Ecotric Gearing change

westmifatbiker

New Member
Region
USA
Looking for advice on changing the gearing on Ecotric Fat26 & Rocket26 (have same components). Stock is 42t chainring and 14-28 rear freewheel running 7 speed Shimano Tourney. I'm not looking at changing shifter/derailer. I'm looking to go opposite of what most of these threads do (which is go faster!). I'm looking to "gear it down" to climb singletrack hills better with the pedals. I believe I can change the rear to something like a Drift Maniac 11-34 so I think I'm set there. The crank stuff is by Pro-Wheel (a china mfr- and I'm not finding a USA distributor). I've attached pics. The bolts merely hold on the dbl plastic chain guard. The chainring appears to be splined onto the crank arm? (which I'm told is the way of the future for rings). Not sure if that silver ring thing is a "hold it on" ring thing or part of the chainring?

Looking for advise. thinking I want a 32 or 34 or something like a real 1x MTB has?



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Sierratim

Well-Known Member
Region
USA
City
Nevada City, CA & Paradise Valley, AZ
I don't own one of these bikes I'm going to venture a guess that at their price point they have a conventional square taper bottom bracket vs the newer and more expensive direct mount style.

This Park Tool video demonstrates crank removal for Square, ISIS, and Octalink spindles;


You can start by just pulling the drive side crank.

Once the drive side crank is removed remove the plastic chain guards/guides to expose the spider that supports the chain ring. You'll need to measure the bolt center diameter (BCD) to find available replacement chain rings. This page discussss this;


This gear calculator can also you help select the chain ring tooth count you want,


With tooth count and BCD, you're ready to shop.

Good hunting! 😎
 

harryS

Well-Known Member
SierraTim is correct. Square taper cranks. I've swapped enough of them on my inexpensive bikes, including the Ecotric fat 20" folder..
 

westmifatbiker

New Member
Region
USA
All very helpful info.....thank you. Notice that my crank does not have any arms with holes that a chainring would mount to. Looks like the ring goes on the bb shaft & is somehow (splines?) held in place. As I say......those 5 screws you see merely hold on the chainguard. There is really no bolt center diameter (BCD) to measure? Please comment- thank-you
 

westmifatbiker

New Member
Region
USA
So, showing my ignorance about cranks and such- Harry do I simply put an allen wrench in both side of that btm axle, loosen and take off the ring side crank arm. Then I'll have access to the ring (which is I believe attached to said arm). Does it simply slide onto some splines or on the square shaft that's still in the bike? Then where do I get a 32 or 34t ring to replace that 42t. It's a Pro-Wheel crank system made in China that Ecotric uses. I see their website- but shows no US distributor. If anyone has done this.......where on Amazon.....where at Brands Cycle, etc.? Or, do I have to replace the whole crank set-up?
 

harryS

Well-Known Member
SierraTim describes what is needed. You have to use a crank puller after removing the allen bolt. You also have to take off the other arm, if you want both sides to match. Cranks are usually sold with both pedal arms.

Maybe you can find a used 3 speed Shimano mountain bike crank for free somewhere. No one wants them. They're like $25 new, Try it on. Move the chain with your fingers. They're usually like 44/32/22.
 

westmifatbiker

New Member
Region
USA
thanks so much for everyone's guidedance. I guess I'll know when I get the ring side crank off......is it attached to that? could I find/buy just a smaller ring and not the cranks.
 

Sierratim

Well-Known Member
Region
USA
City
Nevada City, CA & Paradise Valley, AZ
thanks so much for everyone's guidedance. I guess I'll know when I get the ring side crank off......is it attached to that? could I find/buy just a smaller ring and not the cranks.
From the pics it appears that the drive side crank and the chain ring are a one piece assembly. Disassembly is the only way to know for sure.

If it is a one piece assembly you'd need to install a new crank arm(s), spider, and chain ring. @harryS suggestion to buy used is the lowest cost approach.

If it is not a one piece assembly, you can shop for a new chain ring knowing the tooth count you want and the BCD. To the Google!