front or rear

[MajorMagnuM]

I found this statement on this webpage..


One of the best motor designs today is called a hub motor. This simple concept places the motor in the hub of the wheel eliminating the need for any connection to the pedaling drive train. With the front wheel being electric and the back wheel being human powered you wind up with an all wheel drive bicycle. Rear wheel human powered, front wheel electrically powered. This to me is the ideal design.

anyone care to agree or disagree?

 

[getadirtbike]

rear

 

[albie]

rear...

i learnt in physics 101 that pushing is better efficiency wise than pulling!

 

[Drunkskunk]

Stick it in the rear. its a lot more fun.



... wait a minute, how drunk am I?

 

[rkosiorek]

front is the easiest to install and needs the fewest tools. that is the only thing going for it. you have to learn a new driving style with front wheel drive and it definitely breaks loose easier under less than ideal riding conditions.

the rear is more work to install but rewards you with better performance. a much more natural feel to the ride. How many front wheel drive motorcycles have you seen?

my vote is if you want easy and quick to assemble get the front drive. if you want more predictable performance go for the rear. yah just go for the rear.

rick

 

[fechter]

If you're using a really wimpy motor, like under 250w, then putting it in front would be OK to me.
At higher power levels, forget it. Look at Gary's video where he's burning the front tire by accident. Even at 'reasonable' power levels, I'd be afraid to give it any throttle when cornering, espcially if there's loose gravel or sand, snow, etc.

 

[Lock]

With the front wheel being electric and the back wheel being human powered you wind up with an all wheel drive bicycle. Rear wheel human powered, front wheel electrically powered. This to me is the ideal design. [/b][/i]
anyone care to agree or disagree?

This is true if you have a limited view of what a bicycle should look like, how it should be propelled, what sort of environment the vehicle is used in, and how it is driven.

On this bicycle, neither wheel is powered:

OK, so you think a "real" bicycle must have a seat eh? ... like this?:

No, no, no... that's not right either! A "proper" bicycle has pedals, like this:

...errr... that's not right either! No chain! No sprockets! No gears! ...and where do you stow the beer???

Personally, I'm trying to put together an ebike (2-wheeled human-electric hybrid) that has a hub motor/wheel in front, and an inline skate "blade" in the back... so how many wheels is that? One? Two? Five? I'll leave that for the nice police officer to decide <grin> ...but I bet I get about half as many punctures as you do <hehe>

Folks like to compartmentalize and label stuff... dunno why. Helps to describe things of course. But also to limit and exclude, I think. Lots of rules back in time for bike racers - NO BENTS! NO WHEELS THAT AREN'T MADE OF WOOD! DERAILEURS ARE FOR CHEATERS!

Do I sound angry? Don't mean to shout! It's usually the vested interests that do all the shouting <smile>.

Back to your question about front or back, for the hub motor? I vote FRONT - `cause I want the back free to "replace" with a skid/ski that snaps over the rear blade, for frolics in wintery parks (1/8 of my city is park lands.)

The back blade also serves to narrow the back end of the vehicle way down, which otta be way easier on my ankles, which are otherwise bloody. From kicking a poorly designed bike that looks like this:

when it otta been something like this:

ooops... better pic:

Lots of good thoughts here on performance eg cornering etc, not so much on commuting in the winters or getting the groceries home <wink>

Now back to your originally scheduled programming <grin>

LOck

 

[Mark_A_W]

My bike is capable of 35km/h without pedalling (so figure out how much power that is), and it handles fine with the motor at the front. It's not good in sand, but no bike is really. If you had kilowatts and tried to climb a steep hill in the rain, well....

I think the most important thing is BALANCED WEIGHT DISTRIBUTION.

If you put all the weight at the back - a high powered motor and batteries on a rack, then your handling will suck. It will speed wobble and pop monos when you don't need it.

One of the US guys with a x5 in the front wheel recently swapped it to the back and said it handled worse. (Can't remember who it was offhand).

If you do a rear motor, IMO you need to midmount the batteries in the frame.

The advantages of a front motor are you don't mess with your gears, and you can put the batteries at the back, and you can lift the wheel to go up a gutter at speed. The disadvantage is it's difficult to implement if you have suspension forks.

And I don't understand the relevance of Lock's post.

 

[getadirtbike]

Without rubbing anyone the wrong way, I've never had a problem fitting a wheel to the rear... and I converted more than 15 bikes last year.... ok ok the dual suspension bikes were a bit of a pain as far as spacing goes, but other than that the rest is smooth sailing.

As far as gears go, the Crystalyte wheels drop straight in. Then you slide my torque arms over the end of the axles, and put the nuts on. You can have the rear wheel changed from a standard bike wheel to a hub wheel in less than 3 minutes..... and all of the gears will work just fine.

