2 x 11 spd GRX 10 - 50 KMC Conversion.

[U1Nanimous]

Just out of interest, anybody else out there that did this? 

I did not do this to target everyday riding, but bike packing trips and gear on bikes suggest I might want to make it easier for myself...

So, here is some Post pics, quick ride around the block confirmed all working good, just have to keep an eye on cross chaining. 

 

30-40 Crank, 

11 - 50 KMC cassette 

Toopre extender 

 

Took some adjusting, but all good. 

 

[Dexter-morgan]

Looks cool with the gold chain on Black cassette.

[BrendanA]

U1Nanimous

22 hours ago, U1Nanimous said:

Just out of interest, anybody else out there that did this? 

I did not do this to target everyday riding, but bike packing trips and gear on bikes suggest I might want to make it easier for myself...

So, here is some Post pics, quick ride around the block confirmed all working good, just have to keep an eye on cross chaining. 

 

30-40 Crank, 

11 - 50 KMC cassette 

Toopre extender 

 

Took some adjusting, but all good. 

 

ive got this exact setup and ive done roughly 10k km since the install with absolutely no issues!

[U1Nanimous]

Did Suikerbos today... love the range, no issues.

The 50T is bit much, but can see the usefulness.

Also.. fitted the Pannier rack and tested the fit with my GIVI Moto bags... must say, looks like it will do the job.

 

[capediver]

On 2/4/2026 at 10:35 AM, U1Nanimous said:

Just out of interest, anybody else out there that did this? 

I did not do this to target everyday riding, but bike packing trips and gear on bikes suggest I might want to make it easier for myself...

So, here is some Post pics, quick ride around the block confirmed all working good, just have to keep an eye on cross chaining. 

 

30-40 Crank, 

11 - 50 KMC cassette 

Toopre extender 

 

Took some adjusting, but all good. 

 

Hi, can you detail your conversion please...
I want to do the same for bikepacking, I currently have:

Crank: Shimano GRX RX600-11,46-30T

Rear derailleur:  GRX RX810 34T MAX

11-34 cassettte

 

Edited Sunday at 05:02 AM by capediver

[U1Nanimous]

31 minutes ago, capediver said:

Hi, can you detail your conversion please...
I want to do the same for bikepacking, I currently have:

Crank: Shimano GRX RX600-11,46-30T

 

Rear derailleur:  GRX RX810 34T MAX

11-34 cassettte

 

Hi,

The conversion is actually easy. 

But, I did need 3 things.

1. CASSETTE KMC CS11S 11-50 HG - Evobikes https://share.google/fDCWpXQdTegAQa5fg

2. New 11spd chain. I got the 11spd SL from KMC.

3. Hanger extender. This was a bit of a question mark as I couldn't get the Goatlink. (More often mentioned).

So I got a Chinese (?) Toopre 36 -52 range.

Toopre Bicycle Derailleur Cassette Extender 34-52T
https://www.takealot.com/toopre-bicycle-derailleur-cassette-extender-34-52t/PLID94410445

 

Removed the old cassette, fitted the new one.

The chain... measured the new chain, max rear to max front... and the chain, out of the box was actually on limit. 

I choose to do the M on M method as to minimize risk of rear mech pull. 

Surprisingly I had some good leeway with the B screw adjustment. If you are unfamiliar with this, check on the Parktool YouTube channel, nice explanation there. 

My mech upper limit screw had some adjustment, but you can check movement yourself. 

Drive the mech to max with your hand, press the body inwards with your thumb, and pedal. You will see if it reach or is hesitant. If you push the chain off, adjust the reach to less. 

Cable tention on mine, took up 1.5 turns.

The more tricky part... 

The extender adjustment... this might take some trail and error... i found that full reach forward, adjust B screw on 51t and it was set. 

Indexing is not the smoothest in the world, but it works. You have considerable spacing on the higher ranges(top pulley wheel to cassette), but, keep in mind cross chaining, and you should be good. 

Don't do Small Chainring - 11T... you will see why. I adjusted B for some slack, but keep the focus on the 51T spacing.

I also have the 810 GRX Mech.

All in my conversion was about R 1 800.

I actually found the KMC cassette alast year on Takealot, think it was R 880 on special. See they have one for R 995.

If you struggle, I would gladly do the conversion for you, but I think Pretoria is a bit far from you 😀 

You can also send me a DM and I can walk you through the install if needed.

Below, note the down angle and Mech attachment. I think this is the most crucial part. 

[capediver]

4 hours ago, U1Nanimous said:

Hi,

The conversion is actually easy. 

But, I did need 3 things.

1. CASSETTE KMC CS11S 11-50 HG - Evobikes https://share.google/fDCWpXQdTegAQa5fg

2. New 11spd chain. I got the 11spd SL from KMC.

3. Hanger extender. This was a bit of a question mark as I couldn't get the Goatlink. (More often mentioned).

So I got a Chinese (?) Toopre 36 -52 range.

Toopre Bicycle Derailleur Cassette Extender 34-52T
https://www.takealot.com/toopre-bicycle-derailleur-cassette-extender-34-52t/PLID94410445

 

Removed the old cassette, fitted the new one.

The chain... measured the new chain, max rear to max front... and the chain, out of the box was actually on limit. 

