New bike with weird front dropout - Need to fit front hub

[Electricmover]

So I have gotten hold of this used bike and are going to make something out of it. I have been a tinker for quite some time.

Anyway the dropout looks superweird and I think the previous owner have welded on some adjuster metal-plates there to make his previous wheel fit or something.

Anyway, the axle of the fronthub is a lot thinner. Now, could I just put this fronthub on there and go ride the bike or do they have to be exactly the same? Axle and dropout. If you look at the third video below, after clamping on the bolts hard on both sides, to make it stick to the bike, the wheel actually spins pretty well and looks like it might work problem-free. Do you think I could just put a torque arm on to there as an extra safety and then get out biking with this thing?

ow's Video - Nov 24, 2024

veed.io

ow's Video - Nov 24, 2024

veed.io

ow's Video - Nov 24, 2024

www.veed.io

 

[JRA]

Does look like someone grafted "torque" washers, I use the term torque loosely as they never work well, to the original fork dropouts. If you current motor's axle is thinner than the washers under load, as with a person aboard adding weight, the motor will spin and tear out the wiring most likely. You could solve all issues by getting a set of torque arms that are generally available in most ebike kit sites that put the axle load onto the fork directly instead of the dropouts.

 

[gromike]

Does the front wheel have a working brake? Does the wheel mount solidly into the modified dropouts.
Personally, I would replace the forks with something unmodified, and then do good brakes and torque arm.
An ebike is heavier and travels faster, so you're gambling with your life if the bike's structure, the front wheel forks and steering in particular, isn't up to snuff.

 

[Electricmover]

Does look like someone grafted "torque" washers, I use the term torque loosely as they never work well, to the original fork dropouts. If you current motor's axle is thinner than the washers under load, as with a person aboard adding weight, the motor will spin and tear out the wiring most likely. You could solve all issues by getting a set of torque arms that are generally available in most ebike kit sites that put the axle load onto the fork directly instead of the dropouts.

Hmm I have clamped it in with the bolts so I guess it is quite tight.

Do you mean an ordinary torque arm that just prevents the wheel from coming of if it spins out of the dropout? Kind of like this simple one here would work?

https://www.aliexpress.com/item/1005006063498630.html?spm=a2g0o.order_list.order_list_main.5.5ea81802uepRkh

 

[Electricmover]

Does the front wheel have a working brake? Does the wheel mount solidly into the modified dropouts.
Personally, I would replace the forks with something unmodified, and then do good brakes and torque arm.
An ebike is heavier and travels faster, so you're gambling with your life if the bike's structure, the front wheel forks and steering in particular, isn't up to snuff.

It mounts solidly when clamped in towards the middle via the bolts. But as you can see from my second/middle video above it is smaller in diameter than the dropout holes. So it sits in place via sideways pressure. Maybe a torque arm would be enough to hold this together? So if it gets loose the wheel does not leave the bike. Just makes it dysfunctional for a while.

 

[Electricmover]

You could solve all issues by getting a set of torque arms that are generally available in most ebike kit sites that put the axle load onto the fork directly instead of the dropouts.

Is that what it does? I thought those things were only so that the wheel did not come off when extra torque was applied or something. Hmm good to know. So what they also do is to load the fork instead of the dropouts huh? ok

But then the hole in the torque arm is the one most important right? That they fit snugly around the axle of the wheel axle?

 

[JRA]

Correct, whatever you use as an anti torque device must fit snugly to your motor axle.

 

[harryS]

Looks like someone welded lawyer lip washers to the fork dropouts. I am wondering how you got the motor in. Did you have to spring the forks apart and slide the motor hubs thru the holes? Can't be good for the steel fork.

Lawyer lip washers intended to keep regular bike axles from falling out if the axle nuts or QR skewers get loose. Not intended as torque washers. In your case, if the welds don't rip out and if the bottom of the steel lip holds, I guess it could keep the wheel from falling out if the nuts got loose. Maybe. It might just round out the steel, spin the motor round and round and tangle up the motor cable,


Your video's are hard to follow, but it doesn't look like you have a very wide axle at all. Is there room between the fork and the motor to add torque washers? These have those anti spin tabs that grab the fork. But a torque arm is better.

I would not ride your front hub. Sure, they spin good with no load, but when you have weight on the wheel, the torque on the axle fasters is a lot lot higher.

 

[PCeBiker]

Correct, whatever you use as an anti torque device must fit snugly to your motor axle.

It needs to be hardened steel as well.
My rear hub motor uses the dropouts as the torque arm and is reinforced on one side.

