Hello! Questions on Racing Bike e-bike conversion

[drekar]

Hello folks!

It is great to find an online community with people who obviously are putting good quality effort into this area. I am a Computer Science person by trade, so I have the "build stuff" urge, but none of the electronics / mechanical know-how. I am really hoping some benefactors here might have the patience to help me with my exceptionally small knowledge on the subject.

So, I have a road bike that I would like to convert into an e-bike. I would like to keep the road-bike (racing bike that is) if possible, but from what I have read a cheaper steel-frame bike is more appropriate. But, here's my general idea:

I can pedal at an average 16mph. I would like to be able to zip along at 35mph (pedal-assisted) for up to 20 miles (again, pedal assisted). the bike is a Specialized Allez tripple, so it is an aluminum frame with carbon-fibre front fork. It has 700c wheels. I weigh 180lbs.

http://mikesbikes.com/images/library/large/spec_allez_tpl_blk_sil_07_m.jpg

I was thinking of getting a Crystalyte 406 with some Lithium-ion cells of some sort to keep the weight down.

Is what I am thinking even possible? Can I even install a hub motor on a racing wheel? What if I put the batteries in a backpack (that would keep the weight high and easy to throw around just like I weighed X more)?

I am going to be documenting this build extensively using photos / video, and do it all from the perspective of "e-biking for dummies". My pie-in-the-sky goal is to have a how-to that is so easy to follow and well-designed (I am a professional web designer as well) that it MIGHT even entice more people join the e-bike fold!

As a side note: Gas aint getting any cheaper, and with the summer upon us, now is a great time to really be evangelizing!

Thank you all for all the excellent information I have read on this forum already, and thanks in advance for the help that I am requesting. When I get this how-to up, I will definitely be giving credit where credit is due!

Best Regards,

~ Luke from Dallas

 

[Lowell]

A hub motor on a racing wheel isn't a problem. If you haven't seen it already, you would probably like this bike:

http://www.austinev.org/evalbum/465

Are you mainly going to cruise at 35mph on your commute? Dallas sounds pretty flat... what's the steepest hill on your intended routes?

 

[drekar]

A hub motor on a racing wheel isn't a problem. If you haven't seen it already, you would probably like this bike:

http://www.austinev.org/evalbum/465

Are you mainly going to cruise at 35mph on your commute? Dallas sounds pretty flat... what's the steepest hill on your intended routes?

um....WOW. That looks like it has the specs I am looking for. Over 40mph, over 20mile range without pedaling, and nothing on it looks bulky at all.

OK, I am going to be frank: I have no idea what the majority of this stuff means, although I have gotten the "jist" from about 10 hours of reading these forums. I am going to pick apart that build as a starting point, and ask more specific questions.

I have been looking around, and noone even has a price for the Heinzmann hub. So, I am going to assume that it is to expensive. What kind of wattage am I going to need to get my 180lbs to cruise along at 40mph? Assuming I am putting in some pedal-along power?

(p.s. thanks for the quick reply.)

 

[Drunkskunk]

Welcome to the addiction.. I mean forum.

what you're looking for isn't that far fetched. the crystalyte line of brushless motors can do this fairly reasonably. you can get the motors with and without being laced into a rim. I got mine from poweridestore.com, and it came with one of those areodynamicly shaped 700c rims.

that one pictured in the link looks like there journyman kit. I'm not a fan of that kit because of the battery mount, but thats a personal issue. I'd prefer the batterys in a bag mounted on a rack behind the seat for 3 reasons. One, it looks cool. its imposable to tell it's an electric bike unless you know what the hub is. Two, its a little more aerodynamic to have the batteries behind you than in the frame. Three. thats were my water bottle goes. (or beer. )

 

[drekar]

Drunkskunk:

First off, thanks for the pointers! I like the idea of having the hub motor on one of those aerodynamic rims (they look fantastic).

Second, Arrogant Bastard Ale is great.

Is your setup a rear-mounted motor? If so, doesn't having the batteries and motor both over the rear wheel make the thing have a little too much weight over that rear tire? I have popped a tire before with just me!

Thanks!

 

[drekar]

A hub motor on a racing wheel isn't a problem. If you haven't seen it already, you would probably like this bike:

http://www.austinev.org/evalbum/465

Are you mainly going to cruise at 35mph on your commute? Dallas sounds pretty flat... what's the steepest hill on your intended routes?

