My Dream Bike

[dogman dan]

Edited, I did have it bass akwards yesterday. But I belive the affect of the weight, whether on the wheel or on the frame to be true in my opinon.

Unsprung weight is on the wheel, between the road and the springs. So your wheel, rack, hubmotor, and swingarm is unsprung weight. Everything above that, frame rider, upper part of the forks, etc is sprung weight. Ideally of course, the sprung weight stays still, while the unsprung weight goes crazy.

So the rack on your bike, is unsprung weight. Like I said, some big debates can form on what's best. I think for sure, I want my battery riding where the shocks are keeping the vibrations to the minimum. But my bike is likely to handle a lot more top heavy as a result. For street riding, I can live with it.

Lots of unsprung weight slows the wheel hop down, sort of like the rebound adjustment on your shocks. So if you have the right amount of unsprung weight, maybe you just simply use less rebound. The key thing is that the bike suspension is tunable, so both of us can just adjust the suspension to a decent ride. To some extent, unsprung weight may be a good thing, but then becomes a bad thing when it gets to be too much. Too little weight, and you have to crank the rebound so the super light wheel doesn't bounce too fast.

 

[mrzed]

Sorry, but you do have it backwards, but you are otherwise correct.

Unsprung weight is everything from the wheel to the spring, and that is what you want to reduce, as it allows faster reaction by the suspension, and less effect on the vehicle beyond the suspension.

 

[dogman dan]

Shit, I do that crap all the time with things. Off to edit.

Ok, fixed it in both posts. Too fast reaction time is not good though. That's why there is oil in most shocks, to slow the reaction time to the desired period. I think it is ideal though, to have a light wheel and adjust the spring period with a rebound knob. But with less rebound, a somewhat heavier wheel can still ride OK, but not as good as the bare pedal style bike.

But a too heavy wheel may be unable to ever react fast enough, and there are other handling issues besides spring rate that heavy wheels affect. It's all about compromises, adjust one variable, and you may affect ten others and have to change those. The guys in the pits at a race go crazy when they start having to change the car mid race too much, and may not have enough laps to ever get it right again.

I see the big challenge for ebikes that perform at a level above a beach cruizer with a kit on it to be how to carry the weight. Even really good batteries weigh 15 pounds to have any decent range. We know where we want to put it for handling, but because of frame geometry or other reasons, you don't allways end up with that 15 pounds in the triangle. Custom frames may be the only real solution. Along the bottom tube of the frame triangle is really the only place to carry the battery. The EV global did that, and handled amazingly well for having sla batteries. But no rear suspension on that frame.

 

[auraslip]

What a beautiful build.

Bravo on the custom rack. Even if it is "unsprung" weight



I was thinking or upgrading to the MTX DXP from my smaller MTX series bag. Currently 3 12v 14ah SLAs fit snugly in the top compartment. Do you think 4 slas would fit in the top compartment of the DXP? If not I might not upgrade and just put the batteries in the panniers. This would make for a lower center of gravity any how.

More importantly can you fit a gallon of milk in your bag?
I hate paying a $2.50 for a half gallon when a gallon is only a dollar more

 

[Green Machine]

I am not sure if the top compartment on the dxp is any bigger than the bag you have...i have an older mtx bag and the compartment sizes are identical to the dxp..the dxp just adds side panniers. But i have seen a much smaller mtx bag with side panniers which is almost half the size of my top compartment...so just check the specifications and see.

You should try the side panniers running SLA's...the lower center of gravity may make a big difference.

I am actually going to buy a gallon of milk tomorrow to go with my new automatic latte machine...i will try to fit the gallon in a side pannier and let you know...but i doubt it will fit.

I will say this..the dxp is an amazing bag for the money...and all that extra room cant hurt. We were just looking at the quality today, and for the price you really get a lot....i guess the made in china thing isnt so bad...quality is excellent.

