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e*thirteen Extended Range Cog

Average User Rating: (Poor)
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1 member review

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The Good:

Let me think on that

The Bad:

Does not hold chain, poor anodization

Overall Review:

I purchased the e-13 42 tooth cog to complete the 1X conversion on my trail bike. I had been running a standard 11-36 cassette with a 32t chainring for a while and wanted a bit lower gear.  I went with the e-13 because it was available through BTI and the One-Up was not. 


The cog installed well and the instructions were clear.  I ordered a 16t cog (not included) to smooth out the transitions.  It had a nice finished appearance.  I used a Sram X9 type 2 rear der. and X9 shifter, a Sram cassette and sram chain.


Shifting in the stand was great, and the flat road test was good as well.  I even tried to put on the brakes to add load to the cog and it worked flawlessly.  Then i took it on a ride and frustration settled in.  When I would shift into this gear, the chain would slip and skip off.  I thought I had a b-tension problem so I adjusted that.  I tried a different chain and that didn't help either.  I called e-13 and they couldn't help.  Finally by running a KMC chain I go it to work most of the time.

I ran this this way for a few months with success.  At one point during this period I removed the cassette and placed it in solvent that I regularly use, and the annodization came off.  It still worked (as well as it did) just didn't look very nice.

Bottom Line

There are many similar products that work much better.  I have installed several varieties on friends bikes and all seem to work well except for the e-13.  The 1x-10 is a great system and I don't miss my front der at all, but as far as expander cogs go the e-13 is on the bottom of the barrel.

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Product e*thirteen Extended Range Cog
Riding Type Cross Country, Enduro / All-Mountain, Freeride / Bike Park, Trail
Material CNC-machined 7075 aluminum alloy
Speeds 10-Speed
Tooth Options Shimano: 40 tooth or 42 tooth
SRAM: 42 tooth
Driver Type Shimano, SRAM XD
  • 0 lb 2.7 oz (77 g)
  • 0 lb 2.5 oz (70 g)
Miscellaneous • Colors: Black, Red, Blue
• Includes a Longer B Limit Screw for Proper Derailleur Set-Up
• 5-year warranty
Price $69.95
More Info

e*thirteen Website

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