Don't Use Aluminum Forks with front hub motors!

General Discussion about electric bicycles.
LI-ghtcycle
1.21 GW
1.21 GW
Posts: 3875
Joined: Aug 29, 2009 11:39 pm
Location: Oregon City Oregon

Don't Use Aluminum Forks with front hub motors!

Post by LI-ghtcycle » Sep 23, 2011 1:39 pm

A friend of mine forgot that both suspension and aluminum front forks are a bad thing with front hub motor and learned the hard way!

He's relatively ok, scrapes and bruises after his front forks breaking at the drop-outs with out warning at full speed (about 30MPH! :shock: ) sending him and the bike flying into the air and doing a 360 before crashing to the ground.

He MIGHT have been ok with some tork arms on that fork (I did my best to drill that into him, even gave him a set of steel forks to use that I had laying around) and I know some here have been able to use both aluminum and even aluminum suspension forks with a front hub motor, but just make sure you really watch those torque arms really close.

There is a reason why Dr Bass is making them with hardened steel, I was shocked to notice that what I thought was "over kill" in a torque plate being 1/4 inch thick, and noticing that even with just pedaling my NuVinci was starting to torque into this plate enough to cut the threads of the smaller axle into the plate, so I am going to be making new ones soon, and hardening them for when I am using my new motor.

I still think you're pushing your luck with good torque arms on each side and any kind of aluminum fork, and don't think just because you're not using a high powered E-Bike that you aren't pushing those drop outs to dangerous limits! It's the smaller diameter axles that have a better chance of spinning the axle since they have a greater fulcrum or mechanical advantage and put greater stress on drop-outs.

My friend might have been hurt a lot worse!

I know it's been said many times before, but especially this time of year with so many new people to E-Biking, I wanted to mention this and hopefully save people some grief!
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
Back on track E-Bronco! Now with Cro Motor Mid-Drive Goodness!
https://endless-sphere.com/forums/viewt ... 28&t=44997

Vision R40 w/3000w MXUS as mid-drive, NuVinci N171B rear wheel as transmission, Silent yet powerful, running 72v 11.6 ah (20s 18650 Li-Ion) to climb hills, tow trailer with zero pedaling when needed!

https://endless-sphere.com/forums/viewt ... 28&t=75247[/size]

User avatar
neptronix
100 GW
100 GW
Posts: 13120
Joined: Jun 15, 2010 5:56 pm
Location: People's republic of Petrolistan ( Utah, USA )
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by neptronix » Sep 23, 2011 2:04 pm

Learning the hard way is sometimes necessary ;)... i am glad your friend is alive and not injured but that is certainly the stupidest thing you can do, ever..

I cracked an aluminum fork in half.. no motor on it.. just a ~3mph collision with a car that had stopped suddenly in front of me, and me doing a front wheel stand.. :p

I can't imagine putting a front motor on one of those.
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

User avatar
Green Machine
1 MW
1 MW
Posts: 1609
Joined: Jan 18, 2010 3:31 am
Location: it doesnt matter .... spark a revolution
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by Green Machine » Sep 23, 2011 3:19 pm

Even with torque arms you guys still say no go?

User avatar
dodjob
1 kW
1 kW
Posts: 310
Joined: Jun 30, 2010 3:46 pm
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by dodjob » Sep 23, 2011 4:28 pm

I must disagree (at least with the title)
I'm using a Bafang+mini-monster (30A) from lyen on a old rock shox judy xl. It works actually pretty well and yes OF COURSE I'm using a torque arm (fixed on the disc mount) ;-)
I have mounted a MAC motor 1000W (rear) + 12FETS 45A on a decathlon rockrider titanium frame and there is no way that it handle the torque. Actually torque arm are (IMHO) vital on any frock mount with more than 15Amps.
The thing is that a front drive motor is really a very pleasant thing. That remind me of my beloved Solex 8) the smoooooothest ride ever ^^
Gruß,
H.
Felt beer-cruiser MAC 8T lifepo4 36V12AH 12FETS4110 http://www.bavarian-ebikes.com

User avatar
dogman dan
100 GW
100 GW
Posts: 34672
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Don't Use Aluminum Forks with front hub motors!

