2kw DD motor front on suspension fork?

Hello,

Any of you have tried to put a 2kw+ motor on a front suspension fork?


I bought an ODK V3 frame, and if I put the motor on the back, there will be too much weight on the rear when I carry passengers.

Having it on the front seems to be a better choice for weight distribution.I need suspension fork as the bike will be running between 25-30mph on city full of potholes.

Motor will be the leaf motor 1500w or mxus V3 turbo.

Thanks

You are sill better with the motor on the rear. The passenger weight will unload the front and a front motor will have poor traction, risking washout in turns when torque is applied on any surface other than perfect. I would set the front suspension supple with extra sag, and use a wider rim to be able to ride lower PSI on the front.

That’s gonna be a difficult hub motor wheel build for strength. Especially for the rear and then if you need to dish to fit? Ugh…

1 or 0 cross depending on motor flange diameter and how heavy is that huge battery pack gonna be?

A BBSHD might work but it’s not ideal since it would need to stick straight down.

Hey, maybe a stoke monkey? That might fit in the triangle behind the seat and give you plenty of power performance along with retaining original weight carrying capacity of the bike.

Definitely fatter tires the better...

battery will be 10+kg

I don't want any geared or mid drive because it's too much maintenance, i need something maintenance free.

rear dropout is 135mm, i'm not sure anything can hold 2 passenger weights on a bicycle tyre?

My street bike does carry a passenger on the rear sometimes. It is a QS 205 built in a 65mm 24" bicycle rim with 14ga spokes and rim washers, 3.0 tire. I have reached 55 mph with a 100 lbs girl as a passenger. I can't say she was feeling good on the unsuspended bitch pad, but the wheel held perfect despite the bad streets. :wink:

My bike would only fit 20" bicycle tyre. I m not sure any moped tyre will fit.......

That is 16" moped or motorcycle tire. Some moped tires are thin and robust. Some 20" bicyle rims are tough, check for Trial or BMX 47mm rims.

Maybe look for a cast scooter motor... They're usually cheap, an 18" is about the same outside diameter as a 20" bike wheel, and the no spokes thing makes it indestructible​ and helps suck the heat out. I take a passenger on mine a bunch without any over heating or load problem.

Even with torque arms to keep the dropouts from exploding (they are way way weaker than rear dropouts), the forward pull off the wheel really messes up the sliding action of the fork... I wouldn't put more than 500 watts or so in the front.

I need to find out these motor 16" tyre that are compatible I think

I wouldn't get casting motor because the day the rim crack due to pot hole, the whole motor would need chaging. I need somethingvI can maintain later on

The rims on mine are massive,and I have one cast motor with over 10,000 miles of hard charging high speed riding on it. I wouldn't worry about the rim doing anything. That same one has a built in drum brake, that I haven't changed the pads on in the 10,000 miles,and it still stops like new.It also has an oversized axle, 12mm on the flats. They do design most scooters around carrying passenger sooo.....

Plus,I usually find them dirt cheap used, so not a huge deal if one failed, but none of mine have.

Have you looked at my SB Cruiser's rear wheels? Between the two of them they certainly hold up more than two passengers' worth of weight.







Ex-Zero rim (don't know maker), doublewall, maybe 50mm wide (the rim is a bit less than the spoke flanges of the MXUS) Radially laced (0 cross) with Sapim 13/14g butted spokes. MXUS 3K 45H motor on left, X5304 on right. Shinko SR741 16" x 2.5" moped tires.




BTW, I've found that I get better acceleration without higher-end stuff (controllers/motors/etc) by using 2WD, both on CrazyBike2 and on SB Cruiser, plus I get redundancy in case something fails I still have one motor. Makes better traction too, since I get power on two wheels vs one, not counting any pedalling (which I can't really help much with anymore).

FWD with higher power does have problems with traction if you end up with a load behind your rear axle, becuase it takes weight off the front wheel.

If the load is in front of teh rear axle then it doesn't take the weight off teh front wheel, but it does apply more of it on the rear than the front.

I don't have great quality suspension forks, but I have found that with the mediocre to crappy ones I do have that sometimes I get binding of the suspension during acceleration or regen braking of the front motor.

I think I have seen a few front suspension 20" forks with steel lowers and dropouts...of course still use torque arms. If you are going to use a wider front tire be sure to check the clearance so they don't rub the fork. I personally would not go over 1000w, especially when it's your safety and possibly a passenger at risk.

Some perspective on how I thrash my cast motor around... the rim is really low on my worries list by now after so many hard miles like this fully loaded...things get bumpy in the second half of it...

[youtube]gux0etlFN18[/youtube]

And thats heavily loaded with a small passengers weight worth of batteries all the time...



And then sometimes lots of batteries AND some friend weight.. plus the rack and rear seat weight. Its pushing 110 pounds (50 kilos) unloaded.

That vid above is basically my full time driving style... lots of throttle and brake...lol. The pulling over at the end was just to give the motor a hand check on the temp... could comfortably hold my hand on it, then it was off for more, and usually go out for 30 or 40 miles at that pace.

[youtube]d_4j0nKATIM[/youtube]

I never would have understood the drive-ability of these small cast motors if I hadn't happened upon a couple, but the casting acts as a nice heat sink, the small diameter starts producing back EMF quickly, no broken spokes, and a self contained brake makes it easy to slap one onto a frame as an experiment, and I'm still on my original pads on one after 10.000 miles. This is the fourth frame its been in for a variety of reasons, and the fifth tire, so I would say they outlast the rest of a bike by a pretty good margin.

Thanks, so you mean no worry about some potholes damaging the casted rim? That's my main fear because I pretty much won't be able to replace it.

And if I get these small motor, which one should I get? The bike is for 20" wheel and 135mm dropout.

They don't go by motorcycle sizing, so an 18" with a big tire works out to about the same as a 20" bike wheel. Some have bigger brake covers than others .. Something to look out for.

I haven't found casted rim motor.

I have however found some bmx rim:
http://www.chainreactioncycles.com/blank-generation-xl-bmx-rim/rp-prod154400

It's 40mm wide so hopefully strong enough.

However, my favourite marathon plus can bear a max load of 80kg on a 20" tyre:
https://www.schwalbe.com/gb/tour-reader/marathon-plus.html

There is also this as moped tyre but I don't know how good it is:
http://www.mytyres.co.uk/cgi-bin/rshop.pl?dsco=110&cart_id=19429164.110.31352&Breite=2.25&Quer=&Felge=16&Speed=&Load=&kategorie=&Marke=&tyre_for=&x_tyre_for=&rsmFahrzeugart=MO&filter_preis_bis=&filter_preis_von=&homologation=&details=Ordern&typ=R-269197

It may be probablematic with me + a passenger + the motor load on it. It would easily go over 150kg which would double the load the tyre can hold. Do you think it's still doable?