---
product_id: 12975928
title: "Wolf Tooth Components 25mm Long B-Screw for Adapting Old deraileurs When"
brand: "wolf tooth"
price: "€ 5.84"
currency: EUR
in_stock: true
reviews_count: 9
category: "Wolf Tooth"
url: https://www.desertcart.ie/products/12975928-wolf-tooth-components-25mm-long-b-screw-for-adapting-old
store_origin: IE
region: Ireland
---

# M4 x 25mm precision screw 18-8 stainless steel durability Optimized for Shimano MTB derailleurs Wolf Tooth Components 25mm Long B-Screw for Adapting Old deraileurs When

**Brand:** wolf tooth
**Price:** € 5.84
**Availability:** ✅ In Stock

## Summary

> 🔧 Upgrade your ride with precision and power — don’t get left behind!

## Quick Answers

- **What is this?** Wolf Tooth Components 25mm Long B-Screw for Adapting Old deraileurs When by wolf tooth
- **How much does it cost?** € 5.84 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/12975928-wolf-tooth-components-25mm-long-b-screw-for-adapting-old)

## Best For

- wolf tooth enthusiasts

## Why This Product

- Trusted wolf tooth brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Maximized Clearance:** Enables use of Wolf Tooth GC 42 and GC 40 large cogs, unlocking bigger cassette setups without compromise.
- • **Precision Engineering:** M4 x 25mm thread size ensures a secure fit and optimal derailleur adjustment every ride.
- • **Proven Rider Approved:** Highly rated by cyclists upgrading GRX and 1x conversions—join the elite who demand more from their drivetrain.
- • **Seamless Compatibility:** Perfectly replaces stock B-limit screws on Shimano mountain bike derailleurs for flawless gear shifts.
- • **Premium Stainless Steel:** Crafted from high-grade 18-8 stainless steel for corrosion resistance and long-lasting performance.

## Overview

The Wolf Tooth Components 25mm Long B-Screw is a premium stainless steel replacement screw designed to adapt Shimano mountain bike derailleurs for use with larger Wolf Tooth GC 42 and GC 40 cogs. Engineered for durability and precise fit, it enables riders to expand their cassette range and optimize drivetrain performance, making it a must-have upgrade for serious cyclists seeking enhanced gear clearance and reliability.

## Description

When using the Wolf Tooth GC 42 (50-3898) or GC 40 (50-3899) replacement cogs with a Shimano rear derailleur, a longer B-screw will be needed for proper adjustment. High quality 18-8 stainless steel screw is compatible with most Shimano mountain bike derailleurs. Replaces stock B-limit screw on Shimano MTB derailleurs Use if you are using Wolf Tooth GC 42 or GC 40 large cogs High quality stainless steel

Review: GRX RD - Made my GRX derailleur work with a bigger cassette than recommended, excellent stuff.
Review: 1x conversion - Fits my GRX RX400 derailleur to improve clearance with a 11-42t 10 speed cassette for a 1x conversion on my topstone. Wish it was black like the original screw but oh well no biggie.

## Features

- Replaces stock B-limit screw on Shimano MTB derailleurs
- Use if you are using Wolf Tooth GC 42 or GC 40 large cogs
- High quality stainless steel

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00LMY7BA0 |
| Best Sellers Rank | #159,302 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #18 in Front Bike Derailleurs |
| Brand | Wolf Tooth |
| Color | Silver |
| Compatible Groove Diameter | 4 millimeters |
| Customer Reviews | 4.4 out of 5 stars 243 Reviews |
| Drive System | Bicycle Derailleur Drive System |
| Exterior Finish | Stainless Steel |
| Fastener Size | M4 x 25mm |
| Fastener Type | Screw (M4 thread size) |
| Finish Types | Stainless Steel |
| Global Trade Identification Number | 00812719020152 |
| Grade Rating | Premium |
| Head Style | Phillips |
| Head Type | Phillips |
| Included Components | Miscellaneous Rear Derailleur Part |
| Item Diameter | 4 millimeters |
| Item Dimensions | 4 x 2 x 0.25 inches |
| Item Highlight | cog |
| Item Weight | 4.54 g |
| Item dimensions L x W x H | 4 x 2 x 0.25 inches |
| Manufacturer | Wolf Tooth |
| Material | Multi |
| Material Type | Multi |
| Maximum Shear Strength | 550 MPa |
| Metal Type | Stainless Steel |
| Model | BSCREW25 |
| Number Of Items | 1 |
| Number of Packs | 1 |
| Number of Pieces | 1 |
| Part Number | BSCREW25 |
| Point Style | cylindrical |
| Screw Head Style | Phillips |
| Screw Point Style | cylindrical |
| Set Name | Single Screw Set (M4 x 25mm) |
| Set Screw Thread Type | M4 x 0.7mm |
| Size Name | 4mm x 25mm |
| Thread Class | 2B |
| Thread Coverage | Fully Threaded |
| Thread Size | 4mm |
| Thread Style | M4 |
| Thread Type | Metric |
| UPC | 812719020152 |
| Unit Count | 1 Count |
| Warranty Description | Limited Warranty |

## Product Details

- **Exterior Finish:** Stainless Steel
- **Head Style:** Phillips
- **Item dimensions L x W x H:** 4 x 2 x 0.25 inches
- **Material:** Multi
- **Thread Size:** 4mm

## Images

![Wolf Tooth Components 25mm Long B-Screw for Adapting Old deraileurs When - Image 1](https://m.media-amazon.com/images/I/61DD++TmylL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ GRX RD
*by A***R on May 25, 2026*

Made my GRX derailleur work with a bigger cassette than recommended, excellent stuff.

### ⭐⭐⭐⭐⭐ 1x conversion
*by M***E on June 15, 2026*

Fits my GRX RX400 derailleur to improve clearance with a 11-42t 10 speed cassette for a 1x conversion on my topstone. Wish it was black like the original screw but oh well no biggie.

### ⭐⭐⭐⭐⭐ Problem solver
*by B***D on July 17, 2025*

Exactly what I needed for a 9 speed SLX derailleur to run a larger 40T granny gear. Nice Allen head with good threads and fit.

## Frequently Bought Together

- Wolf Tooth Components 25mm B-Screw
- Wolf Tooth Components Roadlink
- Wolf Tooth GoatLink for Shimano

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*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-09-21*