Post by dogman dan » Sep 23, 2011 4:55 pm

Welll, as the saying goes it depends. An experienced guy with a good appreciation of the forces involved can run a 1000 w motor safely on alloy suspension forks. But a careless type, with an ignored warning is going to bust his ass, as your friend did. No torque arms, and no C washers, garanteed fail. There's a problem but it aint the fork.

I now have around 6-7000 miles on front hubs, using either cheap steel forks or alloy. Never screwed it up, and never had a problem. People thought I was crazy running a front hub on solid cromo forks at 3000 w. It worked great. At about 4000w though, things got shall we say, a bit touchy, and I crashed out of the race. The forks are still solid and good as new though, because I made proper use of the torque arms.

I really have no worries about my install of a front hub with 1200w on alloy, but I can't help but worry about anybody else doing it if they don't have lots of experience with hubmotors.

The execption to the rule is lame 250 watt motors, that would be unlikely to have a problem.

The key thing is this, don't span a cup in the forks with an oversize washer. You MUST have a spacer washer, such as a C washer, or the nut will put spreading force on the dropout, cracking it. This is why Justin made the C washers.

User avatar
Lessss
100 MW
100 MW
Posts: 2629
Joined: Nov 18, 2006 11:27 pm
Location: Saint John N.B. Canada, Sol 3

Re: Don't Use Aluminum Forks with front hub motors!

Post by Lessss » Sep 23, 2011 8:49 pm

I wonder if hubs might be contaminated with mercury?
2 hr time lapse
http://www.youtube.com/watch?v=Z7Ilxsu- ... ature=fvwp
Give me nuclear batteries I say!! Ripped off by Joshua Goldberg to the tune of almost $900 re headway groupbuy for batteries, no $ no batteries
------------
http://www.openoffice.org/ or https://www.libreoffice.org/
http://distrowatch.com/dwres.php?resource=major

User avatar
auraslip
1.21 GW
1.21 GW
Posts: 3721
Joined: Mar 05, 2010 5:19 pm

Re: Don't Use Aluminum Forks with front hub motors!

Post by auraslip » Sep 23, 2011 9:46 pm

above 1500w is a bit dangerous with a front hub anyways. to much spin. very likely that you'll lay the bike down by giving throttle during a turn and losing traction.

torque arms work. BUT how much can the aluminum handle? It doesn't matter how well the torque arm is done if it's bolted to something that can't handle the power in the first place.

Some here have made steel wraps for their forks to run monster front hubs. Crazy amount of metal working to do though.
THANKS TO EVERYONE HERE WHO TAUGHT ME ABOUT EBIKES. I'M IN YOUR DEBT.

I sell Ebike Brake levers and throttles with custom connectors crimped on! $10 shipped!

ES facebook group

r/ebikes ebikes on reddit

User avatar
amberwolf
100 GW
100 GW
Posts: 25040
Joined: Aug 17, 2009 6:43 am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by amberwolf » Sep 23, 2011 10:01 pm

I run my 36V Fusin geared hub (higher torque at the axle than a DD, AFAIK) at 48V, which gives around 1200W or more, on a cheap steel fork with stamped dropouts, and even with a (cheap) 10mm wrench as a torque arm, it STILL spread the dropouts *and* the wrench end enough to start to spin out. It's now got TWO arms (a crappy version of a clamping "plate" and a 10mm wrench) and it hasn't actually spun out yet, but I can see it doesnt' fit as perfectly flat as it did when I started with them.

So...if I had this on an aluminum fork it'd probably have already cracked or broken the dropouts, and the torque arms would be the only thing really supporting the axle and wheel anymore. :(


I'd say not just a torque arm, but in some case a torque plate of some type is going to be needed for aluminum dropouts/fork lowers. It depends on the design of everything, and the axle flat width, surface area of the dropouts (and washers) for the nuts to grip to, surface area of the axle's shoulder on the in-side of the dropout, etc.

It also depends on the ability of your nuts to stay tight, especially if you are using regen braking--Nord Lock washers would be the best thing to use on the axle nuts to help that.

THe thicker the torque arm or plate, for best surface area contact with the axle flats, and the longer the arm for spreading the load across the fork arm, the better.


