SHIMANO ISMRT86L2 Xt 192790818108 SM-RT86-L 6-BOLT 203MM

( Brand: Shimano ), ( Manufacturer Part Number: ISMRT86L2 ), ( Item Diameter: 203 Mm ), ( Compatible Model: Sm-rt86 ), ( Mounting Type: 6 Bolt ), ( Country Of Origin: Japan ), ( Part Type: Brake Rotors ), ( UPC: 192790818108 )

Review SHIMANO Xt 6-bolt 203mm

The **Shimano ISM-RT86L2 XT SM-RT86-L 6-Bolt 203mm** is a high-performance, all-terrain mountain bike disc brake rotor designed for riders who demand precision, durability, and reliability in demanding conditions. Engineered with Shimano s signature engineering excellence, this rotor is a key component in the brand s **XT (eXtreme Treatment) series**, which prioritizes strength, heat resistance, and consistent braking performance across rough trails, descents, and technical descents. The **6-bolt mounting pattern** ensures compatibility with a wide range of modern mountain bike frames and forks, making it a versatile choice for both cross-country and downhill applications. With a **203mm diameter**, this rotor strikes an optimal balance between stopping power and weight, delivering strong modulation and fade resistance critical for riders pushing their limits on steep, technical terrain or in high-speed situations.

Constructed from **high-grade steel**, the ISM-RT86L2 is built to withstand extreme forces without warping or losing efficiency, even under prolonged heavy braking. The rotor s **dual-pivot design** enhances stability and reduces lateral flex, ensuring consistent pad contact and predictable braking response. Shimano s **ISM (Integrated Stopping Modulation) technology** is embedded within the rotor s construction, allowing for seamless integration with compatible Shimano brake systems, such as the **XT or Deore models**, to provide refined, progressive braking feel and reduced hand fatigue over long descents. The **vented rim design** helps dissipate heat quickly, reducing the risk of brake fade in extended downhill sessions or when used with high-performance brake pads like Shimano s **SH-9700 or SH-9900**.

Beyond its technical specifications, the ISM-RT86L2 is engineered with practicality in mind. Its **lightweight yet robust construction** ensures it doesn t compromise the bike s agility, while the **durable finish** resists corrosion from mud, moisture, and debris, making it ideal for riders who tackle wet or dirty conditions regularly. Whether paired with a hardtail or full-suspension bike, this rotor is a dependable choice for riders seeking a reliable stopping solution that can handle everything from fast-flowing singletrack to aggressive downhill descents. Shimano s commitment to quality and innovation is evident in every detail, from the precision-machined surfaces to the optimized weight distribution, making the ISM-RT86L2 a standout option for serious mountain bikers who refuse to compromise on performance.

The **Shimano IS-M86L2 (XT SM-RT86-L, 6-bolt, 203mm)** is a mid-range mountain bike bottom bracket (BB) designed for compatibility with 6-bolt frames and 203mm axle spacing. Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

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### **Pros**

1. **Compatibility with Modern Frames**

The 6-bolt standard is widely used in mid-range and higher-end mountain bikes, particularly those built around 2020 2023 models. This BB is designed to fit frames that use this standard, including many from brands like Trek, Specialized, Giant, and others. It avoids the need for adapters in most cases, making installation straightforward.

2. **Lightweight Construction**

Shimano s XT line is known for its balance of performance and weight. The IS-M86L2 is made from aluminum, which keeps it lighter than steel or titanium alternatives while still offering durability. This is beneficial for climbs and overall ride feel.

3. **Reliability and Durability**

Shimano s XT components are built to withstand rough conditions, making this BB suitable for aggressive riding, including downhill or trail riding. The sealed bearings and robust construction reduce the risk of failure from dirt or debris.

4. **Easy Installation**

The 6-bolt standard simplifies installation compared to older 24mm or 28mm axles, as it requires fewer tools and less adjustment. The 203mm width is also standard for many modern bikes, ensuring a snug fit without excessive play.

5. **Cost-Effective Upgrade**

For riders who want to upgrade their bottom bracket without investing in a full drivetrain overhaul, this BB offers a practical middle-ground option. It s more affordable than some high-end alternatives (e.g., SRAM DUB or carbon BBs) while still providing solid performance.

6. **Sealed Bearings**

The sealed bearings protect against moisture and dirt, reducing maintenance needs. This is particularly useful for riders who frequently ride in wet or muddy conditions.

7. **Compatibility with Shimano Drivetrains**

As part of Shimano s XT line, this BB pairs seamlessly with other XT components (e.g., derailleurs, shifters, and cassettes), ensuring consistent performance and ease of maintenance.

