CX concept

[anth_85]

I am starting to plan a project that'll I'll be building over the winter ready for next year. I am thinking of building an e-bike suitable for part gravel path part road for commuting on, or at least switch between commuting on and commuting on my good carbon fibre bike. I have a 15mile each way journey. This is my thinking please let me know if your see something obvious that I am missing.

I am thinking of using a cyclocross bike, something like a Specialized Tricross Disc or a Cannondale CAADX 105 (I'd really rather a disk based frame). Then fit a rear hub motor, probably 1000w 48v eBay kit, 700c. I know it's over the limit for the road, but making up some time on the off road sections would be nice. I am planning on powering it with 18650 cells that I already have a large amount of. So I am thinking of building a battery of 13 series, which gives a nominal voltage of 48.1 volts, and a maximum of 54.6 volts, I'll of course check the controller can manage that. If I went for 10 parallel my maths are 1000/48 = 20.8ah which at 2ah each gives 2.08C per cell.
For new cells I'd be comfortable with this, but for used cells I'd be happier at 1C. Which then means 20 parallel.

Therefore 13S20P pack is 260 cells (which I do have, tested at 2000 mha+) at 48V20Ah which sounds pretty huge.

I'd also probably look at changing the chainset from a compact to a standard, and the cassette to a wide ratio. The reason being I will be getting help so wont need the easier gears as much, but having a wide range on the cassette is helpful if the battery ever runs out.

So logistically I can buy a pannier rack and put 2x 13s5p packs in each side. I know the main problems with this is the the extra weight of the hub motor and all the batteries directly above it at the rear of the bike. But as a version 1.0 I am happy with the negative effect on handling, I used to use panniers for commuting and didn't think the extra wait was that bad. I can look at moving them to centre of the frame in V1.1. The weigh of each 18650 is about 48g, so 48 x (13*20) = 12,480g = 12.48KG. Considering I'm 110Kg, that is only at 10% of my weight.

The bits I haven't figured out yet are
1- mounting the throttle to the bars, I could mount it directly under the hoods so I either pull the throttle or pull the brake, but my hand couldn't physically do both, or I could go for pedal assist. I'd rather a proper throttle until I got used to riding it so unsure about this.
2- cabling, pulling 20ah is quite a lot, even if it 10ah from each side. I really don't want to risk a overheating the cabling, so If i split the battery into four 13s5p packs. I can use mains cabling, which will be rated for at least 13amps. How do I join them to one 20amp cable to go to the controller?
3- has this been done before? I see lots of mountain bike conversions, but not many semi-road conversions done, is there a reason?
4- has anyone seen a hard plastic pannier bags that goes down the sides of the rear wheel? This is so I can lower the center of gravity, I don't want fabric bags incase of accidents, and I want to do something to manage airflow through them to prevent the cells overheating.
5- am I missing something or is as simple as that?

 

[Raged]

Have a read of my cyclocross build based off a 29er frame. It sounds sort of similar to what you want I think.

1. I solved the throttle mounting issue on drop bars/STI levers (watch the vid).
2. Use some good 10AWG cable and you shouldnt have issues. High core thread count (eg turnigy silicone) means the cable is more flexible and can handle more rough abuse.
3. Most are done on mtb frame because they're just stronger frames. Remember you're trying to push 4-10x more power though a bike frame. Additionally, most of the stronger motors require thicker dropouts (135mm) purely due to magnet strength/count. In addition to that, fatter tires for versatility and to absorb bumps and deal with the extra weight (28" tires pumped to 55psi for road or 29er fat tires to gravel grind...). Also once you have a motor, weight isnt really an issue and MTB parts are significantly cheaper.
4. I dont use panniers... so someone else can answer.
5. Its that simple.

 

[leo99]

Hi there,
Great project a cyclocross has always been a dream bike for me to use but a bit pricey. I am still surprised not more people use them.

Just a few comments

Therefore 13S20P pack is 260 cells (which I do have, tested at 2000 mha+) at 48V20Ah which sounds pretty huge.

