New Stealth Electric Bike, the Fighter

voicecoils

voicecoils

1 MW
Joined
Sep 16, 2007
Messages
2,173
Location
Sydney, NSW, Australia
I've mentioned the Stealth Bomber before, I've ridden 2 of them and think they are a very refined hubmotor mountain bike design.

DSCF7787.jpg


The Bomber uses a 9 speed crank mounted gearbox, concentric swingarm pivot, monocoque cromo frame to house the lithium pack and finally a successful implementation of a rear disk brake with the hubmotor. It solves many of the compromises that people building bikes especially with the X5 hubmotor have struggled with.

The Stealth Fighter uses the same design concepts, but scaled down. It's lighter and cheaper.

DSCF7823R.jpg


It's 35kg compared with 50-57kg of the Bomber and has a smaller hubmotor, no gearbox, and shorter travel suspension: F160mm R200mm vs the Bomber's F200mm R250mm. It runs 2 speed with a geared bottom bracket or 2x8 speed if a rear derailleur is used.

I'm hoping I'll get to test one out if I can get down to Melbourne at some point :mrgreen:
 
OOOOOOH YEAH. If only somebody wanted me to test one.
 
lol that is, if you want to catch the swine flu in melbourne.... =)
 
Very cool! How much do they cost?
 
velowatt said:
Very cool! How much do they cost?
Click to expand...

It's on the site: http://www.stealthelectricbikes.com.au/stealth_bomber.html

About US$4k, which is in line with non-electric downhill bikes.

I especially like that they've stuck with the singlespeed driveline design for both bikes, no annoying derailleurs to deal with and a useful gear spread for pedaling with electric power. 2 speed bottom bracket in the Fighter and an 8 speed crank mounted gearbox for the Bomber.
 
The Fighter model looks neat. Like more sporty and portable. I'd be interested to see a review of it compared to the Bomber.

I have a Bomber and the suspension (w/ white brothers fork) is definitely heavy duty, literally feels plush like a motorcycle. I didn't think it possible to do with bicycle wheels but they figured it out.

I would probably miss some of the gears. I use a lot of the 9. If I had to pick just two, it would be gear 4.5 and 9th. Then again, beyond 2nd without power is a challenge on the heavier Bomber, so I'd probably choose gear 2 and 6th. Ha ha hard to pick just two.
 
Hey Chris, Can you tell us what your front and rear chainring tooth count are? I can figure out what the overall reduction is if I know that. Theoretically, if you can pedal at 13 km/h in the lowest gear, you should be able to pedal at 80 km/h in the highest gear since your gearbox has a 610% gear spread.

It has the following steps:
1) 0.63
2) 0.88
3) 1.29
4) 1.45
5) 1.67
6) 1.80
7) 2.33
8) 2.96
9) 3.00

With the Schlumpf two speed bottom bracket, you get a 2.5x over or under drive, so you could pedal at 16 km/h or 40 km/h which is probably just about perfect for the lighter & less powerful Fighter model.
 
Ok cool, so the effective gearing looks like this then:

Code: 
13.86	16
19.36	16
28.38	16
31.9		16
36.74	16
39.6		16
51.26	16
65.12	16
66		16

The crank mounted gearbox essentially changes the effective size of the front chainring. At least I think that's a sensible way of thinking about it.
 
Stealth Fighter vids popped up, pretty tame but fun nonetheless:

[youtube]Fb_5YzsoRuk[/youtube]
[youtube]MrZY35zaDLM[/youtube]
[youtube]ns7XndrHq4I[/youtube]
[youtube]t7SsZvR2KbY[/youtube]
[youtube]Oo-Tm9heeTM[/youtube]
 
i live in canberra and would be interested in testing a fighter/bomber, but a heads up, if quietrush is supposed to have a website up yet, then its net showing in google...

otherwise voicecoils, did you find the balance of the bike to be in the right place? where was is in relation to you? (under knees, on pedals?) also, how easy was it to throw the bike around, given that it weighs over 40kg for the lightest version? im trying to figure out how much weight i can add through batteries while still maintaining a manageable bike if the batts go flat...
 
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