Comment, criticize my build. But be nice I’m new!

Long as the gearing is correct or at the minimum in the correct range then these high RPM motors with matching controllers should run like a scalded dog!

I don’t know what u mean by gearing being correct or at the minimum in correct range. If with gearing the max unloaded speed is like 60 and in use it’s only riding around the city barely hitting 30.. it’s going to have like half the torque of what it could.

Could compensate for that with a lot of current from the controller. What battery and motor current limits it has I can’t see
 
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I don’t know what u mean by gearing being correct or at the minimum in correct range. If with gearing the max unloaded speed is like 60 and it’s only riding around the city at max 30.. it’s going to be a lot weaker than it could be. .. like half the torque.
Gearing is "correct" when the motor or engine tops out at the required or optimum speed. Granted I am using a vastly different motor and everything I've built in my past used engines but they topped out at the required speed or slightly above.
 
Yea. his and maybe ur bike are geared for a much higher speed than needed.
That would depend on the end goal. I can't and won't try and speak for anyone else. Speaking for myself I have built a lot of stuff from a 79Z28 that ran 10 second quarter mile times at 6500RPM but I could and did occasionally turn it up and run 9's and even 8's once. I also built a dump truck that would barely run 80mph but it had no trouble at all getting a full load up to 75mph quick fast and in a hurry. Both of these examples had the gearing correct for the desired end use which is what I am planning for my build. Now I aim to see what kind of quarter mile time I can achieve from a homebrew E-bike build. I also want to see how many miles I can run this same bike at legal speeds riding place to place.
 
I don’t know what u mean by gearing being correct or at the minimum in correct range. If with gearing the max unloaded speed is like 60 and in use it’s only riding around the city barely hitting 30.. it’s going to have like half the torque of what it could.

Could compensate for that with a lot of current from the controller. What battery and motor current limits it has I can’t see

My controller is 200Amp max output. But it’s pretuned with battery output being 33% of those 200amps
 
Sorry can you explain this further I’m not sure what you mean
Bmx bikes have little “trail” compared to other kind of bikes. Great for going up to maybe 20mph but beyond that you have to be more attentive and keep your hands on the bars. You can increase the trail with a different fork or drilling/cutting the front dropout on the fork further inward.


It’s not a problem but given the choice it’s nicer with more trail.
 
I've tried similar things on full suspension MTBs that have wheelbase to spare, I wouldn't even consider it on a bike like yours. You'd lose wheelbase and shift your weight forward, neither of which are ideal.
 
I can’t find the frame n fork geometry but it’s stated as “relaxed”.



Further slotting the fork would reduce the wheelbase but the increase in trail might be worth it.
 
A 20" fork? But it looks like that company does recommend the largest offset/ smallest trail for "high speed trails".

If OP wants to spend that kind of money they could have front suspension and a disc brake. That'd be a worthwhile increase in trail.
 
A 20" fork? But it looks like that company does recommend the largest offset/ smallest trail for "high speed trails".

If OP wants to spend that kind of money they could have front suspension and a disc brake. That'd be a worthwhile increase in trail.
I just post it as an example of the variation in fork offset on bmx bikes. I was suggesting they slot theirs.

the trail and offset is often confused. There will be more trail, and stability, with the front wheel closer to the rider such as from more deeply slotting the dropouts and mounting the wheel in more



Or maybe getting a 29r fork, with suspension or not, as it raises the front a little changing the headtube angle and gives more trail. (I’ve done this). Get a fork that has the least (?) offset possible too (meaning the wheel pushed forward the least by the crown shape or dropouts). Could take a pic and see exactly how much trail would come from changing the headtube angle in this way.
 

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There's also more stability in a longer wheelbase, and the fork manufacturer that you linked seems to say that that's more beneficial for high speed handling.
Edit: A 26" suspension fork would raise the front end significantly, there's no need to go for the wrong wheel size. 29er forks tend to come with longer offsets.
 
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There's also more stability in a longer wheelbase, and the fork manufacturer that you linked seems to say that that's more beneficial for high speed handling.
I think a cm of trail will add more stability than a cm of wheelbase.. but why not have both and get a big suspension fork

…if u can find a long fork with little offset.
 
Safety wise, changing the fork for improved braking would be a good idea.
Otherwise, changing the fork for a different amount of castor effect won't gain enough to warrant the investment.
 
Safety wise, changing the fork for improved braking would be a good idea.
Otherwise, changing the fork for a different amount of castor effect won't gain enough to warrant the investment.
i disagree. I’m guessing, drank a beer with socks too hot but it’s easy to import a frame n fork to fusion n see. I’ll be back w it.
 
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The OP has already stated the bike "rides fine". And since handling is largely personal choice, why even bring up steering geometry in the first place? Let him sort-out the issues already mentioned first, and if he feels there's a problem with handling, I'm confident he'll bring it up.

1746745802018.jpeg
 
Has anyone mentioned 219chain?

The pitch is just under 8mm. Its made for high rpm and there are sprockets cheap and readily available in 90-100tooth sizes as well as small front sprockets like 9-13 teeth.

This is a perfect application for 219.

I like this build! Simple and it runs. So many of us get stuck in the planning phase. I love that the OP just built it and went for a ride to figure the details out later. This is the true spirit of endless-sphere in my opinion.

97 tooth for $18


Front sprockets that might fit if the shaft matches
 
The OP has already stated the bike "rides fine". And since handling is largely personal choice, why even bring up steering geometry in the first place? Let him sort-out the issues already mentioned first, and if he feels there's a problem with handling, I'm confident he'll bring it up.

View attachment 369965
Yea pretty much this lol
 
Has anyone mentioned 219chain?

The pitch is just under 8mm. Its made for high rpm and there are sprockets cheap and readily available in 90-100tooth sizes as well as small front sprockets like 9-13 teeth.

This is a perfect application for 219.

I like this build! Simple and it runs. So many of us get stuck in the planning phase. I love that the OP just built it and went for a ride to figure the details out later. This is the true spirit of endless-sphere in my opinion.

97 tooth for $18


Front sprockets that might fit if the shaft matches
Thanks this is a good suggestion if it happens my 35 chain brakes a bunch
 
I don’t think handling is going to be an issue at least in the near future. I’ll just be riding this from my car to job sites and SF has a ton of protected bike lanes now that are mostly flat and straight. Also I won’t be riding like a maniac😉
 
Has anyone mentioned 219chain?

The pitch is just under 8mm. Its made for high rpm and there are sprockets cheap and readily available in 90-100tooth sizes as well as small front sprockets like 9-13 teeth.

This is a perfect application for 219.

I like this build! Simple and it runs. So many of us get stuck in the planning phase. I love that the OP just built it and went for a ride to figure the details out later. This is the true spirit of endless-sphere in my opinion.

97 tooth for $18


Front sprockets that might fit if the shaft matches
Front sprockets are the problem with 219 chain and the my1020. They don't exist, so 219 is only useful as a second stage. I agree 219 would be nice, but it doesn't have huge advantages over #35.
My first attempted e-bike project was a my1020 on my downhill bike. I ran into so many problems that its still unfinished, but I'm also jealous of OPs ability to just build it and figure out the details later. Pedals, front brakes, that can all be solved in time if need be. A 2-3kw big bmx bike sounds like fun.
Also I won’t be riding like a maniac😉
I hope you reconsider this part.
 
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