SunRace MFM300-7 Speed 14-34T Black Freewheel Cassette Sprocket for 7 Speeds, Sports and Outdoor, Black

I buy multiples of these in 7 and 8sp styles for refurbishing used bikes. Shimano compatible and cost effective. I recommend anti sieze paste or red grease for installation so it can be removed in a decade or 2 for replacement.

Shifts great, easy to install, cheaper than the OEM Shimanos.

The mongoose fat bikes are built cheaper, and the gearset is terrible. This cassette gives you a broader gear range with a true low gear.

I like this cassette because it's the only option for a 14-34T 7-speed cassette that has even steps on all the sprockets. All of the other options use the stock smaller sprockets, then have a *huge* jump (like 12 teeth) between 2nd and 1st gear. A couple of downsides though. 1) the horizontal spacing between sprockets on this cassette is wider than the stock 14-28T shimano cassette. Not a huge deal, but it means you can't just swap them out without completely re-aligning the derailleur. Problem #2 *is* a big deal though, and that's that the freewheel bearings are garbage. They're very sloppy and loose, which makes the cassette wobble enough to cause chain noise, and dust/dirt gets inside the considerably sloppy gap between the freewheel hub and cassette barrel, and causes the bearings to become noisy. To give you an idea of just how sloppy the tolerances are, I took mine off the wheel hub, and sprayed solvent inside the gap to clean out the bearing, then injected oil back inside the gap, and presto, quiet bearings again. Having said all this, I'm probably going to order another one of these freewheel cassettes, because for now, SunRace is the only game in town if you want to upgrade your stock shimano 7-speed to have a larger range and lower 1st gear (and still have relatively constant steps across gears).

I got this to replace a Shimano gear set and it fit right in. I have this on an adult trike and it works with the Shimano derailleur and has a 34 tooth first gear making it much easier to pull up the hill with a load of groceries. It has given me no problems and looks like it will last me for a long time. I would buy it again if I need it as it is easy enough to put on once you get the axle shaft set right. I am happy with this set and yes the twist shifter even worked with it.:)

The fat bikes that were sold at Costco, Northrock, is not gear low enough for steep hills or snowy bogging. This fits great and works well with the stock Shimano derailer while providing a larger range of gears. You will need the splined tool to remove the old cassette.

There is a lock ring on this that needs a tool. I contacted the manufacturer and was told they are not meant to come apart. I believe, but not positive, the attached picture is the tool needed to remove the lock ring, but I was unable to find one. The spacing on this freewheel is a little too much which would not be an issue except I can't take it apart and adjust the spacing. I wanted a 7 Spd with this tooth combination, it seems like all the other offerings for a 32 or 34 tooth have a huge jump between the second and first cog so I was hoping to use this. Unfortunately the spacing is slightly larger than the Shimano offerings which work perfectly but do not offer this gear ratio. The rating is for providing a non-serviceable unit, there really is no good reason for that, the company has the tools to disassemble and their customer service on this matter was very disappointing. I don't care that the design was off a little, I could have fixed that.

These things tend to be hit or miss and often require a little research. The research I way heavily on is what other people are saying in their respective reviews. I had an incredibly bent rim and the old cassette was so seized I tried to take the bearingsapart to remove it. A few dozen micro bbs went flying. Not only did this part get my bike in rideable shape, it saved the hassle of trying to rebuild the old one, was conveniently easy to install, it arrived overnight, and and and the gearing ratio is far superior than the old one! Just as everyone has commented your climbing will improve substantially!