What are good components for high-speed e-bikes?

[Toshi]

ultimately i think you'll come to the same conclusions as me: if you want to preserve the backup use of the seattle bus system then you're constrained to a "normal" bike, and that a normal bike doesn't do well with high speeds. if you want to go faster than that i really don't think electricity is there yet, and the gasoline alternatives are compelling once you crack that door open.

that said, if you do want to stick to electric and just want to build up a bike a bit more on the cheap i'd look at off-brand forks such as RST but would avoid expensive current-gen downhill gear. will you run a rear hub? if you're running a front hub then you don't want a 20mm through-axle setup anyway. if you're running a rear hub then you don't want a downhill frame, as the good ones come with a 12mm through-axle setup (rather than a 9mm non-through-axle on standard wheels) and additionally have wider spacing in the 150 to 165 mm range rather than the 135mm that is standard for mountain bikes. then you have the issues of battery mounting… you see why i ended up with a bike that looks how mine looks.

 

[nightowlgk]

That would be easily doable with cycle analyst throttle override (speed and amp limit), a simple version would be just a hidden switch or jumper, security code easily added with a $2 microcontroller, buttons, small relay. I have my override wire cut right now because a faulty speedo sensor wire was causing CA to think I was going faster than 99kph and cutting the power, but the speedo sensor is fixed, I'm going to do the simple version, just a switch. I'll get creative with the location. I don't really want to go much faster anyways, perhaps another 5mph. These days I am much more interested in range and utility (especially cargo capability).

This is like what I have wished for recently. Can you make the CA switch between 2 “speeds” in the form of 2 AMP LIMIT settings? That seems like the best way to conserve power.

I love that I can limit amps when cruising the flats to about 13 amps to maximize range/battery life, but then I come to a hill or trail and want to have some adrenalin fun; what do I have to do?.... Stop and reset the CA….

You must be able to program it in some fashion to take advantage of these features. Maybe a toggle switch to give an increase of “10”, (or x value) amps “boost”? Or, add a specific Hi and LO Amps Limit setting to the menu. I’ve heard about the Infineon Controller “possibly” doing this…..but no concrete info.

Any ideas?

 

[amberwolf]

Most cargo bikes have no suspension which seems crazy, they need a different kind of suspension (for the cargo load), one that doesn't exist yet.

Actually, I think it does, it's just that only one person I'm aware of has ever done it. I think that the air-ride suspensions are suitable for this, but don't yet have one I could test it with. The industrial-sized small ones that Julian Edgar used on the AirTrike 150 at Autospeed are small enough to fit where a regular shock would go, and I think they're probably the perfect solution.

As you load up the bike, just air up the shocks to match the load. Let some of it out when unloading the bike to ride it empty. That's the plan I have for my cargo trike, if I can ever get the shocks themselves.

 

[biohazardman]

I thought about the same sort of things before each of my builds. First build was an older Schwinn 7075 aluminum hard tail frame, I upgraded the rims went wider a bit heavier and double wall as well as 12gauge spokes which many think are not needed. 195 tires helped with the bumps but with a 17lb rear motor and another 15+ in the rear panniers, I could feel the frame on the 65 lb bike twist sometimes when pushing the limits. The bike feels safe up to 25-30 if not pushed hard into the corners. It stopped surprisingly fast with caliper brakes and decent pads. It beat me up not having rear suspension though.

Build 2 was to have a marshmallow ride be a hill climber as well as lighter, stronger, faster and more agile. I tried to buy a decent full suspension bike off craigslist but after two months of being a few hours/minutes late, I had nothing to show for it. So, in a moment of weakness ended up using my bonus from work 1K on a Giant Trance3. 4.2 inches of full suspension travel. Quality built bike it is from the ground up and I would expect most bikes at the 1K and up price range to be decent for e-bike builds. Although the DH bikes should be best. Since I had proven my wheel builds with over 2K of travel, I used the same combination on the new bike with a BMC 600 and some Dewalts. At 52lbs with the stout wheels, this thing feels like it’s just getting started at 30mph. Corners better than I am willing to push it thus far and bumps and curb jumping are marshmallow like even with the inexpensive Rockshocks Dart3 front fork that came stock on hte bike. With the oversized 8-inch rotors installed the cable pull Hayes MX4 brakes stop me on a dime from any speed ;^) The difference is unreal when compared to the Schwinn. No twisty frame feel at all just nice tight and very responsive. Still it is a bicycle not a motorcycle. I don’t go 30mph unless the road is near empty and it is safe to do so . At 60v soon to come it will likely hit near 35-40mph but that does not mean I will be cruising along at that speed but it had better ride up the sides of buildings for what I've got into it. You can make them feel and be safe at higher speeds if you do it right. I too have been looking to build something faster for longer range travel to and from werq.
Finally decided if want to cruise at motorcycle speeds then I should build an electric motorcycle. Pay up the insurance and it will be safer and legal as well.