But the axle flats still bite into the metal on both sides of the dropout and gets jammed.
I have to rotate the axle a bit to "unhook" it to get the wheel out of the dropouts.

 

[Electricmover]

Looks like someone welded lawyer lip washers to the fork dropouts. I am wondering how you got the motor in. Did you have to spring the forks apart and slide the motor hubs thru the holes? Can't be good for the steel fork.

Lawyer lip washers intended to keep regular bike axles from falling out if the axle nuts or QR skewers get loose. Not intended as torque washers. In your case, if the welds don't rip out and if the bottom of the steel lip holds, I guess it could keep the wheel from falling out if the nuts got loose. Maybe. It might just round out the steel, spin the motor round and round and tangle up the motor cable,

View attachment 186638View attachment 186641View attachment 186642
Your video's are hard to follow, but it doesn't look like you have a very wide axle at all. Is there room between the fork and the motor to add torque washers? These have those anti spin tabs that grab the fork. But a torque arm is better.
View attachment 186645
I would not ride your front hub. Sure, they spin good with no load, but when you have weight on the wheel, the torque on the axle fasters is a lot lot higher.

I am trying to send this video where I do the best that I can to film it, while not being able to hold my phone at the same time

To answer both of your questions, I have what looks like a torque washer on one side and on the other side, where the cable is, the torque washer basically sits stuck to the wheel right(?). This is what I point to in the video. So I guess I have torque washers then at least right? Which is what these are called, right?

And about how I got the wheel on and off the bike. Yeah, I press the wheel in from one side and then pull on the other a bit to press it in there too, like I do here. If I reinforce this with a selfmade torque arm or something that might do the job don't you think?

ow's Video - Nov 25, 2024

www.veed.io

 

[PCeBiker]

If I reinforce this with a selfmade torque arm or something that might do the job don't you think?

The flats of your added torque arm will need to line up with where your axle flats are held in your forks now.
That probably won't leave your torque arm lining up against the fork to attach it.

There may not be enough axle space for an additional torque arm ?

 

[m@Robertson]

I'm coming into this party a little late.

As @JRA originally stated, what you have is an ordinary bike where someone has welded on torque washers. Torque washers are a low-functioning way to combat motor spinout... they use that little tab at the bottom (the top on the bike as its sitting upside-down) to become a 'stop' when the washer gets partially spun. But that partial spin is enough to ruin the fork as it allows rocking which means they only slow the damage rather than stop it. Whoever this original guy was, he spun out the front axle. You can see the dropouts are npo longer parallel if you freeze-frame your first video. So he realized his fork was ruined, or he could weld on these washers and use their flats to contain the axle's tendency to spin (because the tabs sure aren't going to do anything on spread dropouts). The remainder of the protection would be tightening the crap out of the axle bolts, and prayer.

What you have is a desperation repair, really. Usually a failure like this is The End and the frame or fork is garbage. The dropouts can't be bent back due to metal fatigue making them bend easy afterwards. Don't take this personally but this is probably the most half-assed salvage I have ever seen. The torque washers being bent steel are even the cheap kind, not the 'better' kind like what @harryS pictured.

That torque arm in Post #4 is the LAST thing you want to use. That is the Grin Tech v1.0 torque arm design and it was abandoned years ago. Its still in use by any number of Chinese knockoffs and they are notorious for fitting loosely, being thin, being soft metal and generally being barely adequate.

I use a Grin v5 on my front motors. I used to use a v2 but the v2 can slip since it has a sliding arm, whereas the v5 cannot since it has just round holes that can't break loose.

This is a v2.0 torque arm. It can slip (it never did) on that arm since its held in place by the torque of the bolt on the arm extension.

This is a v5 torque arm. It can't slip because the locking arm has a round hole on each end instead of a slider down its length. The main bit that fits around the axle also has a way so you can clock it at any angle so you can make it fit no matter what your bike's dropout geometry is.

One of these on each side is what you should use over and above what you have on there now. IF you decide to try and save this fork, which frankly I would not do. Two torque arms bought from Grin Technologies directly is going to run about US$70 (Amazon has them shipped overnight but it costs more), and you are still stuck with this horrendous hack job on the fork. Get a new fork on Ebay and THEN put proper torque arms on it.

 

[m@Robertson]

I am trying to send this video where I do the best that I can to film it, while not being able to hold my phone at the same time

Holy $hit I just watched that video and the torque washers are oversized. Probably 14mm flats meant for a really big direct drive motor in the rear. They provide no anti-spin protection whatsoever.

