Pedaling at high speed

Joined
May 29, 2022
Messages
93
Hello all,

I'm still doing the armchair engineering thing on my upcoming ebike project (money is coming soonish though).
I really want to use this ebike to get a decent amount of exercise.

Here's the problem (I think), around here cars cruise at 35mph on 25mph roads. To keep up with traffic the ebike will need to be able to cruise at 35mph.

Is it possible for a geartrain to be set up to where I am honestly pedaling at that point?

On a side note, I'm impressed with the amount of ebikes being ridden here (Oakland/Berkeley CA).
What I'm not impressed by is how I never see these people actually pedaling their bikes. They seem to use it like a small ICE scooter...

I REALLY dislike it when I'm in an official bike lane and one of these people shoot by me silently. It seems so dangerous...
I think that if you're going to cruise at 20mph you should be on the road with the cars.
Severe differences in velocity is inherently unsafe.
 
The Madmadscientist said:
Here's the problem (I think), around here cars cruise at 35mph on 25mph roads. To keep up with traffic the ebike will need to be able to cruise at 35mph.

Is it possible for a geartrain to be set up to where I am honestly pedaling at that point?

Schlumpf drive.
 
I don't get the idea that you need to keep up with car traffic on a bicycle. It will eat up your battery and range to overcome air resistance at those speeds. You probably won't be contributing much with pedaling at those speeds.
 
The Madmadscientist said:
Here's the problem (I think), around here cars cruise at 35mph on 25mph roads. To keep up with traffic the ebike will need to be able to cruise at 35mph.
That is true nearly everywhere ... well everywhere in the US at least. The simple truth is that if you want to compete with cars then you need a motorcycle .... how do I say this politely ? .... especially if the rider is somewhat robust.
 
This obviously depends on the bike and the rider, but my experience is that you need at least 1500W of assist to pedal at that speed.

As for being able to actually pedal, it is a matter of overall gear ratio on the bike, so the pedaling cadence is acceptable when reaching that speed (like 80)

There is a good tool for that below
https://www.gear-calculator.com/
 
E-HP said:
The Madmadscientist said:
Here's the problem (I think), around here cars cruise at 35mph on 25mph roads. To keep up with traffic the ebike will need to be able to cruise at 35mph.

Is it possible for a geartrain to be set up to where I am honestly pedaling at that point?

Schlumpf drive.

Ha, I thought you were making a crack at how fat I am... Had to look it up. Wow, the english on that page made my head hurt a bit. I had no Idea that such a thing existed...I'll have to think on it.
 
RunForTheHills said:
I don't get the idea that you need to keep up with car traffic on a bicycle. It will eat up your battery and range to overcome air resistance at those speeds. You probably won't be contributing much with pedaling at those speeds.

Well I can tell you this..I got my motorcycle license at 16 been basically a full time rider when I was not on my bike.
I've ridden my bike on crazy busy but fast moving streets in San Francisco. The scariest times were always when the cars were going significantly faster than I. Think up those dang hills...
I don't trust cage drivers. Modern cars are so sound proof they cut the drivers off almost completely from the outside world...and they're always on the phone right?

Short story long, it just feels much safer when I'm moving at around the same speed as cars.
 
Get something like Hammerschmidtt crank. 1:1.6 overdrive ratio.
 
LewTwo said:
The Madmadscientist said:
Here's the problem (I think), around here cars cruise at 35mph on 25mph roads. To keep up with traffic the ebike will need to be able to cruise at 35mph.
That is true nearly everywhere ... well everywhere in the US at least. The simple truth is that if you want to compete with cars then you need a motorcycle .... how do I say this politely ? .... especially if the rider is somewhat robust.

Nope, I'm just fat,..6' tall and 250lbs right on the edge of being officially morbidly obese according to the charts.
With todays tech I can easily afford a 3000W hub motor set-up. I would just like to be a more honest ebiker while I still can.
 
scrambler said:
This obviously depends on the bike and the rider, but my experience is that you need at least 1500W of assist to pedal at that speed.

