Need help chosing the bike and components.

[fibra]

Hello everybody,

this is my first post. My name is Sasha. I am dual sport, enduro motorcycle hobby rider just moved to Germany where those kind of riding is not allowed.
I`m now living at the border of Nature park, and seeing all those beautiful forest trails directed me towards only possible solution - ebike. I have always wanted to build one, and now is the time. I have experience with electronics, mechanics and building RC multicopters and and I feel confident in doing things myself.

There are so many interesting builds and ideas around, but I`m still not sure where to start.
My main concern is durability. It seams there is no durable and long lasting ebike build around that is not based on hub motor. I have seen so many broked bikes, so bicycles are obviously not designed for so much power and stress. To my eye, drive trains, and wheels seams too fragile. Only wheels and spokes that I liked are from mopeds that are laced onto hub motors, but I think hub motors are not up to a task for enduro riding.

About my needs:
I`d like to ride forest trails, long uphills. Some of trails are pretty technical. I don`t care for the speed as much as for the torque. Weight is also not an issue. I`d rather have sturdy bike with beefy wheels. Coming from the enduro motorcycle world I don`t think I need more than 21 at the front, and 19 at the back, so I`m leaning toward smaller wheels that are not more than 24 inch.
I`d like full suspension DH bike that is not too expensive. I have seen some popular used donors ad Kona Stinky and Specialized Big Hit on sales for under 800 EUR. Not sure ow much they are adequate for my build.
I`ll be probably using Cyclone 3000W mid drive with RC batteries.

So, my questions for now:

1. What frame to chose? Should I buy just frame or complete bike? (I don`t mind lack of the triangle space as I plan to carry batteries in my backpack.I`d prefer steel as it is sturdier and can be w elded.)

2. How can I have sturdier drivetrain and wheels?
Can somewhere be bought motorcycle rim laced with motorcycle spokes onto bicycle hub? Similar as people do with hub motor. Can I use BMX chain and sprockets without welding and too much of improvisation? Or it makes more sense to do some serious modification and go with a carting wheels and sprockets. I really, really wanna crank the throttle without worrying bike will be broken!

3. Is the Shimano hub Alfine A8 sturdier, long lasting solution than using cassette? Can it be used with motorcycle spokes?

4. How much of the change can I expect if I put 19 inch wheel at the back of the 24 or 26 inch bike. Will it affect riding very much? I guess it can be compensated by moving the point where the shock is connected to the swingarm.

Any advice is much appreciated!

 

[FluxZoom]

http://em3ev.com/store/index.php?route=product/category&path=47
https://endless-sphere.com/forums/viewtopic.php?f=31&t=61259

https://endless-sphere.com/forums/viewtopic.php?f=3&t=78623 Battery backpack discussion.

 

[motomech]

It's a mistake to take what you think you know about motorcycles and apply it to bicycles, even Ebikes.
DH wheels are stronger than you think, they do 6 ft. drop-offs and the like.
Most Etrail builders either use the stock wheels or modify them to be able to run wider tires for2.5" knobbies. Bicycle wheels can be built quite strong.
It's probably going to be a while before you need to think about a trail Ebike that needs MC wheels and all that entails.
In the same vain, the 3K Cyclone is quite a system for a first timer. Maybe you should think about one of the newer Bafang mid-drives to get started.
And lastly, forget the idea of carrying RC batteries in a pack pack. You wouldn't tie a can of Gas on your body and go dirt bike riding, would you? That is in effect what you are talking about.
The fact that you would even think of such a thing, shows that you have a ways to go in understanding the care and use of Lipo.
Ok, that's it for the preaching, but you might as well know from the start that some time spent reading here is a necessary foundation, then do a moderately reasonable build and learn from that as you go.
Used reasonably, a quality DH or XC bike doesn't fall apart like you are indicating. Getting enough battery to climb long hills and flat tires are things that you more likely have to learn to overcome.

 

[dogman dan]

The main thing you won't find is DH bikes that are steel. Some cheapos may have a steel swing arm, but a stinky or whatever will be all aluminum, with possibly a steel plate at the rear axle. Taking up welding as a hobby is an option though.

But happily, specialized frames for ebikes are out there now, starting with the stealth bomber, and the Greyborg. Also affordable frames from china through EM3ev. Go with one of those frames makes some sense. then you can carry the battery in the proper place, center of the frame.

I won't get into wheels, but I have only taco folded one wheel, and that was on the street, screwing up on a curb. So if you are really riding in sub 30 mph ballpark, I really don't see much need for moto wheels. Try the light stuff first, you might find you like it.

