E-kit for hillclimbing
I am looking for a conversion kit for a bike that is going to be used to climb hills, or most likely - just one per battery charge.
Many of our alpine hiking areas have access roads suitable for bikes, but a medical condition makes steep hill cycling a big challenge.
To ease the pain and effort needed to get to the hiking areas, I want to fit the bike with electric assist - but I can't figure out whether a cheap china kit will do, or if I need to save up for a mid-drive kit.
A few thoughts
-Top speed is nearly irrelevant. The 25kph limit is more than enough. Anything from around 8-10kph would be acceptable speed
-The 250W motor limit could be an issue, and I don't care if the motor is stronger.
-I want the system to be as subtle as possible, so
-a mid motor that is probably the best, is most likely not going to be the solution I want.
-Range: 10-12 kilometers would be nice, but most access roads are half that.
-Total ascent: easily 800-1000 metres
-Rear hub motor is most likely required. A front hub drive might spin out too easily in the steep gravel roads?
-Price... is obviously of the essence... otherwise I'd go buy a nice mid-drive Scott e-aspect
The bike to be converted is an older 27-speed Merida Matts Juliet with hydraulic disc brakes. I'm not sure how to fit a kit to a bike with hydraulic brakes, as most of the kits seem to have wire-based handlebars to replace the existing. Is the engine cut from brake handles absolutely necessary? I have seen the tektro handles for hydraulic, but I want to change as little as possible on the bike.
I am fully aware that I may be asking too much here, but I have been looking for a solution for a while not finding it, so your advice will be most appreciated.
The mid-drive Scott E-aspect 720 is sooo sweet, but it's unfortunately going to break my budget and I'm not sure how suitable it would be.
Thanks in advance!
Mid-drive will give you the best hill climbing ability obviously.
However, there is another option that is brand new on the market. Specifically a two speed hub motor were the low gear nearly doubles the torque compared to a regular hub motor (high gear same as regular hub motor).
Here is a link to an article about them and how they work: 2-speed hub motors are a new idea with great potential | ELECTRICBIKE.COM
For your application and XD two speed rear hub with manual throttle might do the trick. It is possible to run an e-bike without brake cut off switches. I have done so myself. If you do the main important things I would to make sure your master on/off switch for your system is within easy reach just in-case the throttle goes haywire and gets stuck on full and won't release. Otherwise just make sure you release the throttle before applying brakes.
The rear disk brake XD with a 7-speed freewheel is about 10-to-15mm wider then a standard rear hub. So if your frame isn't steel and spreadable to that much wider drop-out size then you might have to drop down to only a 5-speed freewheel to fit in standard drop outs and even then still slightly tight. The XD is a screw on freewheel hub motor not a cassette hub. Only a few hub motors anyway are cassette hubs.
Hi, and thanks for fast and interesting response! I have read through the forums on the XD, and it seems very promising. Instead of modifying the Merida, I am toying with the idea of dedicating an older Scott v-brake bike to be electrified.
Personally I'm of the mind that probably the best bike to convert would be an old name brand steel frame mountain bike with V-brake mounts on the rear. XD rear hub with rear V-brakes and a seven speed spool so everthing fits nicely in the rear and then put a modern front suspension fork on it with front disk brake. Rear V-brakes, front disk brake combo hard tail with good modern front suspension. Modern click shifter brake handle combo units on the bars (new old stock 7x3 Shimano still available online) and call it good.
Sounds like you and I have similar ideas as far as this motor. I really don't need another e-bike myself since I've already got a dozen or so bikes half or so of them e-bikes but I've just got an itch to try out this new XD two speed hub for myself. Been on my mind so when I saw your post I thought I'd point it out to you as well.
Very good point on v-brake rear and disc front!
In regards to the most suitable frame, I think spinningmagnets said that the v-brake version would fit the normal 135mm spacing?
I've never owned an e-bike before, but if I can find a solution that will assist with the hills - many new areas will become available for my main activity, mountain hiking .
Bonnie has already responded to me by mail, and this is the item list and prices I was quoted for a v-brake rear hub model
one double-speed motor-----------111USD
double-speed sine-wave controller---21USD
LCD display-----------------------24USD( optional, but other brand's display won't work with our controller)
What's the H/A/L switch and PAS? Do I actually need the display for anything sensible? The future owner of the e-bike is not very much interested in technical stuff, so simplicity is preferable.
I just looked closer at the drawings sent to me by Bonnie, and I'm a little uncertain what model to use.
These are the alternatives:
- double-speed motor, v-brake, single freewheel - is 156mm wide
- double-speed motor, v-brake, 7s - is 135mm wide
I'm not quite sure I understand the difference between the two, apart from the fact that one is 19mm(!!) wider than the other. Not sure which bike that has that for a stock spacing?
Last edited by DuetDeux; 07-11-14 at 02:58 AM.
Starting with the disclaimer that I don't currently have one of these motors myself yet so everything I say should be taken with a small grain of salt. I am looking into getting one or more of them myself and have been researching them myself as well though.
Answers that I'm 99+% sure of:
----- H/A/L switch is for the motors double speed function, H = locked in high gear, L = locked in low gear, A = Automatic. In the automatic mode the motors controller changes between the two motor gears as needed automatically based on your speed and it takes about a second for the gear change to take place and the motors power cuts out while the gear change takes place. Pedal gearing is unaffected it just gives the motor more torque at lower speed for hill climbing in low gear compared to a normal hub motor.
