# wide range 11-42 10 speed Sun Race cassette issue



## laksboy (Sep 4, 2007)

Just recently upgraded from a Sun Race 11-40 to a SR CSMX3 11-42 for a little bit more of a lowest gear. This is the "highest end" version with the alloy carrier and more importantly, alloy 42t final cog. The extra 2t were great EXCEPT that under max torque load, they skipped...

The chain only had 70 miles on it and everything was working fine before the swap. The chain was not dropping down to the 36t just skipping in place at crux climbing moments. Rendering it unusable in our 23 mile event. 

had it not been skipping, the range was great. The 11-40 has been good for us but the 36 to 40t final shift never seemed quite enough. The extra 2t really made the difference and felt great, except the whole slipping thing.

XX rear derailler, 30t oval front ring, 230 lb team (10.5 year old stoker).

Any thoughts?


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## unikid28 (Oct 11, 2017)

Maybe it's bending/bent? I believe I saw another thread where Alex said the Sun Race was not a good choice for tandems. And could have issues with bending cogs, etc.

FYI I recently bent the largest cog on my e*thirteen TRS race (9-46) cassette on my XC bike. And I'm only 170 with my gear on.


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## laksboy (Sep 4, 2007)

They're not bent. I'm in contact with Sun Race re: warranty or "downgrading" to an all steel version. I will also try screwing out the B-tension screw further to slightly improve chain wrap. Other than that, I may have to try the Shimano HG500 which is apparently getting good use from the e-bike crowd according to Amazon reviews (also 10 spd 11-42)


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## unikid28 (Oct 11, 2017)

Hopefully the b-screw fixes it for you. I was going to suggest that as well but assumed you had tried that already. If not, then hopefully the warranty or "downgrade" works out.

My warranty e*13 cassette arrives today. I read somewhere about tandem teams using the e*13 stuff to get the wider range 1x11. Based on my experience on my single I would steer them clear of it.


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## twocicle (Mar 9, 2017)

laksboy said:


> They're not bent. I'm in contact with Sun Race re: warranty or "downgrading" to an all steel version. I will also try screwing out the B-tension screw further to slightly improve chain wrap. Other than that, I may have to try the Shimano HG500 which is apparently getting good use from the e-bike crowd according to Amazon reviews (also 10 spd 11-42)


Maybe late to the party, but I don't like to see a thread die without a final posted.

I have had similar issues with other large cog setups and the problem was insufficient chainwrap when using the largest cog. Sometimes a limiting factor is the RD ability to handle very large cogs (ie: road derailleurs even with a Roadlink added) and wrap enough. As you are increasing cog size, it may be necessary to add a couple chain links in addition to adjusting the B-screw. Use as much chain as the RD can uptake while still providing some tension.

FWIW, our current setup is 3x 44/32/22 and a SunRace 11-42 CS8 11spd, with a Shimano CN-HG701 chain (the newer and stronger design with direction specific, special inner plates, etc) and M8000 derailleurs. This is working absolutely perfect and not one chain skip.


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## unikid28 (Oct 11, 2017)

twocicle said:


> FWIW, our current setup is 3x 44/32/22 and a SunRace 11-42 CS8 11spd.


Glad to hear the 11 speed is working for you. Do you find yourself using all 33 gears? Just curious about your setup and riding situation.

I was thinking about moving to a 2x setup with a larger cog + more gears and maybe moving the timing chain over to the empty ring on the right to simplify things.


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## twocicle (Mar 9, 2017)

We have also run this as a 2x setup (38/24) without issue, but I prefer the range of the 3x. This is on a Fandango 29er with 2.5" front, 2.4" rear tires. 

Initially we thought we would ride mostly gravel roads, but I ride a lot of single track on my single and after coaxing my stoker to let me take her on single track with the tandem, she loves it and prefers it to anything else. 

Obviously it is not good to crosschain too much and so you should not use the extreme inner chainring to outer cog, or outer chainring to inner cog. Using the drivetrain wisely, you end up not using 4-6 cogs. What makes for a good setup, is one that you can ride a lot in each chainring without constantly shifting the front. 

On my single trail 29er I use a 1x 10-50 and do a lot of climbing plus the usual rough stuff. On the tandem it needs a bit more range upper and lower for the more aggressive terrain we ride (steep up, fast down). I am looking at going to a full suspension trail tandem, but still see us using a 2x on that.

One rule of thumb I have for the mtb tandem... use all steel cogs, no exception. Our chainrings are high quality Praxis 3x, but it seems they stopped making those in the last year.


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