# 11-42 Sunrace cassette for a road climber



## bluesky6 (Jul 23, 2013)

Here's yet another cassette that I just received for a different project. Yes, I've a cassette fetish. 

This is the CSMX3, a 10-speed 11-42 wide range cassette that Sunrace is selling. There's a long thread discussing the Sunrace cassettes at mtbr.com.

However, I'll not be using it for a mountain bike. I'll be putting together a road bike for climbing some of the relatively steep hills where I live where the 12-28 and 11-32 cassettes on my other bikes won't work (age being the primary limiter).

The plan is to build a 1x10 bike using this cassette along with a SRAM GX long cage derailleur, SRAM Force 10-speed shifters, and a yet-to-be-determined chainring mounted on a SRAM Force crankset.

The SRAM GX long cage derailleur is needed to deal with the 42T cog. A medium cage would have been sufficient had I bought the 11-40 version of the cassette. The shifters are left over from a previous project bike. If I didn't already have them in hand, I'd probably gone for the Rival1 11-speed shifter to do a 1x11. 

For the chainring, I'll likely start off with 34T which means using the crankset as is (the 50T will be the bash guard ).

Front:








Rear:








The last cog is alloy (gasp!).


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## AndreyT (Dec 1, 2011)

You know, with the right adapter and a little technical ingenuity you could probably just use another chainring as one of the cogs. Put a 53 there - that would be cool...

BTW, that cog with red alloy spider in the center looks a bit like a floating disc brake rotor. Would be nice to fit it as one, just to piss off those anti-disc crybabies.


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## bikerjulio (Jan 19, 2010)

> The SRAM GX long cage derailleur is needed to deal with the 42T cog. A medium cage would have been sufficient had I bought the 11-40 version of the cassette.


Don't confuse chain wrap capacity with upper jockey clearance.

As a 1X the chain wrap is only 31T. No problem any RD. The clearance is the issue.


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## MMsRepBike (Apr 1, 2014)




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## bluesky6 (Jul 23, 2013)

bikerjulio said:


> Don't confuse chain wrap capacity with upper jockey clearance.
> 
> As a 1X the chain wrap is only 31T. No problem any RD. The clearance is the issue.


Some of the Sunrace resellers are recommending long cage (min 31T chainwrap) for the 42T and medium (29T chainwrap) for the 40T.

SRAM specifies long cage for their 10-42 11-speed cassettes but apparently doesn't support *-42T for their 10-speed parts. Go figure. 

I agree on the clearance part. If you look at the long thread on mtbr.com, I've a post on the use of a 11-40 cassette + GX medium cage on my wife's road bike (I know, wrong forum) where I described having to turn in the B-screw to get sufficient jockey-40T cog clearance).


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## roadmaster (May 3, 2016)

the long cage derailleur does have more chain wrap capacity + more jockey clearance


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## bikerjulio (Jan 19, 2010)

SRAM GX only comes in one cage length. And cage length has nothing to do with clearance. That was my point.

A short cage RD would handle OP's situation as long as there was sufficient clearance as @MMs video points out.


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## Lelandjt (Sep 11, 2008)

bluesky6 said:


> Some of the Sunrace resellers are recommending long cage (min 31T chainwrap) for the 42T and medium (29T chainwrap) for the 40T.
> 
> SRAM specifies long cage for their 10-42 11-speed cassettes but apparently doesn't support *-42T for their 10-speed parts. Go figure.
> 
> I agree on the clearance part. If you look at the long thread on mtbr.com, I've a post on the use of a 11-40 cassette + GX medium cage on my wife's road bike (I know, wrong forum) where I described having to turn in the B-screw to get sufficient jockey-40T cog clearance).


You're saying the GX derailleur worked on your wife's bike with Sram 10spd road shifters?


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## roadmaster (May 3, 2016)

bikerjulio said:


> SRAM GX only comes in one cage length. And cage length has nothing to do with clearance.


yes it has. The long cage derailleur comes with a different jockey offset for more clearance to the biggest cog.


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## bikerjulio (Jan 19, 2010)

roadmaster said:


> yes it has. The long cage derailleur comes with a different jockey offset for more clearance to the biggest cog.


perhaps english is not your first language? comprehension?

a particular rd can be made with a long cage and lots of clearance, but the fact of having the long cage did not cause the greater clearance. they are separate issues.


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## roadmaster (May 3, 2016)

bikerjulio said:


> perhaps english is not your first language? comprehension?
> 
> a particular rd can be made with a long cage and lots of clearance, but the fact of having the long cage did not cause the greater clearance. they are separate issues.


Just to be clear I think the OP was well aware of that causality but you decided to school him nevertheless. On a long cage rear derailleur both cage length and pulley offset change to accommodate a wider cassette + more chain wrap. (e.g. - there is no long cage derailleur with same pulley offset)

And as you pointed out correctly English isn't my first language.


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## cxwrench (Nov 9, 2004)

roadmaster said:


> Just to be clear I think the OP was well aware of that causality but you decided to school him nevertheless. On a long cage rear derailleur both cage length and pulley offset change to accommodate a wider cassette + more chain wrap. (e.g. - *there is no long cage derailleur with same pulley offset*)
> 
> And as you pointed out correctly English isn't my first language.


But there was for years and years, which is why people like julio and I make the distinction between capacity and wrap. When Shimano made road triples both the SS (short cage) and SGS (long cage) had the exact same capacity. The amount of chain they would wrap was the only difference. They both maxed out with a 27t cog.


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## bikerjulio (Jan 19, 2010)

roadmaster said:


> Just to be clear I think the OP was well aware of that causality but you decided to school him nevertheless.