As for being able to actually pedal, it is a matter of overall gear ratio on the bike, so the pedaling cadence is acceptable when reaching that speed (like 80)

There is a good tool for that below
https://www.gear-calculator.com/

Wow, that is quite a web page! Someone spent a lot of time on it.
If I'm reading it right, big if, A 52-12 at 80 rpm is theoretically what I need.
 
The Madmadscientist said:
E-HP said:
The Madmadscientist said:
Here's the problem (I think), around here cars cruise at 35mph on 25mph roads. To keep up with traffic the ebike will need to be able to cruise at 35mph.

Is it possible for a geartrain to be set up to where I am honestly pedaling at that point?

Schlumpf drive.

Ha, I thought you were making a crack at how fat I am... Had to look it up. Wow, the english on that page made my head hurt a bit. I had no Idea that such a thing existed...I'll have to think on it.

2.5X, makes your 46 tooth chainring into 115.
 
The Madmadscientist said:
scrambler said:
This obviously depends on the bike and the rider, but my experience is that you need at least 1500W of assist to pedal at that speed.

As for being able to actually pedal, it is a matter of overall gear ratio on the bike, so the pedaling cadence is acceptable when reaching that speed (like 80)

There is a good tool for that below
https://www.gear-calculator.com/

Wow, that is quite a web page! Someone spent a lot of time on it.
If I'm reading it right, big if, A 52-12 at 80 rpm is theoretically what I need.

I used this calculator, but it came up with 60T up front and 11T (like the cheap DNP freewheels have), gets you to 35mph @ 80rpm.
https://www.bikecalc.com/speed_at_cadence

60T is about 10" diameter.
 
The Madmadscientist said:
I REALLY dislike it when I'm in an official bike lane and one of these people shoot by me silently. It seems so dangerous...

Sorry if I startled you; that was me. :oops: I just ordered one of those hanging dingle bells that always rings for my bike, so I'm not so silent. :D
 
E-HP said:
The Madmadscientist said:
scrambler said:
This obviously depends on the bike and the rider, but my experience is that you need at least 1500W of assist to pedal at that speed.

As for being able to actually pedal, it is a matter of overall gear ratio on the bike, so the pedaling cadence is acceptable when reaching that speed (like 80)

There is a good tool for that below
https://www.gear-calculator.com/

Wow, that is quite a web page! Someone spent a lot of time on it.
If I'm reading it right, big if, A 52-12 at 80 rpm is theoretically what I need.

I used this calculator, but it came up with 60T up front and 11T (like the cheap DNP freewheels have), gets you to 35mph @ 80rpm.
https://www.bikecalc.com/speed_at_cadence

60T is about 10" diameter.

Huh, I put in 26" wheels with a 4" tire and at 90rpm it gave me 52-12 for 34.9mph .
I'm guessing you put in different wheels?
 
The Madmadscientist said:
https://www.bikecalc.com/speed_at_cadence


Huh, I put in 26" wheels with a 4" tire and at 90rpm it gave me 52-12 for 34.9mph .
I'm guessing you put in different wheels?

Here's what I used. 26" rim, 2.4" tire.
Cadence.jpg
 
The Madmadscientist said:
Here's the problem (I think), around here cars cruise at 35mph on 25mph roads. To keep up with traffic the ebike will need to be able to cruise at 35mph.

Give up that line of thinking right now. Cars will pass you because you're on a bike. The faster you go, the faster they will be going when they overtake you. It is not a safe strategy. You'll just be going a whole lot faster when things go wrong.

I used to hit 55 mph going down a long steep hill on my way to work in Seattle, and despite the street being limited to 35 mph, drivers would pass me at 65 mph or more, because they need to pass cyclists more than they need to obey the law or maintain reasonable speeds.

Cyclists have been going bicycle speeds since ever. That's the safe speed to go when you're on a bike, because it's the speed people expect and are accustomed to. You might think you're safer going motorized speed, but you're not.