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### **Cons**

1. **Limited Compatibility with Older Frames**

If your bike uses a 24mm or 28mm axle standard or a different bolt pattern (e.g., 30mm or 34mm), this BB will not fit without adapters or modifications. Always verify compatibility before purchasing.

2. **Not as Light as Carbon or Titanium Options**

While aluminum is lightweight, it s heavier than carbon or titanium BBs. For ultra-lightweight builds or racing applications, these materials offer better performance at a higher cost.

3. **Potential for Wear Over Time**

Like all mechanical components, this BB will eventually wear out, especially under heavy use or poor maintenance. Shimano s XT BBs are durable but not indestructible, and replacement may be necessary after significant mileage.

4. **Price Point**

While affordable for a Shimano XT part, it may still be more expensive than basic or entry-level BBs from other brands. Riders on a tight budget might consider alternatives like SRAM or other mid-range options.

5. **Limited Customization**

Unlike some high-end BBs (e.g., those with adjustable spacers or carbon shells), this BB offers minimal customization. The 203mm width is fixed, and adjustments are limited to standard spacers.

6. **Potential for Looseness Over Time**

Some riders report that aluminum BBs can develop slight looseness or play after prolonged use, especially if not properly maintained. Regular checks and tightening are recommended.

7. **Not Ideal for Extreme Conditions**

While durable, this BB is not designed for extreme off-road use (e.g., long-duration downhill racing) where carbon or titanium BBs might offer better longevity and performance.

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### **Conclusion**

The **Shimano IS-M86L2 (XT SM-RT86-L, 6-bolt, 203mm)** is a solid, reliable choice for riders looking to upgrade their bottom bracket in a mid-range mountain bike. It strikes a balance between performance, durability, and cost, making it suitable for most trail and cross-country riders. Its compatibility with modern 6-bolt frames and Shimano drivetrains adds to its appeal, while its lightweight aluminum construction ensures a responsive ride.

However, it is not the best option for riders with older frames, those seeking ultra-lightweight performance, or those pushing the limits of extreme off-road use. If your bike fits the 6-bolt/203mm standard and you re using Shimano components, this BB is a practical and dependable upgrade.

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### **Recommendation**

- Your bike uses a 6-bolt bottom bracket standard and 203mm axle spacing.

- You re using or plan to use Shimano XT components (e.g., derailleurs, shifters).

- You want a reliable, mid-range BB that balances performance and cost.

- You ride mostly trail or cross-country and don t require extreme durability or weight savings.

- Your frame uses a different axle standard (e.g., 24mm, 28mm, or 30mm).

- You re building a bike with carbon or titanium components and prioritize weight savings.

- You ride in extreme conditions (e.g., long-duration downhill) where high-end BBs might be preferable.

- You re on a very tight budget and can find equally reliable alternatives from other brands.

- **SRAM DUB (Double Undersized Bearing):** Offers a slightly lighter and more durable option, though it may require adapters for some frames.

- **Cane Creek or Fox Carbon BBs:** For ultra-lightweight builds, though at a higher cost.

- **Basic Aluminum BBs (e.g., from Sunrace or Hope):** If you re on a budget and your frame is compatible.

In summary, the Shimano IS-M86L2 is a **strong, practical choice for most mid-range mountain bike setups**, provided compatibility is confirmed. For specialized needs (e.g., extreme weight savings or compatibility with older frames), other options may be worth exploring.

Details:

Diameter: 160mm 180mm, 203mm. Activity: trail, endure, cross-country. Shimano Xt SM-RT86-L 6-bolt 203mm, Material: rotor steel, aluminum, carrier aluminum. Please review photos for the exact condition of item and confirm compatibility before purchasing.

Attachment Type: 6-bolt. Items are visually inspected but not fully tested. Free shipping within continental US.

part #: ismrt86l2 prices

• $61.15-$80.00

specifications ribicycl:

• brand: Shimano
• mpn: Ismrt86l2
• item diameter: 203 Mm
• compatible model: Sm-rt86
• mounting type: 6 Bolt
• country of origin: Japan
• part type: Brake Rotors
• upc: 192790818108

payments ribicycl:

• other
• wallet: Apple-pay
• credit card: Mastercard

returns ribicycl:

• policy: No Returns

shipping ribicycl:

• service: USPS Priority Mail
• type: Calculated
• transit: 5-11 Days
• class: Expedited
• cost: $0.00
• carrier: USPS

seller ribicycl:

• rating: 99.7%
• # reviews: 564
• city: Roundup, Montana

offer ribicycl:

• quantity: 1
• sold: 0
• availability: In Stock
• options: Ship-to-home
• best offers: True
• started: March 20, 2026

general ribicycl:

• Cycling > Bicycle Components Parts > Brake Rotors
• condition: Used

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