Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.

New: Take Part in the May's Giveaway: Win the LIVALL PikaBoost 2 E-bike Conversion Kit


Help! Tool for removing SHIMANO MF-HG20 cogs
#1
Hello there,

I'm trying to clean my Shimano MF-HG20 freewheel, and want to disassemble the cogs. But I found there is a lock ring that seems need a special tool to remove it. Could you please teach me what the tool's name is?

It is in 46mm diameter and has 8 notches on it. The notches are semicircle.

[Image: ojGvsuPL7Sfaywur8]
   

Thank you.
  Reply
#2
I do believe that is called a Lockring Spanner Wrench.

There are more than a few types.

Have you tried using a regular spanner wrench and a chain whip yet?
  Reply
#3
(07-30-2021, 01:17 PM)ReapThaWhirlwind Wrote:  I do believe that is called a Lockring Spanner Wrench.

There are more than a few types.

Have you tried using a regular spanner wrench and a chain whip yet?

Thank you for your information.

I will try to find a Lockring Spanner Wrench that fits the notches. I have a Bottom Bracket Lockring Wrench for crank lockring and I tried to use it with a chain whip, but because the notches are not square that makes the wrench can not hold the notch firmly.
  Reply
#4
Note that the specific tool for that cassette however may not be acquirable by natural means.

It could have been a manufacturing side exclusive tool only Shimano has.

You could go to a Machine Shop/Tool & Die, and one of the engineers could possibly make you a tool to remove it.

You're looking to spend a pretty penny though for their service.
  Reply
#5
A Park Tool LRT-3 Lockring Tool 'might' work.

However a freewheel is rather cheap. For example you can get a MF-TZ500-6 or MF-TZ20-6 6-speed freewheel for under $30.

If you just want it cleaner, spray between the gears with something like WD-40 and 'floss' between the gears with a thin rag.
  Reply


Possibly Related Threads...

Forum Jump:

[-]
10 Latest Posts
Urtopia Carbon Fold
Today 12:25 PM
POLL: Are non-recumbent riders looking a...
Today 10:58 AM
Wearable Fitness Trackers
Today 10:30 AM
Safest bike helmets
Today 09:55 AM
Gu/SiS/Energy Gels replacement
Today 09:29 AM
How waterproof are eBikes?
Today 08:20 AM
Ebike
Yesterday 07:08 PM
What was your first bicycle?
Yesterday 08:51 AM
Rookie looking for a bike
05-17-2025 03:25 PM
New Member
05-16-2025 03:46 AM

[-]
Join BikeRide on Strava
Feel free to join if you are on Strava: www.strava.com/clubs/bikeridecom

[-]
Top 5 Posters This Month
no avatar 1. Flowrider
20 posts
no avatar 2. Painkiller
19 posts
no avatar 3. GirishH
16 posts
no avatar 4. enkei
15 posts
no avatar 5. meamoantonio
12 posts