cyclocross ebike project

anth_85

10 mW
Joined
Mar 31, 2015
Messages
29
Location
sunderland, UK
I am planning my first e-bike that will be used 99% for commuting. The route I'll take too and from work is about 15miles each way partially on the road getting into and out of town and partially cycle route that is 50:50 tarmac / (smothish) gravel. I am used to cycling on a road bike to work but there are parts I just don't feel comfortable on it, either the roads are too fast, I'm too fast for the path or the bike cant handle gravel. So I am thinking of using a cyclocross bike as a base as I like drop handles rather than flats and it means I can avoid the faster roads. Which one I haven't decided. It will be through the cycle to work scheme so I was looking at something around £600-700. I'm sure I saw one a month or two ago that was 1x11 but I cant find it now.

For a motor I am pretty set on a BBSHD, probably with the screen removed and I'll just put my garmin on it instead. I don't want the pedal assist either, I'd rather just use a throttle and control it myself.

For a battery I am about 50 cells into testing a 14S10P build, aiming to have them all around 2400-2500mAh to give a 52v,24Amp pack. Which should give me range to get to and from work without charging at work. I have been looking at the blackburn outpost large frame bag http://www.wiggle.co.uk/blackburn-o...|pcrid|67090793342|pkw||pmt||prd|5360740373uk
which I am 99% sure will be big and strong enough to hold the weight of the battery, and keep the weight in the middle rather than over the back wheel.

There are a few things I am still to decide on,
1) which bike? I know not all have threaded bottom brackets so that narrows it down. I'd also really prefer the right shifter cable routed through the bar tape for a cleaner look. My old Sora one used to drive me nuts aesthetically. So in that price point it is probably a tiagra groupset with mechanical disk brakes like Spyre TRP.
2) spot weld vs solder? I have soldered 18650s in the past, making a 150Ah 12v battery suitcase with built in inverter to use in my caravan off hookup. The advantage to that was I could use fuse wire on each cell, the negative to that was the cells getting hot and difficulty getting solder to stick to some of them. I also don't need to buy a spot welder, but a spot welder gives a much cleaner finish.
3)BMS? There seems to be a few different ones for 52V/14S packs, all from china and mostly with poor reviews depending on where your looking. I'd rather not spend a fortune to be honest, and would be tempted to go without one if I could figure out a way to balance charge a 14S pack, my iMax b6mini doesn't get close to 14S.
4) charger? Obviously linked to the previous issue, if I do get a BMS do people usually use a scooter charger or something similar? I'm not bothered about quick charging, I'd rather it charged slower as it will be charged overnight for about 12 hours so a slower charge would be better for the cells.
5) legality? I am in the UK. I know the limits are rubbish and the laws massively out dated, but the law is the law. I'd like to be able to flick a switch when going onto the road to be road legal, then flick it to be full power when off road, is this possible on the BBSHD, or is it a matter of being sensible and regulating it yourself.
6) throttle I've seen a few on drop handle bars online and it does look possible, I'm not sure how accessible it would be from on the hoods to on the drops though, which got me thinking to whether something would be rigged up to the left shifter which wouldn't be used for gear changes, it would negate the need to have the brake sensor as you'd struggle to brake and use the shifter at the same time. Has anyone seen anything like that?
 
Riding gravel with drop bars will never be comfortable, no matter the bike. This is the kind of terrain where you need to shift your weight on the tail, and a wide flat handlebar is happiness. :wink:
 
MadRhino said:
Riding gravel with drop bars will never be comfortable, no matter the bike. This is the kind of terrain where you need to shift your weight on the tail, and a wide flat handlebar is happiness. :wink:

I had a wide barred mountain bike, i commuted on it a few times, filtering through slow moving traffic was a nightmare, it was just too wide and felt like I was going to hit every wing mirror i passed. I much prefer being on the hood on a narrower bar. Then getting down on the drops when going a bit faster really helps aerodynamically
 
A ) A heavy BBSHD on a Cyclocross Bike ? Why ?
Are you going up massively steep hills ? What is the Grades and lengths of hills you are going up ?
Are you willing to change a 10/11 speed chain every month or every couple of weeks ?

Because You are in England there is someone there that has done many different e-bikes for people, he has not posted here for almost a year , I think his user name is D8Veh ? He is in Telford, he has many hills in that town , and once posted that for many people a rear hub motor like the Q100c CST , or for hills the Q128 c CST is almost as efficient as those Befang Mid-Drives . I am using a Q100c CST on a Road bike/presently flat bar, but going to convert to drop bar soon , with 10 speed gearing ( My Sram PG1050 Wi-Fli 11-32 cassette fits onto my Q100c CST )
and I have just started using 2 x 7s packs . ( really 4x 7s packs ) and it is work going up any hill with a little hub that puts out 450-600 watts on 52 volts , but it is light weight and I can pedal with power off for part of my rides.


