N00b in need of advice

Hi All,

I was hoping to get some advice as I don't really know much about ebikes. I've searched the forum for a bit but can't find exactly what I'm looking for.

I'm looking to convert my existing bike to an electric bike and want to make sure that I get the right conversion kit. My first task conversion will be testing out the viability of an electric bike for use mainly to get my partner to the train station, she's not really a fan of exercise, it's only a short trip to the station (about 5km each way). For me I'm potentially looking to get something a bit more serious that I'll be able to pedal assist to the city and back (charge the battery at work) which is about 35km each way, I'm reasonably slim (75kg & 182cm).

I'm looking to do a rear wheel conversion on my existing bike, I've been talking to a friend about this who's also looking to do the same and he's thinking about getting a magic pie 3: http://www.goldenmotor.com/magicpie/magicpie.html it might be a bit of overkill for my partner (I was thinking maybe a front wheel conversion for her because of the distance and her size? Thoughts?). My main concern with this is the wheel size, I measured the size of my wheel the other week and got 25 inches which they don't have. I don't know whether I did it right so I was looking for some guidance on that (The wheel was flat at the time I measured around, but I also tried the diamater and got around 25 too). The tyres I've got on there are 700x 28C @ 120 PSI which seems too large for a 25 inch tyre. I get the feeling its a 26 inch that I'm measuring wrong.

The Bike:
Giant CRX4 2006
Hybrid (upright, with road tyres)
3 front, 8 rear gears

My main things are:
- How do you measure the wheel of the bike for the conversion? (inflated tyre? full tyre? just the rim?)
- How good are electric bikes?
- Will they all allow pedal assist?
- Do they work with road tyres?
- How do the regular brakes go with an electric bike?
- How do the rear gears work with the conversion kit? Do they still work?
- What size battery?

Anything else I need to know?

Thanks in advance,
Michael

michaeldowling said:

The tyres I've got on there are 700x 28C @ 120 PSI which seems too large for a 25 inch tyre.

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If the tires are marked as "700" then that is part of the wheel size:
http://sheldonbrown.com/26.html

- How good are electric bikes?

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As good as the parts you get for them, if making your own, from really really crappy, to really really excellent.

Same with prebuilt.

- Will they all allow pedal assist?

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Not directly. Some require extra equipment (like a Cycle Analyst v3 plus some type of torque or cadence sensor.

- Do they work with road tyres?

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THey work with whatever tehy're designed for, or whatever you build them for, depending on which you choose.

- How do the regular brakes go with an electric bike?

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If you mean the levers, you should keep your existing levers and use something like the HWBS (hidden wire brake switch) documented in at least one thread of that name, if possible. Then you have known-quality cable levers, instead of potential junk (almost all ebrake levers I have had are not useful for pulling actual brake cables).

- How do the rear gears work with the conversion kit? Do they still work?

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Depends on your kit. If it's a front kit, it doesnt' change anything. IF it's a rear kit, it depends on your rear gears (number, type, etc). IF it's a middrive, thru your gears, then all the rear gears should still work, but the front ones may be limited to just one (depends on the kit).

- What size battery?

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How far do you need to go?
How fast do you want to get htere?
How quickly do you want to get to the speed you need to go?
Are there hills, or is it flat?
How much does the rider weigh?
How much does the kit (minus battery) and any cargo and the bike weigh?

Michael, you need to update your profile to let us know where you are. It does make a difference regarding advice you would be given.

Having gone through your process six months ago, the whole thing can seem overwhelming at first. You need to spend a couple of weeks poring through this forum, reading lots and lots of threads. After about a week a lot of it will start to make sense. Use the search feature to look things up.

Second, you should find a friendly bike shop near your location, who can help with the items you don't understand. They're in business so they have to pay bills... make sure you buy some of the necessary items from them. It make take a few shops before you find one where the staff are interested in your project and willing to support you. My local Performance Bike shop fits the bill for me. The other shops couldn't be bothered.

Regarding the tire size, Google is your friend (https://answers.yahoo.com/question/index?qid=20100607125219AA5q9JY)

Tyre sizes tell you:
The diameter of the wheel - in this case 700 mm (about 27.5 inches)
The width of the tyre - in this case 28 mm (about 1.1 inches)

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Electric bikes can be great and they can suck. We have no idea how handy you are with tools, or how willing to break stuff. eBikes will be mainstream in 20 years but that's a long way off.

First you need to come up with a budget. Mine was $2000 - $3000.... yes that much. You can get by with less but it's going to be expensive (not in 20 years but for now yes).

So once we know where you are, your budget, requirements and how much you can do yourself, then the folks can give you sound advice.

Good luck. It's a lot of fun.

All the usual questions, but we don't mind answering them over and over.

Unless you cannot use a rear motor, get a rear. Fronts are for bikes with special rear wheels, like internal gear hubs, or coaster brakes.

Does your partner have a bike? Or do you want one bike to do both? You can start with a rear magic pie on your bike, and then size the battery for the shorter ride for now. So a 36v 10 ah lithium battery would be good. That will help keep the initial budget down. Then later you can get a much larger battery if you will use the bike.

Each kit has some differences, and the bikes as well. Once you get your kit, we can help you work out details, use or don't use the ebrakes, etc.

Cheap Pedal Assist sucks, so forget about it for now and learn to use the throttle. It's not hard even for those who never used a throttle.

