Extreme Hill Climber Fat Tire MTB Project.

[commuter ebikes]

I had not thought of the freezer and oven. Thanks, Dan. I would choose "motor in the oven, hub flange and bearing assembly in the oven". I wonder what the maximum safe heat would be for a sealed cartridge bearing.

[Gr8fun]

I have put one part in freezer the other in oven. Just drop in place. No press needed. No real high heat either.

[commuter ebikes]

I tried pressing the bearing into the freewheel mounting flange (easy) and then trying to press the side cover onto the axle (nope!) here, at 20:53 in this video https://www.youtube.com/watch?v=QA2qQkexj2g.

I have tried pressing the drive side cover onto the axle using the clamping pressure of the eight side cover bolts, but the bearing did not seat completely. One could try to use a socket to seat a bearing as seen at 2:39 in this video https://www.youtube.com/watch?v=QETuIW0_0wo

[commuter ebikes]

If you have the room (135mm would be really tight!), you would use enough freewheel spacers to allow a little empty space between the top of the freewheel mounting threads and the inside of the bottom of the locking flange (if you are using, for example, a White Industries freewheel). This gets you maximum clamping surface area between the freewheel and flange, at the freewheel spacer and bottom of the freewheel driver.

Alan, you totally nailed it when you wondered where the freewheel lay against the motor, asking if I had used freewheel spacers. By not using freewheel spacers, I failed to take advantage of the flat circular area (pictured below) at the base of the freewheel driver.

[commuter ebikes]

Hopefully, these two pictures will help show how to maximize the clamping surface area. Maximizing the surface area between freewheel and the flange helps prevent the freewheel from losing contact with this clamping surface area and being able to strip the threads.

[Alan B]

That's what I was concerned about. I didn't use my White freewheel exactly because of that reason, and I used the Dicta brand instead, because they sit all the way down on the Cromotor. I was planning to turn off the extra threads so the White could sit fully against the flange, but never got around to it. The Dicta works fine, but it does wear out about as often as my Moped tires do, so I just replace them at the same time. Lubricating the Dicta does extend its life as well. Additionally the White is wider and I'm not sure there is enough space on my 135mm setup.

[commuter ebikes]

This is a freewheel which has no material to interfere with tightening it all of the way down against a freewheel spacer:



This is a good thing because when you tighten it down, the bottom of the freewheel driver gets maximum contact with the freewheel spacer for maximum clamping and thus resistance to losing contact and getting a chance to spin forward and strip the threads.

[commuter ebikes]

I spent a long time at White Industries this morning talking with Alec, mostly about how the freewheel driver (I was calling it a freewheel body) engages the freewheel mounting flange and thus driving the wheel forward. White Industries is a huge, high tech outfit; anybody would have been impressed. Alec was generous with his time, and he was so knowledgeable about the matter being discussed that the conversation with him made my suffering over my twin catastrophic mechanical failures worth it!

The end result is that White Industries is going to manufacture ten freewheel mounting flanges (pictured in post #123 above) made of 8620 steel, case hardened and then electroless nickel plated. This order will set me back about $2,000.

The problem was twofold. One problem was that the major diameter of the 1.370 inch (or 1.375 inch, depending on who you ask) X 24 tpi male threads on my existing freewheel mounting flanges was a bit too small. This resulted in threads that were too shallow. I had this same problem when I tried to roll spoke threads at home on a Cyclo spoke threading tool. The steel spoke threads were too shallow and the brass nipple stripped the spoke threads (I solved this problem by buying spokes threaded on a Phil Wood machine).

When my freewheel mounting threads stripped, the nearly indestructable threads on the inside of the White Industries freewheel driver just tore through the shallow threads on my freewheel mounting flange, which I believe is made of "automotive steel" which may be 1018 steel.

The other contributing factor was how I had installed the freewheel on my flange. I used no freewheel spacers, so the underside on the freewheel driver had nothing to clamp on to, except a small surface at the top of the threads (I will post photos of these clamping surfaces). The freewheel will be less likely to strip the male threads (on the freewheel mounting flange) if I maximize the clamping surface area. This will be accomplished by tightening the freewheel against an aluminum freewheel spacer.

