Cheap 9-speed 11-38+t cassette... XX1 killer
Was reading here:
10s 11-39 cassette
Read a few other places. Sounds like the last 3 cogs on SRAM cassettes are a single fixed body, and the rest can be shuffled around?
Take your existing 11-34 SRAM 950 cassette:
Buy the 11-32 SRAM 950 cassette:
Buy the Action Tec 39T Ti cog:
Action Tec Home Page
Remove the 3 cog fixed body from your 11-34:
Remove the 23 and the spacer:
Add the 3 cog fixed body from the 11-32:
Add the spacer from the 23 and add the 39:
Ratio changes yields a somewhat balanced:
20T + 20% =
24T + 16.7% =
28T + 14.3% =
32T + 21.9% =
Total cost to loose front derailleur with $30 for 32T SS chain ring:
Loss in gearing, considering going from 24/36 11-34 to 32 11-39:
6.6 gear from top end, now 5.8 (old second gear was 5.5)
1.4 gear from bottom end, now 1.6 (old second gear was 1.6)
Thoughts? Does this work - specifically moving the 3 cog fixed body away from the end of the cassette?
Last edited by Lindahl; 07-20-2013 at 08:44 PM.
tagged for future reading
Another option would be:
Where the '*' indicates the transition from the cogs on the 11-34 to the cogs on the 11-32. You get the 20% jump at 15-18 instead of 20-24 this way.
Could you just skip buying the 11-32, cassette, take off the 23T from your 11-34, and add the 39 to get:
I know the jump from 20 to 26 is big, but is it doable?
Actually, there's a guy on EBay named MTBtools that sells 36, 38, and 40 T cogs. Not titanium, but a lot cheaper than Actiontech.
I converted an 11-32 to an 11-36 one time, by taking off the 12:
That seems to make a lot more sense than buying a whole new cassette just to vary the top 3 tooth gaps a bit.
38 Tooth Cog for Mountain Bike Cassette 38t Sprocket | eBay
That seems kinda interesting. How heavy is it?
Originally Posted by smilinsteve
On MTBR, the reputation is infamous.
I've read more than a couple first-hand posts about the MTBTools cogs getting bent pretty easily. Thats why I'm leaning towards Action Tec.
Last edited by rideit; 07-20-2013 at 06:56 PM.
Pretty heavy. There are no good 11-36 9 speed cassettes, other than the Shimano HG-61 which is heavy. So, I thought I could save weight by buying a light XT cassette and adding the 36, but by the time I did that, it weighed about the same as an HG-61.
Originally Posted by Vespasianus
Yes mine bent.
Originally Posted by Lindahl
I think its more of a problem with the cog being properly supported against the neighboring cog. If you set it up right so that the nuts on the back of the cog are in contact with the cassette, it should be supported fairly well. With mine, the nuts didn't quite touch, which means there is basically no lateral support on that big cog.
If I was to try that again I would email MTBtools to discuss that problem. He is definitely a good guy.
When I bought my 36, it got shipped to the wrong state because I didn't update my paypal account info. He dealt with my problem, got the package returned to him, and reshipped it to me for no extra charge.
I don't know about Action Tec, but it seems there cog would also need some kind of lateral support.
Good feedback smilinsteve. That does make sense. Maybe a larger machined spacer would do the trick. Large enough to mate the 38 with the 32, and the 41 with the 34. Would be a bit heavier though - but this is less about weight and more about economimcally gaining a good granny in 1x9.
The 41 has some appeal in this configuration:
The 38 would also work:
For me, it was in the first ride on it.
Originally Posted by Lindahl
Others have attached chainrings bolted to the 34T cog. Some more homegrown than others:
Anybody ever made a 27t 5 bolt 74mm chainring ?
Show pics of your 1x9 setup
DIY 42T Cassette Cog
It looks like you get the benefit of the larger cog plus free support by bolting it close to the teeth (where the chain torques is). Seems like a much better than trying to use the Ebay cogs or Actiontec cogs, where they attach directly to the freehub. It looks like a lot of work to machine and attach the BMX and 5-chain chainrings to the cassettes. 3 and 6 bolt chainrings would work much better, since they'd align with the struts on the cassette cogs - probably just have to drill holes in the 32T or 34T cassette cog and bolt it together - relatively little DIY work.
Found these references for 3 and 6 bolt chainrings at a relatively good price:
Cranks and Chainrings
3 Bolt 86mm BCD Chainring
The tricky part would be spacing it off the base/end of the freehub, so that the chainring-cog is properly aligned along the freehub with the last 9-speed cog position. Probably just a couple extra spacers are required that go between the 32T or 34T cassette cog and the base of the freehub - if you don't do this, the cassette can slide along the freehub (to the #8 position), and the chainring-cog will be pushed towards your spokes, possibly even into them.
If you want to get really fancy, machine in some ramps to improve shifting up to the new 38T/40T/42T chainring-cog.
Last edited by Lindahl; 07-21-2013 at 08:54 AM.
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