Hill climbing vs speed - kit options

[alexk-il]

Hi,

I am very new both to cycling and to e-bikes. I am planning to built by own dream-bike and I've still got a lot to learn.

Anyway, I understand that some cyclers use the 20" motors for 26" bikes to increase the maximal speed. Of course, the torque (and the hill climbing ability) is lost.

1. Is it possible to do the opposite - to use 28" motor in 26" weels to improve the hill climbing ability? I understand that the max speed will drop below 15mph.

2. Will the overvolting from 36V to 42V in this case increase the max speed back to 15mph limits?

Many thanks,
Alex

 

[stevebills]

dont bother building a dream bike find a rich girlfriend and order a Stealth Bomber

 

[banbury frank]

Hi Alex

what you need is a direct drive motor and 48 / 60 volt battery

if you look at the nine continents motors you can have different windings

so RPM per Volt

so up to 3,000 watts

see this link it enplanes all

The Grin Cyclery

The Grin Cyclery

WARNING These are for off road use only


They have changed the name to the GRIN Cyclery I wonder WHY





Frank

 

[flecc]

1. Is it possible to do the opposite - to use 28" motor in 26" weels to improve the hill climbing ability? I understand that the max speed will drop below 15mph.

2. Will the overvolting from 36V to 42V in this case increase the max speed back to 15mph limits?

Many thanks,
Alex

Roughly speaking, yes Alex. You may well have to change a motor's controller to handle the higher voltage though.
.

 

[Jon]

Alex,

Im at the same stage as you here. I have decided that im going to get an ebike, a pre built on on the cycle to work scheme (fingers crossed) so that i can start to enjoy the benefits straight away. While im enjoying that i am going to buy a good mountain bike and use that as a starting point to build on. I have seen a mongoose which was very light, hydraulic brakes, good front suspension which can lock out etc and then get a conversion kit to make it an off roader and install a 1kw motor.

Im just trying to learn about what is a good 1kw motor or alternative option, where to mount the stuff, 36v or 48v etc etc. Do i import or buy a kit fro this country and pay more but get some recourse. Ive seen some kits from alienbikes, xipi (which i think is banbury frank, BNSbattery sell some. Im just unsure on quality, performance rear wheel or front the usual newbie stuff.

 

[Deleted member 4366]

Hi,
1. Is it possible to do the opposite - to use 28" motor in 26" weels to improve the hill climbing ability? I understand that the max speed will drop below 15mph.

2. Will the overvolting from 36V to 42V in this case increase the max speed back to 15mph limits?

The answer to both questions is yes.

The 42v battery will push more amps through the motor, so that also will give you better hill-climbing ability. You should try it and let us know how it compares with a 36v standard motor. The only problem that I can see is that most controllers and BMSs have a low voltage cut-off that'll be too low for you, so you need a meter on the handlebars or some other device to tell you when to stop discharging the battery, or you need a custom BMS or a programmable controller, all of which brings more expense.

 

[Deleted member 4366]

Alex,

I I have seen a mongoose which was very light, hydraulic brakes, good front suspension which can lock out etc and then get a conversion kit to make it an off roader and install a 1kw motor.

My advice would be that if you want to fit a 1kw motor, you don't want a lightweight mountain bike. You want a very strong downhill type with a very strong frame and wheels, good brakes and big tyres.

 

[Jon]

My advice would be that if you want to fit a 1kw motor, you don't want a lightweight mountain bike. You want a very strong downhill type with a very strong frame and wheels, good brakes and big tyres.

Any suggestions? The mongoose was reasonable in weight and build around 11 or 12kg i think. It had decent hysraulic brakes and front suspension. I am concerned about rear suspension if i mount a rear hub ive heard issues with mixing the two.

 

[Cyclezee]

Just to let you know, eZee have available 48v 11Ah batteries with Panasonic cells, an optional 25A controller which will handle up to 54v and a 400w 350 rpm motor in a 700c/28" wheel. Please note this setup would be for off road use only.

 

[banbury frank]

Hi Alex and Jon

Come try one In Banbury

Give you a good starting point

Frank

 

[alexk-il]

Any suggestions? The mongoose was reasonable in weight and build around 11 or 12kg i think. It had decent hysraulic brakes and front suspension. I am concerned about rear suspension if i mount a rear hub ive heard issues with mixing the two.

Hi,

Which model is this Mongoose?

I would prefer to stay within the legal onroad limits, so anything above 350 is not an option to me. I am also not sure if overvolting the 250W engine from 36V to 42V will keep the bike within the law, but, hey, I am going to use the slower engine to start with .

Anyway, while I don't have a lot of cycling experience, I would be very concerned in putting 1KWt motor in a front sping suspension fork. Assuming your Mongoose is not the top model, the low quality of the front suspension can be critical for a comfortable and safe powered ride on a bumpy road. I think the rear motor hub would be a better choice.

Cheers,
Alex

 

[Jon]

Hi frank,

Yea i saw your kit on your website i felt the price was a little high and it only has a 10ah battery i would be hoping for about 16ah with that much power at hand. I suppose it is lighter but i could imagine it running flat quickly with such a high power hub. I thought it was interesting how the comuter kit had a boost 1800w thats some serious power. What is the expected top speed while using boost on a flat surface with little head wind?

