cycle tourist new to pedelecs

[boomboomdolls]

Hi all,

I'm looking to build a DIY pedelec for my trusty tourer 26 " wheel, v brakes, I go cycle camping in Scotland . I can maintain 200 watt power output myself for 3 hrs or so but as I've gotten older and the weight of what I carry has increased, I weigh 68 kg , loaded bike 30 kg the hills are getting harder after a day five.

Do you think i'd be better off with a rear hub 10 speed Shimano,or front hub motor I was thinking 250 watt an extra 100 would be just amazing halfway up a climb!

I'm ok to carry two batteries as I wild camp so was thinking , x2 500 W/hrs does 7 kg for both seem right ?
I'm thinking each battery would last a day 100 watts an hour = 5 hours is this right ? though think probably longer as only use on bad headwind or steep hills

i average about 13 mph on tour but would be nice to be able to use the top gear with my 200 watts and the motors output for getting some places quicker.

48 V or 36 v ? and what sort of controller?

apologies for so many questions any pointers greatly appreciated-- hoping my pedelec will replace the car thanks

 

[Benjahmin]

A rear hub on a 10 speed is, I think, doable but the wheel dish will be pronounced because of the width of the gear cluster.
Front hubs can be 'lively' on steep surfaces (especially if the surface is loose or greasy) but nothing that an experienced cyclist can't handle. Also, if you're carrying front panniers, this will help a lot when you move your weight forward over the bars. OK on steel forks and make sure to fit a torque bracket.
Not sure about your power usage estimate. I think you may find that you use it more than you currently think. Reasons being
1 The extra weight
2 Power assist feels so great (like having Brad Wiggins as stoker) that it becomes labourious and heavy to ride without it.
Have a look at Woosh for kit availability. Others will be recommended.

 

[boomboomdolls]

Benjahmin ---

many thanks for the solid advice and whoosh recommend

 

[vfr400]

For touring, you shouldn't use anything other than a rear hub-motor. All other solutions work. The difference isn't a deal-breaker, but you'll find a rear motor so much nicer.

Your bike isn't ideal for conversion. What makes it good won't give you so much advantage when you fit a motor, and can actually bring disadvantages, like your gears. It might be an idea to get a different bike to convert, as the cost wouldn't be high considering the cost of the electric kit. You can get an ideal bike to convert for between £100 and £200 - something like a Carrera Kraken with 26" wheels can be had for not a lot now that 26" wheels have gone out of fassion. Also, you really need disc brakes to deal with your higher average speed.

Not all kits are the same. As you're a regular cyclist, I'd recommend that you get a kit that can provide adjustable power. Most give you adjustable speed, which is not the same. For adjustable power, there are some on Ebay, but you need to know which ones they are, and they can only be recognised by the LCDs. Some of us make mix-and-match kits to get exactly the characteristics we want by buying the bits directly from Chinese resellers. The motor itself isn't so important, but there are a couple of things you need to consider:

You don't need so many gears when you have electric assist, but if you like to put in most of the drive yourself, I think 9-speed would be good. There are two main types of motor with regard to that. You get cassette motor (normally with a C in the designatio) that have a normal Shimano type spline to take any cassette that you want, including some 10-speeds. The other type are freewheel motors, that take the screw on freewheels up to 7 speed. All cassette motors are a bit wider than the standard 135mm, so you have to spring your frame a bit to get them in.

Secondly, each motor has its own max speed, independent of how much power you put through it; however, the max speed depends on voltage, so you can increase or decrease the maximum speed by changing the voltage, so a 260 rpm motor at 36v becomes a 328 rpm one at 48v, and a 260 rpm 48v one becomes 201 rpm at 36v. You need around 240 to 260 rpm to cruise at 15 mph when you have it set to the legal limit. You need 328 rpm to be able to cruise at 20 mph. It's very important that you understand this principle and you must know what speed you'll be getting when you order the kit/bits.

It's

 

[Deleted member 16246]

For touring, you shouldn't use anything other than a rear hub-motor. All other solutions work. The difference isn't a deal-breaker, but you'll find a rear motor so much nicer.

Could you explain a bit more about this?

