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[LiveandLetDrive]

Good stuff, I've been wanting to undo the loss of top speed that came with the smaller diameter supermoto tire.  Don't really care in the dirt as I always turn the torque down to ~60% anyway.  Maybe that's just the lack of traction in dusty drought-stricken CA!

How could there be significant chain slack variation when the motor is coaxial with the swingarm pivot?! I always thought that was a nice engineering advantage over most bikes.


With my DID ZVM2 (if I recall correctly) the chain is definitely the loudest part of the bike but I wouldn't call it obnoxious, just a "zzzzzz...." with speed.

And the FX will easily bonk into its 89mph speed limit.  I used to commute on the bike daily and spent a lot of time there.  I've never ridden on one battery on the street to test that top speed, just a few times on the dirt and once Supermoto.  It just starts losing power way too quickly (faster than the half capacity would lead you to expect) and even seems to overheat faster.  Maybe if you're MXing and only doing a few laps.  The weight saving is nice.

[rayivers]

How could there be significant chain slack variation when the motor is coaxial with the swingarm pivot?! I always thought that was a nice engineering advantage over most bikes.

On my bike there's almost no variation in slack due to swingarm movement.  With this 71T sprocket, though, there's a significant change due to wheel rotation, mostly from the loose fit of the sprocket's center hole on the hub which virtually guarantees eccentricity of some kind.  On my other bikes there's so much slack needed I wouldn't even notice, but on this one I should be able to set what I'd consider the 'ideal' amount of slack (about 1") and expect it not to vary due to wheel or swingarm motion, only wear and stretch.

Ray

[acacia1731]

Great info about sprockets - thanks all.

Has anyone tried an o-ring chain to see if it was less noisy?  If the noise is from the chain slack bouncing, then it makes sense that an o-ring chain might help.

[rayivers]

I was thinking about adding a chain tensioner using a soft-compound skateboard wheel, just to damp out some of the noise and control chain whip - maybe I'll try it this winter while the swingarm's off.  I'll definitely be going with an X-ring chain next time too.

Ray

[trikester]

I haven't used the soft skateboard wheels on a Zero yet but I've used it on other machines I've built and I have one as a chain tensioner on my Zero powered e-trike. To cut a slot in the wheel for the chain I mounted it on a rotary head on my mill table. I sprayed it with liquid propane to freeze it to -40*, to temporarily harden it, and then cut it with an end mill as I cranked it around.

Caution - Make sure there are no ignition sources (sparks, flame, etc.) nearby when spraying propane!

Trikester

[trikester]

I have avoided O-ring chains on my Zeros because they add a lot of rolling resistance and would reduce range. However, I don't know how much so maybe someone has had experience with this and can shed light on the subject. It sure is tempting to go O-ring for dirt riding.

A motorcycle mechanic near my shop has told me they make a significant reduction in mileage on ICE bikes and when a bike comes into his shop he changes the O-ring chain to a standard chain.

Trikester

[rayivers]

Thanks for the info on slotting rollers!  Up till now I haven't slotted mine, going the way-too-wide route instead - but it surely can't hurt to have more centering and protection fron side-impact derailments.

From what I've read online the X-ring chains were developed specifically to reduce rolling resistance over O-ring types, but we'll see.  If I can get the noise level down a bit and improve the maintenance/lube-filth issues at least a little, I don't think I'll mind losing some range, but that's just me.  If there's a big range drop, it should make itself known in the first few rides before anything really gets worn much and a new chain can go on.

Ray

[MrDude_1]

How could there be significant chain slack variation when the motor is coaxial with the swingarm pivot?! I always thought that was a nice engineering advantage over most bikes.

When the bike is in motion, the top half is pulled tight, so all the slack goes to the other half.
The slack on the bottom actually, gets "thrown" around based on load.
Chain itself can stretch under load, so even if its fully tensioned, it can be tossed around under speed and load changes.