel. Know what you are doing here please. Us bicycle mechanics really do not enjoy seeing people bring in mangled bikes and having to tell them that the cost to fix the mess will probably cost more than a new bike. Also, be aware that a larger biggest-cog may require you to run a longer chain or risk derailleur damage if the Large/Large cog/chainwheel combination is ever selected (not a good idea to cross-chain like this but still the chain should be able to do it should a mistake happen.)
In my opinion the only downside of this cassette (and any decent bargain cassette for that matter) is a small-medium weight penalty. More expensive units will weigh much less -and may shift slightly better, but not too much -the most important thing in indexed shifting is a high-quality cable and housing followed by a good high-quality indexed shifter lever/brifter. But don't forget proper adjustment of all the components being essential also for everything to work well together. The skill-set necessary to do this is beyond many home bicycle mechanics, at least for the first couple attempts until they learn the tricks.
The tools needed to remove this cassette are a cassette locking tool such as:Park Tool Cassette/Rotor Lockring Removal Tool FR-5/FR-5G a wrench capable of holding the tool, and a chain whip like this: Park Tool HCW-16 Chain Whip/15mm Pedal Wrench. It's not a hard job to physically remove and re-install the cartridge. If your bike was working well when you swapped it should be fine with maybe a small adjustment of the cable to account for small manufacturing tolerances. If you put a bigger largest cog on you will need to adjust the B-tension screw for more clearance.
BEFORE ORDERING: Check your derailleur rating by searching for it here on amazon to be sure that it is rated for a larger cog than you have. Most Shimano medium-cage derailleurs are rated for 27-tooth max but you can usually get away with 28. 30 might be iffy. 30+ tooth largest cogs really need to have a mountain derailleur with a long cage and not a medium-cage (or small cage) road derailleur.
Sorry if this review seems super-long but there is a lot of material here to cover. Good luck with your new cassette, riding should be fun and there is nothing wrong with wanting your bike to shift well and be geared for your type of riding.
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Here is my story with this product. I love SRAM products. However, I purchased this cassette along with a SRAM PG 950 9 Speed chain. I have SRAM x-7 shifters, and X-7 Derailleurs. I put everything on the bike, and the chain kept skipping. I realized that it was skipping on the highest (smallest) cog. I thought perhaps the small cog was not on right, or was not tightened enough, so I checked these things and it was fine. I kept adjusting the der. and still the same skipping. It was very frustrating. I had a hunch that the der. hanger may be bent on this bike, so I purchased a new one (over $30.00). I put it on with no changes in shifting. The only part of the drive train that I had not replaced was the rear der. I thought that this had to be the problem. I purchased a new x-7 rear der. (about $50.00). I installed it and it still skipped the same way. UGGGGG!!!! I thought about it some more and decided that something may be defective with the highest gear. I was going to put the old small cog on and see if that may fix the problem. That is when I realized that the lock ring seemed to be bit large and was partially covering the teeth! I looked at the old lockring from the cassette I removed (also a SRAM), and it was considerably smaller. I used it and it fit like a glove, and did not cover any of the teeth. I put my bike back together, and the problem is resolved!! I am a bit peeved though because I bought a hanger and a rear der. that I did not need to replace. I wish I had thought about the small cog before purchasing parts, however, since something is brand new, it should work. I want to email SRAM and let them know about this issue. I cannot find an email address for them. Their site keeps prompting you to call your local dealer.Best Deals for SRAM PG950 Bicycle Cassette (9-Speed)
Got about 2000 outdoor miles on my first one. Replaced it and have 12,000 miles on my second one. Though these are mostly spinning miles. I will buy again.Honest reviews on SRAM PG950 Bicycle Cassette (9-Speed)
This cassette came with my Cannondale SL3 when I purchased it 1 year and 2 months ago. Since this was my first mountain bike I punished the cassette because I did not know what I was doing by:* Shifting while climbing
* Not lubing the chain as needed
* And generally not maintaining the drivetrain
This cassette lasted for 1,600 miles, 95% of that on trails. Let me qualify the trails. In S. Florida the park trails have many short technical climbs and descents which require constant gear changes. 1,600 miles of this type of punishment.
This cassette is outstanding!!
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