There seems to be a range of views on the advantages of crank vs hub drives. I was strongly advised to go for a crank drive, by different suppliers who had both on offer, when I was planning my pedelec, on the grounds that using the bike's gears would enable the motor to keep up a more efficient rev range and enhance torque and climbing ability. Experience so far is that I've had some rough gear changes, dropping gears on a climb, and that my partner is sometimes catching me up on hills on her hub motor, though she may be in a higher PAS mode than I am. Her Bafang hub motor is much louder in use, especially on hills than my BS01 Bafang Crank drive.

I live in a very hilly area, quite far up the South Tyne Valley and climbed to 1148 feet yesterday out of the valley to the south, in the North Pennines, probably a thousand feet of climb in about 2.5 miles. The terrain is pretty much the same to the North from here. The map is clickable so you can see the contour heights.

 

[vfr400]

Hub motors are generally more reliable, require less maintenance, are significantly kinder to the drive train, give a more comfortable riding experience (more user-friendly), are cheaper, have lower running costs and are more durable.

WIth a crank motor, you have to be in the right gear all the time and shifting is nowhere near as nice. The hub-motor takes load off the drive train to make everything easy, but a crank-motor loads it up with something like 5 times the load of a hub-motor system, so it wears out chain and sprockets, and if you mess up a shift, you can completely smash your derailleur and chain. The only real advantage of a crank-motor is that it can give its max power at all speeds, so you can get high torque in a low gear and high speed in a high gear, while as the torque from a hub-motor is more speed dependent. You're light, so you don't need the high torque, and even a heavy person can get adequate torque for all circumstances from a hub-motor if they run at 48v.

People will try to argue that crank motors are more efficient, but there is no evidence to support that, and the only actual test data published shows the opposite. My independent tests showed more or less identical efficiency when I took a hub-motor the same as one in one of my bikes and mounted it as a crank motor, then rode the two bikes side by side over varied terrain. The reason some people claim that crank motors take them further than hub-motors is that their crank motor had a torque multiplication system, which is what more or less every one from a shop has, and that system makes sure that you have to pedal hard to get high power.

I've simplified it a bit because a lot of it is about the control system rather than the type of motor, Shop bought bikes with crank drives generally have torque multiplication systems, so motor power rises with your own effort. This brings me to the next point. With a hub-motor and cadense sensor system, you can set the power to whatever level you want and pedal as hard or not hard as you want. You are master of the system. The shop-boughtcrank-drive bikes normally have 3 levels of assist, each with different multiplication factors. Their algorithms are actually more complicated, but that's it in a nutshell.

The two main crank-drive conversion systems are Bafang BBS**, which has a cadence sensor system, and TSDZ2, which has a torque multiplication system. Personally, I'd avoid the TSDZ2 because too many reliability issues.

One other thing: Some people say that torque multiplication systems feel more natural, which is true, but the counter side is that they take away your choice about how hard to pedal.

One final point to reiterate the point that it's the control system rather than the motor which translates your inputs into motor output (power and noise), It's important to choose the right components with the right characteristics to get what you want. For hub-motors, there are many different types of contoller. Some are horrible and some are very good. Often, people making comments have no idea about these differences. You need a sine-wave controller if you don't want motor noise. I can guarantee you that my hub-motor is quieter than your BBS**.

Your rides are similar to what I do. Nearly every ride involves the Severn Gorge, which has climbs as steep as 30% and basically 300m down and 300m up again. I've weighed up to 105kg (now 90kg) and I've never found my middle-sized hub-motor, at 48v and only14A, lacking in power.

 

[Deleted member 16246]

Hub motors are generally more reliable, require less maintenance, are significantly kinder to the drive train, give a more comfortable riding experience (more user-friendly), are cheaper, have lower running costs and are more durable.

WIth a crank motor, you have to be in the right gear all the time and shifting is nowhere near as nice. The hub-motor takes load off the drive train to make everything easy, but a crank-motor loads it up with something like 5 times the load of a hub-motor system, so it wears out chain and sprockets, and if you mess up a shift, you can completely smash your derailleur and chain. The only real advantage of a crank-motor is that it can give its max power at all speeds, so you can get high torque in a low gear and high speed in a high gear, while as the torque from a hub-motor is more speed dependent. You're light, so you don't need the high torque, and even a heavy person can get adequate torque for all circumstances from a hub-motor if they run at 48v.

