Hey cycling enthusiasts! Are you looking for a reliable and high-performing rear derailleur for your 9-speed mountain bike? Look no further! The Shimano Deore RD-M591 SGS is a popular choice for riders seeking a balance of performance, durability, and affordability. This guide will dive deep into everything you need to know about this fantastic piece of equipment. We'll explore its features, benefits, installation, maintenance, and common issues. Get ready to level up your understanding of the Shimano Deore RD-M591, guys!

What is the Shimano Deore RD-M591 SGS?

So, what exactly is the Shimano Deore RD-M591 SGS? Simply put, it's a rear derailleur designed for 9-speed drivetrains. The "RD" stands for Rear Derailleur, "M591" is the model number identifying it as part of Shimano's Deore series, known for its blend of quality and value, and "SGS" refers to the cage length. SGS stands for Super Long Cage, which means it's designed to accommodate a wide range of cassette sizes, often used in mountain biking to handle big gear jumps, especially for those steep climbs. This particular model is a workhorse, designed to handle the rigors of off-road riding while still providing smooth and precise shifting. It's a significant upgrade from entry-level derailleurs and offers a noticeable improvement in performance and reliability.

This rear derailleur is a component of your bike's drivetrain system, responsible for moving the chain between the rear cogs or sprockets of your cassette. This shifting action allows you to change gears, adapting to different terrains and riding conditions. The Shimano Deore RD-M591 SGS is known for its smooth and accurate shifting, even under load, and its robust construction, which helps it withstand the bumps and impacts that are common in mountain biking. This makes it an ideal choice for recreational riders, trail enthusiasts, and even some cross-country racers. It's a great example of Shimano's commitment to providing quality components that enhance the riding experience. And the best part? It won't break the bank! This makes it a popular choice for many cyclists looking for an upgrade that offers a lot of value for its price. Think of it as a solid investment in your cycling fun. The long cage design is key, as it provides that wider range of gear options. This is especially helpful if you're tackling challenging climbs or varied terrain. The Shimano Deore RD-M591 SGS ensures you can find the right gear to conquer any trail. So, if you're looking for a dependable, cost-effective, and high-performing rear derailleur for your 9-speed mountain bike, this might just be the perfect fit.

Key Features and Benefits of the RD-M591

Let's break down the features and benefits of the Shimano Deore RD-M591 SGS, shall we? This derailleur offers several key features that contribute to its popularity and excellent performance. One of the most important is its smooth and precise shifting. Shimano is renowned for its shifting technology, and the RD-M591 is no exception. It delivers crisp and accurate gear changes, ensuring a seamless riding experience. This is crucial for maintaining momentum and efficiency on the trails. Another key feature is its durable construction. Built to withstand the harsh conditions of off-road riding, the RD-M591 is made from high-quality materials and designed to take a beating. This means it can handle rocks, roots, and other trail obstacles without skipping a beat.

The long cage design (SGS) is another significant advantage. As mentioned earlier, the long cage allows the derailleur to accommodate a wide range of cassette sizes. This gives you more gear options, making it easier to tackle steep climbs and descents. The long cage also helps maintain proper chain tension, which is essential for smooth and reliable shifting. The low-profile design is another benefit. This design helps to minimize the risk of damage from trail hazards. It also tucks the derailleur closer to the frame, reducing the chance of it snagging on rocks or other obstacles. The Shimano Deore RD-M591 SGS also incorporates Shimano's Shadow technology. This design keeps the derailleur tucked in, reducing the chances of it getting damaged by trail debris.

Moreover, the derailleur is relatively easy to install and adjust. While it's always recommended to have a professional mechanic do the job if you're not comfortable, the RD-M591 is generally straightforward to set up and fine-tune. This makes it a great option for those who like to do their own bike maintenance. The benefits of these features are numerous. You get improved shifting performance, increased durability, greater gear range, and a more reliable riding experience. The Shimano Deore RD-M591 SGS is designed to enhance your time on the trails. It's built to last, perform reliably, and help you enjoy your rides to the fullest. Overall, this is a fantastic package that combines great features with a reasonable price. You can't go wrong with it!

Installation and Adjustment Guide

Alright, let's talk about getting this beauty installed on your bike. Installing the Shimano Deore RD-M591 SGS isn't rocket science, but it's important to do it correctly to ensure optimal performance. First things first, gather your tools. You'll need a hex key set, a screwdriver, a chain whip (if you're replacing your cassette), and possibly a torque wrench. Begin by removing the old derailleur. Disconnect the cable and unbolt the old derailleur from the frame. Make sure to note how the cable is routed. Then, attach the new derailleur to the frame. Most frames have a derailleur hanger, and the RD-M591 will attach to this. Tighten the bolt securely. Next, route and attach the shift cable. Thread the cable through the derailleur and clamp it in place. Make sure the cable is seated correctly in the cable anchor bolt.

Now comes the adjustment phase. This is where you fine-tune the derailleur to get those perfect shifts. Start with the limit screws. These screws (High and Low) control the range of motion of the derailleur. Adjust them so the chain doesn't fall off the cassette when shifting to the smallest or largest cog. Then, you have the B-tension screw, which sets the distance between the upper pulley and the cassette. This affects the shifting performance. Use this screw to adjust the gap according to Shimano's specifications, usually a few millimeters. After the limit screws and B-tension are set, adjust the cable tension. This is usually done using the barrel adjuster on the derailleur or the shifter. Index the gears by shifting through all the gears and making small adjustments to the cable tension until the shifting is crisp and accurate.