I choose to do the M on M method as to minimize risk of rear mech pull. 

Surprisingly I had some good leeway with the B screw adjustment. If you are unfamiliar with this, check on the Parktool YouTube channel, nice explanation there. 

My mech upper limit screw had some adjustment, but you can check movement yourself. 

Drive the mech to max with your hand, press the body inwards with your thumb, and pedal. You will see if it reach or is hesitant. If you push the chain off, adjust the reach to less. 

Cable tention on mine, took up 1.5 turns.

The more tricky part... 

The extender adjustment... this might take some trail and error... i found that full reach forward, adjust B screw on 51t and it was set. 

Indexing is not the smoothest in the world, but it works. You have considerable spacing on the higher ranges(top pulley wheel to cassette), but, keep in mind cross chaining, and you should be good. 

Don't do Small Chainring - 11T... you will see why. I adjusted B for some slack, but keep the focus on the 51T spacing.

I also have the 810 GRX Mech.

All in my conversion was about R 1 800.

I actually found the KMC cassette alast year on Takealot, think it was R 880 on special. See they have one for R 995.

If you struggle, I would gladly do the conversion for you, but I think Pretoria is a bit far from you 😀 

You can also send me a DM and I can walk you through the install if needed.

Below, note the down angle and Mech attachment. I think this is the most crucial part. 

Excellent, thanks! I saw a few YT vids on this now and it seems pretty straight forward, just getting the chain length and that B screw sorted...I also saw the angle of the extender makes a difference to the shifting...

Will definitely give it a bash to reduce some of this:

 

 

Edited Sunday at 10:16 AM by capediver

[splat]

5 hours ago, capediver said:

Hi, can you detail your conversion please...
I want to do the same for bikepacking, I currently have:

Crank: Shimano GRX RX600-11,46-30T

Rear derailleur:  GRX RX810 34T MAX

11-34 cassette

 

I added a Shimano 11-40 cassette and Wolf Tooth Roadlink DM to my set-up.

Shifting isn't as crisp as the stock 11-34, but it works fine and is a really nice gear range for my 'fuller figure'.

 

https://evobikes.co.za/product/wolftooth-roadlink-direct-mount/?srsltid=AfmBOoqdz2VyI8BIRvgxNgv58OKzxXZjitUgjObTcae7UfWZncUGG-Gz

 

https://bikehub.co.za/classifieds/item/cassettes/884159/shimano-xt-11-40-cs-m8000-11-speed-cassette?return_to=L2NsYXNzaWZpZWRzL2FsbC1hZHM_cz0xMS00MA

 

Edited Sunday at 10:37 AM by splat

[capediver]

13 minutes ago, splat said:

I added a Shimano 11-40 cassette and Wolf Tooth Roadlink DM to my set-up.

Shifting isn't as crisp as the stock 11-34, but it works fine and is a really nice gear range for my 'fuller figure'.

 

https://evobikes.co.za/product/wolftooth-roadlink-direct-mount/?srsltid=AfmBOoqdz2VyI8BIRvgxNgv58OKzxXZjitUgjObTcae7UfWZncUGG-Gz

 

https://bikehub.co.za/classifieds/item/cassettes/884159/shimano-xt-11-40-cs-m8000-11-speed-cassette?return_to=L2NsYXNzaWZpZWRzL2FsbC1hZHM_cz0xMS00MA

 

Cool!....our fuller figures need all the help they can get!

My fear is that I will now have the gears to do those 10%ers fully loaded but not the legs!!!!

[U1Nanimous]

So, I will honestly say that the 13+% Climbs still makes itself known, but it is easier. 

I thought about the XT cassettes for the conversion, but right now not regretting the bigger ratio. 
I'm aiming to do Suikerbos again this weekend... more testing... 

 

Sidenote. Also love the range I'm getting on the big chainring with the bigger rear ratio available. 

Now, looking for some Front Fork racks, anyone got some ideas? 

[capediver]

7 hours ago, U1Nanimous said:

So, I will honestly say that the 13+% Climbs still makes itself known, but it is easier. 

I thought about the XT cassettes for the conversion, but right now not regretting the bigger ratio. 
I'm aiming to do Suikerbos again this weekend... more testing... 

 

Sidenote. Also love the range I'm getting on the big chainring with the bigger rear ratio available. 

Now, looking for some Front Fork racks, anyone got some ideas? 

Front fork rack:

These take a massive beating when the gravel gets bad so if you got mount inserts on you front fork, 3 are better than two and you must be careful not to overload...and use locktite!

Options are:

1: for bottles or small bags:

I got these but don't use the mounting inserts on the forks, instead they get mounted with a rubber backing strip and fully taped with Gorilla tape...going nowhere..,. and bags only carry light stuff like clothes or water bottles

https://www.takealot.com/rockbros-bike-front-fork-shelf-with-bike-fork-bag-road-cycling-r/PLID100292395

 

If you want to pack heavier, then the Old Man Mountain rack adapters are good as the load is carried on the axle they supply...@7:40

2: front mount carrier racks that can also carry small panniers: A few expensive options here...but again, some use the mounting inserts on the fork

https://www.cycletouring.co.za/product-category/touring-bikepacking/front-racks/

Hope this helps