 

[fibra]

http://em3ev.com/store/index.php?route=product/category&path=47
https://endless-sphere.com/forums/viewtopic.php?f=31&t=61259.

I thought it is better to buy good used bike than just a frame, and it is plus if I`m going with stock bike. If I will be customize it more, than it would be better to use some of those frames. It all depends of the route I will be going.

It's a mistake to take what you think you know about motorcycles and apply it to bicycles, even Ebikes.
DH wheels are stronger than you think, they do 6 ft. drop-offs and the like.
Most Etrail builders either use the stock wheels or modify them to be able to run wider tires for2.5" knobbies. Bicycle wheels can be built quite strong.

Well, I don`t pretend to know everything about motorcycles, I am just trying to compare what I know from experience dirtbikes to DH that are used for similar kind of riding. I know bike frame wont snap from 6 ft. drop-offs but I have seen and read everywhere that wheels and drivetrain are not designed for high stress of electric motors. I have SEEN broken chains, spokes and freewheels.

It's probably going to be a while before you need to think about a trail Ebike that needs MC wheels and all that entails.
In the same vain, the 3K Cyclone is quite a system for a first timer. Maybe you should think about one of the newer Bafang mid-drives to get started.

I`m sorry if you spend a lot of money and hours finding what is right for you, but I`m trying make as best decision right from the start before I throw away a lot of money testing various systems. I know that Bafang is much simpler solution for beginner, but I think Cyclone suits me better. You should take into account that I said about having building experiences and that I feel confident. Being a newbie doesen`t automatically means not knowing nothing about what I`m dealing with. I`m trying to gather some critical information for my needs.

And lastly, forget the idea of carrying RC batteries in a pack pack. You wouldn't tie a can of Gas on your body and go dirt bike riding, would you? That is in effect what you are talking about.

As I mentioned, I have experiences with lipos and know its dangers add proper way of charging, discharging and carrying. Not all people are tape gluing batteries to the frame or just throwing them into backpack. I am really appreciate your concerns but I would appreciate even more if you used your experience to answer some of my questions. :wink:

 

[fibra]

The main thing you won't find is DH bikes that are steel. Some cheapos may have a steel swing arm, but a stinky or whatever will be all aluminum, with possibly a steel plate at the rear axle. Taking up welding as a hobby is an option though.

Uh, welding aluminum is not my cup of tea, that is why I prefer a steel.

But happily, specialized frames for ebikes are out there now, starting with the stealth bomber, and the Greyborg. Also affordable frames from china through EM3ev. Go with one of those frames makes some sense. then you can carry the battery in the proper place, center of the frame.

Yes, those are nice frames, but could be bit cheaper. It really is not some technology involved in it. Just a matter of precise welding. For some more money I can find a whole used bike. I`m not trying to be super cheap, but just to get as much as I can for what I am paying.

I won't get into wheels, but I have only taco folded one wheel, and that was on the street, screwing up on a curb. So if you are really riding in sub 30 mph ballpark, I really don't see much need for moto wheels. Try the light stuff first, you might find you like it.

OK. I might try the stock wheels I got on the donor bike, but I don`t really expect them to last.

 

[motomech]

As I mentioned, I have experiences with lipos and know its dangers add proper way of charging, discharging and carrying. Not all people are tape gluing batteries to the frame or just throwing them into backpack. I am really appreciate your concerns but I would appreciate even more if you used your experience to answer some of my questions. :wink:

You are the one that informed us that you intend to carry Lipo in a back pack for off road riding
What did you expect me think?

Good luck

 

[fibra]

You offended me, then you changed your post? I never offended you, so not sure what is your problem dude!? If you don`t have anything to say about tings that I have asked, than just don`t. You don`t have to shit on me for a welcome just because I`m new to this forum. You know nothing about me but you started to show me my place from the begging with that attitude... "what you think you know..."

 

[ecycler]

1. Do you huck big jumps or just like to trail ride? How fast do you intend to ride? This will influence the frame choice.
2. DH rims are indeed pretty strong, but the answer for you depends on the weight of the bike and how reliable you need everything to be.3
3. I am not familiar with the Alfine.
4. The 19 inch will probably balance the bike pretty well if you have the batteries mounted in the frame further forwards. It will significantly heavier than a 26 inch bike rim and slightly smaller in diameter with a decent tire.

Also, Pelican makes backpacks. I recently got one and like it. My intention was to use it for commuting with a laptop without fear of rain or crashes destroying it. It would be an easy way to safely carry lipo. I have done quite a bit of riding with LifePo4 batteries in a backpack. It is not a bad way to roll, but being tethered can be be a pain sometimes.