But...should you need an alloy fork becuse you can't find a steel one to meet your other needs, making steel tube covers with new clamping dropouts on them is probably the best first choice, and then torque plates/arms that are securely fastened down for zero wiggle would be next.

User avatar
dogman dan
100 GW
100 GW
Posts: 34672
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Don't Use Aluminum Forks with front hub motors!

Post by dogman dan » Sep 24, 2011 10:59 am

Again, Justins torque arms work quite well, and when used with a c washer do a pretty outstanding job of controlling the torque of a motor up to 1000w. About 3000 miles on this, and never a problem. It's all about a perfect install, including a nice tight fit of the torque arm on the axle. In my case, the 9c motor axle fits those torque arms very snug.

LI-ghtcycle
1.21 GW
1.21 GW
Posts: 3875
Joined: Aug 29, 2009 11:39 pm
Location: Oregon City Oregon

Re: Don't Use Aluminum Forks with front hub motors!

Post by LI-ghtcycle » Sep 24, 2011 1:12 pm

dogman wrote:Welll, as the saying goes it depends. An experienced guy with a good appreciation of the forces involved can run a 1000 w motor safely on alloy suspension forks. But a careless type, with an ignored warning is going to bust his ass, as your friend did. No torque arms, and no C washers, garanteed fail. There's a problem but it aint the fork.

I now have around 6-7000 miles on front hubs, using either cheap steel forks or alloy. Never screwed it up, and never had a problem. People thought I was crazy running a front hub on solid cromo forks at 3000 w. It worked great. At about 4000w though, things got shall we say, a bit touchy, and I crashed out of the race. The forks are still solid and good as new though, because I made proper use of the torque arms.

I really have no worries about my install of a front hub with 1200w on alloy, but I can't help but worry about anybody else doing it if they don't have lots of experience with hubmotors.

The execption to the rule is lame 250 watt motors, that would be unlikely to have a problem.

The key thing is this, don't span a cup in the forks with an oversize washer. You MUST have a spacer washer, such as a C washer, or the nut will put spreading force on the dropout, cracking it. This is why Justin made the C washers.
Agreed, and don't get me wrong, I am sure many have had good luck with using torque arms, AND aluminum forks, but I just wanted to point this out again.

The "C" washers are another needed thing, I wish I was feeling better and then maybe I could go visit him and see what forks he tries next, he had a bad back, and the sold forks with cheap tires (he's trying to go too cheap on some things IMHO) aren't helping, not to mention the cheap frame with poor geometry all working to make him more uncomfortable, and he wants to use suspension forks to help with that.

I got him going to look at some used forks, hopefully steel RST's or something similar in a suspension fork, but he's funny, doesn't like using a computer, so he doesn't get the benefit of all the information here, or you all would have stopped this accident from happening the minute he mentioned his intention.

I just want to also mention that smaller hub motors with smaller axles can have the same force exerted on the forks as some more powerful motors since they have a smaller surface to spin-out and it would take less force to have the same damage, and remember if your dealing with a direct drive, it's more about the controller and battery than the motor's rated out-put.

I also agree that it goes for all frames and drop out types too, as I have never trusted any hub motor even on sturdy steel frames to go with out some form of torque arm/plate.
Thank you Justin_Le for your selfless act of kindness! We all are in your debt.
Back on track E-Bronco! Now with Cro Motor Mid-Drive Goodness!
https://endless-sphere.com/forums/viewt ... 28&t=44997

Vision R40 w/3000w MXUS as mid-drive, NuVinci N171B rear wheel as transmission, Silent yet powerful, running 72v 11.6 ah (20s 18650 Li-Ion) to climb hills, tow trailer with zero pedaling when needed!

https://endless-sphere.com/forums/viewt ... 28&t=75247[/size]

User avatar
amberwolf
100 GW
100 GW
Posts: 25040
Joined: Aug 17, 2009 6:43 am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by amberwolf » Sep 24, 2011 3:42 pm

Well, realistically a cheap suspension probably won't help with his bad back--it may actually make things worse because of the pogo-ing. ;)

Beavinator
1 kW
1 kW
Posts: 406
Joined: Aug 17, 2010 1:08 pm

Re: Don't Use Aluminum Forks with front hub motors!

