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[trikester]

I have placed an order with Hollywood Electrics for what amounts to an FXU model. It will be all FX in power, wheels, tires, etc., but mounted on the XU suspension for low stand-over height. Everything FX except the XU suspension. However, the factory won't build to a dealer's specifications, so Harlan will be making the mods himself. He will be creating the "FXU" for me.

I suggest to Zero that they add an FXU as a standard option. It won't cost them any design time, so it seems like a "no brainer" to me. I have had many happy years, and thousands of miles, of riding the ever popular Yamaha TW 200's, in all kinds of terrain. I'm an older rider (now 77) so I'm a "dirt cruiser" not a "balls out" "catch big air" rider and I don't need the suspension travel of a typical dirt bike. I like to be able to easily dab or tripod with my feet in some nasty situations. To me the FXU would be like an electric TW 200 (without the big tires), but with more power and all the other dirt riding benefits of Zero's electric bikes, including fantastic handling.

A lot of shorter women could go dirt riding with their boyfriends or husbands on this bike and be able to keep up, which the XU alone might have trouble doing, with its reduced power and street tires. The TW 200's have been popular for many years to this category of rider and even tall riders like me (6' 2") who have a relaxed dirt riding style.

Think about it ZERO. Add an FXU to your list of products. 

Trikester

[protomech]

I think they missed out not giving the XU 5.7 a Size 4 controller. $2500 delta between both the FX 2.8/5.7 and the XU 2.8/5.7, but you get a lot more for the money in the FX.

[Marshm]

The 2 bikes look very similar.  I wonder if the forks and shock are the same, just the spring length and something internal to limit how far they extend.  It appears the XU is 15 pounds lighter.  Thats a a pretty big difference.  I wonder where that comes from.  

How do they switch to chain drive because it looks like the rear sprocket for the belt is very large diameter.  It doesn't look like the gear ratio will be the same, because typically sprockets don't come that big for chain.  The switch to chain is typically for offroad use, but gearing faster is probably not what most offroad people want.  Anyone know the gear ratios of the belt verses the chain? 

[amahoser]

How do they switch to chain drive because it looks like the rear sprocket for the belt is very large diameter.  It doesn't look like the gear ratio will be the same, because typically sprockets don't come that big for chain.  The switch to chain is typically for offroad use, but gearing faster is probably not what most offroad people want.  Anyone know the gear ratios of the belt verses the chain? 

Belt drive generally uses larger rear AND front sprockets. I assume that this is because a belt cannot bend enough to accomidate a small front sprocket. When they switch over to chain, they use a much smaller front sprocket... and in turn use a smaller rear sprocket. The effective final drive ratio remains the same.

Jose Soriano

[trikester]

The forks and shocks are not the same but they fit the same frame. That's why Harlan can make me an "FXU".  I get the high power controller of the FX with the lower stand-over height of the XU. I don't know where all of that 15 lb weight saving comes from. Probably a little here and a little there. The tires of the XU are probably lighter but of course I will have the tires of the FX and then probably change those to Kenda K270's.

As to chain conversion. When I changed my 2012 DS from belt to chain I actually geared it a little lower than the belt drive, on purpose. Yes the front sprocket is a lot smaller on the chain drive and so is the rear. I like the smaller rear as it is less likely to hit rocks.

Trikester

[ed5000]

So Harlan will have a FX frame and a XU motor left over.  I'm assuming he'll put these parts together and come up with a XUF bike.  A bike that would be great for a tall person who has an aversion to speed.

[protomech]

 

XU and FX use the same motor, Zero 75-5.

Primary differences:

* Front forks
* Rear shock
* Size 4 (FX) vs Size 2 (XU) controller
* Wheels (21" and 18" vs 19" and 16")
* Tires

Rear sprocket size looks close to the same. Front sprocket may be different, XU has a lower top speed.

So to make a FXU, you start with a FX then exchange everything on the above list except for the controller (maybe not wheels?). Seems like it'd be easier and cheaper to start with an XU then swap the controller. Perhaps the XU uses finer gauge wiring that is not suitable for the larger controller.. or perhaps the controller simply can't be ordered by itself.

[trikester]

No, no no, you guys misunderstood me! I start (Harlan starts) with an FX and just changes the front and rear suspension to those three parts from the XU product line. I said before; everything is FX except the front and rear suspension. That's all. change three parts on the FX. You are making it too complicated. No motors,. controllers, wheels, etc., etc., left over, just 2 front shocks and 1 rear shock extra, taken off the FX

It's an FX with the XU suspension. Get it?

Trikester

[protomech]

Ah.

[Tudor]

Guess there will be a spare 'UXF' then for the tall commuter, the scavenged XU with trikester's discarded FX suspensions

[trikester]

There we go! Any tall commuters out there looking for a tall XU? I'll have a suspension for sale 

Actually I won't, because Harlan is taking care of the conversion project and he probably has plans on dealing with the unused FX suspension.

Since I have done all of my other various conversion projects on my 2010 and 2012 DS's by myself, it will be pure pleasure to have someone else doing the work this time around.  Go Harlan!

BTW - Since I'm a mellow dirt rider (not mellow dirt, mellow rider) some may wonder why I don't save money by putting the FX wheels on a XU instead. Because I often do long slow, steep, climbs, out here in the mountainous (and often hot) west the higher current. more HP, capability of the FX should make it more durable under those conditions. One very steep and rocky climb I did last summer (on my 2012 DS) I probably didn't get over 10 MPH because of constant rocks, fallen tree limbs, and rut dodging. Ten MPH doesn't provide much cooling air.

