SHIMANO Altus Mountain Bike Rear Derailleur - Direct Mount - RDM310

Installed my Shimano Altus RDM310 and it works GREAT with the Shimano Mega Range freewheel. A noticeable improvement from the stock Shimano Tourney that came with the bike.

Giving this derailleur 5 stars for value. It cost a third of what I just spent on a repair part for my Sram XO derailleur. No carbon fiber, no bling factor, but the old derailleur my son's bike came with had enough slop that it could not be adjusted to shift accurately. This took less than 5 minutes to install and dial in. Beware that the instructions suck, but you can always look on the Park Tools or Shimano websites or YouTube for instructional videos on how to set it up if you don't already know how. Great value...

Talking entry level derailleurs here...I used this to replace my Shimano Tourney derailleur that bent during an MB ride...I tried to bend the Tourney back but to no avail...the chain kept slipping. Frankly, had I known, I would have immediately replaced the stock Tourney with the Altus. The shifting is much smoother, faster and on-target (once properly adjusted). Oh, and I also took 2 chain links out to tighten my chain...I suggest if you're going to do this, check out some youtube vids.

Knowing Shimano's reputation from experience, this Shimano Altus in form and function should be sound. It benefits from the company's "trickle down" technology, where engineering gains on the top level Dura-Ace and XTR line eventually make their way down to the lower models. Unfortunately, I had to return this component, because of the weight. Undoubtedly, it would have provided trouble-free service, and normally would be a good replacement part for a worn derailleur. Also, apart from any psychological detriment, the added grams in weight would be undetectable. But my application is part of a comprehensive effort to lighten my bike, and this component was a poor choice on my part. The Shimano line of products remains worthy; as a side note, I ordered a Shimano Ultegra 6800 GS road derailleur in its place, which should elevate the shifting experience ALONG with shedding weight, on my vintage Klein mountain bike.

This is working very well as a replacement for my bike so far. The thing that I like most about it is that all the moving pieces are metal, because some parts of my old (OEM) derailer were plastic. It seems well made so far and shifts between the gears smoothly and quietly.

I have a 15 year old Raleigh comfort bike that was not shifting well despite attempts to adjust it. I considered a new bike as I have many thousands of miles on this one. I decided to purchase this Altus buying the direct mount option in black to replace my tired Acera. Upon receiving the new unit it looked identical to the old unit except looking new and in black vs the old silver. Installation was easy for me as I work on my own bikes. There are good videos on YouTube on how to replace for those who have limited mechanical skills. Mine took 20 minutes to replace and adjust. My bike now shifts like a new bike again. With new confidence that my bike has many more good miles in it, I will hold off buying a new bike and put a few more dollars into replacing the chain which is heavily worn and stretched. This is not a high end unit at all but excellent for the price range.

I bought this to replace a derailleur that I broke due to operator error. The installation part was easy. The adjustment part was more of a challenge. It does not come with instructions. Fortunately, there are many sources online that provide all the information you need to know. After a couple hours of study and a couple hours of working with the new derailleur I had it tuned and adjusted perfect. Took the bike out today and only had a couple minor adjustments to make. Perfect now. Smooth and reliable. I would recommend this to someone with good mechanical and direction reading skills. A bike maintenance stand is needed. This is a DIY replacement part but for a regular rider with the desire to do your bike so you can get it dialed in exactly how you want it to react. If I break this one I will get another one.

Went from stock 7 speed freewheel & Tourney derailleur both Shimano. Absolutely horrible gear range in stock 7 both front and rear. To a 8 speed freewheel which “required“ (as I told my wife😂🤪) to change out the shifter, derailleur, bottom bracket, crankset, chainrings & chain. Altus groupset is working great after indexing. Lot crisper, smoother, easier, quieter shifts. Very happy for the price. Am going to make one change to shifter cable, going to run housing all the way back to derailleur. Will update if adversely affects shifting or derailleur operation. From what I’ve read & bought, shouldn’t be a problem.

Bought this to replace a Shimano Tourney derailleur on my partner's son's bike. Easy to fit and has an excellent chunky look, with large 13 and 15 tooth jockey wheels. He says his shifting is really smooth now and so far it's holding up nicely to all the cycling he's been doing. Would buy this again to replace another Tourney or no-name derailleur.

Used this to replace a bent and worn Altus rear deraillieur on my grandson's Mountain bike from Halfords. The design of this new Altus was different to the old one but it went on easily, was easy to set up and works like a dream. The Jockey wheels are bigger especially the lower one and the attachment to the frame hanger is different appearing to be more direct and rigid, resulting in crisp gear shifts.

Failed after 2/3 month and hardly any miles put through.Literally fell apart, screws on jockey wheels really loose and no threadlock, weak rear plate bent during simple gear change and the whole mech fell apart leaving me stranded miles from home and injured due to it literally exploding apart on a easy ride (flat road doing about 12 mph middle gears)My old acera lasted over 30,000 miles until both jockey wheels wore down to ninja stars,Yet this one I bought didn't even do 200 miles and yet screws came loose and the whole unit disintegrated.Would not recommend to anyoneMaybe its a fake/clone but even if it was, it should not have broken in the way it did. Could have caused very serious injury

Paired with the altus m310 speedfire shifter, it works wonders! Had a very bad crash recently and I was surprised this is still perfectly working and still straight as both chain and deraileur hanger snapped! Really raccomend it, for a great price too! Leave a "helpful" please :-)

Updated my kids Hotrock 20 from poor 6 speed to a much better 8 speed, 32T upsize from 28T will help in those ascents. Combined it with a Shimano Altus shifter and derailleur. Only mod required was the addition of a slim washer to each side of the rear axle of the wheel to give a bit of clearance for the smallest sprocket.Recommended

Exactly as described, well packed and fast delivery!It came with grease pre-applied so it saves you buying some!Good Quality and a Great price.

A snapped derailleur ruined my ride on Sunday. Jumped onto Amazon on Sunday same day had my replacement monday i fitted and had a ride out works as it should fine i just need to tweek it to make gear changes perfect.

Bought as replacement for a friends bike . easy to fit & set up. working great so far . recommend replacing theshifter cable at the same time as we found the old one was starting fray & had to rush out & get one locally.

I had to replace my old one because of the main joint dusting.getting stuck - this did a good job and runs well so far.

Used this to replace a similar older model on my Giant Cypress bike. Good fit and vast improvement in gear changing. Great item.

Cheap well made would buy again, shifts smooth good quality for the price, really is a solid product

Well made and works efficiently as is the case with all Shimano equipment. If it doesn't work properly it won't have been set up properly (limit screws and cable tension)

Very easy to replace broken Shimano unit with this one, easy to adjust to back cogs

Shimano deralieur's seem great. The last one only died due to intense cyclo-cross racing. I replaced like for like.

Fit perfectly works as it is supposed to great price an all so easy to fit