Post by Beavinator » Sep 24, 2011 4:47 pm

I just think aluminum forks and hub motors do not mix. I would never even consider it even with torque arms. :mrgreen:

User avatar
dogman dan
100 GW
100 GW
Posts: 34672
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Don't Use Aluminum Forks with front hub motors!

Post by dogman dan » Sep 24, 2011 5:04 pm

It aint luck. It's installing the motor using the correct procedures, which should be used for any fork of any kind.

But it's a bit more life or death, to screw it up with alloy forks. Kind of like gassing up the car. The proper procedure results in no problems for a lifetime. But get back in the car, rub your fuzzy sweater all over nylon seat covers, then get out and touch the nozzle handle making a nice fat spark into gas fumes and suddenly you have a real problem.

But you dont' say you can't use gasoline because it's too dangerous, you just say be carefull with gasoline and don't do certain things.

casainho
100 kW
100 kW
Posts: 1443
Joined: Feb 14, 2011 2:43 pm

Re: Don't Use Aluminum Forks with front hub motors!

Post by casainho » Mar 16, 2012 8:17 pm

LI-ghtcycle wrote:A friend of mine forgot that both suspension and aluminum front forks are a bad thing with front hub motor and learned the hard way!
I wish I did read this message a week ago. I started to use 2 years ago a 180W motor on my aluminion fork MTB. After a year a changed to a 250W motor and a week ago to a 500W Bafang BPM (with controller giving ~1500W). I just had 30 seconds to test drive this 3rd motor 500W Bafang BPM!! It just broke the aluminium fork dropouts and luckly it as just after a start so I were at no more than maybe 10km/h.
Right now I am aware of the need of torque arms and already bought a pair and I will use next time (I am still afraid after a week but I am thinking I will go back to this Bafang "monster" motor on the same aluminium fork/bicycle but this time with the torque arms.

My original message:

PUTA MADRE, I almost killed myself!!

I went to make a quick test drive after my mechanic got the motor laced and the brake disk ready. The first thing I verified was that the wheel skidded (and I weight near 100kg). I drove for 60 meters and my mechanic told me after that I went for more than 50km/h, that I were quicker than a motorbike!! He told me that he were afraid.

At the end of the 60 meters I braked and turned back, were I decided to pull the throttle to full and again the wheel skidded and I quick decided to make a small raise the wheel so it could run at full speed and than skid even more when touching in the road, BUT, when the wheel touch the road it instead broke the fork!!! I took a fall, and I am ok but I could be dead for now if this happened when I got high speeds.

Image

Image

Image

https://endless-sphere.com/forums/viewto ... 60#p548462
Developer of the Flexible OpenSource firmware for EBike motor controllers:
- Kunteng/BMSBattery VLR FOC motor controller: https://opensourceebikefirmware.bitbucket.io/
- TongSheng TSDZ2 mid drive motor controller: https://opensourceebikefirmware.bitbuck ... ment_tsdz2

User avatar
Ykick
100 GW
100 GW
Posts: 5945
Joined: Nov 26, 2009 6:10 pm
Location: San Diego, California

Re: Don't Use Aluminum Forks with front hub motors!

Post by Ykick » Mar 16, 2012 8:36 pm

Glad you lived to tell. Yep, when they snap, they snap...
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

- Frank Sinatra

User avatar
MadRhino
100 GW
100 GW
Posts: 5060
Joined: Sep 03, 2010 5:28 pm
Location: Montreal QC Canada

Re: Don't Use Aluminum Forks with front hub motors!

Post by MadRhino » Mar 16, 2012 8:57 pm

Building anything powerful with a front hub motor is dangerous, and alu forks are only adding another danger to the list. Build with a rear motor, or build legal power if you really want to go front. We are not on 4 wheels, there is absolutely no advantage to front traction, other than saving the cost of a freewheel.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

User avatar
shock
1 kW
1 kW
Posts: 481
Joined: Oct 18, 2011 8:52 pm
Location: Motor City
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by shock » Mar 16, 2012 10:36 pm

My reasoning tells me not to use front motors at all...
High Voltage

User avatar
Green Machine
1 MW
1 MW
Posts: 1609
Joined: Jan 18, 2010 3:31 am
Location: it doesnt matter .... spark a revolution
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by Green Machine » Mar 17, 2012 4:25 am

Front motors have some advantages especially if you are like me and do not like derailleurs. Imo iGH shifters are the way to go on an ebike when weight isnt much of a factor...and front wheel drive often times improves the balance of the bike.

