Info on stripping a DNP Epoch freewheel

I thought I'd start a new thread on this...as the old previous thread is not so descriptive.


I bought a New 11-28 DNP Epoch freewheel

but the back end is sticks out a bit more, so the unit is wider as per this pic



The one on the left is a 11-32 I think.



All the threads on these are standard threads, so they undo in the normal fashion...anticlockwise.

If you do not have a Long reach DNP Epoch removal tool, then by stripping the freewheel on the motor, you should be able to get all the cogs off, then the carrier..to enable you to use the standard tool..as the 'depth' disappears when the splined carrier comes off.
To unscrew the splined stepped carrier from the freewheel you would need to put a strap wrench around the back on the the collar that I ground away, and then turn on the splines.


View attachment 4
Here is the compete freewheel with just the small collar removed and all the sprockets taken off.
Take note that all the small ones are standard Cassette-style splines and are polarised...but the bigger 3 are not polarised





The freewheel unit seems to be a sealed unit...there are no cir clips or further indications that anything else will unscrew. WRONG. I STRIPPED IT. SEE FURTHER DOWN THE THREAD...it is just those two dimples that look very much like spot-welded pins or similar...either way, opening it is likely to be a one-way process












This last pic is where I took too much metal off the back.
Go back up and look at the first picture, and then back to this one, you will see an extra 'ring', this is the race that holds the balls for the bearing in place...I exposed it all by grinding too much metal away from the back.

The groove cut through is just so I could see a profile of the unit, and where I realised that the rear outer ring, on the backside, was in fact not a retaining ring. I assumed it was a ring screwed to a protruding section of the splined body, but cutting through it showed the truth, that it was part of the inner section, the ratchet mechanisim.

Very interesting.
This sort of what I was hoping to see when the retaining ring was removed.
Thanks for the surgery shots!

What looks like a retaining ring on the back, the big one, is not in fact a ring.

The one on the front next to the 11 tooth is a locking ring, but the back one, that I thought was another locking ring is in fact part of the ratchet mechanism. It is also the stop that the big sprocket butts up to.

Going back a few years, Dr. B stripped one to make a 5 speed 11t, hereyou will see a different design to the carrier. Looks like a mega range unit.


Three steps on the free wheel mech

This is totally off topic, but this is the first post I've seen recently of a DNP rear gearset.

In my DNP 11-32, some teeth seem to be malformed, and the chain slips in that gear a couple times every rotation. No other gear, or gearset has that problem with the chain, and I've inspected the chain for signs of wear.

I thought it was just poor manufacturing quality, but it seems yours have the same "malformed" teeth as well. I've been told some gearsets have teeth which appear to be malformed, but are designed to nudge the chain to encourage shifting if the derailleur isn't perfectly set. I don't know what that looks like, but to have two completely different gearsets with similar looking deformations would seem a little unlikely, and it would seem that these "malformed" teeth might actually be intentional and I'm slipping for another reason.

Can you tell me whether your chain slips in any of your gears?

Thanks, and sorry for derailling (no pun intended) your thread.

I can't say, as I have not used mine yet, since I trashed it.
But many, if not all, gear clusters have these odd looking teeth as far as I know

Always possible that it is not the chain slipping but the freewheel instead.
Sealed units so you can't strip to clean and grease. EDIT ...WRONG.. I STRIPPED AND RE GREASED ONE..SEE LATER IN THIS THREAD.

Stripping, flushing, soaking in petrol, degreasing then, soaking in thick oil, EP0 liquid grease, possibly heated, is the only way I have ever re lubed one.

If your chain is actually slipping off the sprocket teeth to left or right, it's probably a chain alignment issue, helped along by the "deformations" you see on the teeth that are made to help it do that.

If it is slipping (skipping) up and over the tip of teeth, lengthwise along the chain, on hte same sprocket, then it's probably either not wrapped enough around the sprocket, not engaging enough teeth, or else it's simply not tight enough tension under load. (or both).

It can also be caused by wear on the teeth and/or chain. This can be measured easily enough; see Sheldon Brown's website about chain wear.

OK, here is a very quick update..

I am on the wrong side of two or four beers pus a glass or two of red wine..i have written this post three times now with pics..and then deleted ..