 

[fibra]

1. Do you huck big jumps or just like to trail ride? How fast do you intend to ride? This will influence the frame choice.

I would like if I can make some jumps. I`m more into technical riding than speed.

2. DH rims are indeed pretty strong, but the answer for you depends on the weight of the bike and how reliable you need everything to be.3

I thought long thing bicycle spokes could be weak spot, not rims. Having smaller rims (shorter spokes) to me seams stronger. I`ve seen some BMX old school 20 inch wheels with HD thick spokes that draws my attention.

4. The 19 inch will probably balance the bike pretty well if you have the batteries mounted in the frame further forwards. It will significantly heavier than a 26 inch bike rim and slightly smaller in diameter with a decent tire.

If using 20 inach BMX back wheel with 24-26 inch at the front wouldn`t affect the bike handling too much, I would be very happy.

Also, Pelican makes backpacks. I recently got one and like it. My intention was to use it for commuting with a laptop without fear of rain or crashes destroying it. It would be an easy way to safely carry lipo. I have done quite a bit of riding with LifePo4 batteries in a backpack. It is not a bad way to roll, but being tethered can be be a pain sometimes.

I didn`t know Pelican make backpacks, but my initial idea was exactly to use Pelican case for battery with integrated circuit breaker so I can throw it in a backpack and carry around I`m already using one for my quadcopter battery packs. I love Pelican. Off course, some HD cable with proper shielding is a must, but that is not a problem. I`ll check their backpacks. Thanks for the info!

 

[fibra]

This is the wheel that I was mention. It is ARAYA 20" x 2.125"

 

[ecycler]

I would like if I can make some jumps. I`m more into technical riding than speed.

Get some quality dual crown forks with 20mm axles and 180mm+ travel. The better your suspension, the less stress you are going to put on your wheels.

I thought long thing bicycle spokes could be weak spot, not rims. Having smaller rims (shorter spokes) to me seams stronger. I`ve seen some BMX old school 20 inch wheels with HD thick spokes that draws my attention.

You may be surprised here. Do a lot of reading on spokes. Bigger gauge does not always equal better. You have to match the tension to the rim you are using.

If using 20 inach BMX back wheel with 24-26 inch at the front wouldn`t affect the bike handling too much, I would be very happy.

I have a bike with a 17inch MC wheel in the back and a 26 inch DH wheel in the front. It handles great on the street, but the rear wheel is a little too small for my liking for technical offroad terrain. It is very common for dirt bikes to have a larger wheel in the front, but the combination I just described looks a bit cartoonish. Average people definitely notice and ask what is going on with the bike... The other issue with a 17 inch (which is just about the same size as a 20inch BMX) is that it really doesn't not roll as well over rough terrain and obstacles as well as something with a larger diameter. Which is why I would recommend a 19inch MC or 24/26 inch bike wheel.

Off course, some HD cable with proper shielding is a must, but that is not a problem. I`ll check their backpacks. Thanks for the info!

Shielding is not necessary. Just make sure you install a quality fuse and use some good 8-10gauge Silicon or PTFE wire.

 

[millzy555]

There is nothing wrong with carrying lipo's in your back pack!, There is so much exaggeration with regards to lipo's. Treat them well and you wont have an issue. It is much easier to ditch your backpack in the event of a fire than having them strapped to your bike. Just protect them with padding to stop rubbing etc. Goodluck!

 

[macribs]

If you get a 19" motorcycle rim and add a 19" x 3" tire your outer diameter of the wheel will be around 25" or even 25.5", so pretty close to standard MTB wheel @26".
SO I don't think you should worry about ride quality using motorcycle rim. To save some weight you can use high quality hubs with large flanges and rather then using motorcycle spokes you can use ie 3 butted dh spokes. Super strong where needed and slimmer elsewhere.

I know you said backpack, but if you have the chance consider getting batteries in the triangle.
If you can find yourself a low priced good quality donor bike in Australia you could contact es member samd. He does quality custom builds out of DH bikes. That way you can have him build you a battery box on a DH frame. Might be ok price wise too, as I think the AUD is still low against the Euro. Check him out. Even the donor bike can be cheaper for you if you get it from Australia due to low AUD.

 

[fibra]

Thank you all for the answers, I find it very helpful! I might have some more questions soon. For now I`m more clear about direction I`m going. I`ll see what are best sources for getting the bike or frame from. Ordering from down under might be cheaper, but shipping might be more expensive. I`ll see. I would be nice to have my batteries in the triangle, I just said I`m not concerned much about it. If it fits, cool, if not, I don`t mind to have it in my backpack. I think it could be beneficial having some weight off the bike, but that is really not important criteria for choosing the frame, but for the motomech seams valid reason to call me an idiot, even I obviously not only one with that idea in mind.