Sorry Lowell, I was so eager to write back I forgot to answer your question. For the most part dallas is pretty much flat. There is the odd hill here and there that is suprisingly steep, but 99.9% of the time: flat.

For the commute, I could see this being stop-and-go traffic where there will be approximately .5 mile flat segments between lights/stops where I will need to keep up with traffic that hits 35 - 40mph. I can only hit 16 - 18mph under person-power

Thanks! (this is going to be fun *looks at tools and wrings hands*)

 

[drekar]

OK, so after doing a ton of reading and still feeling like I know nothing, I figure I might as well dive right in...

So, as far as I can tell, for a rear hub motor setup tweaked for top speed on relatively flat grouond, I need the following:

* A Bike
* Motor with high top speed
* Batteries
* Battery management System
* Two thumb throttles (one for upright, one for in the drops)
* battery gauge
* Controller
* Kevlar reinforced tires
* Rack for batteries
* Bag for batteries with quick-disconnect
* Charger(s)

I have the following performance requirements:

* 35 mph cruise (40mph burst)
* 20 mile range.
* little maintenance

Making the following assumptions:
* Always pedal assisting to obtain performance requirements
* very very few hills
* 180lb rider who can contribute 14-17mph

I have tentatively decided on the following components:

* The bike I currently have: Specialized Allez Tripple
* Crystalyte 406 (rear wheel mounted in an aerodynamic shaped or enclosed rim)
* The 48v 12 A-h Lipo battery pack (not sure where to get it from)
* Kevlar from my local bike shop
* Rack + bag from local bike shop

I have not decided on the following necessary components:

* Thumb throttle(s)
* controller (35 A??)
* chargers
* wiring

I have not decided whether or not I will need the following:

* Different gearing for 40mph speeds
* Splash guards
* extra clothing in case of crash (body armor?)


Does the above make sense? Is it possible? Will I be able to meet the above without spending out my nose? Please add/subtract/change the above! Be harsh! Adjust my expectations with a crowbar if necessary!

If the above is possible for a "reasonable" price, wow, there is no reason to wait...

Thanks again!

- Luke

 

[Lowell]

You'll need more than 36 volts to meet your speed requirements. Play around with the simulator at:

http://www.ebikes.ca/simulator

Other than that it sounds like a good list of parts.

 

[drekar]

Thanks Lowell, I modified the post to include a 48v 12a-h pack

 

[CGameProgrammer]

I think you'll need 20 Ah minimum to maintain those high speeds over 20+ miles, even with pedaling.

 

[drekar]

I think you'll need 20 Ah minimum to maintain those high speeds over 20+ miles, even with pedaling.

Yeep! That's going to get expensive. Ballpark, what might that sustain? 30mph with pedaling? Or, vice-versa, maybe range would be more reasonable at 10-15 miles ish?

 

[Miles]

Yeep! That's going to get expensive. Ballpark, what might that sustain? 30mph with pedaling? Or, vice-versa, maybe range would be more reasonable at 10-15 miles ish?

drekar,

You might find this power calculator useful:
http://endless-sphere.com/forums/viewtopic.php?t=538

 

[CGameProgrammer]

Yes, I would expect 12Ah to support 10-15 miles at 35 mph. I have 48V 12Ah lead-acid batteries, which act more like 6-7 Ah batteries if the discharge rate is high (but lithium doesn't suffer from that) and I can go perhaps 7 miles at full speed before the batteries start sagging a bit under full load. However this was partly without pedaling since it had a minimal effect above 30 mph, but your bike is probably geared for higher speeds.

With pedaling, a more aerodynamic position (racing bike), and superior lithium batteries, 10 miles is very easily achieved and 15 likely is as well, but I think 20 might be stretching it.

 

[Mathurin]

Kreuzotter is your friend for figuring out power requirements:
http://www.kreuzotter.de/english/espeed.htm

I see the bike comes with 700X23c, I foresee pinch flats... Does it even have fender or rack mounts? If it does, it may not be possible to fit much larger tires in it, I'd be looking at touring tires in >30-35.



If I had that bike I'd be leaning towards a setup more like this one:
(Minus the flatbars.)

<embed src="http://www.youtube.com/v/gKE_JmdNPT4" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350"></embed>

 

[eP]

Yes, I would expect 12Ah to support 10-15 miles at 35 mph. I have 48V 12Ah lead-acid batteries, which act more like 6-7 Ah batteries if the discharge rate is high (but lithium doesn't suffer from that) and I can go perhaps 7 miles at full speed before the batteries start sagging a bit under full load.

drekar want 12Ah Li-Po batteries, so it should be enough for what he need.
And he could faster recharge Li-Po for next trip.