3 ) & 4 ) Not going to use a BMS ? , well just make two 7s packs and get a good charger like this ... https://hobbyking.com/en_us/turnigy-accucel-8-150w-7a-balancer-charger.html
Just connect them in series for your ride, then un-plug the series wire harness and charge them individually.


6 ) We are all waiting for someone to design a throttle for Drop Bar Road Bikes/ SDI shifters/brake levers. The way some have done it is to use a thumb throttle, I tried that and it is , Not , ergonomic. My Idea is to make something thin enough to fit onto the front of one of the brake levers, that is like a computer mouse pad, with + & - ( Up/Down ) pads, that will work electronically in two ways. Press once for 1 Km increments in speed, or Press continuously on one up or down pad for acceleration / deceleration.

So far no one has developed/Designed/made one. Can you find someone to design and make them ?






anth_85 said:
For a motor I am pretty set on a BBSHD, probably with the screen removed and I'll just put my garmin on it instead. I don't want the pedal assist either, I'd rather just use a throttle and control it myself.

For a battery I am about 50 cells into testing a 14S10P build,

3)BMS? There seems to be a few different ones for 52V/14S packs, all from china and mostly with poor reviews depending on where your looking. I'd rather not spend a fortune to be honest, and would be tempted to go without one if I could figure out a way to balance charge a 14S pack, my iMax b6mini doesn't get close to 14S.

4) charger? Obviously linked to the previous issue, if I do get a BMS do people usually use a scooter charger or something similar? I'm not bothered about quick charging, I'd rather it charged slower as it will be charged overnight for about 12 hours so a slower charge would be better for the cells.

6) throttle I've seen a few on drop handle bars online and it does look possible, I'm not sure how accessible it would be from on the hoods to on the drops though, which got me thinking to whether something would be rigged up to the left shifter which wouldn't be used for gear changes, it would negate the need to have the brake sensor as you'd struggle to brake and use the shifter at the same time. Has anyone seen anything like that?
 
ScooterMan101 said:
A ) A heavy BBSHD on a Cyclocross Bike ? Why ?

a BBSHD weighs about 6kg. Which is about the same as a similarly powered hub motor but it is mounted in the middle of the bike rather than on the rear wheel which is worse. All motors are heavy. It's not like I'm going for a carbon fibre frame, it will be aluminium and probably weigh about 11-12kg so with the battery the whole thing will probably be around 20kg, heavy for a bike, not heavy for an e-bike. But it has the advantage over a mountain bike for me that I find drop bars more comfortable, and it will be faster than a equivalent powered mountain bike.

ScooterMan101 said:
Are you going up massively steep hills ? What is the Grades and lengths of hills you are going up ?
Are you willing to change a 10/11 speed chain every month or a couple of weeks ?

there are some hills, none I would call massively steep, but I'd like to get my commute down to 40-45mins. Do you think it would eat through a 10/11 speed chain that quickly?

ScooterMan101 said:
3 ) & 4 ) Not going to use a BMS ? , well just make two 7s packs and get a good charger like this ... https://hobbyking.com/en_us/turnigy-accucel-8-150w-7a-balancer-charger.html

that's a good idea for splitting the pack up into two 7s, that could be done pretty easily.

ScooterMan101 said:
6 ) We are all waiting for someone to design a throttle for Drop Bar Road Bikes/ SDI shifters/brake levers. The way some have done it is to use a thumb throttle, I tried that and it is , Not , ergonomic. My Idea is to make something thin enough to fit onto the front of one of the brake levers, that is like a computer mouse pad, with + & - ( Up/Down ) pads, that will work electronically in two ways. Press once for 1 Km increments in speed, or Press continuously on one up or down pad for acceleration / deceleration.

So far no one has developed/Designed/made one. Can you find someone to design and make them ?

It was just an idea, I would have to have a play around with the shifters in front of me to see what I could bodge up. I do like your idea of it being like a cruise control type of input, but you would also have to figure out someway of disengaging it when you brake.
 
A cyclocross is the perfect commuter for me. I have a drop bar road bike that I commute on like you. It is coming close to a cyclocross bike as I’m squeezing bigger tires onto it (32mm).

Just bought a cyclocross bike – I think 40cm 700c tires are good for a fast light commuter. Only the newer gravel/cyclocross bikes can take this size. I do have a couple electric mountain bikes (full suspension and hard tail) but I would much rather commute on a drop bar bike.

