Mountain Bike Reviews Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
44 Posts
Discussion Starter · #1 ·
Looking to convert my son's 3x9 to 1x9. Sunrace has a 40T 9-speed cassette. Anybody know what derailleur would work with that? The Altus that's on there only goes to 34T, maybe there's a link similar to the wolf tooth goatlink??? Thanks!
 

·
Registered
Joined
·
1,390 Posts
Not sure about 9spd derailleur for a 40T cassette. You could go with standard 11-34 cassette and select appropriate chainring size to get ratios dialed in. If going 1X you are probably already changing crank/chainring anyways.

I converted my Heckler to 1X9 and used standard XT cassette (11-34, XT 773 derailleur, med cage), Shimano Zee crankset and replaced the 32T chainring with a 30T Raceface chainring.

Before converting, with the 3X (22/32/42) I spent 95% of my time in middle ring (32T) but did use granny for short punchy climbs. Swapping chainring to 30T got me into desired range for pretty much everything.
 

·
Registered
Joined
·
790 Posts
I converted my 3x9 to a 1x9 with a 40t cassette. Mine is an Alivio but I believe the range is the same as an Altus. I just added a Wolf tooth road link. It dropped the derailleur just enough, I didn't even have to readjust anything, it shifted clean right off the bat.
 

·
Administrator
Joined
·
11,822 Posts
Not sure about 9spd derailleur for a 40T cassette. You could go with standard 11-34 cassette and select appropriate chainring size to get ratios dialed in. If going 1X you are probably already changing crank/chainring anyways.

I converted my Heckler to 1X9 and used standard XT cassette (11-34, XT 773 derailleur, med cage), Shimano Zee crankset and replaced the 32T chainring with a 30T Raceface chainring.

Before converting, with the 3X (22/32/42) I spent 95% of my time in middle ring (32T) but did use granny for short punchy climbs. Swapping chainring to 30T got me into desired range for pretty much everything.
Looking to convert my son's 3x9 to 1x9. Sunrace has a 40T 9-speed cassette. Anybody know what derailleur would work with that? The Altus that's on there only goes to 34T, maybe there's a link similar to the wolf tooth goatlink??? Thanks!
I have done what sturge has done and been using it for years and it is pretty simple and well geared.

However I saw this the other day and am not sure if it can use a shimano cassette but depending on what you are building it could be an option: https://www.boxcomponents.com/Box-Two-E-9S-Drivetrain_9
 

·
In Transit
Joined
·
1,097 Posts
Well it turns out the original Altus derailleur works just fine, just had to pin the b-screw. Talk about a cheap 3x9 to 1x9 conversion, the 40T Sunrace cassette and 30T NW chainring together cost just over $40 from thebikesmiths.com.
This is fortuitous - I'm about to go the same route on the 3x9 XT drivetrain on my hardtail. The price on that Sunrace cassette is the best I've seen!
 

·
Registered
Joined
·
44 Posts
Discussion Starter · #8 ·
This is fortuitous - I'm about to go the same route on the 3x9 XT drivetrain on my hardtail. The price on that Sunrace cassette is the best I've seen!
Word of caution, I think part of the reason this is working for me is that the Altus spring is not tight at all and allows the cage to extend further than it should. You may need a longer B-screw, even then, you may need to bend the B-screw so that it stays "on-target" as the derailleur rotates up and away from the hanger.

BTW, also from the Bikesmiths I got a NW 30T chainring for like $15. Plus free shipping. $40 total for the conversion!
 

·
In Transit
Joined
·
1,097 Posts
Word of caution, I think part of the reason this is working for me is that the Altus spring is not tight at all and allows the cage to extend further than it should. You may need a longer B-screw, even then, you may need to bend the B-screw so that it stays "on-target" as the derailleur rotates up and away from the hanger.

BTW, also from the Bikesmiths I got a NW 30T chainring for like $15. Plus free shipping. $40 total for the conversion!
Thanks for the heads up.

Which chainring did you get BTW? The Shun ring says 10/11-sp compatibilitiy and the First Components ring saying 11sp compatibility only in the description.
 

·
Registered
Joined
·
44 Posts
Discussion Starter · #10 ·
Thanks for the heads up.

Which chainring did you get BTW? The Shun ring says 10/11-sp compatibilitiy and the First Components ring saying 11sp compatibility only in the description.
I got the Sun MTB-03. I'm sure there's compatibility issues abound with this setup, but my son isn't thrashing trails, and this 1x conversion just allows him to think less when riding.
 

·
In Transit
Joined
·
1,097 Posts
I got the Sun MTB-03. I'm sure there's compatibility issues abound with this setup, but my son isn't thrashing trails, and this 1x conversion just allows him to think less when riding.
No doubt.

In an instance of "well, that escalated quickly", I ended up ordering an XT 11sp drivetrain rather than potentially mess around with goat links and bent b-screws since this is going on my hardtail. On the plus side, it only cost me six times as much as the Sunrace cassette. :p
 

·
XC iconoclast
Church of Real Metal
Joined
·
2,198 Posts
Well it turns out the original Altus derailleur works just fine, just had to pin the b-screw. Talk about a cheap 3x9 to 1x9 conversion, the 40T Sunrace cassette and 30T NW chainring together cost just over $40 from thebikesmiths.com.
I found this out too, Altus 8-speed medium cage did just fine w/o an extender on 11-40t, I don't know how, but it did. And...then...I destroyed that RD by shoving the bike in the back seat of a sedan car and slamming the door on it lol. Oh well, it's only $20.

The Alivio, Deore, or Deore XT 9-speed long cages with an extender should be fine; I'm doing Alivio right now and have an unused Deore waiting in the garage later. Just be vigilant about if the chain falls off the front chainring or not, since these RD's do not have a clutch. I've even had the chain drop with a narrow-wide chainring and had to put a chainring guard right up next to it in order to keep the chain from swinging off to the right. Works great now.

I'm also doing an 8-speed Acera w/o an extender with 11-40t on a different bike and that actually works too but I can tell it's really straining the RD and the hangar --- I've already had to pry back the aluminum hanger with pliers because it got bent forwards and I could not drop the rear axle in/out. So that or the RD will eventually break for sure, I'm just being lazy right now because the extender doesn't fit the hangar properly so I'm riding it and trying to avoid 40t unless I really need it.
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top