SHIMANO Altus Mountain Bike Rear Derailleur - Direct Mount - RDM310

A great derailleur for the price, shifts perfectly and quietly and is totally silent while operating on all sprockets. It is easy to install with a just a few allen wrenches, I didn't bother taking apart the chain, I just disassembled the cage slightly to get the chain inside it. Adjusting was slightly more difficult. The only issue is that there are no paper instructions for installation and especially ADJUSTING it. It is essential to adjust the low and the high limits to align the upper jockey wheels and chain with the low and high sprockets, THEN just as importantly, when derailleur is on smallest sprocket remove ALL slack on the cable by pulling the cable tight when the cable attachment bolt is loose, then retightening the bolt, and/or by screwing the cable adjustment barrel until the derailleur just starts to move inward to the next gear. Maximum rear sprocket size is supposedly 34 tooth, and I found it best the adjust the B tension screw inward quite a bit (the one on the bracket that limits the derailleur front and back swivelling) to help the upper jockey wheel clear the larger sprocket (28 tooth in my case) better. Once installed and adjusted, it worked PERFECTLY every time.

I bought this derailleur to replace the stock unit on a beach cruiser that I converted into a motorbike. I needed something sturdy and, most importantly, with enough clearance to fit around the HUGE sprocket that I have on the bike (34 teeth). This unit fit the bill perfectly - only required some minor adjustment with the set screws and within 15 minutes I was back in action. The only thing I needed to do we steal a longer B-screw (the screw that determines how far the derailleur's upper flywheel sits from the cassette) from the old derailleur, because the screw that came with this one wasn't long enough. This is ONLY because my bike is a beast of customization and I needed to improvise - but the longer B-screw worked flawlessly. In case anyone else out there is attempting to build a shiftable motorbike, I highly recommend this rear derailleur. It's super easy to install, came properly tuned right out of the box, is very sturdy and solid when riding, and most importantly it fits over just about any sprocket size you might have in the back! They make a ridiculous 42-tooth sprocket which I'm going to try putting on this bike (because the clutch doesn't like taking off even with the 34T sprocket...) and I'm confident this derailleur will even work with that.

If you're looking for a wide-range derailleur that's safe to use with small wheels, this is the one. I got this for a recumbent trike with 20" wheels because the stock derailleur got dangerously close to the ground in some gears, but I didn't want to give up my large hill-climbing winch gears. This derailleur solves that problem with extra-large jockey wheels, which allows Shimano to shorten the cage and improve ground clearance without sacrificing capacity. The price is fantastic, and after several years and ~10k miles of mixed riding it still works beautifully. What makes this derailleur really special is that, while it doesn't have the highest capacity around, it's the only wide-range model I know of that supports both small wheels *and* front derailleurs. If you're looking for low gears, that's an incredibly powerful combination, with gear inch ranges rivaling high-end gearboxes and gearhubs costing thousands. And for ~$20! Best purchase ever. The only maybe-downside is it's only 8 speeds, but honestly that's good enough, and 8-speed chain is stronger, longer-lasting, and much cheaper than 10/11/12 speed chain, so that's actually another pro in my book.

This derailleur is pretty decent and is a cost effective and performance worthy piece of machinery. I chose this over Acera for price and performance. It is a little heavier. However, I feel that the performance is smoother and more accurate than Acera. In past experience, I found that Acera has less chain retention and is a little more snappy. This Altus is a bit more precise and smoother. This makes it an ideal upgrade or replacement. I like the larger lower pulley for the increased chain retention and quiet shifting. Also, like most Shimano derailleurs, it is easy to set up. For the price and quality, I see no problems here. Personally, I don't like the blobs of bright green grease used in the ends of the parallel spring. This is more of a minor annoyance. If you ever do trail rides, you know what I mean. However, I remove the grease with a small flathead and leave a minuscule amount. I wish I could rate this a 4.5 rather than a 4. Overall, it's really good for its quality and price. I highly recommend this for your needs. I will buy again.

Paired this with a Shimano Altus right side trigger shifter, 7 speed. Installed this onto a Mongoose Ardor due to the cheap Pro Rush derailleur binding the chain up real bad when hitting a small jump or bunny hopping a little higher than an inch. Like, the derailleur would skip the chain off one of the pulley cogs and it would stick between the metal guides and the cog. These two, once installed and tuned, are tuned to work perfectly with each other. My derailleur hanger was checked with my Park Tools DAG alignment tool, and the derailleur hanger wasn't really bent hardly at all, but it doesn't hurt to ensure good hanger alignment before installing any new equipment. This derailleur is working fine on the Pro Rush freewheel 7 speed gear set, since it's paired with its proper Shimano Altus shifter counterpart. That's where people mess up, is pairing a new derailleur like this Shimano with the older shifter like the Pro Rush that was on the bike. I'll update the review if the Shimano Altus just breaks or craps out, but the first ride out it shifted very very nicely, and even handled several little jumps with no chain slippage or binding. I just am not ready to upgrade the rear wheel to a free hub with higher than 7 speeds, so finding this derailleur and shifter combo worked out great. :)

Excellent quality well-named brand very good

Nice durable Shimano derailleur! It restored my Trek's shifting back to new. It's quick, reliable and doesn't require much maintenance. Would definitely buy again.

Had to replace mine. Easy to install. Easy to adjust speeds. Works as it should.

Byta av bakre växeln Fungerar perfekt till ett enklare växelsystem. Byt även kuggkransen och kedjan Instruktion för justering finns på nätet

Original parts and speed delivery

Great Derailleur , used on a Mid-Drive Electric Bike and now have smooth change In most Power Settings . This Derailleur is used for Bikes with a "Derailleur Hanger" ( a small bit of metal which fits from the Derailleur to the Bike Frame ) and is Not for Older Bikes that fit directly to the Bike Frame ( so called "Direct Mount" Derailleurs ) I believe you can also find these on Amazon . Genuine Shimano due to correct Retail Packaging , Correct Oversize 15-tooth tensioner and 13-tooth pulleys . Also the Derailleur Cable holder is the correct one , it has a Allen Key Head on it. ( The ones from E-Bay , I believe are “copies” , have a normal Nut that holds the Derailleur cable , do not have the correct Retail Packaging and also these units make a number of different noises on each pedal Stroke) Better to pay £2 more from one Sold Directly at "Amazon as the Seller" that works Correctly than a Poor Quality "copy" from E-Bay. ( Buy Cheap ..... Buy Twice .... ) I Hope this Helps. Best Regards Bargain Hunter

My bike had an old Shimano Nexus system and it was time for a replacement. This one works responsive and every screw does its job to adjust every part.

Het werkt heel goed en zonder problemen