As dogman said...as long as you are careful and take precautions, there is no reason hub motors cant be used up front.

User avatar
dingoEsride
100 kW
100 kW
Posts: 1160
Joined: Apr 15, 2010 2:09 am
Location: Perth, Australia
Contact:

Re: Don't Use Aluminum Forks with front hub motors!

Post by dingoEsride » Mar 17, 2012 6:04 am

Ive been using alloy forks with front hub for thousands of K's, but as with anything take precautions just like walking eg. don't walk into a post or a brick wall cause it may hurt, a good quality fork, torque arms are a must and for high power use the power gradual, they do seem to have nice balance and handling, and of course don't power too much into corners or wheel may slip, but the same can be said for rear drive, also avoid regen braking cause this will create continual opposite forces
ride like the wind

User avatar
dogman dan
100 GW
100 GW
Posts: 34672
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Don't Use Aluminum Forks with front hub motors!

Post by dogman dan » Mar 17, 2012 7:13 am

Something to think about, whether the motor is front or rear. Say you pop a small jump, the motor starts spinning faster in the air. Then when you land, that's going to be a serious spike of torque.

Front or rear motor, you can tear stuff up even at lowish power levels if you are relying only on the pressure of the nut to controll torque.
For sure, you have to do it right to run high power on a front hub. When I did it, (3000+W) it was steel forks, and several bolts attaching the two torque arms. No weak hose clamps for that much power.

casainho
100 kW
100 kW
Posts: 1443
Joined: Feb 14, 2011 2:43 pm

Re: Don't Use Aluminum Forks with front hub motors!

Post by casainho » Mar 17, 2012 10:14 am

dogman wrote:Something to think about, whether the motor is front or rear. Say you pop a small jump, the motor starts spinning faster in the air. Then when you land, that's going to be a serious spike of torque.
That was exactly what I did on the only first 30 seconds I had the bicycle with me - I lift a bit the front wheel because it was funny to get it skidding, and when the wheel got to the ground/road, the wheel/motor went ahead and left me and the rest of bicycle to behind :-) -- well, in reality I did jumped over the handlebars.

I got a opinion here that makes me decide to going front wheel motor since I will always be pedaling:
Assuming the battery is located at the rear of the bike, you get a better weight distribution (as opposed to a typical front wheel drive).
Also, practically you get a two wheel drive (rear wheel pedaling and front wheel motor assistance). A two wheel drive is better for use on slippery surface because you get better handling (Just like a four wheel drive automobile). Another thing is that the front wheel motor assistance won't cause any unintended wheelies on sudden acceleration.
What do you guys thing of this?

I will be driving only on tarmac road and only at sun days but maybe on some corners I may get some sand and/or watter.
Developer of the Flexible OpenSource firmware for EBike motor controllers:
- Kunteng/BMSBattery VLR FOC motor controller: https://opensourceebikefirmware.bitbucket.io/
- TongSheng TSDZ2 mid drive motor controller: https://opensourceebikefirmware.bitbuck ... ment_tsdz2

User avatar
MadRhino
100 GW
100 GW
Posts: 5060
Joined: Sep 03, 2010 5:28 pm
Location: Montreal QC Canada

Re: Don't Use Aluminum Forks with front hub motors!

Post by MadRhino » Mar 17, 2012 4:29 pm

Your leg power is nothing compared to the power that can be fed to a hub motor, calling it 2 WD because you pedal is dreaming if you feed it anything more than 500W. The fact is that a motor can make your front wheel slide in a curve on anything but a perfect surface, if it has more than legal power. The only thing needed is some sand, water hole, or just a distraction that make you shift your weight incorrectly. Front motors are for low power, anybody building high power on the front and riding above 30 Mph is 5 times more likely to miss a turn. Controlling a rear slip is difficult already, a front slip will result in a loss of control most of the time, even with the best riders who have the nerves to avoid over reacting.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

User avatar
dogman dan
100 GW
100 GW
Posts: 34672
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Don't Use Aluminum Forks with front hub motors!