People will try to argue that crank motors are more efficient, but there is no evidence to support that, and the only actual test data published shows the opposite. My independent tests showed more or less identical efficiency when I took a hub-motor the same as one in one of my bikes and mounted it as a crank motor, then rode the two bikes side by side over varied terrain. The reason some people claim that crank motors take them further than hub-motors is that their crank motor had a torque multiplication system, which is what more or less every one from a shop has, and that system makes sure that you have to pedal hard to get high power.

I've simplified it a bit because a lot of it is about the control system rather than the type of motor, Shop bought bikes with crank drives generally have torque multiplication systems, so motor power rises with your own effort. This brings me to the next point. With a hub-motor and cadense sensor system, you can set the power to whatever level you want and pedal as hard or not hard as you want. You are master of the system. The shop-boughtcrank-drive bikes normally have 3 levels of assist, each with different multiplication factors. Their algorithms are actually more complicated, but that's it in a nutshell.

The two main crank-drive conversion systems are Bafang BBS**, which has a cadence sensor system, and TSDZ2, which has a torque multiplication system. Personally, I'd avoid the TSDZ2 because too many reliability issues.

One other thing: Some people say that torque multiplication systems feel more natural, which is true, but the counter side is that they take away your choice about how hard to pedal.

One final point to reiterate the point that it's the control system rather than the motor which translates your inputs into motor output (power and noise), It's important to choose the right components with the right characteristics to get what you want. For hub-motors, there are many different types of contoller. Some are horrible and some are very good. Often, people making comments have no idea about these differences. You need a sine-wave controller if you don't want motor noise. I can guarantee you that my hub-motor is quieter than your BBS**.

Your rides are similar to what I do. Nearly every ride involves the Severn Gorge, which has climbs as steep as 30% and basically 300m down and 300m up again. I've weighed up to 105kg (now 90kg) and I've never found my middle-sized hub-motor, at 48v and only14A, lacking in power.

Wow. Thanks for that very detailed response. Plenty to think about there. I am just about to go for a ride with my partner now. She is on her way on her cheaply acquired Pendleton Somerby Rear hub bike that I wrote about a week or so back, so I will have to get my kit on and get going, but I appreciate your information.

I have noticed that when I rode that bike to test it out for her, that it flew up the hills with little input from me, unlike my Bafang BBS01 which goes up fine as longa as I sweat a bit.. It also seems to do a heck of a lot of miles for an 8.8 Ahr battery - especially since the battery was dead when we got it and probably is not at top spec from being left a year uncharged before it came our way. I reckon she gets 35 miles on it and it has never been near at the end of ts charge, though they do tend to drop off a cliff when they get down a bit as far as the indicators are concerned.

Thanks again.

 

[vfr400]

The Pendleton has a speed control system, so you get max power at start off regardless of what level your on. Each level has a different speed cut-off and an associated algorithm that reduces power when you get to that speed. That system is OK for very low powered bikes, but terrible if you have high power. Current control is much better because it gives a different power in each level, so you can set the amount of assist to what you want and then pedal as hard as you want. Not many OEM hub-motored bikes have current control. Instead the better ones add a ramp to the start up power to take away that initial kick.

Everything is simple, but when you go into detail, it starts to look complicated until you figure it out, then it's simple again. As I said before, getting a hub-motor to give the characteristics you want means getting the right bits, not just any kit. Some kits do have the right bits though if you know what you're looking for.

 

[stevenatleven]

I have a front hub motor on my touring bike. Its a Surly and has very strong steel forks which is why I chose the front motor, it also means i dont have to disturb the gearing which is 16speed.I haven,t had any problems with wheel spin and I regularly take it offroad but because of the lack of suspension I tend to keep to good tracks/fire road kind of thing. The front motor i have is a 500w Bafang bpm 48v with a 17.5Ah battery which gives me about 840w or about 60 miles max with assistance on level 2 which gives me about 200w. the kt controller/lcd 3 has 5 settings giving about 100w in 1, 200w in 2, 300w in 3, 400w in
4 and at level 5 it gives you everything about 850w which can get you up anything. I am about 100kilos so i would imagine you would get much more miles than me. I never camp and stay overnight in hostel/B&Bs where i can charge the battery. I am just back from a week tour of Scotland and it was great, the motor takes all the apprehension of big climbs away.

 

[Deleted member 16246]

Given that you have sturdy forks, it looks like the simplest possible way to do a conversion. Glad it works for you so well.