Gravel bikes are like cyclocrross bikes, just more stable (lower, longer, slacker geometry). That might work for you, but I did make a bike like that and never really used it as it was too slow to maneuver for me.

If you can maintain 10mph or more on your hills, a hub motor is going to be easier and less trouble. (Lighter weight (2kg), no maintenance, no issues shifting). If you have hills or want more power – mid drives are the ticket (to a point).

Throttle: everyone I have seen has PAS or something that is really kluged together on a drop bar bike. I use a push button on/off switch for my throttle as I’m only using the motor for high speed. I don’t need a motor below 15mph, personally. You can see my sig for some of my light weight commuters.
 
anth_85 said:
ScooterMan101 said:
6 ) We are all waiting for someone to design a throttle for Drop Bar Road Bikes/ SDI shifters/brake levers. The way some have done it is to use a thumb throttle, I tried that and it is , Not , ergonomic. My Idea is to make something thin enough to fit onto the front of one of the brake levers, that is like a computer mouse pad, with + & - ( Up/Down ) pads, that will work electronically in two ways. Press once for 1 Km increments in speed, or Press continuously on one up or down pad for acceleration / deceleration.

So far no one has developed/Designed/made one. Can you find someone to design and make them ?

It was just an idea, I would have to have a play around with the shifters in front of me to see what I could bodge up. I do like your idea of it being like a cruise control type of input, but you would also have to figure out someway of disengaging it when you brake.

My design is pretty simple.

My throttle button is on the inside of the hood, thumb accessible from the drops or on the hoods, but not on the bar flats. To adjust top speed, just insert a rheostat dial. I don't adjust the top speed of the motor much since I have a light weight build and use the motor to boost top speed. Wouldn't work quite so well with too much power...
 
I love the style of the Planet X Kaffenback - steel frame, fits 32c tyres. Some call it a cyclocross, but it is more a mix of road and cyclocross...

http://www.planetx.co.uk/i/q/CBPXKAFFRIV/planet-x-kaffenback-sram-rival-22-road-bike
 
chas58 said:
My throttle button is on the inside of the hood, thumb accessible from the drops or on the hoods, but not on the bar flats. To adjust top speed, just insert a rheostat dial. I don't adjust the top speed of the motor much since I have a light weight build and use the motor to boost top speed. Wouldn't work quite so well with too much power...

have you got any photos of this setup? i had a look through your thread in your sig but couldn't see any.
 
anth_85 said:
chas58 said:
My throttle button is on the inside of the hood, thumb accessible from the drops or on the hoods, but not on the bar flats. To adjust top speed, just insert a rheostat dial. I don't adjust the top speed of the motor much since I have a light weight build and use the motor to boost top speed. Wouldn't work quite so well with too much power...

have you got any photos of this setup? i had a look through your thread in your sig but couldn't see any.

Where did I post that??? Can't find it.

I had a little button from one of those led strips they sell at autoparts stores. Nice low pressure button. But I ended up using a doorbell from Lowes, because it was long and low pressure. Wrapped it in an inner tube to make it match the rubber on the hoods.

Don't laugh. :shock: :lol:
https://www.lowes.com/pd/Heath-Zenith-Black-Doorbell-Button/50237309
 
Get a full suspension mtb not a cyclocross bike. If you ride over 20 MPH it will be really nice even on regular road and of course it will be a godsend offroad and on gravel.
 
flat tire said:
Get a full suspension mtb not a cyclocross bike. If you ride over 20 MPH it will be really nice even on regular road and of course it will be a godsend offroad and on gravel.

Thanks but I disagree for these reasons
-I find drop bars more comfortable
-the roads and paths I'm on are generally smooth enough on my current road bike which has 25mm tyres, going upto 32mm tyres makes a big difference for the little bit gravel
-for my budget the suspension would be pretty low end
-fixed rear gives more space inside the frame for the battery
-bike will be lighter so will handle better
 
You haven't ridden an ebike before. It will suck unless it's very slow, or you ride only on very smooth roads which you will QUICKLY find yours are not, even if you now think they are.

A used MTB with decent suspension can be had for around USD $400.

Also, you can put your battery on the top tube or on the sides of the frame. It doesn't need to go inside.
 
Thanks, I will keep that in mind. I am still going for a cyclocross bike though, I know the roads I'll be on pretty well from riding my road bike on them, I can normally do about 18mph on flat sections and 25-30mph on downhill so know pretty much were every pot hole is, and there certainly aren't enough to warranty full suspension. With the BBSHD and frame bag battery however if I do find it too uncomfortable it wouldn't be too much work to transplant the whole setup onto a different bike. In fact that would be something I could think about doing for the winter months.
 
