Road Bike vs. Mountain Bike Conversion

[tekintl]

Ok, so I am an avid cyclist who is really interested in E-Bikes. I have a long commute in medium traffic about 13 miles each way.
My question is why do I only see slow, heavy mountain bikes converted? Has anyone taken up the call to create a light, fast, long range road bike?

I just envision my all carbon fiber road bike with top end components that weighs about 16lbs fitted with a lightweight hub and li-ion battery. Bionx claims to have a kit that weighs 15.6lbs. so a total weight around 32lbs.

Thanks!

 

[Link]

Strength. The heavy mountain and downhill bikes are made to take a serious beating, while top-end road and racing bikes are designed with expensive materials to be as lightweight as possible while being just strong enough to handle the stresses of paved riding. Ebike components put stresses on the bike (particularly the dropouts) that they weren't really designed for, so heavy but durable steel frames are quite choice for conversions.

There's no reason why one couldn't design a light ebike if it were made specifically for that purpose, but we're just a comparative drop in the bucket that is bicycle sales.

And "light and long-range" borderlines on oxymoron around here.

 

[D-Man]

Its probably because nobody wants to buy one of those $5000 15lb bikes. Hey if you got the money, go for it! See what happens. It could break but you don't know till you try. You might want to check the dropouts and see if they have metal inserts for added strength.

 

[julesa]

Its probably because nobody wants to buy one of those $5000 15lb bikes. Hey if you got the money, go for it! See what happens. It could break but you don't know till you try. You might want to check the dropouts and see if they have metal inserts for added strength.

You can get a really nice lightweight aluminum road bike for around $800. I wouldn't put a front hub motor on one of those though -- not sure I'd trust the forks. You could put a geared hub motor on the rear wheel with torsion bars. It won't be silent, but the lighter weight will make up for the little extra noise it makes when it's running.

Does ezee sell a rear hub motor kit? ... on the other hand the ezee top speed's around 25mph even if you take it up to 48v which might seem kinda slow on a nice road bike...

 

[dirtdad]

Motor in the rear is a problem, too, road hub spacing is 130mm in the rear, mtb is 135. Many people have to widen mountain bike frames as it is to get a rear hub to fit. And you dont want to widen carbon or aluminum.

I would go with with a nice beefy steel fork. A 29er MTB fork should give you good strength and comparable geometry. I think a gear reduction motor would be good, too. Small, light, and you get a freewheeling hub.

 

[John in CR]

tekintl,

With ebikes weight is only a concern if hills are involved, and even then a bikes weight is only a fraction of total weight. Bike weight is only really an issue if you have to carry it. I've got both aluminum and steel ebikes with little difference in performance, because batteries, motor, and I add up to 125kg. Keep in mind you're not dealing with the less than 200W continuous available with human power where every gram seems important. Also, remember that China is still a communist state, and no one is in a hurry to get to work. They put almost 20 million new 2 wheeled electric vehicles on the road each year, so stuff produced for them dominates the market, resulting in the slow ebikes you see on the road.

You aren't limited to slow though with an ebike, and I'd fly right by you at 50kph+ on a commute on either my aluminum or steel bikes. It's not that exotic frames can't be used, but aluminum and exotic frames do require special consideration due to stresses in specific areas that aren't an issue under pedal power (a safety issue that can't be underestimated). Unless you're willing to drop several thousand on what is essentially a handmade bike designed for off-road use (ie outside gov't power restrictions, so high speed is possible), I'd suggest starting with a cheap steel frame bike and DIY an ebike that is comfortable to ride. Then once you learn the ebike ropes and determine what you really want and need, build your exotic material based dream ebike.

John

 

[zilla]

i after a couple of months of lurking here was thinking the same thing about road bikes...they are designed to make the best speed and distance from a very limited power sorce(the rider)
it seems to me if a mountain bike is about 15% slower than a road bike the road bike is a better canidate for the conversion if the bike used on the road

the weight and need to use a very wide slow heavy rim put me right off hub motors so i went the elation bottom bracket route its been on a very heavy road race styled triax crimsion bike for about a week now as a test setup it only takes about 2 hours to fit

this bike is about the worst road race bike money($75) can buy its a walmart /kmart special has the shittist components ...the brakes dont work the spokes are not tight and the tyres not round it weighs about twice what a decsent road race bike does well over 12 kg and i think may have been assembled buy a retarded monkey but it does have 700c wheels and very thin low rolling resitance tyres

the elation kit is only 300w and weighs 6kg/13lbs and freewheels so no it works as a unpowered bike still but it goes very well 32kph 20mph without pedaling 45kph/28mph while pedaling mildly i am yet to find the end of its range or even take one bar off its battery meter (lipo4 10ah) and have gone to work and back twice about 12km with out recharging including a hill that most of u flatland guys would call a MOUNTAIN

so being pleased with the peformance on what is the weakest slowest heaviest road race bike in the world im now getting an old 2000ish full carbon framed kestrel 200sci ready for the kit it has carbon everything including 4 spoke carbon wheels (a bit of bling)it weighs less than 7kg rides easy and is fast,very fast with the elation kit on it should weigh less than 28lbs

i am in awe of the knowlage and ingenuity of the members of this forum but the high powered high weight way is not for me

 

[deecanio]

Ok, so I am an avid cyclist who is really interested in E-Bikes. I have a long commute in medium traffic about 13 miles each way.
My question is why do I only see slow, heavy mountain bikes converted? Has anyone taken up the call to create a light, fast, long range road bike?