OP said


> The SRAM GX long cage derailleur is needed to deal with the 42T cog. A medium cage would have been sufficient had I bought the 11-40 version of the cassette.


Which implied to me at least that a gentle schooling might not hurt since people often mistakenly associate a "long cage" RD with having more clearance.



> On a long cage rear derailleur both cage length and pulley offset change to accommodate a wider cassette + more chain wrap. (e.g. - there is no long cage derailleur with same pulley offset)


If you mean upper jockey clearance to the cassette, then you are completely wrong. At least as a generalization.


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## EddNog (May 20, 2016)

bluesky6 said:


> Here's yet another cassette that I just received for a different project. Yes, I've a cassette fetish.
> 
> This is the CSMX3, a 10-speed 11-42 wide range cassette that Sunrace is selling. There's a long thread discussing the Sunrace cassettes at mtbr.com.
> 
> ...


I'm running the full 50/34 compact double crank with the 11-40 all-steel black version of that SunRace cassette on my road bike (Breezer Venturi) perfectly fine. The GX 2x10 long cage RD has NO problem with clearing the 40T cog, shifting all the way to 50x40, shifting all the way to 34x11 (not that I will purposefully ride either of those combinations) or shifting into any other of the 18 possible gear combos. 10-speed Force crank, 10-speed Force shifters, 2013 Red Yaw FD. Shifting is excellent, no problems with too much slack on the smaller end of the cassette. There is some noise using the two largest cogs in the big ring but again, I will almost never ride those combos anyway. I HAVE NOT done any backpedal testing--I don't backpedal on my road bike, ever. I only ever backpedal on my MTB, which I've done a 1x10 conversion using the 11-42, black all-steel version of this SunRace cassette with, but I used a OneUp RadR cage for that (and it's off topic, so going to leave that discussion offline).

-Ed


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## 4Crawler (Jul 13, 2011)

I just put one on my cross bike this weekend, works great. Keys to success are the Wolf Tooth RoadLink 
RoadLink ? wolftoothcomponents.com
and then backing off the B-tension screw that I had cranked way in to run the previous 11-36 cassette:

Picture in small-large combo:








Running a 9sp MTB triple up front, a 9sp rapid rise XT M770-SGS RD in back and a full length KMC chain. Can shift to all combinations although the small/7-10 cogs run a slack chain. Can back pedal in small ring, middle and large rings will drop to the 36T if back pedalling. With the RoadLink in there and a longer B-tension screw, you could probably clear a 50T cog if such a thing existed.

Been on a few rides now and the cassette works nice now that it's all adjusted properly. Only minor complaint is the 15T-18T jump in small end. With the 11-36, you had 2T jumps from 11-21 then bigger jumps. The 11-42 has 11-13-15-18-21. Not really sure how it could be changed (11sp I suppose) but that 20% jump is right in the place I normally run on the road.

Did get a chance to try out the new lower gear today up in the dirt. Did really well on some steep loose dirt/gravel climbs. It took a while to get the hang of the slower climbing speed, lots of low speed wobbles. Later on it clicked that I needed to up the cadence and crank 80-90 RPM up the steeper sections and maintain better balance.


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## bluesky6 (Jul 23, 2013)

@EddNog, @4Crawler: very nice. Thanks for sharing.

My project has been slow moving partly due to a (now aborted) attempt to sell the project bike.

I'll be swapping out the 105 components on the bike for a SRAM Force 10-speed but with a GX rear derailleur long cage. It sounds like the chain wrap on the derailleur will just about let me run 2x10 with the cassette (11-42) and compact chainrings (34/50).

Pic of the current progress so far below. Since this is a climber, low weight is important, I've a custom-built Kinlin XR200 rear wheel, with a 195g Michelin Service Course Pro4 tire. Of course, all the weight savings are eaten up by the very big Sunrace cassette


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## EddNog (May 20, 2016)

bluesky6 said:


> @EddNog, @4Crawler: very nice. Thanks for sharing.
> 
> My project has been slow moving partly due to a (now aborted) attempt to sell the project bike.
> 
> ...





That setup will work. It may not like extreme cross-chained combinations, but it WILL work.

-Ed


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## EddNog (May 20, 2016)

EddNog said:


> That setup will work. It may not like extreme cross-chained combinations, but it WILL work.
> 
> -Ed




Here's mine:


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## aclinjury (Sep 12, 2011)

can you go big/big combo? Seeing how big the 42t is, it appears that the chain will rub against the top part of the front derailleur if you go big/big (not that you would want to go big/big, but I'm just asking).


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## BCSaltchucker (Jul 20, 2011)

bingo. I agree with MMS, Wolf Roadlink is the key

I am putting one on my next bike, with a 40T XT 11sp cassette, mid cage ultegra, compact crank. bailout gear for my world-travel bike. I think I am fine with 32T around here on my other bikes.

I don;t know much about Sunrace though. I suspected they were inferior to the 3 majors? I put a 9sp $30 Sunrace on one 9sp 105 bike and it worked horribly, so I went back to shimano which worked much better. I also put a 7sp Sunrace thread-on cluster on my italian friction-geared vintage bike, and of course being campy friction it works fine.


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## EddNog (May 20, 2016)

aclinjury said:


> can you go big/big combo? Seeing how big the 42t is, it appears that the chain will rub against the top part of the front derailleur if you go big/big (not that you would want to go big/big, but I'm just asking).


Shifts fine into big/big, but it does make some noise in the big ring on the two largest cogs, so while rideable without issue, I stay away from it to prevent long-term damage.

-Ed


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