Front Hub Motor w/ Front Shock (Steel)...

[ecowheelz]

I've heard conflicting opinions about mounting a front hub motor on a cheap fork with shocks. The fork and dropouts are both steel just like most cheap bikes purchases at Wal-Mart or other large retail stores. I'm using a 36V, 500W E-BikeKit, so it's not overly powerful. Some people say it's OK to use front shocks as long as they're steel and the motor isn't over 600 watts, but I rarely see any pics of people using a front hub motor with front shocks. Since we'll be installing kits for customers, I want to make sure nobody comes back with a smashed-in face and tries to sue us

Unfortunately, there's not a lot of choices if you're looking for a bike with a solid steel fork.... and I know customers would prefer a front shock. Of course, we could install a new fork or choose a rear wheel kit instead. But we'd like to use the E-BikeKit for most installs... and Jason eliminated the rear wheel kits (for now)...

 

[icecube57]

I got shocks on my front 1000w Golden motor. With X5 torque arms too. Mines is pretty solid Not fatigue even with regen braking. I dont have the pinch tube fork. But Im pretty sure dogman will assure you that his pinch tube Walmart cheapie bike work ... with a slight modifcation but it work swell for him. 3k miles i think and no issues. Ive put around 1000 miles on mine in the two months ive had it. Nuts still tight no rotation in the drop out. Good as new.

 

[dogman dan]

Squashing a pinched tube fork in a vise to make clearance for a motor may be fine for me to do, but I doubt as a shop owner I would do if for anybody. Cover your rear and don't go modifying a consumer product for money. If the motor fits without the squashing the tube more to make it fit, that is a different story.
Liability wise, it shouldn't be that risky to mount a motot into an all steel suspension fork. Some say the steel head tube pressed into an aluminum part could break, but the all steel ones I am running are welded everywhere. An all steel, all welded fork should be as strong as the welds on a regular chromoly fork.

I wouldn't go installing any motors on aluminum front forks, even though we know how to do it safely. Customer later on, takes off wheel, reinstalls it improperly, cracking the dropouts. Of course he'll swear in court he never touched it. This ebike thing is a liablilty time bomb. You take a bike, and modify it to add a motor. Lawyers are going to love asking shop owners to see the engineering reports on this modification. But if you stick to installs on steel bikes you are just less likely to have the event that lands you in court.

This is my bike with the cheap steel forks and the aotema motor. It won't fit unless you squash the forks a bit more to make the clearance, so most people just get a bike with a plain fork.

 

[ecowheelz]

Squashing a pinched tube fork in a vise to make clearance for a motor may be fine for me to do, but I doubt as a shop owner I would do if for anybody. Cover your rear and don't go modifying a consumer product for money. If the motor fits without the squashing the tube more to make it fit, that is a different story... This ebike thing is a liablilty time bomb. You take a bike, and modify it to add a motor. Lawyers are going to love asking shop owners to see the engineering reports on this modification. But if you stick to installs on steel bikes you are just less likely to have the event that lands you in court.

We're never going to install a kit on an aluminum fork - that's for sure. We want to follow "industry standards" and manufacturer instructions (by-the-book) to protect ourselves. We've also created a "liability waiver" for customers to sign when we install a kit to further protect ourselves. But it hasn't been clearly defined whether or not steel forks with shocks are OK. Most manufactureres only state that it's recommended to use steel forks - with no mention of shocks.

Dogman... what do you mean by "pinching the fork"? With the "display model" we're working on now, we simply filed the dropouts slightly and the motor seemed to fit great...

 

[dogman dan]

If you don't know what I mean, then you have no problems. On my first motor, a WE brushed, BD36, the motor case would simply be too wide to fit between the tubes. On the cheap pinched tube forks the dropouts are made by pinching the tube onto a flat bar that is welded to a rod inside. up to 4" from the dropouts there is nothing in there that moves, so you can pinch the tube some more, and get the clearance for a bd36 motor. It just depends on the motor type whether this is needed or not. On my new Aotema brushless, the motor might fit without a problem. I don't know since all my bikes have the tube pinched allready. It looks like a tight fit, but it might go. There is a thread with pics buired somewhere. fitting a motor on cheap suspension forks or something like that is the title. I wouldn't sweat it if the fork is all steel and the motor fits. Some have posted concerns about forks failing at the head tube, on ones that have an aluminum alloy part there. I think hogwash, since braking forces exceed motor forces, and the part isn't made signifigantly different on each side of the head tube where it is pressed into the fork. Sure it can fail there, but I bet if it does somebody rode it into an object like a car bumper, or took big hucks off jumps with it causing a crack. In any case, the cheaper steel suspension forks are all steel and all welded, and they look pretty safe to me. The dropouts on these cheap suspension forks are much thicker and stronger than a beach cruiser fork in my opinion. I think a rim will fold before these forks do.

The flip side of these forks is that they don't do much. They are NOT off road forks. But they do help with rouger paved roads, or heat cracked pavement.

Of course , if the motor fits between the tubes, they can be run on alloy forks, but it is a risk so just tell em, install it yourself. If your instructions caution against it, you should be ok. Of course refund the money if they take it home and change their mind. I think 90% of front fork spinouts are caused by poor fit, not the suspension or the alloy. On the steel suspension forks the fit is not too bad since they aren't intended for quick release hubs. I'd notch a washer before I filed away a lawyer lip though.

 

[ecowheelz]

The forks we're using for our "demo" are cheap, steel forks with pinched dropouts. But the motor fit fine and we didn't have to do any modifications except for filing the dropouts slightly...

Wouldn't pinched dropouts be better anyways? Seems like the welds on a welded dropout would create a weak point that would be more likely to break. But with pinched dropouts, there's no "break" between the steel and it's all one piece...

 

[dogman dan]

That is the way I see it. 2800 miles now on the pinch tube dropouts, no torque arms, who needs em with a good install on a good strong dropout.