I'm a huge CX fan and I think it would be rad. You can setup on my my Maxwell bikes as cx with drop bars, there is 40mm clearance. It's not really a cx geometry as much, but check it out and see if it gives you any ideas.

My primary bicycle has been a cyclocross bike for 10+ years (just rode it in this morning). I raced cyclocross one year an it was awesome. I got tired of paying fees just to get my ass handed to me so I just watch the races now :D

My bike is a fantom cross from circa 2007, that might be worth looking into as a fame choice.
 
I don't have as much experience as many here, but have commuted a couple thousand miles in the 8 months I've been into ebikes and done a lot to my bike (a radwagon) to make it work well for me, also got my wife a simpler throttle only ebike...just a few ideas here-

My first thought is 15 miles in ~40 minutes is going to take some pretty good average speed. IME with commute times the biggest things to figure out are what your biggest obstructions to your average speed are. Is it the time to accelerate back to 20-25mph in stop and go? Is it that you have to take a longer route because you can't keep up with traffic for a stretch? Or on the other hand if you have a bike path with minimal stops or hills, you probably only need a few hundred watts to stay in that 20-25mph range.

One thing to be aware of is that you can only put so much power/torque into a narrower, higher psi tire before it will spin out. This will probably then require some experimenting with chainrings and cassettes and rather you will do tubeless and lower psi etc...My guess is on this type of bike is you would want a BCD 130 adaptor so you can get a bigger ring up front. I assume this is the main reason most of the people with e-roadbikes are opting for smaller/lighter geared hub motors. For my own sake I would probably look at 2wd with a q100h on the front and a q128c on the rear (this is what I'm also doing with my radwagon)...that way the traction is distributed and those two motors are actually lighter than one bbshd- But also I'm finicky about the drivetrain. I like a very smooth, well-maintained drive to pedal into and the one BBSHD I rode only had around 500miles on it and it was pretty beat up already.

I also wouldn't rule out the PAS without trying it in your scenario. I find most ebike throttles make it kind of hard to hold a steady amount of power while pedaling other than 100%. The PAS on the other hand does a nice job of maintaining some various intermediate power levels if you set a consistent cadence.

But it is (somewhat literally) different horses for different courses here...It might be a good idea to test ride some ebikes if you can. For instance I think a both a throttle (even if it's just a 100% button) and a PAS is really nice, because the throttle can really help in stop and go or high speed, but the PAS is really nice on mixed use paths where you want a consistent 200w etc.
 
Thanks ryan, very informative read. I will try the PAS with the BBSHD, since i'll have all the parts anyway. I have read the throttle can be difficult to modulate.

My main issue with my commute route is the stop start nature, the route I used to take had 35 sets of lights over 12miles! The final straw was a new un-needed set at the bottom of a dip. Before i could get up to 30-35mph coming down the hill to be able to keep above 20mph for most of the way back up. Now I have to stop at the bottom and start from standstill 90% of the time. This is part of the reason I am looking at trails and alternative routes to avoid the number of lights. I have found another route but it is more hilly and still has about 25 sets of lights.

There is a short (1/2mile) part of 50mph dual carriageway coming off a set of lights, on a bit of a hill that I normally do about 12-13mph up, I'd feel much more comfortable at 20-25mph. There isn't really much choice unless you go on the path, which I refuse to do at the speeds I do under my own power nevermind electric power too.

I was looking at a larger chainring adapter, otherwise I'd expect to spend nearly all the time in the 11/12/13 gear on the rear, so a larger chainring would protect those smaller cogs by freeing up the larger ones for the same ratio. I like the sound of the dual hub motors for traction, but for a first ebike project wiring it all up correctly sounds like a big ask compared to a BBSHD which has pretty much everything integrated already. I do think regarding traction that as long as your progressive on the throttle (or use PAS) then a 32mm slick tyre will be able to cope, it will certainly be better than a nobbly wider mountain bike tyre.

I don't know anyone in the north east of england with an ebike to try out unfortunately, unless someone on here is offering...
 
grindz145 said:
My bike is a fantom cross from circa 2007, that might be worth looking into as a fame choice.