Welcome to ES****Do this before your first post or now (it's retroactive)*****
Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum) and save it. Once done, your location will appear in every post so you won't have people asking where you are ever again. This will help people help you. Example: Wylie, TX, USA. or just USA, but country as a minimum, and country is the most important. There are many cities with the same name all over the world. Without knowing what country you are in it's hard to make any recommendations. Thank you.

Have a look at Dillenger kits. They're pretty cheap an based in your country. In case you don't know, you're limited to 250w in your country. Make sure your gf understands that. There's also some other requirements like the bike only giving power when you pedal. As long as she's not too heavy, a 250w kit should be ok. If you want something more powerful, make sure that the battery can give enough current. Check the CONTINUOUS current rating of the battery. For 250w, you need anout 10 to 15A, for 500w about 20A and 750w about 25A at 36v. You can get away with a bit less current at 48v.

Be sure to invest in some thick Kevlar tires and puncture resistant tire tubes. This is very important when your riding. You don't want to get flats.

lester12483 said:

Be sure to invest in some thick Kevlar tires and puncture resistant tire tubes. This is very important when your riding. You don't want to get flats.

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I'll second that. Had an important meeting first thing in the morning and got a flat. Have switched to Schwalbe Big Apple tires with puncture tape and Slime tubes.

Make sure you practice a puncture fix at home (including actually using the pump you're going to carry) so it will be second nature WHEN it happens on the road.

It's usually much cheaper to buy from within the country you live from a volume seller. In AU;
http://www.ebay.com.au/sch/i.html?_sacat=0&_from=R40&_nkw=48v+1000w&rt=nc&LH_PrefLoc=1

Hi Micheal
Check out Ballarat ebikes. Samd is a member on ES and very helpful. Info on the site is limited but you'll pick up what you need here. Good price and quick freight etc. helps buying locally, it's just up the rd! The bbso2 mid drive kit could suit you. Easy to install if you've done a bit of bike work. it has pedal assist and is quite light. Wheels are untouched so It doesn't matter what size they are or if you puncture. You'll loose the triple chain ring at the front though for the single that comes with it. Easiest if you have cable pull brakes already for the ebrakes.
Anyway have fun.
Kieren.

michaeldowling said:

I'm looking to convert my existing bike to an electric bike and want to make sure that I get the right conversion kit.

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Top 10 eBike Conversion Kits & Where to Buy

- How do you measure the wheel of the bike for the conversion? (inflated tyre? full tyre? just the rim?)

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You can put a hub motor on almost any wheel. Common sizes are 29'er, 26", 20". The smaller the wheel, the faster the bike. You can use your existing wheel, but would then need to lace the motor in yourself. Most of the good vendors in the above list will lace a motor for you and its worth the price. EM3ev for instance offers the common wheel sizes and options for the rim & spokes. I used them, an Alexrims DX32 rim and Sapim Spokes. If you want to lace the rim yourself, you may want to consult my Rim & Spokes section of the MXUS build.

- How good are electric bikes?

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A quality build will be a very satisfying ride. Just depends on matching your needs well and getting a motor & battery that suit, in a budget you're comfortable with.

- Will they all allow pedal assist?

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All eBikes are pedal-assist, in that they allow you to both pedal and use the motor. Some are "pedalecs" meaning there is no throttle, taking its que from your pedalling.

- Do they work with road tyres?

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Yes, which is just a question of rims. I put a Maxxis Hookworm 2.5" tire on my Alexrims DX32, for a Trek Shift 3 and it worked great! You might want to measure your frame to make sure the width of the tire of your choice will fit.

- How do the regular brakes go with an electric bike?

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The MAC 10T kit I got gives you choice when purchasing - either a sensor in a new brake lever or a HWBS Sensor that you put between caliper brakes. Some bikes have hydraulic disc brakes. Some have calliper brakes. Some who have callipers upgrade to disc for better braking, because you're going faster.

- How do the rear gears work with the conversion kit? Do they still work?

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For a rear kit, you'll need to get a freewheel. Get one that has the same number of gears as for the wheel you're replacing. All the good vendors sell all the accessories you'll need to successfully complete a conversion, including freewheels.

- What size battery?

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This is an important and rather big topic, which you'll want to research well before buying. EM3ev, for instance offers lots of options. The simplest thing to do is to tell your choosen vendor how far and how fast you want to go and take their recommendation on battery. To briefly answer your question, a battery has a voltage (V) size and a amp-hours (ah) or capacity size. The more volts, the faster you'll go. The more amp-hours, the farther you'll go.

Hi All,

Thank you all for the advice, a lot of information to digest. It's all been very informative and helpful.

Now, onto the research.

Michael

arkmundi said:

The smaller the wheel, the faster the bike.

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Ah, this depends on other things; by itself it isn't strictly true.

Given the exact same motor, and the same voltage, and same controller/current limit, at WOT on a level flat road, a smaller diameter wheel should drive the bike *slower* than a larger diameter wheel, presuming that there is sufficent power to drive the bike to the max speed that wheel's diameter and the voltage used would be capable of.


Now, the smaller diameter wheel might well reach it's top speed quicker than the larger, depending on the current limit and the motor's capabilities, but all else being the same it shouldn't actually reach a higher speed than the larger wheel.