Trikester

[Marshm]

You mention those steep hill climbs.  This is something that I cannot seem to understand yet about electric.  My assumption is that a gas dirtbike 5th gear and the zero have about the same gear ratio because the top speed is basically the same.  The gas bike has the torque to pull 5th but you have to get the rpm up around 3000 to get that torque.  The electric can pull that gear ratio at 2 rpm.

On a steep hill, my gas bike cannot pull 5th, it bogs down and can only pull 2nd.  I would think the gas bike 2nd gear would put more torque on the rear tire than the Zero.  So that means the Zero cannot go up that hill that lugs my gas bike down to 2nd?  Maybe I need to run real numbers, but I thought someone had said before that their numbers showed the gas bike lower gears have way more torque than electric. 

So I am concerned about this hill situation.  In all street riding, this condition will not occur, but in dirt riding it does.  For example, a hill in the sand dunes.  I have actually approached hills topped out in 5th and then on the way up I constantly downshift as the motor lugs out.  I actually got down so slow and then just dug in, that vehicle just could not climb that hill.  What would electric do on such a hill?  Does the e-bike still need gears for hill climbs? 

[protomech]

Marshm - you're correct, a bike like the Zero is geared for about the same as the top gear on a small bike.

Typically, the torque curve on an electric bike is flat, at least to a point. When you twist your wrist at 0 mph you get the same acceleration force as you get when you twist your wrist at 50 mph, neglecting aero drag.

Gas bikes typically produce very little torque at low RPMs (< 2k rpm?). Their torque curve is not flat, especially at low RPMs. At low speeds you must downshift to bring up RPMs and avoid the low torque hole, even if you don't need the torque multiplication of the shorter gear.

A 250cc gas bike in 2nd gear makes about as much wheel torque as the 2012 Zero DS/X. In 1st gear the gas bike makes more torque. If you find on a gas bike that you need all the torque first gear provides then the electric may be geared too tall. But if you need 1st just to avoid the torque hole in 2nd gear low RPMs, then you may be fine.

The 2013 Zeros will make significantly more wheel torque than a 250cc bike, in any gear. They're probably closer to a 450.

Edit: Look at this post and read a few posts down, where I show wheel power vs RPM at different gears for a Ninja 250 vs a 2012 Zero S. DS is geared a little shorter (more torque) than the S.

[Marshm]

Ah thanks.  That is a nice graph that shows all 6 gears and the Zero plotted as well.  I see, the Zero falls somewhere between 2nd and 3rd, closer to 2nd.  That is actually quite impressive. It can pull 2nd through 6th the same as that Ninja.  So maybe a little gearing change lower, the Zero FX would probably work for me everyplace I go offroad.

I think you are right, I downshift to 1st to get the rpm up to where I have torque.  If I lug out 2nd it will just stall at some point.  So I don't think I need the torque of 1st gear, I just have no choice if i want to go that slow.

I do notice on tough trails sections I am forced to go a certain speed because that is what my engine will do.  If I find myself wanting to go a bit faster, that means revving the heck out of the motor which I hate.  If I go up a gear the jump can be too much.  I also like to use the higher gear because it accelerates faster if I need a burst.  If I am revving the heck out of 1st, a twist of the throttle doesn't do as much.  If the Zero will accelerate the same all throught this range of speed, that is a benefit for offroad use.  Interesting.  Thanks for the clarification.  

[trikester]

I do notice on tough trails sections I am forced to go a certain speed because that is what my engine will do.  If I find myself wanting to go a bit faster, that means revving the heck out of the motor which I hate.  If I go up a gear the jump can be too much.  I also like to use the higher gear because it accelerates faster if I need a burst.  If I am revving the heck out of 1st, a twist of the throttle doesn't do as much.  If the Zero will accelerate the same all throught this range of speed, that is a benefit for offroad use.  Interesting.  Thanks for the clarification.

I didn't realize until I started riding my 2010 DS what a huge advantage electric power is in dirt riding. In riding gas bikes of course I would have to kick it down when hitting a climb. Sometimes I wouldn't go low enough to keep the rpm's up and I'd stall out - as has been said. The thing I love about dirt riding electric is that if I suddenly come on a steep climb, that I couldn't see ahead of time, all I have to do is twist the throttle and go up. Same thing when riding fast in a clean stretch and then coming to a tight, tricky, spot, I just brake and then power through it, not having to take time to shift out of a higher gear, or back up after cleaning it.

I've made this statement here before: It is my judgement that any dirt rider who starts riding electric will not want to go back to gas bikes in the dirt. The torque available at any time is huge advantage. I can see, as some have suggested, the usefulness of a two speed gear, lower for dirt and higher for pavement, on street legal bikes, but I don't know if it would be worth the extra weight and complexity.

I have also said before: Any hill I can't climb on my 2012 DS is a hill I don't want to be on. I'm sure that traction is the thing that would determine the maximum slope to climb on dirt. That's a reason I put the 5.6", K270, tire on the rear. I've been up some pretty steep hills where even that tire was beginning to lose traction (running low pressure), but still made it over the top. Speaking of tire pressure, on dirt I usually (unless its going to be very hard pack) run 10 lbs in the front and 15 lbs in the rear. I've then gone out onto pavement and the bike still handles well even though the pressures are way below what I normally use for street riding.

That's my 2 cents.

Trikester