Also, you're building a bike that plants you hard on your butt, with no option to stand up on the pedals. The faster you go, the harder that thing you missed because you were going so fast will slam your spine. That's not going to be any fun at motorcycle speeds.
 
Hey All,
I just realized this a bit too late.
Recumbent riders have basically been dealing with this issue for a very long time.
One place has what they call a 'triple speed' set-up.
They have a 3 speed Sturmey-Archer, with an 11 speed cassette (11-50) with a triple chain ring to deal with the large spread in speeds that the 'bents are capable of.
That seems like a lot of mechanical widgets to go wrong.
I wouldn't go that far but I could do something similar with a 11 speed 11-50 cassette and a 60 chain ring.
I just have to get comfortable with the idea that I will always have to use the motor to help me take off from a stop.
With the semi-stretch-chopper frame I am planning I'm basically halfway between a standard upright bike and a full on recumbent.
I just need to steal more from the full-on 'bent folks.
 
The Madmadscientist said:
I wouldn't go that far but I could do something similar with a 11 speed 11-50 cassette and a 60 chain ring.
I just have to get comfortable with the idea that I will always have to use the motor to help me take off from a stop.

You're thinking a 60/50 gear is too tall to pull away from a stop without a motor? Depending on your choice of rims and tires, that's about a 34 inch gear. It's low enough to be of no use except for hill climbing and pulling away from a stop.
 
The Madmadscientist said:
DogDipstick said:
Get something like Hammerschmidtt crank. 1:1.6 overdrive ratio.

They died a while ago.
https://www.bikemag.com/gear-features/matter/prelude-to-a-shift/
And wow, the BB had to be machined to very close tolerances...


DogDipstick said:
something like


There are many offerings of planetary cranks now, this day in age, from our industrious maker friends in China. For 1-200$.

Yes the HS is still very expensive.
 
Stealth_Chopper said:
Legend
DD3.jpg

I realize now that I'm going to have to solve this problem without the IGH.
Unless there is a sudden dramatic drop in mid-drive prices..
It's gotta be a hub drive for me.
 
Chalo said:

You're thinking a 60/50 gear is too tall to pull away from a stop without a motor? Depending on your choice of rims and tires, that's about a 34 inch gear. It's low enough to be of no use except for hill climbing and pulling away from a stop.

It's a first draft.
Remember I weigh 250lbs and the bike is gonna weigh at least 125lbs....
The 11-50 cassette will have large steps but from what I've read they are doable with e-assist.
So, thats where my head is at now.
I'm planning on a 26" wheel with a 4" tire so far.
 
The Madmadscientist said:
The 11-50 cassette will have large steps but from what I've read they are doable with e-assist.
So, thats where my head is at now.
I'm planning on a 26" wheel with a 4" tire so far.

Unless you're building a mid drive. you'll never use that 50 tooth cog in the rear. I'd be surprised if you use anything more than about 26 to 30 teeth in the rear. Any bigger than that and you won't be able to pedal fast enough to keep the motor from bogging down and frying itself...unless you can pedal like a hamster. With 60 front and 26 rear and 80 cadence, you'll be going 15mph, which is a good speed to avoid meltdown when climbing a hill. With 50 in the rear, you'll be going 7.5mph, so too slow, so you'll never use it.

I use 46:16 for climbing hills, 46:18 if it's super steep. That would equate to 21T and 23T rear when using 60T front.
 
Hello All,
Sound several old threads from 2016-2017 that talk about an ATS crank drive which is a clone of the much more expensive Scholsh <sp?>
They both make a 1-2.5 which I think would be perfect for me.
Not sure if either would work on a wide 'fat bike' BB...still looking. In one thread someone says they have a model that uses a torque arm instead of the 45 degree milling. If this is true that would be great as it would be bolt on.

Found the ATS website and they do have a version for wide BB.
Sent them an email to see and if they ship to the U.S. now...
 
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