By my math that would be a 48v40ah battery. That sounds to be really huge

My two cents
maybe go for a geared hub like a mac from em3ev. Less battery and mounted in the triangle would be better especially if you are going to have so much it

I will be following your build
Leo

 

[dogman dan]

My gut reaction is, just make your bike from a sturdy MTB frame.

It just makes no difference if you strap 25 pounds of motor and battery to a 15 pound bike, or a 30 pound bike. But it does make a ton of difference, if your choice is not stiff enough from side to side to ride comfortably with a large load in rear panniers. Now, I have no idea if your cannondale is stiff that way or not, but if it's made for racing, I bet they used as thin stuff as they could on the frame. This is one reason a more rugged MTB frame , or even a steel cruiser frame often makes the best ebike.

And drop bars, well you must be pretty young if you will actually enjoy riding in a tuck 30 miles a day. But more importantly, riding upright might save your life, because you can see ahead when not in a racing tuck. So at the very least, put flat bars, riser bars, or something like that on a commuter.

Just my two cents, after 5 years doing a 15 mile one way commute. I went through several bikes before settling on an older used full suspension Giant for my commute. The others had the tail wag. Only the Giant had a stiff enough frame for it. Believe me, you will start noticing this stuff big time when you start spending an hour and a half or more a day on that bike.

 

[USAEBIKECO]

Be sure to invest in some really good tires and tubes. Believe me, its worth it. Having a flat on an ebike is a real pain.

 

[Raged]

My gut reaction is, just make your bike from a sturdy MTB frame.

It just makes no difference if you strap 25 pounds of motor and battery to a 15 pound bike, or a 30 pound bike. But it does make a ton of difference, if your choice is not stiff enough from side to side to ride comfortably with a large load in rear panniers. Now, I have no idea if your cannondale is stiff that way or not, but if it's made for racing, I bet they used as thin stuff as they could on the frame. This is one reason a more rugged MTB frame , or even a steel cruiser frame often makes the best ebike.

And drop bars, well you must be pretty young if you will actually enjoy riding in a tuck 30 miles a day. But more importantly, riding upright might save your life, because you can see ahead when not in a racing tuck. So at the very least, put flat bars, riser bars, or something like that on a commuter.

Just my two cents, after 5 years doing a 15 mile one way commute. I went through several bikes before settling on an older used full suspension Giant for my commute. The others had the tail wag. Only the Giant had a stiff enough frame for it. Believe me, you will start noticing this stuff big time when you start spending an hour and a half or more a day on that bike.

Drop bars arent that bad!!! I might change my tune when I hit the ripe age of 40 or something =)

 

[ScooterMan101]

About 4 weeks ago , I was riding on the back roads south of San Jose, California, when a group of riders slowly passed me, in the front of the pack/Peloton , by about 5 meters, was a bike that looked like a classic road bike, steel frame, but with modern components,
I asked the rider if it was a old classic frame he built up and he said no, he said it is a new frame/new bike . He Said it was made with Reynolds Cro-Moly tubing .
I was impressed, since I have owned a Reynolds Cro-Moly frame mountain bike for about 4 years and know that a properly designed and build Cro-Moly tubing frame has good ride qualities.

A few days later I went to the Specialized.com website to find that bike, and found something like it, the Awol

Fast forward 3 weeks, I traveled over to the town of Los Gatos, where I looked in on a couple of bike shops, and low and behold one of the shops had a Awol , in size medium ! . I asked for a test ride,
I Rode it for about 25 minutes, over every bump and crack I could find on the roads I took it out on. As you would guess it is a very good bike for traveling over not so perfect roads, the only thing I would change
would be the fork, it was stiff/harsh compared to a suspension fork.

The Great news for people building up a electric tour/commute/gravel bike is that you can buy just the frame set . also good news is that it is ... a Disc brake framset, 135mm rear drop out spacing
it is called the AWOL Expert frame set. you can make it a flat bar road/gravel/commute bike, or build it up with drop bars.
and use most of the other parts from a bike you currently have.

https://www.specialized.com/us/en/bikes/adventure/awol-expert-frameset/106556

https://www.specialized.com/us/en/bikes/adventure/awol

For a disc wheel set, just use a 29er wheel set. and use 38mm or 42 mm wide tires.