I just envision my all carbon fiber road bike with top end components that weighs about 16lbs fitted with a lightweight hub and li-ion battery. Bionx claims to have a kit that weighs 15.6lbs. so a total weight around 32lbs.

Thanks!

Hi tekintl,

that sounds like an awesome road bike, 16lbs????
As the guys say you would have to be very careful putting any type of kit on that and make sure you understand the implications of the extra stresses involved.
as a noobie i would agree on getting a cheap shite bike to test out your selected running gear before you make any changes to an expensive roadbike.
imo you should pay attention to the rc motor threads currently in progress here as you could save a mass of weight with the rc controllers and motors instead of using a heavy hub motor.
Can you post a picture of your carbon roadie please?
i think if done right you could make a monster ebike out of it but know what your doing before you tamper with such an expensive bike.


Cheers


D

 

[tekintl]

Ok so I think I may have this figured out. Everyone seems to agree that I will need a stronger bike. So keeping that in mind what do you think about using a Cyclocross bike. They are designed to be rugged but also lightweight (9.4 kg). IThe price on this one from a local bike shop will cost about $1300.
Would this be a good canidate? I think the rear dropout is 130mm and most kits are 135mm. Is this a major problem or can it be fixed.

 

[Ypedal]

My .02 on this.

I started with a featherweight Giant ATX aluminum frame with a Wilderness Energy kit.. it worked well, i then moved to a lighter folding bike with a crystalyte dual speed and nimh, it was faster and lighter..

Then i did a 180 and got a Norco Chaod DH bike, aluminum frame, but dual crown forks and full suspension, with disks.. 72v 20ah of lithium and have never looked back.

The bike weighs frickin 80 lbs + but tough as nails and cushy comfort with brakes that work even at 30 mph+ without complaint.

To each his own, that's what makes this hoby so much fun, it's a custom thing. If light weight road bike is what you really want.. go for it ! and let us know how you make out !

Either an elation, or cyclone kit, a geared puma/ezee/bmc type with lithium, all sorts of ways to do this.

 

[deecanio]

oooh im getting a bad back just looking at that roadbike


cheers,


D

 

[andys]

Bionx is the only kit that I know of that has something that should fit a road bike. I have two mountain bikes I converted with the BMC geared hubs from EV tech. The kits have a lot of power, and you end up traveling at 10MPH (or more at 48 volts)faster than you would on a regular bike. That extra speed really beats you up without any kind of suspension unless you ride on perfectly manicured roads. 10 pounds one way or another on an E-bike has almost no effect on performance whatsoever, and neither does the classic back and neck killing aero riding position.

If I wanted to build a really light weight e bike, i wouldn't go the road bike route. I would start with a higher end hard tail mountain bike, like this one linked below at under 22 pounds. I'd put on a 8 pound geared rear hub, and add a 6 to 8 pound LIPO battery from e-bikes.ca. you could run mountain bike slicks if you wanted a tiny bit more speed and efficiency. You'd end up with a package under 40 pounds that would "FLY"


http://www.bikesdirect.com/products/motobecane/fly_pro_09.htm

http://us.itselectric.ca/Batteries_s/24.htm

http://www.texaselectricbikes.com/catalog/brushless-geared-motor-p-163.html

 

[nomad85]

The Trek 7.3 fx is a midrange road/fitness bike with 135mm dropouts. Works well with my 407 rear motor. 30mph at 48v.

 

[dogman dan]

Opinions are like, well you know, everybody has one, here's mine.

There are some exceptions, but the common hubmotor kits just plain weigh so much that the bike weight, 15 pound bike vs 30 pound bike doesn't matter as much as you would think. The motors range from 15-25 pounds and the batteries from 10 to 40 pounds. Take my setup. 30 pounds of motor and battery, and that is pretty light since have llifepo4. Put 30 or 40 pounds in a backpack, and ride your lightest bike, and then ride a wallmart MTB. Yes you still can feel the difference, since you can put out maybe 250 watts, but the ebike won't notice it since it puts out 500 to 2000 watts unless your are Australian and limited to 200 watts. Sure it still matters to be lighter, but not enough to spend $1500 on a bike when you need that money to buy good batteries.