Post by dogman dan » Mar 17, 2012 5:00 pm

I still use a front hub on my best commuting bike. It just makes it better all around because with the motor up front, I can carry more cargo in the panniers in back before it gets too squirrely. I carry a 15 pound battery on top of the rack, and often carry more battery or cargo in the panniers. In my case, it's a Y frame bike, so carrying any battery in the triangle is out.

So it's definitely a compromise. It's good within a certain envelope, and bad out side the limits. It works good for me for riding on dry pavement, or wet that is not too steep. It's no good for dirt riding, trail riding. You just gotta have a rear hub for that. Dual hub can be nice in dirt, but really I prefer to have a light front so I can pull a small wheelie over larger obstacles. I run 1200w max, 48v. So I burn a little bit of front tire rubber, but nothing that alarms me. You should get quickly used to a small wheel spin the first foot or so as you start. Do be cautious about going from 0 throttle to full on a corner with wet or sand. But if you are already spun up, you can power through a corner fine.

Occasionally front hub in dirt can be fun. On the right surface, and with a good tire, you actually can do front hub drifting just like a rear wheel drift. It's just harder to do, and if you blow it it hurts more to crash. But it Is fun. You can ride dirt roads with a front hub, but you will do some wheel spinning. So if you have a dirt shortcut, it's not forbidden. If you are building a bike for dirt though, it must be rear hub, or at least dual hub.

User avatar
motomech
1 GW
1 GW
Posts: 3032
Joined: Sep 11, 2010 12:21 am
Location: Tucson Az.

Re: Don't Use Aluminum Forks with front hub motors!

Post by motomech » Mar 17, 2012 7:03 pm

One of my fav. builds was Chinaphil's "Quest for Super Stealth".

https://endless-sphere.com/forums/viewto ... =chinaphil

Built specifically to negociate steep, winding, mountain paths in his part of China, and do it in a silent fashion, he mounted dual MXUS mini-motors.

See it in action,

http://www.youtube.com/watch?v=WDm7lIHih8U

Not one to be given to exaggeration, he wrote,

QUOTE= " I always carry batteries (4 off 6s 5,000mAh 25C) in a backpack, easy to hear the LV buzzers.

Just climbed some 15% inclines and the speed is higher than the 500W Cyclone bike with all of its gearing - guess 15km/h versus less than 10 km/h - the inclines are narrow so there is no time to look at speed readouts.

At this stage I am content with the visual stealth, audible stealth, hill climbing ability and top speed."- END OF QUOTE

For technical, tight "trials" type riding, I'm thinking dual mini's would be hard to beat. Obviously, with this type of riding, the idea would be to keep both wheels on the ground. If a guy is "smoking" the trails, railing berms, jumping etc., yeah, a DD rear would be the way to go.

Splitting relatively low power between wheels creates a traction advantage, not to mention the small amount of added unsprung weight, less stress to the chain stay, better overall bike balance, etc.

2WD drive definately has it's place, I.M.O.

For low-powered assist riding, my FWD has been great, no control problems at all.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, Crazy Bobs run ghetto tubeless. 25 mph. Mean Well HLG-320H-54A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 14S LiPoly elifebike 9-FET 20A controller. 23 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

User avatar
MadRhino
100 GW
100 GW
Posts: 5060
Joined: Sep 03, 2010 5:28 pm
Location: Montreal QC Canada

Re: Don't Use Aluminum Forks with front hub motors!

Post by MadRhino » Mar 17, 2012 7:55 pm

motomech wrote:...
2WD drive definately has it's place, I.M.O.

For low-powered assist riding, my FWD has been great, no control problems at all.
For that, I agree. Yet, steep climbing doesn't benefit at all of a front motor, for it has no significant traction on 15% incline and up. The only advantage of a 2 WD is to share the heat, so it could climb longer before bust, and that is only if the climb is not too steep to let the front motor help at all. For climbing steep, nothing can beat high power on the rear wheel, and sharing the power with a front motor only steal some off where it is needed, along with adding weight in a discipline where it is so important to be light.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

Post Reply