So I received two new DNP epochs today, and 8 and a 7 speed.

the 8 is deeper, despite the dished largest sprocket.

It turns out the carrier is a fraction deeper (1.69mm on the large splines section)....but ...all is not lost


it is possible to fit the dished sprocket and its spacers on to the smaller (Shorter) 7 speed unit.....if you have a lathe to hand.

You need to thin down the inter sprocket spacers to about 2.8mm from 3.3 mm and take a section off the back section.

I'd like to make this into a 5 or 6 speed unit, but that would need machining the small spines off and re threading the top section.
The splined carrier screws over the freewheel mech, and the larger section for the freewheel can not be made any thinner due to the thickness of the freewheel, so the smallest these could be made is six speed,

I finally did get around to stripping the ratchet mech. Not sealed as i first wondered.

The collar to remove to strip the the ratchet is the only reverse 'left handed ' thread on the DNP.

Ideally you would make a tool with a flat plate and two pins to remover the collar, or maybe you already have a tool for the job.....but if not a centre punch in to the dimples and a hammer does the job.






Simply a matter of gripping the outer unit and turning the collar clockwise to unthread it. It was very tight, so maybe the application of a little heat on the collar would help. A chefs kitchen blowtorch or small welding gas pencil flame ideal.

I did not have the correct tool to hold the unit with the internal splines, so i crudely ground a bar as you can see in the pic and stuck in in the vice. This holds the unit while you tap the collar to undo it....remember clockwise to remove

Note the very thin shims/thrust washers . that are directly underneath the threaded collar. on my unit, one was stuck to the collar with light grease. So check that you don't lose it by letting it fall off .

After removing the threaded collar, the outer just lifts away. Do this in a plastic tub also...just in case your balls drop :lol: They should be secure in their cage, but you never can be sure that you won't dislodge one.
The three ratchet pawls, held in place with the spring ring, which is easy to remove with a small flat blade screwdriver or piece of bent wire. The pawls then fall out. Do this job in a plastic box too, so the pawls don't flick away and disappear under the workbench.

Ball bearings and their cages too just lift off.









After stripping it is then a matter of cleaning in a solvent to remove all the old grease / oil etc replacing the ratchet pawls and spring collar, the re packing with a light grease. Any grease that is too thick will hinder the action of the ratchet pawls as the spring mech that opens the pawls is not that powerful

I have also managed to rebuild a 7 speed unit, with the 'dished' 8 speed largest gear, so making an 8 speed on the narrower 7 speed splined body.

My initial plan was to make a narrower 5 speed unit..11-32 or 11-34 using the 8 speed largest dished gear, so the whole unit would sit closer to the hub motor. Due to the thickness of the ratchet mech it is not possible to reduce the number of large splined sprockets, and the only way to reduce the number of small spline sprockets would be to turn down the small splines on the carry and re thread the end after reducing its length.
that is the next job...on the scrap ones before I damage another working unit.

So now I have an 8 speed that is thinner than the original 7 speed unit, it sits closer to the hub, and no longer needs a spacer on the axle. I actually have more clearance than I need between the 11 tooth and the frame.
This thinner unit was achieved by turn gin small amounts off each gear, each spacer and also the seat where the 8 speed sits. I have actually achieved my objective of moving the cluster over closer to the hub TOO well. The derailleur now drags on the hub when in the 32 tooth sprocket. Now I'll have to space it out a bit.

Further update.

yesterday I managed to thin down the 7 speed 11,13,15,18,21,24,30 unit to a 5 speed. 11,13,18,21,30


Overall width is now down to about 32mm.

I took thickness off both the rear of the unit, the freewheel mechanism, the inside of the splined carrier, and the front of the splined carrier. Need a M30 x 1.0 die to re tap the thread though.

I refer to the following pics in the next paragraph. where I reduce the overall thickness of the freewheel unit, so it sits deeper in the carrier.