I would love to pop down but its about a 2 hour drive, shame i was looking the other Sunday as i passed Banbury on the way to watch Stoke at Wembley.

 

[alexk-il]

Roughly speaking, yes Alex. You may well have to change a motor's controller to handle the higher voltage though.
.

Thanks a lot for your reply. I am not sure what type of the controller would be better (and keep my bike closer to legal limits) - 36V/350Wt or 48V/250Wt or even 48/350?

Thanks
Alex

 

[Jon]

Hi,

Which model is this Mongoose?

I would be very concerned in putting 1KWt motor in a front sping suspension fork. Assuming your Mongoose is not the top model, the low quality of the front suspension can be critical for a comfortable and safe powered ride on a bumpy road. I think the rear motor hub would be a better choice.
Alex

I would agree with you on that i would have a fear that if i hit the throttle on a corner with 1kw the bike would just go from under me using front wheel drive. I have always prefered the idea of letting one wheel drive and the other steer.

This is one of the bikes i was looking at well ill stick a couple of links in they are pretty much the same
Tyax Comp
Tyax Elite
Tyax Sport

I also like the GT bikes like the Avalanche 3 Hydro mainly the frame style but feel its over priced because of the name. I also like the spec on the Claud Butler Capewrath but yet to study the spec.

Let me know your thoughts. I went and sat on a few Mongoose ones today and they felt really comfortable

 

[alexk-il]

The answer to both questions is yes.

The 42v battery will push more amps through the motor, so that also will give you better hill-climbing ability. You should try it and let us know how it compares with a 36v standard motor. The only problem that I can see is that most controllers and BMSs have a low voltage cut-off that'll be too low for you, so you need a meter on the handlebars or some other device to tell you when to stop discharging the battery, or you need a custom BMS or a programmable controller, all of which brings more expense.

Oh, just saw your reply. This is something I wasn't expecting... Frankly, I was ready to go all the way into building/ordering my own custom battery/chrger, but this "BMS" thing is still new to me . I'll do some RTFM on the web, before asking silly questions about battery related technologies.

Thanks

 

[alexk-il]

I would agree with you on that i would have a fear that if i hit the throttle on a corner with 1kw the bike would just go from under me using front wheel drive

Additionally your front suspension may also do some nasty jumping under full power. I've seen this on cheap front wheel drive cars where too much power is pushed through low quality front suspension.

Anyway, I've noticed your bikes has disk brakes. This may certanly limit availability of your kits.

 

[flecc]

Thanks a lot for your reply. I am not sure what type of the controller would be better (and keep my bike closer to legal limits) - 36V/350Wt or 48V/250Wt or even 48/350?

Thanks
Alex

I wouldn't worry too much about the legal limits for the moderate change you have in mind. The 250 watt legal figure is largely notional, an approximation of average power delivered. Our makes of legal motors are capable of delivering sustained powers ranging from over 300 watts to well over 700 watts, most makes around 450 watts. You are unlikely to run into trouble on that account, especially if keeping to the assist limit.

Choosing the 48 volt / 250 watt rated motor option is probably the least obvious, using a motor specified as legal here, but I'd choose the 36 volt 350 watt option for the wide choice of quality batteries that are available, and their lesser bulk and weight.
.

 

[Jon]

Most that i have spoke to seem to think disk wont be a porblem with the kits i have been looking at. The pre built ebike im hoping to pick up from Bob at juicy bikes has disks.

I think i read that the kists Frank offers are ok with disks and the 8fun ones certainly are. You just need to ensure you front forks have suitable clearance.

Im still uming over what bike to get never mind the kit lol. Ill be at this for months at this rate

 

[Scottyf]

There's many options to consider but only one main question.

What do you want the bike for?

From that question alone we can start to understand your need's and how to help you achieve that goal.

 

[alexk-il]

What do you want the bike for?

From that question alone we can start to understand your need's and how to help you achieve that goal.

That's an easy one .

I need the bike for mostly commuting/weekend rides. I know Cytronex would cover most of my requirements, except the cost, torque and the number of assistance levels. My requirements are:

1. Have unassisted ( or with minimal assistence) rides on weekends. Minimal drag is essential
   
2. To get to work without sweating (~3 miles).
   
3. I plan to get in shape over the time, so I'm ready to sweat on my way home. The required assistance is supposed to gradually reduce over some time (6 months, or am I optimistic?). Anyway, multiple assistance levels are essential.
   
4. There is a 1.5 miles uphill section on my way home. Regardless my fitness level, I would like to have an option to go uphills as fast as possible. I am ready to tweak the motor/power to optimize the torque.
   
5. The max speed shoudl be as high as possible within the legal 15mph limits. If I nee to go faster I will be using my car with 6 airbags and a full comprehensive insurance .
   
6. Optional requirements - stealth (rear hub motor?, battery somehow disguised as a bottle, Topeak bag, frog, etc.), quiet (Bafang, Tongxin, ???), under £500 for the kit including battery.
   
7. 6. Should be fun while I build the bike