QuietMike

Hi, I am fairly new to bikes just to start off, but learning a lot.
I have a juiced scrambler e-bike, it has a single chain ring and a 7 speed freewheel 14-28t
i replaced the freewheel with another 7 speed a 11-28t,
it shifts fine and the gearing is exactly what i wanted, but it has a problem i have not been able to solve.
with the original freewheel, if i was at a stoplight or whatever, in 1st gear (28t), i could spin the pedals backwards to position then on the other foot etc.

with this new freewheel, same gear, now when i move the pedals backwards the chain falls onto 2nd gear, and will then jam if you continue to move the pedals backwards.

i don't understand why this one does this and the original didn't,
I figured that the chain-line was at the extreme and pulling the chain to a more straight position, (though it didn't do that before)
so i installed a 3mm spacer between the freewheel and the hub - in an attempt to move the freewheel further outside, to help with the chain-line when in first gear.
it has helped but only a little.
can anyone help me fix this, or explain why this freewheel does this?

Fredo76

The new freewheel probably sits a little closer to the spokes. Tightening the cable a bit, either by pulling it tighter through the clamp bolt, or by lengthening the housing with a barrel adjuster, should line up the cogs again. Or you could put a thin spacer ring in before screwing the freewheel back on. Watch out for small-cog clearance if you do that. It's also possible that your derailleur got bent out of alignment somehow, so look to see if everything still looks straight. Be sure to check your limit screws after any fiddling.

Iride01 

Does the chain go slack on the top run when you backpedal? That might indicate the new FW isn't as free wheeling as it should be. Perhaps it might just have too much grease packed into it and with use the bearings will push the excess grease out of the way and it'll loosen up.

FBinNY 

The issue relates to the tooth profile.

When the chain comes from the side, there's the likelihood of a tooth catching on a plate rather than sliding in.

Picture a boat coming into a slip from angle. A typical pointy front boat will get the bow in then sort itself out, but a square fronted barge is likely to hit on a corner.

This may improve over time as the teeth wear, or can be resolved by grinding or filing the inner corner of each tooth.

bboy314

One other potential issue - with some e-bikes, the rear hub comes with a freewheel with more clearance than normal for a wider axle. It’s possible that the new freewheel is binding on something like a cone or dustcap, preventing it from smoothly spinning backwards.

trailangel

Wow! Tell me what brand 7 sprocket freewheel with an 11 tooth small you bought so I can get one.

QuietMike

they’re on Amazon, seems to be the only one out there by a company called Drift maniac, it’s much better than the 14t, the other gears are slights different to, except 1st

tFUnK

I assume you also replaced the chain when you replaced the freewheel?

maddog34

A quick search brought this option up... there are others too.
https://www.ebay.com/itm/20429449240...Cclp%3A2047675

maddog34

probably a cheap, Worn chain not meshing well with the new teeth on the Cassette... just a guess

the new cassette may have some poorly cut teeth or even bent teeth too.... just another guess.

and then there's the fact that cheap gimmicky freewheels are manufactured in low budget sweat shops and maintaining any semblance of good quality is not on their list of things to do... just a fact garnered from decades of experience.
does the new freewheel look like a drunk sailor at 02:30 hrs., Saturday when you spin the wheel and don't pedal?? that would be a big clue....