---
product_id: 12975928
title: "Wolf Tooth Components 25mm Long B-Screw for Adapting Old deraileurs When"
brand: "wolf tooth"
price: "119 kr"
currency: DKK
in_stock: true
reviews_count: 9
url: https://www.desertcart.dk/products/12975928-wolf-tooth-components-25mm-long-b-screw-for-adapting-old
store_origin: DK
region: Denmark
---

# 25mm M4 x 0.7mm precision screw Premium 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:** 119 kr
**Availability:** ✅ In Stock

## Summary

> 🔧 Upgrade your ride, dominate every trail with precision!

## 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?** 119 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.dk](https://www.desertcart.dk/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

- • **Race-Proven Reliability:** Trusted by riders to withstand muddy, demanding mountain bike conditions.
- • **Engineered for Large Cogs:** Specifically designed to support Wolf Tooth GC 40 & GC 42 cogs up to 42 teeth.
- • **Simple Upgrade, Big Impact:** Easy installation that unlocks your drivetrain’s full potential and gear range.
- • **Precision Fit for Shimano MTB:** Seamlessly replaces stock B-limit screw for flawless derailleur tuning.
- • **Premium Stainless Steel Build:** Crafted from corrosion-resistant 18-8 stainless steel for long-lasting performance.

## Overview

The Wolf Tooth Components 25mm Long B-Screw is a high-quality stainless steel replacement screw designed to optimize Shimano mountain bike derailleurs when paired with large Wolf Tooth GC 40 or GC 42 cogs. Engineered for durability and precision, it ensures proper derailleur adjustment and enhanced drivetrain performance, making it a must-have upgrade for serious MTB enthusiasts.

## 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: Perfect for Shimano B Screw - I used this to replace the B limit screw on my Shimano derailleur after it was bent in a particularly muddy mountain bike race. It works perfectly!
Review: For those lower gears - If you want to thumb your nose at Shimano’s claimed largest sprocket size, get this. As long as your derailleur hanger has a large-enough flat for it to bear against, it will work fine for up to 40- or 42-tooth cogs. Some people turn it around, so the head of the screw meets the land to provide support.

## 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 | #161,149 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 | 4.3 4.3 out of 5 stars (241) |
| 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 Type | Phillips |
| Included Components | Miscellaneous Rear Derailleur Part |
| Item Diameter | 4 Millimeters |
| Item Dimensions | 4 x 2 x 0.25 inches |
| Item Weight | 4.54 g |
| Manufacturer | Wolf Tooth |
| Material Type | Multi |
| Maximum Shear Strength | 550 MPa |
| Metal Type | Stainless Steel |
| Model | BSCREW25 |
| Number of Pieces | 1 |
| Part Number | BSCREW25 |
| 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 | 1.0 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

### ⭐⭐⭐⭐⭐ Perfect for Shimano B Screw
*by D***C on July 5, 2024*

I used this to replace the B limit screw on my Shimano derailleur after it was bent in a particularly muddy mountain bike race. It works perfectly!

### ⭐⭐⭐⭐⭐ For those lower gears
*by A***T on October 8, 2022*

If you want to thumb your nose at Shimano’s claimed largest sprocket size, get this. As long as your derailleur hanger has a large-enough flat for it to bear against, it will work fine for up to 40- or 42-tooth cogs. Some people turn it around, so the head of the screw meets the land to provide support.

### ⭐⭐⭐⭐⭐ 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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**Shop now:** [https://www.desertcart.dk/products/12975928-wolf-tooth-components-25mm-long-b-screw-for-adapting-old](https://www.desertcart.dk/products/12975928-wolf-tooth-components-25mm-long-b-screw-for-adapting-old)

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*Product available on Desertcart Denmark*
*Store origin: DK*
*Last updated: 2026-04-24*