 

[Electricmover]

Yeah, but then I know at least. And I think I will either change the fork, since I have one in mind, but I am not sure if it will fit. Will show you when I get home later today. Or if it does not fit I will probably throw away the frame.
I actrually bought this and got hold of a strong big front motor-wheel, controller and a bunch of other stuff that I stripped of the bike. So the idea was to throw on a weaker more simple front wheel motor on this one and then sell it. Because I normally like to do more robust, faster and stronger bikes.

But I don't want to sell it if it could be dangerous. So last try will be to check out if the other fork might fit later today. I did try this new front wheel-motor with a battery and some other ebike stuff I got hold of and it seems to work well. So it would be a bit disappointing if it does not work because of this weird front fork the guy welded on(or the guy before him not sure) with washers, but that is life.

 

[m@Robertson]

"it could be definitely is dangerous"

You can try and save it yourself if you are on a budget and are willing to assume the risk with your eyes open, but selling it on to someone else is a big time liability risk.

If replacing the fork, I dunno if you are up on that sort of thing but a front motor on a suspension fork is just as bad of an idea. They tend to snap their alloy dropouts clean off even with torque arms. The few bikes that are sold that do a front motor use steel solid forks, or a neutered front motor coupled to a fork with specially reinforced dropouts. Replacing a fork should be successful so long as you have nearly the same fork blade length. Whats called the 'axle-to-crown' length. Shorter blades will screw up handling really bad. Thats a lesson I learned the hard way. Also there is the steering tube. A straight one is pretty much universal and almost certainly what it is that you have.

 

[Electricmover]

"it could be definitely is dangerous"

You can try and save it yourself if you are on a budget and are willing to assume the risk with your eyes open, but selling it on to someone else is a big time liability risk.

If replacing the fork, I dunno if you are up on that sort of thing but a front motor on a suspension fork is just as bad of an idea. They tend to snap their alloy dropouts clean off even with torque arms. The few bikes that are sold that do a front motor use steel solid forks, or a neutered front motor coupled to a fork with specially reinforced dropouts. Replacing a fork should be successful so long as you have nearly the same fork blade length. Whats called the 'axle-to-crown' length. Shorter blades will screw up handling really bad. Thats a lesson I learned the hard way. Also there is the steering tube. A straight one is pretty much universal and almost certainly what it is that you have.

Ok check this out. This one I had lying around. It is also a budget fork but it has pretty solid dropouts I think.

But I don't know if it would work to switch this type of fork with the one sitting on the bike. The vintage type of screws that puts the other fork in place right now are that old school type. Would it be possible to switch these forks?

I guess the new one should be put in place via a starnut like they normally are. But this old fork is stuck in place using that vintage style screw-set from the 1700s.
I think I have some of the screws needed to put a new fork in place and I have done it before, although it was a pain in the ass. But the question is if it is possible to switch these two? What do you think?

ow's Video - Nov 25, 2024

www.veed.io

 

[harryS]

Here's the thickness difference between those lawyer lip washers and torque washers. If a motor can crack off cast aluminum dropouts, it's going to bend the soft steel on those lips.




So you really did spread the fork to get the wheel on. Grind off those welded washers.

 

[PCeBiker]

. But the question is if it is possible to switch these two? What do you think?

I'm thinking no.
Your original steerer tube is threaded so it is most likely steel with a smaller diameter than the spring fork steerer tube with an unthreaded alloy steerer tube.

The steerer tube may be too short as well.

 

[harryS]

You're better taking a picture and uploading to this website. There are two kinds of forks. Threaded and threadless, and you had you hand covering the end of the other fork in the video, but I think it's threadless. And within each category, you have 1" and 1-1/8" diameter stems, making four kinds of forks.

A further distinction is suspension forks vs hard forks, AS a general rule suspension forks are a poor choic for motors if they are made of alloy, which is brittle. You can get away with suspension forks if you have a smaller motor plus good fasteners, which include torque arms. Changing forks takes experience and a bunch of parts, Going from threaded to threadless means you have to buy a new step to hp;d the handlebars.

I think it would be simpler to grind off the welds on the first forks, and use good fasteners.. Makes it easier to change a flat tire, Your motor doesn;t look too big either,




.

 

[Electricmover]

It is too bad that it cannot be used right away, because it looks like the wheel sits pretty well in place between the forks now and it spins pretty well on the throttle. But if you guys think this is dangerous I will either change the fork, or if you think the other fork does not work either, the I will just throw away the frame to the junkyard after I have stripped the steer, backwheel and crank. Looks like this right now with the weird dropout fork still in place. So at least I know the motor, battery and controller is going to work on another bike if I build one:

ow's Video - Nov 25, 2024

www.veed.io