Look at the freewheel unit in the picture,
First strip it, remove bearings, pawls etc and de grease...see second pic with bearing sand pawls still in place.
The ring with the indents in, it can be machined down by the depth of those indents..but leave a little to allow re assembly.
Then machine the outer thread portion and the central (internally splined ) section. Take all of this down by about 0.75mm.this may vary ..don't go too far in to the bearing race seat.
You will also need to remove two or three outer threads as the internal thread on the splined carrier is not as deep and if you leave that many threads on the mechanism it binds when screwign the outer splined unit back on.
You also need to remove maybe 1mm or so from the back plate of both freewheel parts. (the bit that butts up against the hub side plate) Leave the inner section slightly thicker to allow the mech clearance to spin.

Re assemble the mechanism












The carrier needs to be machine internally. The flat section on mine was about 1.75mm. I took it down to 1.4mm.
Then machine off some of the largest diameter section. Do this a bit at a time, test fitting the freewheel to see it still spins. If you do get to a point where you have taken a bit too much off the outer splined depth, you may still have enough to remove some material off the inner flat..but you are seriously weakening the unit as is..so go careful.

Where the sprockets 'step' up the shoulder, it is between gears 18 to 21 so they have to stay, as does the 11 tooth. But you could do 11, 15, 18 21 30 rather than 11 13 18 21 30.

Last thing I did was to machine off the small splines, to a depth great enough to aloo removal of one gear and spacer.
Final step will be to re thread the now machined down section to tighten the collar up against the 11 t.

Ignore the wonky ness..that is camera distortion. An original next to a re worked unit. Original has the broken freewheel inside it




View attachment 5





You need a spacer first..as you can not remove enough of the freewheel to loose all the space. If you have an 8 speed unit..the 34 tooth gear is dished, so you may be able to fit that and a smller spacer..but then you may have clearance issues with the derailleur and the hub in the largest gear..I did.

it may also be possible to reduce the thickness of each cog spacer, and use a 10 speed narrow chain..so you could may be able to get 6 or 7 speed on even with the reduced freewheel width. So you'd have a 7 speed at 9 or 10 speed spacing .




View attachment 2





Just need the die to tap the new thread now.

NeilP said:

If you do not have a Long reach DNP Epoch removal tool, then by stripping the freewheel on the motor, you should be able to get all the cogs off, then the carrier..to enable you to use the standard tool..as the 'depth' disappears when the splined carrier comes off.
To unscrew the splined stepped carrier from the freewheel you would need to put a strap wrench around the back on the the collar that I ground away, and then turn on the splines.

=

Click to expand...

Hi NeilP,

I am looking at a situation where the inside of the freewheel interface is likely stripped because I was turning the tool the wrong way. Even a new tool , going in the correct direction is useless after two tries. Now, the freewheel is still good with many more miles on it, hopefully, but my question is, how do you get the cogs off? Chain whips? My plan, when its time for replacement is to take all the cogs off which will allow me to remove the motor cover and replace the motor cover and a new freewheel as I happen to have said motor cover. Hopefully that makes sense, I can take pictures if needed.

Is this the process?
https://youtu.be/uwGCZuWPQGk?t=113

Thanks.

I wish I could help you, but it has been nearly 5 years since I did that.

I honestly have no idea now, sorry

Good luck

NeilP said:

I wish I could help you, but it has been nearly 5 years since I did that.

I honestly have no idea now, sorry

Good luck

Click to expand...

No problem, knew it was an of chance because the thread was so old. Thanks anyway.

Sunder said:

This is totally off topic, but this is the first post I've seen recently of a DNP rear gearset.

In my DNP 11-32, some teeth seem to be malformed, and the chain slips in that gear a couple times every rotation. No other gear, or gearset has that problem with the chain, and I've inspected the chain for signs of wear.

I thought it was just poor manufacturing quality, but it seems yours have the same "malformed" teeth as well. I've been told some gearsets have teeth which appear to be malformed, but are designed to nudge the chain to encourage shifting if the derailleur isn't perfectly set. I don't know what that looks like, but to have two completely different gearsets with similar looking deformations would seem a little unlikely, and it would seem that these "malformed" teeth might actually be intentional and I'm slipping for another reason.

Can you tell me whether your chain slips in any of your gears?

Thanks, and sorry for derailling (no pun intended) your thread.

Click to expand...