----- PAS = "Pedal Assist Sensor" its a sensor some e-bike systems use that attaches to the bikes bottom bracket and tells the controller if you are pedaling or not and to a certain extent how fast you are pedaling. Most e-bike controllers can be set-up with such a sensor so that there is no throttle on the handlebars for the motor and just the PAS sensor and when you start pedaling it turns the motor on and the faster you pedal the more it throttles up the motor and when you stop pedaling it turns the motor off. Some european countries actually require that for e-bikes to be legal in their countries. I do find such a system beneficial when riding in thick in town traffic (got that kind of system on one of my other bikes) since then I don't have a throttle to fiddle with and I can just concentrate on watching traffic around me and just pedal. Having a manual throttle on the handlebars though is nice if you want to use the motor without pedaling. The one bike I have that uses a PAS also has a manual throttle as well and if I don't touch the throttle it works off of the PAS only and then if I'm like beat tired commuting home late at night after a long day I can use the manual throttle keep the motor going even when I'm not pedaling or am pedaling pretty pathetically. That kind of hybrid system is generally referred to as PAS with manual throttle over-ride.
----- On PAS only bikes especially an interactive LCD display with setting buttons can be helpful and is often equipped with varying levels of assistance as to how strongly the motor responds to your pedal input. Think of it like a matching system, do you want the motor to just match your input or do you want it to more then match or maybe even just help a little to conserve battery power? Most PAS systems with LCD displays have a number of assistance setting levels as numbered settings like 1-to-7 levels of assistance. The often also include a battery charge left display and such. Most of my e-bikes I don't have such a display but I can see where they can be useful.
------ Bikes that have dropouts that are wider then 135mm include: Most Quality Tandems (bicycle built for two as the song about Daisy goes), Fat Bikes (those bikes with super wide tires built for floating on top of sand and snow and such), and then some downhill bikes (those crazy downhill jump crazy bikes with big shocks front and rear) have wider drop outs as well. I'm not aware of any that are specifically and exactly 156mm off the top of my head but I do know the wider ones are out there in those applications. I think though that in many ways its a function of this motors design that sometimes it ends up fatter then normal in some configurations. For a normal run of the mill mountain bike most of them have 135mm drop outs although some of the newer ones with 10 or 11 gear spools on the rear end (but not all of course) have 142mm rear drop outs.
----- Yes, the current claims and buzz are that if you go with V-brakes you can get a 7-speed freewheel motor without disk brake mount that will fit in the standard 135mm rear end and its only if you insist on having a disk brake on the rear that you have to spread the rear drop outs 10-to-15mm wider because the motor with disk brake mounts is that much fatter. So only the guys who insist on having a rear disk have to spread their frames rear drop out width. In my case I can weld my own thin wall steel tubing frames completely from scratch or heavily modify existing steel frames and have already done so for previous projects so I'll probably order my motor(s) with what I want and then make the frame fit the motors rather then the other way around, I understand that most others don't have that option.
Answers that I'm not so sure of:
----- Probably get the LCD display and the PAS and the manual throttle and then when you got them decide what you actually need/like and put the extra parts in a box for later use if desired at a later date or hock them online. When ordering stuff from all the way across the ocean shipping can be a big expenditure and often and extra couple little pieces in the big box make little to no difference in shipping cost and better to have more then you need in the first shipment then have to order additional parts later and pay the big shipping charge all over again for just a couple cheap parts you ended up needing when you thought you weren't going to need them at first and end up paying three or more times the cost of the parts in the second shipment for the shipping cost.
----- Sounds like that single freewheel 156mm motor either has the drum brake body (just used without the drum brake with V-brakes that act on the rim) or is an extra wide version of some sort. The 7-speed is going to be the one to go with for most mountain bikes and its just a matter of changing out the shifter on the bars to one indexed for the lower sprocket count compared to the 8-10 sprockets on most modern mountain bike rear ends (obviously there is also the 11 sprocket option on some high end modern bikes and 7 and even 6 sprocket rear ends can be found on lower end or application specific quality bikes but the 8,9, or 10 sprocket rear end is currently what is on most modern quality bikes). As I mentioned decent quality Shimano 7-speed rapid fire click lever shifters are still available so the 7-speed/sprocket rear end is sort of the cross over point where the older freewheel technology and the modern free-hub technology cross paths and you get cross compatibility.
I have a couple of very steep hills on my commute (30% gradient) and I ended up getting a 1680W mid drive. It is the best thing I've ever done, low gear, full RPM and it just powers up them no worries.
turbo1889, thanks for your insight - it's very valuable for me.
Delphinus, thanks for chipping in...you are touching on a very key issue here for me. Some of the acess roads will easily go above 20% gradient, maybe touching onto 30% but mostly for very short periods of time. Which mid drive did you get? I don't want the motor to be too obvious, particularly not if it's going to be way over the legal limits. It's very very unlikely that we will be stopped half way into the outback, but the 3rd party mid-drives are very easy to spot.
I went with the 1680W system from AFT Ebikes
When hitting the steep part of the hill in bottom gear I am pulling about 2000W, on the rest of the hill (still quite steep) its pulling about 1000W.
For steep hills like this I'm very glad I got the higher power motor. I have a max speed limit set through the cycle analyst which stops me being too heavy on the throttle through town. Don't be a dick and you should be right even if they are easy to spot. The motor itself is small so no way any officials to see how much power it actually has. I also have a 3switch to set different power levels eg road legal option for through town. Then I only enable the full power when off public roads (of course!).
Here's one more suggestion for anyone who reads this thread and wants to consider several options: Kepler's Carbon "Super Commuter" | ELECTRICBIKE.COM