Another important point is that some freewheels have an open end (pictured below). This functions well because the freewheel gets tightened all the way into the freewheel spacer which gives you all of the clamping surface area that a freewheel spacer can provide.

All of the White Industries freewheels have the locking flange at the top of the threads; if you don't use freewheel spacers, you only get the small surface area at the inner top of the locking flange which, in my case, allowed the freewheel to lose contact with this reduced clamping surface area and proceed to strip the threads.

[Gr8fun]

Geared hub front and rear. drive will not match a mid drive. Did see there was a hub motor with a sturmey 5 speed built in. That would do it..... Maybe. A bit spendy.

[MoneyPit]

Has anyone tried this experiment with an AWD hub motor bike? Mine is amazing in hills although its not at the power levels yours are and I have only informally tested it in hills at home (Monterey CA area). I originally built it up to run as a commuter on flat ground - my business is in Fresno CA where its table-flat.

I'm running two Bafang 750w motors with a 52v Luna Storm battery for rear (25R cells) and two parallel'd Luna 30Q mini cubes for the front. 35a controllers on each motor. Managing traction on the front motor is surprisingly straightforward but then again its a great big fat bike. I originally hung the battery and controller for the front in a bag under the bars so the weight would aid in traction, but found it unnecessary and now the battery is in a rear rack trunk while the controller is in a (much smaller) handlebar bag up front to minimize exposed wiring.

I'm not expecting such a setup to beat a mid-drive, but I'm pretty sure it would beat up on a rear-drive-only hub motor even running 72v. AWD has been extraordinary on a bike, at least to me.

[Gr8fun]

If anything should have failed climbing those hills it should have been my sturmey 3 speed hub. But then again they have been breaking for over a hundred years to learn how to make them as durable as they are today. It is up to me to find the breaking point.

[Gr8fun]

Something is very wrong with this picture. Those freewheels should not have stripped out. Ask white. This is not looking good.

[calfee20]

I would take my wheels to a shop that has a wide enough press to seat the bearings. Then you wouldn't have to remake the wheels. Why has this not been a point of failure for every BBSHD driving a freewheel which is quite common.

I know you won't want to hear this but I think I could assemble that without a press.

[Alan B]

Sorry to hear of your problems. I don't understand what is happening here.

Did you visit White Industries already?

Before going forward I would suggest conducting a thorough failure and root cause analysis to understand what actually is happening, and where the torque transmission occurring. How many threads are engaged and what is resting on what when the freewheel is fully seated? Is there a spacer between the freewheel and the hubmotor? White Industries may be a huge help in all this.

White Freewheels are often used to transmit MOTOR torque from mid drives to the rear wheel, You are only asking for it to transfer pedal power. This failure seems surprising.

Note that a mid drive will put considerably more torque on the freewheel threads than this hubmotor setup.

If the freewheel is slipping on the threads it would seem possible to remove it. Do you have a removal tool that will fit the slots over the large axle?

[commuter ebikes]

Things are looking up already. The very busy Vladimir S. at Zelena Vozila has two new Cromotors ready for me with 170mm dropouts, spare axles, freewheel mounting flanges to replace my stripped units, drive side motor covers and extra snap rings.

I ordered these 170mm dropout motors and spare axles with a very long total axle length (260mm!). I will be hopefully be able to jam in enough axle spacers to spread my steel frame and cram a 5-speed freewheel in there and still have enough axle length to fit my torque plates as well as engage all of the threads on my axle nuts.

The 5-speed freewheel has a 13T small cog so that will raise my spinout speed by about 19% (to 25mph). So I am back to tall gearing for commuting in my flat city.

My last hope of obtaining short gearing would be to weld in the threaded shaft of the freewheel and assemble the rest of the freewheel parts while it is on the side cover. Unfortunately, there is a flange in the way. This, together with the lack of access on the underside of the freewheel, will almost certainly make it impossible to weld the freewheel body onto the side cover. Plus who wants to have to lace and true the wheel, buy new spokes, nipples, freewheel mounting flange and side cover, and reseat an axle bearing every time you replace the freewheel? You have to think that welding a freewheel onto a hub motor side cover is a terrible idea.

The flange that would get in the way of welding at the threads is pictured here. It has four notches in it.