 

[dogman dan]

The DH type mountain bikes would be a much better candidate for high speed travel due to much much stronger frames. My cheapo mongoose wallbike frame will sway like crazy if I swerve around a broken bottle at 30 mph. Not even thinking of going faster on that frame.

I have a similar Giant to yours now, and really am impressed with the strenth of the frame. I'd love to put a motor on it, but it pedals so nice I'm leaving it like it is for awhile.

If you ever got a high speed wobble going on a bicycle going down a long steep hill, you never want to do it again. I got one at 50 mph on a ten speed peugot once. A pickup ran me off the road and into the gravel at 50 mph. The frame looked like it was rubber.

 

[wildnrg]

I think a XC or all mountain bike would be better than a downhill bike because they weigh less, so unless you plan on landing a huge jump, the 4-5" of travel on the shocks would be plenty.

I lock out my shocks on road for a firmer feel and no bounce (not that you'd get much when you ain't pedaling).

I think disc brakes are a must, since mounting the electric kit I've notice more effort required to stop the bike. hydraulic disc brakes work well in wet conditions and require less effort than cable driven rim brakes.

For wheels I'm using Mavic Crossmax SL tubeless, they weigh half as much as the standard MTB rims, which means less rotating mass, better acceleration, and they are damn strong, at $800USD for a set, you'd hope they are good.

 

[biohazardman]

The DH type mountain bikes would be a much better candidate for high speed travel due to much much stronger frames. My cheapo mongoose wallbike frame will sway like crazy if I swerve around a broken bottle at 30 mph. Not even thinking of going faster on that frame.

I have a similar Giant to yours now, and really am impressed with the strenth of the frame. I'd love to put a motor on it, but it pedals so nice I'm leaving it like it is for awhile.

If you ever got a high speed wobble going on a bicycle going down a long steep hill, you never want to do it again. I got one at 50 mph on a ten speed peugot once. A pickup ran me off the road and into the gravel at 50 mph. The frame looked like it was rubber.

Got the wobble on a Honda 125 at 55mph on the freeway. The look of horror on the lady's face in the car next to me was priceless. I was to busy to be scared and managed to ride it out just by slowly relaxing on the throttle. Wobble quit at about 35mph. Once I had investigated a bit I found the only thing holding the rear axle had been the weenie of a chain adjustment bolt that was stock on the bike. The axle had been loose for quite some time, new bike to me so I did not know, and rounded out the slot in the frame to a huge hole. The chain adjuster broke on the freeway and that is why the handlebars ripped side to side about six inches in the high-speed wobble. I welded it up a few days later and the bike was as good as new. Still it was one of those experiences I could have done without in my life.
You will love the Giant frame as an e-bike it is so tight and predictable. Hard to believe it is so nice. It is a shame that I did not know this sooner as this is everything I did not know I wanted in the first bike till after I put some major miles on it. ;^) I put some spare rims and tires on the Giant, as I bought it without, and rode it couple hundred yards before I came back and tore it apart.

 

[dogman dan]

I've had the wobble at 90 mph on a kz 750 once. Gives ya respect for wobble. I gotta lot of two wheel experience, but I'm still amazed I survived it, the stuff I did in my 20's. Used to go out on rainy days so I could slide on crosswalk stripes. Hit the crosswalk, lock the rear wheel and whee!

I obviously know squat about really high end bikes. DH and all mountain would all look the same to me. The point I wanted to make is the better fs mtb's have frames that while looking simiar, are tons stronger and stiffer than the low end frames of any kind. Other high end frames, like roadbikes or comfort bikes, are made for lightness and sacrifice some stiffness in the process. A bmx frame for jumps might work good too though.

My new to me bike is a Giant OS3, not a particularly outstanding MTB, but to me, 4.5 inch travel forks and 5.5 in the rear is a whole new world for me riding trails. I'd feel pretty safe on that bike at 40 mph, but love it on the trails too much to mess it up with a motor yet.

 

[liveforphysics]

If you start from a motorcycle, and $1000-1500 seems expensive to you, then you end up with a very very sad E-bike power motorcycle. It's going to be painfully slow with crap range. It's going to require registration, and licences and other BS that makes it more costly and sucky.


I got my downhill bike on craigslist for something like $500-600 bucks if I remember right. Pretty damn cheap. It's brakes and chasis have proven to be adquate for 64mph. The rotors turn blue, and the pads smoke sometimes, but it's held up fine. I've eaten curbs head-on at 40+mph with it by accident, and the 8" of suspension soaked it up with out hurting the frame, or causing me to loose control of the bike. That's better than I can say for most streetbikes, which break rims, crack frames, and otherwise wreck badly when driven over curbs and things at 40mph.

If you want a stable feeling bike, it comes down to frame geometry. You can be setup to be nimble, or setup to be stable. Most normal bikes are setup to be nimble, and downhill bikes are often a bit of a middle ground between nimble and stable.