I am starting to plan a project that'll I'll be building over the winter ready for next year. I am thinking of building an e-bike suitable for part gravel path part road for commuting on, or at least switch between commuting on and commuting on my good carbon fibre bike. I have a 15mile each way journey. This is my thinking please let me know if your see something obvious that I am missing.

I am thinking of using a cyclocross bike, something like a Specialized Tricross Disc or a Cannondale CAADX 105 (I'd really rather a disk based frame). Then fit a rear hub motor, probably 1000w 48v eBay kit, 700c. I know it's over the limit for the road, but making up some time on the off road sections would be nice. I am planning on powering it with 18650 cells that I already have a large amount of. So I am thinking of building a battery of 13 series, which gives a nominal voltage of 48.1 volts, and a maximum of 54.6 volts, I'll of course check the controller can manage that. If I went for 10 parallel my maths are 1000/48 = 20.8ah which at 2ah each gives 2.08C per cell.
For new cells I'd be comfortable with this, but for used cells I'd be happier at 1C. Which then means 20 parallel.

Therefore 13S20P pack is 260 cells (which I do have, tested at 2000 mha+) at 48V20Ah which sounds pretty huge.

I'd also probably look at changing the chainset from a compact to a standard, and the cassette to a wide ratio. The reason being I will be getting help so wont need the easier gears as much, but having a wide range on the cassette is helpful if the battery ever runs out.

So logistically I can buy a pannier rack and put 2x 13s5p packs in each side. I know the main problems with this is the the extra weight of the hub motor and all the batteries directly above it at the rear of the bike. But as a version 1.0 I am happy with the negative effect on handling, I used to use panniers for commuting and didn't think the extra wait was that bad. I can look at moving them to centre of the frame in V1.1. The weigh of each 18650 is about 48g, so 48 x (13*20) = 12,480g = 12.48KG. Considering I'm 110Kg, that is only at 10% of my weight.

The bits I haven't figured out yet are
1- mounting the throttle to the bars, I could mount it directly under the hoods so I either pull the throttle or pull the brake, but my hand couldn't physically do both, or I could go for pedal assist. I'd rather a proper throttle until I got used to riding it so unsure about this.
2- cabling, pulling 20ah is quite a lot, even if it 10ah from each side. I really don't want to risk a overheating the cabling, so If i split the battery into four 13s5p packs. I can use mains cabling, which will be rated for at least 13amps. How do I join them to one 20amp cable to go to the controller?
3- has this been done before? I see lots of mountain bike conversions, but not many semi-road conversions done, is there a reason?
4- has anyone seen a hard plastic pannier bags that goes down the sides of the rear wheel? This is so I can lower the center of gravity, I don't want fabric bags incase of accidents, and I want to do something to manage airflow through them to prevent the cells overheating.
5- am I missing something or is as simple as that?

 

[ScooterMan101]

Link to article ?

Link to Video ?

="Raged"]Have a read of my cyclocross build based off a 29er frame. It sounds sort of similar to what you want I think.

1. I solved the throttle mounting issue on drop bars/STI levers (watch the vid).
[/quote]

 

[dogman dan]

Nothing wrong with drop bars for riding open roads. Or riding with your hands on top of the drop bars.

What I mean is, ride in a racing tuck in a city commute, and you risk not seeing the car that kills you. I really do believe that if you ride a city commute for several hours a day, its a good idea to ride with your head up, looking for those cars that are trying so hard to kill you.

The other thing I say a LOT, is don't ruin your favorite bike with a motor kit. I have 3 very nice vintage steel road bikes, none of them motorized.

 

[Raged]

Link to article ?

Link to Video ?

Have a read of my cyclocross build based off a 29er frame. It sounds sort of similar to what you want I think.

1. I solved the throttle mounting issue on drop bars/STI levers (watch the vid).

Its in my sig : https://endless-sphere.com/forums/viewtopic.php?f=6&t=70549