I bought one of those 6 months ago. I love it - love pedaling it too much to put a motor on it. But yeah, something that can take 40mm tubless tires would be great. I'm thinking a gravel bike with longer, lower, slacker geometry would be a little better. I did build an ebike like that, but personally it just wouldn't turn in fast enough for me. I love the cross bike.
 
anth_85 said:
chas58 said:
My throttle button is on the inside of the hood, thumb accessible from the drops or on the hoods, but not on the bar flats. To adjust top speed, just insert a rheostat dial. I don't adjust the top speed of the motor much since I have a light weight build and use the motor to boost top speed. Wouldn't work quite so well with too much power...

have you got any photos of this setup? i had a look through your thread in your sig but couldn't see any.

here it is:
drop bar throttle.jpg
 
RyanC said:
My first thought is 15 miles in ~40 minutes is going to take some pretty good average speed. IME with commute times the biggest things to figure out are what your biggest obstructions to your average speed are. Is it the time to accelerate back to 20-25mph in stop and go? Is it that you have to take a longer route because you can't keep up with traffic for a stretch? Or on the other hand if you have a bike path with minimal stops or hills, you probably only need a few hundred watts to stay in that 20-25mph range.

One thing to be aware of is that you can only put so much power/torque into a narrower, higher psi tire before it will spin out. This will probably then require some experimenting with chainrings and cassettes and rather you will do tubeless and lower psi etc...

Just some data points:
FYI, I do 12.5 miles in 38 minutes (or a little faster, depending on the bike). My cruising speed is either 22mph or 25mph. My average speed is 20-21 mph including stops. My speeds are much more consistant on an ebike. All with a Q100. I only have to stop about once a mile though.

I don't have any problem with spinning out. My legs and the motor are averaging 500watts to the rear wheel, 1000 watts on hard acceleration. Good tires and technique help.

I do agree, one wants to minimize using the smaller cogs in the rear. I try to keep at 14t or bigger - using 17t on my single speed.
 
anth_85 said:
Thanks ryan, very informative read.

Sure-

My route is about the same, I go through downtown, so there are also 30+ stops, lights and signs in a 10 each way mile commute. What was eye opening for me was when I took my wifes bike one day. Her's has a geared hub motor up front, max speed of about 17mph. Mine stock was a DD motor, max speed of around 25. But the difference is the geared motor has much faster acceleration. On her bike, in spite of it being slower, I made my commute in about the same time. That's when I added a q100h to the front, and am going to swap to a 2nd q128c in back to even cut that down more. Now my riding style has changed to where I just let the motors do most of the work to get me back to 25mph, and then I put my ~200w into the pedals and have the motors add in the rest to hold that 25mph once there. I guess that due to not fatiguing myself for the acceleration I might actually burn slightly more calories this way, at the cost of it all clearly moving away from a 'bike like' experience...Also now I have optimized my drivetrain for 25mph riding (54t chainring, and I use clipless even with all the stops).

I think it's a pretty good bet that with the stock chainring, and on a middle cog, you are going to spin out with a peak of 1500w coming from the bbshd, and especially if you plan to pedal from a stop too. Not the end of the world if you find a good way to modulate it, or simply don't downshift as much, but both of those solutions do represent some loss of acceleration potential (and stress on the reduction gear for not downshifting). At some point if you never end up putting the full power of the motor to ground, then you have more motor than you actually use. Are you wanting to go ~40mph?

That all being said I have no idea exactly where the rubber meets the road on that...Maybe with something like the marathon supreme tubeless 40c and a lower-than-roadbike PSI you would be able to max the the throttle from a stop. Or on the other end of the spectrum if you are wanting to get into the 40+mph or have some big long hills with no stops then you will use all that power.

Again just thinking out loud here though...I love the idea of a CX commuter myself and it's on my back burner.
 

Just some data points:
FYI, I do 12.5 miles in 38 minutes (or a little faster, depending on the bike). My cruising speed is either 22mph or 25mph. My average speed is 20-21 mph including stops. My speeds are much more consistant on an ebike. All with a Q100. I only have to stop about once a mile though.

I don't have any problem with spinning out. My legs and the motor are averaging 500watts to the rear wheel, 1000 watts on hard acceleration. Good tires and technique help.

I do agree, one wants to minimize using the smaller cogs in the rear. I try to keep at 14t or bigger - using 17t on my single speed.[/quote]


Yeah that all sounds right...A BBSHD @ 52v is a lot of motor though. At least I have a q100h on my radwagon, so I do know that one, and I have ridden a BBSHD mountain bike. By no means am I disagreeing with any of the ideas put out here, just kinda throwing my experience into the mix as well. From your posts I think it's clear you are a pretty serious cyclist. I'm a pretty fit guy who wants to pedal and get some exercise, but the correlation to a real bike experience is a relatively low priority for me, as long as I can pedal and not hamster wheel I'm good...some people here hardly want to pedal at all.
 
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