 

[FluxZoom]

There is nothing wrong with carrying lipo's in your back pack!, There is so much exaggeration with regards to lipo's. Treat them well and you wont have an issue. It is much easier to ditch your backpack in the event of a fire than having them strapped to your bike. Just protect them with padding to stop rubbing etc. Goodluck!

Unless you are knocked out in the process of having your lipos damaged or whatever battery in general shorting out (power leads, even fused ones, can short out and start a fire) and turning into hot burny firey death strapped to your back. Even just having a shoulder or arm broken in a bike wreck could mean a difficult, slow or impossible swift removal of a backpack to where at best your clothing light on fire. Is this worth betting your wellness or life on? Not a chance I'd take.

 

[slacker]

no where did i read that motomech called you a idiot. maybe you should not be so sensitive and when asking for advice you can take what you consider good and ignore the rest. Good luck in your journey.

 

[ecycler]

One thing you will need to consider as well with going to smaller wheels is to make sure that you have proper pedal clearance with the frame setup you choose. Pedal strike has led to many bad crashes especially offroad where the terrain is bumpy.

 

[fibra]

Unless you are knocked out in the process of having your lipos damaged or whatever battery in general shorting out (power leads, even fused ones, can short out and start a fire) and turning into hot burny firey death strapped to your back. Even just having a shoulder or arm broken in a bike wreck could mean a difficult, slow or impossible swift removal of a backpack to where at best your clothing light on fire. Is this worth betting your wellness or life on? Not a chance I'd take.

I` don`t get it? Are you trying to scare me now? I`m 40 yrs. not a teenager. I have told you I have experiences with lipos and I know what am I doing. Giving a friendly advice to pay attention would be enough, but continue preaching and scaring about dangers relay makes no any sense. 8)

no where did i read that motomech called you a idiot. maybe you should not be so sensitive and when asking for advice you can take what you consider good and ignore the rest. Good luck in your journey.

As I said, he called me an idiot than edited the post. You can see it is edited or you can ask him yourself. I reall don`t care.
I`m not sensitive, but motomech started pretty arrogantly from beginning which escalated into calling me an idiot. I came here to learn something, get some answers and exchange the ideas. I was not rude nor impolite, so I don`t wanna anybody offenses me just because bigger post count.

One thing you will need to consider as well with going to smaller wheels is to make sure that you have proper pedal clearance with the frame setup you choose. Pedal strike has led to many bad crashes especially offroad where the terrain is bumpy.

That fact I missed. I`m still imagining I`ll be riding offroad motorcycle. I was thinking about putting engine guard, but pedals wasn`t on my mind. Thanks for the advice! I`ll better start with stock bicycle and try different options later on.

 

[millzy555]

There is nothing wrong with carrying lipo's in your back pack!, There is so much exaggeration with regards to lipo's. Treat them well and you wont have an issue. It is much easier to ditch your backpack in the event of a fire than having them strapped to your bike. Just protect them with padding to stop rubbing etc. Goodluck!

Unless you are knocked out in the process of having your lipos damaged or whatever battery in general shorting out (power leads, even fused ones, can short out and start a fire) and turning into hot burny firey death strapped to your back. Even just having a shoulder or arm broken in a bike wreck could mean a difficult, slow or impossible swift removal of a backpack to where at best your clothing light on fire. Is this worth betting your wellness or life on? Not a chance I'd take.

Cmon....your talking worst case scenario here. Not sure how you would get knocked out but anyway. Stop with the scare-mongering and offer some advice/ solutions. Everyone knows the risk associated with lipo, yet theres a huge percentage who use them.

 

[dogman dan]

Calm down guys. He can carry his lipo any way he wants. But he will have problems if he dings them in crashes. He knows that. All he's got to do is get hard case, or put his packs in some kind of semi hard protective box.

 

[macribs]

Hm I didn't even think of the safety aspect
My #| reason for battery in triangle would be to aid the balance and center of gravity.

 

[John in CR]

Fibra,

You've only talked about frames. If you ride with wheels going airborne then a backpack battery (a pain in the a$$ due to the wire connecting you to the bike) makes sense, so you end up with a featherweight electric motorcycle with pedals. For that kind of riding you don't want a hubmotor though. Also, for slow technical riding up hills, as much as I love hubmotors, that's not what you want, because they have real heat issues at low speed high torque, though you might consider 2wd.

