Is 11-Speed Overkill on eMTBs?

Discussion in 'Mountain, Trail' started by LimboJim, Oct 31, 2017.

  1. LimboJim

    LimboJim Active Member

    I have a few eMTBs; two were specced with 11-speed drivetrains and two with 10-speeds. I've put a couple thousand fairly hard trail miles on them thus far, and have noticed a trend: 11-speed chains wear out faster! I suppose this is logical given that they have to be be thinnner than 10-speed chains, but given the heavy torque provided by mid-drives, why are so many higher-end eMTBs still equipped with 11-speed components?

    I recently read Park Tool's "When to Replace a Worn Chain," which says "If you are using a chain designed for ten or fewer gears, replace your chain as it nears the 0.75 percent mark. If you are using an eleven or twelve speed chain, replace your chain once it has reached 0.5 percent wear. For two-sprocket or single speed bikes, replace your chain as it reaches the 1 percent wear mark." Using this guideline, I find myself replacing 11-sp chains every 200 miles!

    Clearly we still need well-spread gears for steep climbs and fast flat runs on eMTBs, but SRAM's new 8-speed EX1 groupset covers an 11-48t range, eliminating some of the unnecessary (IMO) in-between gears provided by 11-speed cassettes. I predict that all the major drivetrain manufacturers will follow suit, hopefully sooner than later... When it comes time and my cassettes wear out, I plan to use this more sensible setup.

    My 2014 Haibike FS RX might be the exception. Its 10-speed drivetrain only ranges from 11-36t, and I suspect the Bosch motor was tuned to work best within that ratio. Jumping to a 48t cog might wreak havoc - has anyone tried?
     
    Last edited: Oct 31, 2017


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  3. itsaulgoodman

    itsaulgoodman Member

    I agree, they are. My mountain bike came with a 10 speed setup, and even that seems like too much. I had actually increased the size of the front chain ring because I was getting so annoyed having to shift through the gears so quickly.

    I recall Court mentioning in his video that one of the drive train manufacturers came out with an ebike specific 8 speed drive chain, which makes sense. I think it was SRAM.

    Yep SRAM EX1. Found it: http://ebike-mtb.com/en/sram-ex1-lowdown-first-ever-e-mtb-drivetrain/
     
  4. indianajo

    indianajo Member

    The 7 speed Shimano rear cluster, used on many bargain bikes and e-bikes, has left me thinking I was getting old and slow, then walking home. The inner race comes unscrewed, the cluster rubs on the shaft a while as balls drop out, then the last ball to drop makes it lock up: until you get off and push. The method of securing the inner race, a steel ferrule tightened against an outer nut, strikes me, as totally inadequate. Especially after a long walk home pushing the bike.
    I've had the previously popular 6 speed shimano rear cluster, the axle shaft break in two. It had a 5/16" diameter threaded shaft, which has been corrected to 3/8" in the 7 speed.I weighed about 180 lb when I broke it, on the road, but was carrying groceries in a rear basket.
    I don't know of any problems with an 8 speed SRAM. But the regulars on roadcyclereview.com won't hear of any other rear cluster but the shimano, sram, or campelli 11 speeds. Even though the chains last less than one summer even cranking one self.
    By contrast, I rode a 5 speed shimano rear cog about 12 years, (15 speed mtn bike) and never wore out the chain. The 3rd speed cog lost the tips of it's teeth, instead, which caused skipping. Neither did I ever wear out a chain on the Sturmey Archer 3 speed I owned for 30 years. However three speeds were okay for flat Houston & Kansas, but not hilly Southern Indiana.
    One advantage of eleven speeds, with 28 to 11 cogs to choose from, one doesn't radically need a shifting front sprocket, until the grades go over 10%. Which makes it compatible with mid-drive e-bikes, that delete the multiple front sprockets.
    BTW I ride >2000 miles per year, and don't wear out 6-7 speed chains in 3 years. I've changed frames more often than that, due to stability problems , incompatibility of old frames with new components, and the broken axle mentioned above. 6-7 speed chains are thinner than 5 speed. Single speed chains IMHO never wear out: we used them in industrial baking for seasoning dispensers.
     
    Last edited: Oct 31, 2017
  5. TrevorB

    TrevorB Member

    My bosch CX eMTB came with 15t chainring and 11spd 11-42t cassette, could climb anything. I've since changed it to 14t and 11-46t as I prefer have lower gearing. A 14t with 9spd 11-40t would be equivalent to original gearing but would lose XT clutch which is critical with CX to stop chain suck in mud. SLX or XT 10spd with 11-42t would be best combination as chains and cassettes are slightly cheaper while having good range.
     
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