 

[auraslip]

I'm gonna cut really small holes in the back of the side panniers and wrap the SLAs in bungie nets that strap on to the bottom of the rack through the holes. I have a problem with them jumping around in the top rack!

Let me know about the gallon of milk. It's the ultimate test!

= :wink:

 

[Green Machine]

I'm gonna cut really small holes in the back of the side panniers and wrap the SLAs in bungie nets that strap on to the bottom of the rack through the holes. I have a problem with them jumping around in the top rack!

Let me know about the gallon of milk. It's the ultimate test!

= :wink:

Ok Ok..i admit this is the wierdest request i have gotten in my short tenure here as an ES Poster :wink:

But even though i doubted it would fit...a gallon of milk easily fit in one of the paniers...in fact...with room left over for a 6 pack of budweiser cans as well.

Coast is clear...this is the bag you need to go out and buy ...i wonder if topeak might give me a commision.

 

[doc007]

any updates on that Ellsworth build?

 

[Green Machine]

Really taking our time sourcing components on this one..trying to make everything perfect...right now waiting on black hq spokes, and a 6x6x2 lipo battery that weighs 6.7 pounds.

The rack is taking a long time to custom machine....pretty sick looking however...matches the frame pretty good.

Once the rack is done it should come together pretty quickly...probably a week or two.

 

[auraslip]

YES GALLON TEST + SIX PACK TEST PASSED!

I will have topeak send you a check =)

 

[doc007]

Really taking our time sourcing components on this one..trying to make everything perfect...right now waiting on black hq spokes

SWEET, not sure if you ordered these yet but a forum member Holmes seems to be selling low gauge spoke on the For Sale thread. He will also build the wheel up for you if you like ...im in no way associated with Holmes, just doing some researching myself for a future build.

Best of luck with the Ellsworth build cant wait to see pics of the build!

 

[DervAtl]

That's a really nice build, extremegreenmachine. I love the attention to detail you have given it. I'm super impressed with your light! Talking about stealth! You've given me a lot of ideas. Great thread to watch.

 

[nomad85]

.this is the bag you need to go out and buy

Really nice build!
I have a bag from the same line, after a few months the main zipper got all messed up. I've had 2 topeak bags, only one (newer) had the bad zipper design, hopefully yours has the good one.

Care to go into more detail about the dc-dc converter setup? I'm thinking about setting one up to handle lighting and to power various chargers from the main pack.
Thanks!

 

[Green Machine]

Here is the New Rogue build on a ride with the owner and Illia himself:

This bike features a custom machined rack.

Notice that this bike is using the much smaller lipo packs (6.7 lbs) 10 ah packs.

As seen in the picture this bike has 2 10ah packs loaded in that tiny bag.

 

[gcholman]

Hello,

Long time lurker... I have gone back to this thread several times. I like the quality, US-made bikes you started with. Any updates? How are they holding up? What would you change?

I am 6'3", 220lbs, looking for a reliable setup to take me to work. (13.8 miles, 1300ft elevation gain over about 11 miles. Going home is all downhill, but can plug in at work.)

Thanks in advance for any replies!

 

[Green Machine]

At some point i changed the motor on the green bike to a crystalite. This seemed to be a big mistake and i wish i would have kept with the bmc.

The bmc is extremely reliable if you keep it under 2000 watts.

If i could change things i would run a bmc or a mac and keep it under 2000 watts. I would have skipped the complicated dc to dc converter and stuck with a cycle luminator with built in voltage convertor.

One thing annoying about the bike is the battery is not suspended and makes for a rugged ride. It makes the bike not too trail worthy. Fire roads and small bumps but no jumping or real rugged stuf. This is the true challenge for an offroad conversion bike...what to do with the batttery.

The full suspension makes it hard to mount the battery in the triangle.

Thats why designs like the phasor cycles and the stealth bomber are so good.

Honestly if i did it all again i would start with a phasor cycles frame and go from there.