Years ago I had some chain "jumping" problems w/ a DNP Enoch and read somewhere (perhaps Sheldon Brown), that due to the "shark fin" shape of the teeth, some extra care in adjusting the derailleur could be of benefit. Basicly, the derailleur is adjusted further under and as close to the gearset as possible. Worked for me.
As a side note, I use the DNP on my 2WD and after having to buy a replacement due to wearing out the 11 T gear, I removed the shifting stuff and just leave on the sm. gear all the time. I didn't really need to downshift and I think not having the chain climbing over the gear extends it's service life. When starting and climbing hills (times I would normally down shift), I just engauge the frt. motor.

^ I have not found that on Sheldon Browns website, it mostly talks about everything else like Chain Wear - including stiff links, Cable Routing - or how its routed around the bottom bracket, gear wear, lube, flexible frames. There are about 3 or 4 pages on Sheldons website on various subjects around auto shifting and skipping.

Chain wear and elongation is what wears sprockets and makes them skip. You can get typically 2 or 3 chains worth of life out of a cassette or freewheel, as long as you replace the chain before it's elongated past its operating limits. If you let it go too far, you'll reshape the sprocket teeth to the point that they skip when used with a new chain.

One of the reasons I recommend against DNP freewheels is that the sprocket teeth are poorly formed and made from more wear-prone metal than Shimano or the better grades of SunRace freewheels.

That is good to know!

Chalo said:

One of the reasons I recommend against DNP freewheels is that the sprocket teeth are poorly formed and made from more wear-prone metal than Shimano or the better grades of SunRace freewheels.

Click to expand...

Seem to remember that there was no other option at the time. Think it was that there were no other cassettes available with an 11 tooth . There was a shimano that was made but almost impossible to find, and if you could find New old Stock, they were selling for hundreds of dollars.

The DNP was the only one available, cheap and cutting one up like I did to make a custom one was not a problem.

I did two like this, so I’d have a spare.

But if you are making an e-bike and running it as Twist and go and not PAS, chain wear /tooth wear will be negligible.

This was for a 24 series, 100volt 18 MOSFET build bike running about 80-100 amps... pedalling was merely to look legal

NeilP said:

Seem to remember that there was no other option at the time. Think it was that there were no other cassettes available with an 11 tooth .

Click to expand...

There are abundant cassettes available with 11t high gear-- probably most of them. But what you have isn't a cassette. It's a freewheel. Your wheel can only take one or the other, and most hub motors take freewheels.

Chalo said:

There are abundant cassettes available with 11t high gear-- probably most of them. But what you have isn't a cassette. It's a freewheel. Your wheel can only take one or the other, and most hub motors take freewheels.

Click to expand...

Ah well OK , I got it the wrong way around.
So in that case, when I did that, how ever many years ago, there was not other 11 tooth free wheels around, just the DNP or the ‘rocking horse shit ‘ Shimano version.

Not touched bicycles or e-bikes for a good few years now.

NeilP said:

Ah well OK , I got it the wrong way around.
So in that case, when I did that, how ever many years ago, there was not other 11 tooth free wheels around, just the DNP or the ‘rocking horse shit ‘ Shimano version.

Not touched bicycles or e-bikes for a good few years now.

Click to expand...

Exactly the reason I have a DNP. I've got about 5000 miles on mine and it is holding up fine - though I use paraffin wax and my DNP is nickel plated. So maybe that mitigates the wear issue?

markz said:

That is good to know!

Chalo said:

One of the reasons I recommend against DNP freewheels is that the sprocket teeth are poorly formed and made from more wear-prone metal than Shimano or the better grades of SunRace freewheels.

Click to expand...

Click to expand...

Except for those of us that need an 11 T sm.gear on a freewheel, there is no other choice.
I'm of the opinion that the quality of the Epoch did improve 2 to 3 years ago.
My current one(3rd?)runs quiet and smooth.
I think all the DNP's are nickel plated.

I'm easier on freewheels and cassettes now than when I was young and fast. More diligent about keeping things lubed, equipped with more bikes to spread miles among, and just not that ambitious about riding hard.

I would have jumped at the opportunity to use freewheels or cassettes with 11t high gears back then-- and it would have been a bad idea. They're inefficient and hard on chains, and they shorten the service life of everything they touch (if you use them).