As to the type of bike, it gets real personal and preferential. A big issue is theft, so my garage sale bikes at least wont set me back to replace, and I get real carefull about leaving my battery in a parking lot. The motors I run are on the cheap end, and at least for awhile, nobodly even knows what it is. So when I park my bike at a store, it looks like a $150 mongoose. I live in the desert, and my motor is not on EPO so the v brakes on the bike are good enough for me at 20-25 mph. The full suspension, front hub bike I ride balances good, and doesn't weigh so much or go so fast I need disks, but I don't bend any more wheels since I went to a full suspension MTB.

Other folks run much faster, need the best brakes money can buy, and at those speeds, carrying that weight, are constantly tweaking on the spokes. DO NOT underestimate the beating an ebike can give your body and your bike. The young can handle it no problem, but with a few crushed disks in my back I can't.

I can't stress this enough, do not ruin your nice roadbike by making an ebike out of it. One of the only things I got right when I started, was leaving my vintage motobecane alone. Nowdays it's a lead sled, but to me it's still my ol favorite bike, and when cold weather comes I'll be riding it to a bus stop instead of doing 15 miles on the ebike.

We get a lot of posts from new folks wanting the hottest, fastest etc etc right off the bat. My opinion is to get a cheap 26" wheel bike, cruiser, MTB, comfort bike, whatever. Then pick out an moderate power, inexpensive motor and some sla batteries and learn about ebiking with less costly stuff. Once you know what it's like and what you want, then get out the big bux. All you need to know to buy the first kit is a few things, do you want to ride and peadle, or peadle and use the motor just for uphills. For option 1 any kind of motor will do. for option 2 you need a freeweeling motor, such as chaindrives, or geared hubmotors. Regular hubmotors produce a lot of drag unless you power em up.

 

[DahonElectric]

There are so many interesting opinions posted here, but I think people seemed to have missed the real reason why real road bikes aren't really good candidates. Frame materials notwithstanding..

Yes, you can do it with a road bike. JVBIKE offers one here at http://jvbike.com/bikes/CRD_BionX.htm. I know these bikes without the motor. Frame materials on modern bikes are really really stiff and safe.
After all, they are designed to withstand the maximum weight and power an average human being can put out. If it breaks, then bike companies will get sued! You know how easy it is to file a lawsuit in the states. So, I'm not worried about the frames when you are considering something like from BIONX per se.

But the real reason a lot of people chose mountain bikes as opposed to road bikes has I suspect to do with bike fit. Most mountain bikes have a relaxed non aerodynamic fitting than a normal road bike would call for, which is what we would call musculature positioning (using muscle groups and your core strength) to suspend the rider on the bike. Whereas, a more relaxed upright fitting requires less muscles and more skeletal positioning like we do sitting on a chair. We are used to this. Some of us may do this for 8 hours a day. If you ask them to sit on a gym ball, they would instinctively loose balance or will become uncomfortable with their backs (backs get sore because of the weak core on the front and relying too much on the latimus dorsi muscles to keep the upper body upright). Riding a custom fitted road bike calls for the same core strength stability that sadly to say, most people lack. They may be physically fit, but probably structurally unfit. A fit road biker uses the core and muscles to balance him or her on the bike, which usually means riding on bigger gears. BUT, electric bikes are for those who don't ride or can't ride on the big rings for most of the time. And besides, you don't need to. Which means, if you convert a road bike to electric, you will notice that you will want to move your saddle backward and raise your handlebar a bit since you now won't be pushing the big gears with the same effort as you did without the motor. Ask yourself this question. Do you see motorcyclists adopt aerobars on their bikes to go faster when they have a motor? Just look at the Harley riders -- very upright. The very reason road bikes geometry call for a human rider is defeated as soon as a motor is added.

Weight is not an issue on the flats -- aerodynamics is, which is why if you want to go fast on an e-bike, you need to construct some kind of aerodynamic front fairing and adopting a front aerowheel like the Spinergy. Weight becomes an issue when you are going up the hill, but a carbon bike is like 1/10th of the total weight of the riding package. Just imagine if a 145lbs rider rides a 15lbs bike, the total weight is 160lbs. Now imagine a 250lbs rider riding the same 15lbs, the total weight is now 265lbs. Bike weight is insignificant unless you are competing in a race, where a matter of minutes or seconds counts as you witnessed on the recent Tour De France competition.

In my view, the best conversion bike is either a cheap hybrid or a cheap mountain bike (both have 135mm drop out spacing for sure). Most of them are relatively light weight, by about 5 to 6 lbs more overweight than the lightest carbon ride. But believe me, once you have a motor on, you'll blow these guys by on the hills like you wouldn't believe.

Me, I'm having a blast with my Bionxed Dahon MuSL!