For durability and real performance, you don't want something that drives the bike chain through the gears. Sure it will get you slowly up steep stuff, but there's no way to make it durable. For low maintenance and performance for the riding you want, ie like a motorcycle but better (lighter, more nimble, no shifting), you want 10-15kw or more with a real chain or belt driving the left side, and gear it relatively low (for better low speed performance and efficiency), say 60-65kph top speed.

Since you have metal working capability, build a new swingarm that includes mounting the motor on the swingarm as close to the pivot as practical for minimal effect of unsprung weight, no issues of changing chain length during suspension travel, and to keep the motor from acting on the bike's rear suspension that is much more compliant than a moto.

John

 

[WoodlandHills]

There is nothing wrong with carrying lipo's in your back pack!, There is so much exaggeration with regards to lipo's. Treat them well and you wont have an issue. It is much easier to ditch your backpack in the event of a fire than having them strapped to your bike. Just protect them with padding to stop rubbing etc. Goodluck!

Unless you are knocked out in the process of having your lipos damaged or whatever battery in general shorting out (power leads, even fused ones, can short out and start a fire) and turning into hot burny firey death strapped to your back. Even just having a shoulder or arm broken in a bike wreck could mean a difficult, slow or impossible swift removal of a backpack to where at best your clothing light on fire. Is this worth betting your wellness or life on? Not a chance I'd take.

Cmon....your talking worst case scenario here. Not sure how you would get knocked out but anyway. Stop with the scare-mongering and offer some advice/ solutions. Everyone knows the risk associated with lipo, yet theres a huge percentage who use them.

My recent endo left me with my bell rung for at least 30 sec. And due to a broken collarbone I was totally unable to get even a vest off of me w/o outside help some minutes later. I shudder to think what would have happened if I was wearing a burning backpack: I'd get it off, but it sure would hurt!!!!

BTW, I was wearing a full face Bell helmet, add broken jaw to my injuries if the chin bar had failed! Even more reason IMHO not to wrestle with a backpack full of batteries after a crash, burning or otherwise...... You have to plan for a worstcase scenario if you are alone not the best!

 

[fibra]

Come on guys, all that empty talk about injuries and dangers of batteries as far as I`m concerned off-topic. Riding DH bike and jumping from the rocks in woods is not safe by itself, so let`s cut the shit. I would appreciate if we don`t discuss about safety issues here any more. I`m sure there are right place in the forum where you can tell all that scary storied.

Fibra,

You've only talked about frames. If you ride with wheels going airborne then a backpack battery (a pain in the a$$ due to the wire connecting you to the bike) makes sense, so you end up with a featherweight electric motorcycle with pedals. For that kind of riding you don't want a hubmotor though. Also, for slow technical riding up hills, as much as I love hubmotors, that's not what you want, because they have real heat issues at low speed high torque, though you might consider 2wd.

John, first thank you for the advises. I have never liked an idea of hub motor for off-road bikes. I don`t know why are people using them at all except for its clean look. For me it is only for the road.
Idea of using 2WD was always interesing to me. First 2WD motorcycle that I have seen has mechanical connection to the engine which is pretty complicated and I have never liked it. Hub motors seams neace for 2WD but I still dont like them. I am thinking a lot lately of Internal-Gear Hubs on both wheels with some reduced speed brushless RC motor. Comming from the RC world I cannot get rid of the idea of using them. But, that might not be my first build. I might cook that idea bit more as I go.

For durability and real performance, you don't want something that drives the bike chain through the gears. Sure it will get you slowly up steep stuff, but there's no way to make it durable. For low maintenance and performance for the riding you want, ie like a motorcycle but better (lighter, more nimble, no shifting), you want 10-15kw or more with a real chain or belt driving the left side, and gear it relatively low (for better low speed performance and efficiency), say 60-65kph top speed.

I agree completely. For my ultimate ebike build I would do exactly that, but for the first build I would like it to be bit more modest, so as I said I am thinking of using some of those IGH. Shimano Alfine 8 seams to be pretty durable. If I put big sprocket on it I might drive trough the chain directly from te RC motor. In that case sprocket might not be so enormous as in first configuration. But that is just idea.

Since you have metal working capability, build a new swingarm that includes mounting the motor on the swingarm as close to the pivot as practical for minimal effect of unsprung weight, no issues of changing chain length during suspension travel, and to keep the motor from acting on the bike's rear suspension that is much more compliant than a moto.

John

That was exactly what I am mostly attracted to but with smaller back wheel with moped rims and thicker spokes.
Here is the nice example of the idea that compensates the loss of the pedal clearance and incorporates the motor. Off course, having the motor closer to the pivot.

Another inspiration is this build. I love it.