Indexing the gears is key. As you shift through the gears, pay attention to the speed and precision of the gear changes. Use the barrel adjuster to fine-tune the cable tension. If the shifting is slow or imprecise, make small adjustments until the gears shift smoothly up and down the cassette. It might take a few tries to get it perfect, but patience is key. Finally, double-check everything. Make sure all the bolts are tight, and the cable is routed correctly. Test the shifting again to make sure everything is working properly. Remember to consult Shimano's instructions or a professional mechanic if you're not comfortable with any of these steps. Take your time, and pay attention to detail, and you'll have a perfectly tuned Shimano Deore RD-M591 SGS ready to hit the trails! This process is essential for getting the most out of your derailleur and enjoying a seamless riding experience. Following these steps will ensure optimal shifting and performance.

Maintenance and Troubleshooting

Proper maintenance is key to keeping your Shimano Deore RD-M591 SGS running smoothly and extending its lifespan. Let's cover the essential maintenance tasks and common troubleshooting issues. Regular cleaning is essential. After each ride, especially if it's muddy or wet, clean your derailleur. Use a brush and degreaser to remove dirt, grime, and debris. This prevents these elements from affecting the derailleur's performance. The frequency of cleaning depends on the conditions you ride in, but it's best to keep your derailleur clean. Lubrication is another crucial step. After cleaning, lubricate the moving parts of the derailleur with a bicycle-specific lubricant. Apply the lubricant to the pivots and pulleys. This reduces friction, ensures smooth shifting, and protects against wear and tear. Make sure to wipe off any excess lubricant. Too much lubricant can attract dirt.

Checking for wear is important. Regularly inspect the derailleur for signs of wear and tear. Look for loose bolts, bent cage, worn pulleys, or damaged cable. Replace any worn or damaged components promptly. Pay attention to the chain. A worn chain can affect the performance of your derailleur. Check your chain for stretch using a chain checker. If it's worn, replace it to avoid damaging the cassette and derailleur. Let's delve into common troubleshooting issues. If the shifting is slow or imprecise, it could be due to several factors. Check the cable tension and adjust it using the barrel adjuster. Make sure the cable is not frayed or damaged. Check if the derailleur hanger is bent. A bent hanger can affect the shifting and might need to be straightened or replaced. If the chain is skipping, it could be due to a worn chain or cassette. Inspect these components and replace them if necessary.

If the derailleur is making noise, it could be due to a lack of lubrication or loose bolts. Clean and lubricate the derailleur and tighten all bolts. If the issue persists, check for other sources of noise. The RD-M591 is a durable piece of equipment, but regular maintenance can significantly extend its lifespan and ensure optimal performance. Doing these things can save you from bigger headaches later. Don't underestimate the importance of regular inspections and maintenance to prevent small problems from turning into bigger, more expensive ones. Keeping the RD-M591 well-maintained will keep you rolling smoothly on the trails.

Upgrading and Compatibility

When considering the Shimano Deore RD-M591 SGS, you might be thinking about upgrades and compatibility. Let's explore these aspects to help you make informed decisions about your bike's drivetrain. As for upgrades, the RD-M591 is part of the Deore series, which is a mid-range component group. This means that while it offers excellent performance for its price, there are higher-end groupsets, such as SLX, XT, and XTR, which offer improved shifting, lighter weight, and more advanced features. Upgrading to a higher-end derailleur can provide noticeable improvements in shifting performance, especially under heavy loads. However, it's important to consider your riding style and budget when deciding if an upgrade is worth it. For recreational riders and trail enthusiasts, the RD-M591 is often sufficient. If you're a serious racer or a rider who demands the absolute best performance, an upgrade to a higher-end derailleur might be a good idea. Consider your needs and priorities.

Now, let's talk about compatibility. The Shimano Deore RD-M591 SGS is designed to be compatible with 9-speed drivetrains. It's important to note this, because it won't work with 8-speed or 10-speed (or more) systems. It's designed specifically for 9-speed cassettes and shifters. You can't just mix and match components from different speed groups. Make sure that your cassette, chain, and shifters are all compatible with 9-speed systems. Mixing components can lead to poor shifting performance and potential damage to your components. Also, the RD-M591 is compatible with most 9-speed cassettes that have a wide range of cogs. The SGS (Super Long Cage) design of this derailleur allows it to handle cassettes with larger cogs. Ensure the derailleur is compatible with the range of cogs on your cassette. Before making any upgrades or replacements, it's always best to consult a bike mechanic or the manufacturer's specifications to ensure compatibility and avoid any issues. Understanding the compatibility requirements can prevent compatibility issues down the line. Keep in mind that when upgrading, you might need to replace other components, like shifters, cassette, or even the chain.

Conclusion: Is the Shimano Deore RD-M591 SGS Right for You?

So, after exploring all the features, benefits, and considerations, is the Shimano Deore RD-M591 SGS the right choice for you? If you're looking for a reliable, durable, and affordable 9-speed rear derailleur for your mountain bike, then the answer is likely yes. It's a fantastic option for recreational riders, trail enthusiasts, and even some cross-country racers. The RD-M591 offers excellent performance and value for the money.

It's not the highest-end derailleur on the market, but it provides smooth and precise shifting, robust construction, and a long cage design that is suitable for a wide range of cassette sizes. The Deore series is known for its reliability and performance. The RD-M591 is a workhorse that can handle the rigors of off-road riding. It's a dependable and cost-effective upgrade for your bike. The features like the smooth shifting and the durability, it's a solid investment that will enhance your enjoyment on the trails. If you're upgrading, make sure to consider compatibility with your other components. Overall, the Shimano Deore RD-M591 SGS is an excellent choice for riders who want a high-performing and reliable 9-speed rear derailleur without breaking the bank. It's a testament to Shimano's commitment to quality and value. It's a great choice, guys!