 

[Lowell]

48x12 = 576Wh = 18Wh/km which is workable for that speed. Of course you're not going to want to drain the battery more than 80% on a regular basis so take that into account with your calculations.
With long flat roads you'll find yourself wanting top speed all the time, so if your bike can go 40mph, I bet you will hit 40mph more often than you think.

 

[Ypedal]

Welcome aboard Drekar ! 8)


- Batteries : just like most batteries, if you want them to last as long as possible, you need to size them up to the job.. have you covered the whole " C " rating thing ?

A 12ah battery, drained at 6amps = 0.5C
A 12ah battery, drained at 12amps = 1 C
A 12ah battery , drained at 24amps = 2 C

2C is as much as you should drain NImh/Nicad/Lithium for long service life. Yes.. you can use more than 3C and in some cases up to 20 C with fancy RC lithium packs.. but a candle that burns twise as bright.. burns half as long... :wink:

If in any way possible, try to find a way to mount the batteries inside the frame's triangle.

- Motor : I sugest you take your bike down the biggest hill you can find.. switch to the tallest gear you have and figure out how fast you can honestly pedal with your gearing.. avoid any motor that goes faster than this as you will end up using the bike as a motor-only thing with reduced range.. harder on batteries etc.. Record your speed and get back to us ! hehe..

 

[Liberator]

Used to race with guys who rode Allez Comps and the Specialized bikes are indeed rock solid. My concern is that you say it's an aluminum frame. If you go with a powerful hub motor does anyone have any concerns about the dropouts getting ripped off of the bike b/c of the motor torque (even in a rear motor)?

 

[Ypedal]

If the rear of the frame has a Stainless Steel hanger supporting the dropout on the derailer side, it should be fine, at 48v.. Can you take a closeup picture of both sides of the rear frame ?

 

[Drunkskunk]

Drunkskunk:

First off, thanks for the pointers! I like the idea of having the hub motor on one of those aerodynamic rims (they look fantastic).

Second, Arrogant Bastard Ale is great.

Is your setup a rear-mounted motor? If so, doesn't having the batteries and motor both over the rear wheel make the thing have a little too much weight over that rear tire? I have popped a tire before with just me!

Thanks!

Yep, Darn good beer!

Yeah, mine is a rear hub,and I'm running SLA batteries so its real tail heavy, about 50 pounds total directly on the back axle. I'm on a hybrid instead of a road bike, running 40 series tires, and they're not having any problem. a 20 or smaller sized tire might have problems with the weight, but I wouldn't want to be on a tire that small at 40mph. might try a 25 to a 28 sized

 

[Ypedal]

No problem with this 20" wheel at 40 mph !! ( 100 psi kevlar tire tho)

 

[drekar]

Very nice!

Wow, you all are being a great help. I am still digesting the info and playing with all the calculators and such... I am tempted to step up my components a bit.... Should I consider stepping it up to the X-Lyte 5303 motor with two 48V 10A-h packs (for 20A-h), or will the 406 do? I am trying to keep the overall cost down as much as possible *sheepish poor-college student grin* I suppose I can drop down my requirements to 30mph for 20 miles as well...

I will go do the "how fast can I pedal on my gears" but I seem to remember topping out at 30-ish mph.

I will also go take some close-up pics of various components.

Thanks for all the calculators and such, you are all being a huge help.

 

[Ypedal]

The 4 series will get the job done just fine, if you want to turn your bicycle into a scooter then the X5 is your man.. but to retain the bicycle feel and use, staying with the 4 series makes battery choice alot easier..

The X5 needs a 40 amp controller to perform it's job well, this means sizing up the power pack accordiingly.. 20 amps in a 4 series will do 30 mph . Look at Knightmb's setup for example !

 

[Lowell]

The X5 hubs do have an efficiency advantage over the 4 series, but weigh an extra 8-9lbs. I would suggest trying to find an ebike store local to you and test ride a few different setups. You might even be able to find ebikers local to you that will show off their bikes.

I wouldn't put an X5 hub on a road bike since a relatively aero road bike should be able to go plenty fast on the flats without X5 power.

 

[drekar]

OK, sticking with 406 then!

Perhaps I should put longer gears on the bike? such that I can comfortably pedal when going 35-mph... I definitely remember my top being 32 or 34mph, and that was with my legs going pretty quick....