Weight distribution is another issue. Probably the worst combination is rear hub motor with batteries on the rack. If you're going to use a rear hub, you have to at least have the batteries mid mounted.

Front hub makes sense if you've got less power.

I guess it's all a balancing act.

 

[Mark_A_W]

I've got a nine speed cluster. How do you handle that? New shifter?

How about the disc brake? There's no V-brake pins on my frame.

I don't know of a motor that will accomodate 9 speeds cluster plus a disc in 135mm (market opportunity!!). That's why I ended up front wheel drive.

I see why you use downhill frames, a 150mm dropout would really help.

If is was to do it all over again, I'd try for a rear motor, mid batteries. But front does work.


As for the front wheel spinning out while cornering - it hasn't yet. You do need to be careful, on dirt or when it's wet - like driving a Ute in the wet. Fine on dry bitumen. I was worried too, but I got my motor cheap enough on Ebay that I just wanted to try it and it's turned out ok. In fact I tend to full power through a corner when I have to stop pedalling in case the pedal hits the ground. With 2kw I wouldn't dare do that

 

[getadirtbike]

Admittedly I've only done the disc brakes on downhill frames. For that you only need a couple of spacers If you've got disc brakes you'd be crazy to go back to V-brakes.

As for the 3 minute wheel change, I was referring to the 7 speed set up with V-brakes.

You can put a 9 speed cluster on the X5 motor, you just need to space the axle out a bit to stop the cluster from touching the frame and dish the wheel accordingly. Alternatively you could just change your shifter and run the 7 speed as you mentioned.

Now you're thinking...what about the 135mm dropout?? The rear triangle of the frame is actually quite flexible in that department. It's relatively easy to stretch the frame by a couple of millimetres and slot the rest in.

I was just looking at a hardtail bike that I'm doing at the moment and it'd be hard to get a disc onto it purely because the disc will interfere with the rear triangle.

The other hard tail that I've got wouldn't be a problem. It's funny because I never really thought about the rear discs on a hard tail up until now. Everything I've ever done has used V-brakes

Ok Ok, if we're talking about disc brakes then it's not as easy as I mentioned.

I'm beginning to understand your reasoning and your fondness of the front hub motor.

 

[BiGH]

can't sleep....


the problem with converting existing bikes is that nothing is designed for the general public. We all design our bikes as we see fit, to suit our situations.

Now as much as i would love to have mid mounted batteries, i as yet haven't worked out a way to have the battery pack in the frame AND have it removeable for when i'm @ work (have to park and lock the bike outside at a univeristy). While my bike might be too twitchy for some, it suits my riding style, just as other's bikes don't suit my riding style and i find them weird.

I personally don't like FWD for anything high powered....

however AWD is better than rwd.. but by that i mean dual motors. pitty bout the cost

 

[Mark_A_W]

my bike might be too twitchy for some

LOL, you mean me. Yep, I found it um, twitchy, to put it mildly - once I got the front wheel back on the ground!

 

[safe]

The answer is.... "it depends".

The law limits peak power to 750 watts, 500 watts or 250 watts depending on where you live. If you want a performance machine then you will naturally want to exploit what power is allowed to make it the most usable and efficient. To do that you want a motor that has gears in order to be able to reach your top speed and also climb a steep hill. So from a "purists" perspective... someone whose goal is perfection as far as performance... you would want a motor with multiple gears or a CVT (continously variable transmission) to make the motor power more useful. Using gears adds roughly 25% more power, 25% less heat and 33% better efficiency.

However... people like the hub motor because it's simpler.

So your decision will have a lot to do with a "simplicity verses performance" question.

 

[Dr. Shock]

I like my 600w dc front hub with a 7 speed rear. No handling problems, as my 4 DeWalts are mounted halfway down the rear wheel. It handles as well as it did before the motor. Cruiser frame, no suspension, 26x2.125 ancient, cracked no-name tires. The secret is having a 250 lb rider, which adds a lot of inertial stability.

Before I got the hub motor, I had a 300w 24v scooter motor running at 36v with a chain drive to the front wheel. I actually liked that setup quite a bit, but being shy, I didn't like having all the neighbors and school children looking at me, so I got the hub motor.

 

[BiGH]

my bike might be too twitchy for some

LOL, you mean me. Yep, I found it um, twitchy, to put it mildly - once I got the front wheel back on the ground!

not just u :wink:

other no road bike riders felt the same.

but my bike got an upgrade hookworm front tyre and its going to get a back one.. .later when i can move my rear pannier rack up i'll put it there.