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[MorbidBBQ]

I just took my 2013 S for its first 100% balls to the wall test ride after getting the new monolith battery.

Upgrades in order of relevance:
High speed gearing
2015 12.5 KWH battery
"Zero" Windscreen
Top case rack
Fender eliminator
x-mount for cellphone on handlebar.

I was running it in custom/eco mode with everything set to 100 (100% torque, speed, rear brake, regen brake).
In the past I had noticed minor speed wobble in the high 90s.

As I accelerated past 102mph, and then past 107 (my previous expected top speeds), I hit 110 and hit the scariest speed wobble ever. https://en.wikipedia.org/wiki/Speed_wobble

I think that when the Zero went into thermal protect mode, it applied hard braking to the rear tire (due to eco mode settings), and gave me some violent shakes until I got back down to ~70mph.  I saved the logs, but don't know how to view them.

1) Are all zero's susceptible to this due to body design?
2) Is this due to tire pressure, or suspension configuration?
3) Would this issue be minimized in sport mode?
4) Has anyone else experienced this?
5) Whats the top speed people have gone with the  98/25 high speed gearing option?

[mrwilsn]

Wobble or weave?

Try to lay flat.  It should help.  Just don't sit back up until you've slowed back down.  Also, if the back tire is worn and flat and the front tire is fresh that can make things worse.

Richard posted this video a few months ago that discusses the phenomenon.



http://electricmotorcycleforum.com/boards/index.php?topic=5833.msg43205#msg43205

[evtricity]

I've had my 2014 Zero SR up to 120mph on the track  (16/58 gearing)  and never had speed wobbles at any speed after hundreds of laps with top speed over 110mph.

While the Zero's have a low trail figure I've found them to be very stable and so I don't see any inherent design issue.

The instability may have been caused by a lack of weight on the the front wheel and/or road bumps. Tyre pressure or suspension setup could exacerbate the issue eg. The stock Zero front suspension rebound is too fast so the bike can continue bouncing rather than returning directly back to a neutral position after compression.

The Zero shouldn't increase regen when it starts thermal cutback. Thermal cutback starts at much higher current levels 300+ amps than the max stock regen settings allow (under 50 amps reverse) and the continuous sustainable output would still be over 100A so I don't think thermal cutback contributed to the instability.

Lastly, at least on the stock 2014 SR the bike won't regen over 4000rpm. Not sure if  this is the same for the 2013 but you can readily test this yourself to confirm.

[MorbidBBQ]

Wobble or weave?

Thanks for the video.  It would be considered weave as defined there.  I forgot to mention that I have the rack for a topcase installed as well (but didn't have the topcase on).

I'll have to remember to lie down on the tank.  It's never been an issue on any other motorcycle I've driven at significantly faster speeds.  Must be a weight balance thing.

[Killroy]

My suspension was really far off.  A suspension shop had to cut a lot of pre-load spacer to get the sag within spec.  I recommend everyone do a suspension set up if they have not done so 

[NEW2elec]

MorbidBBQ any chance your fork is misaligned or bearing going out? 

[quixotic]

How big is your windscreen?  And is it handlebar mounted?  Or frame mounted?  I used to get occasional incipient "tank slappers" on my old Beemer with a larger handlebar mounted windscreen, until I exchanged it for a frame mounted unit. 

[MorbidBBQ]

MorbidBBQ any chance your fork is misaligned or bearing going out?

At 1800 miles...I hope not.  Is there any way to tell for sure?

[MorbidBBQ]

How big is your windscreen?  And is it handlebar mounted?  Or frame mounted?  I used to get occasional incipient "tank slappers" on my old Beemer with a larger handlebar mounted windscreen, until I exchanged it for a frame mounted unit.

Handlebar mounted.  I thought a windscreen would give better range, & be more aerodynamic, thus smoother at higher speeds.
Looks like maybe no?

[BrianTRice@gmail.com]

How big is your windscreen?  And is it handlebar mounted?  Or frame mounted?  I used to get occasional incipient "tank slappers" on my old Beemer with a larger handlebar mounted windscreen, until I exchanged it for a frame mounted unit.

Handlebar mounted.  I thought a windscreen would give better range, & be more aerodynamic, thus smoother at higher speeds.
Looks like maybe no?

I have not experienced this with my Parabellum at 95 mph (for testing, of course! So I can charge more often ... right), so I don't think it's an issue for us.


Sent from my iPhone using Tapatalk

[togo]

How big is your windscreen?  And is it handlebar mounted?  Or frame mounted?  I used to get occasional incipient "tank slappers" on my old Beemer with a larger handlebar mounted windscreen, until I exchanged it for a frame mounted unit.

Handlebar mounted.  I thought a windscreen would give better range, & be more aerodynamic, thus smoother at higher speeds.
Looks like maybe no?

Windscreens may or may not improve energy efficiency. It depends on the windscreen and in particular the curvature at the edge- does it direct the air at steep angle to other air, or does it direct it backwards, parallel to the the prevailing air motion?  Most windscreens are for comfort or looks.  Only parabellum actually guarantees improved fuel efficiency, and they don't make a model for zero. And only Brian T Rice has adapted a big parabellum to a Zero as far as I know.