Building a quality 11t freewheel

[auraslip]

I know the quality (and the price!) of the dnp epoch 11t freewheels bothers people. Other than the odd vintage shimano 11t freewheel popping up on ebay, it's our only choice though.

What I'm wondering could we build a better one?

Could we se a quality shimano freewheel and replace the cogs with either

Cogs from the DNP

Or even better, cogs from a cassette?

I know these questions probably answer themselves to those with experience, but I have little experience with the drive train of a normal bicycle.

[neptronix]

The cogs seem to be all part of one large unit, and not seperable.. at least the lower ones.
I don't think you can mix and match. That seems to work with a cassette but not a screw-on freewheel.

I saw the DNP Epoch with the 11t.. but never heard of the brand. What's wrong with the DNP Epoch? total crap?

[Ykick]

What's wrong with the DNP Epoch? total crap?

I've had one ($30-$40 shipped) for a short period of time (1,000 miles?) it developed a "squeak" when cold and seemed stiff even at room temperatures. I shot some WD40 into the thing and it seemed to quiet down for a while but not much confidence in the "dull sound" of the thing when freewheeling.

I recently faced the decision of swapping it over to my new 9C DD rear but opted for a trusty old Shimano 13T. I'd like to have an 11T on rear hub but I don't think the DNP freewheel is high enough quality IMO.

[neptronix]

Ahh Ykick.. i had a feeling. That is unfortunate.
My solution is a 13t and a single 48t gear in front.

[auraslip]

http://forums.mtbr.com/showthread.php?p ... ost7787283
This thread is really helpful!

This pictures shows the lock ring from a shimano hyperglide freewheel.

It's not the same size as a bottom bracket lock ring. That is sad because the TPI of a bottom bracket is the same thread as on our hub motors. Fixed thread on sprockets also share this thread, but I don't think we'd want to attach that on to our bikes

[auraslip]

You can see here freewheel and cassette sprockets are not compatible. In fact freewheel sprockets are usually proprietary grooves! Cassettes are interchangeable.

So.....I guess I'm going to order a single speed 11 tooth freewheel.....

or maybe I can get a machine shop to make an 11tooth sprocket that fits on shimano hyperglides

[itselectric]

I don't know if this is right place or time to provide addition information, but if I sound like self-promotion, please let me know i will get off from this topic.

I have direct connection with DNP. I met with top level manger in 2010 in Toronto, Canada. I have address some of common problem with DNP products. One of them there wasn't enough grease injected into freewheel, which they have corrected since 2009.

Here are some background information, that I hope some of you may find it interesting:
My understanding to produce 11 tooth freewheel is very difficult, especially in 7 speed. I can't remember why. DNP had almost abandoned 7 speeds 11 tooth completely, which I have convinced them no to do so. Now, they are in middle re-design 7, 8, 9 11-tooth freewheel. And I am involved in beta testing with their new freehweel. This is a lot of works, this involve installing 7, 8, 9 speed freewheel on each brand of motor (crystalyte, bafang, mac, bmc, bionx, etc...). We are looking for spacing problem, which motor will not fit for the new freehwheel and what other problem we can find. Then we road test the bike to see if it had any skipping problem. So far, the 7 speed had passed our test, but 8 speed had failed. The first batch of prototype actually stuck on 7 gear, the 2nd batch will skip between 7 and 8, you can see the result in this video here:
http://www.youtube.com/watch?v=cmT9h9HYFOo

and the prototype of 9 speed is on its way.

Coming back to original topic, if you know there is problem with the current DNP 11 tooth freewheel, I can help to address the problem, and ask the manufacturer to improve and produce a better quality products, so we can all get a better products. If there is enough communication in this topic, I can ask DNP to join in for the conversation.

Here is what I like to suggest:
1.) please list out 3 thing that bug you with the current DNP freewheel that you have, but please make suggestion instead complain only
2.) You can join me for beta test for new production 11tooth freewheel. I will pay for the shipping cost, freewheel, etc.. If you have more then one type rear motor would be better, and I would need feedback from you.

And if we have enough feedback to manufacturer, we could have excellent products in 2011.

Ken

[miuan]

Lubing that POS DNP freewheel is crucial to keep it running. Mine had run out of lube after 1000 miles, so I had it rebuilt/relubed at the shop. Another cool idea is to keep it submerged in oil for a couple days and stir it from time to time, so it gets lubed thoroughly. It may get messy later however, because all that oil will slowly be getting out once installed.

[Jeremy Harris]

When I went into my LBS to try and see if they could get me one of the DNP 11t freewheels (shipping from ebikes.ca was just too expensive) the chap frowned and asked why I'd want to buy something as crappy as DNP. He then pulled out a box of badly worn and broken DNP freewheels to show me and said he'd never ever stock them again as they were total crap. Somehow I doubt that it was just a lack of lubrication that caused the problems; the few I looked at might was well have been made from soft cheese.

As a quality alternative, I've just bought an new, but old stock, Regina 6 speed freewheel to try on my folding ebike. I've not fitted it yet, so can't say how well it works, but the quality feels good. To give some idea of how they've made a 12t gear fit a freewheel core, here are some photos:

Regina Freewheel 1.JPG (164.13 KiB) Viewed 3558 times

The freewheel is a close ratio one, 12t to 18t, but that will be fine for my 20" wheels with a 50t chainring and 170mm cranks. You can just see that the three smallest sprockets are screw fitted (with a right hand thread) to the front of the freewheel body, so they need to be removed to get at the larger bearing retainer underneath. Here's a photo of the freewheel partially dismantled:

The two larger sprockets are threaded on to the rear face of the freewheel with left hand threads, with one sprocket remaining an integral part of the freewheel body.

Maybe it would be possible to fabricate something like this? They aren't made any longer, probably because the cost of manufacture must have been high when compared to the Japanese monobloc freewheels with non-interchangeable sprockets, plus I suppose that cassettes just took over anyway.

Jeremy

[Hyena]

Now, they are in middle re-design 7, 8, 9 11-tooth freewheel. And I am involved in beta testing with their new freehweel. This is a lot of works, this involve installing 7, 8, 9 speed freewheel on each brand of motor (crystalyte, bafang, mac, bmc, bionx, etc...)

Why so many gears ? A 6 speed freewheel would suffice for the majority of ebikes and there's no drop out width issues. Something like the current 6 speeds but with the smallest gear being an 11t.

Hell, bring back 3 speed freewheels! I'll take an 11-18-28 with a 48t single speed chain ring thanks

[bobc]

For an alternative approach (much bigger chainring) look at the folding bike picture 1/2 way down 1st page of this
viewtopic.php?f=28&t=24676&start=0
that was laser cut in 2mm stainless - cost about £20. + you might need a longer chain ;^)

[Jeremy Harris]

For an alternative approach (much bigger chainring) look at the folding bike picture 1/2 way down 1st page of this
viewtopic.php?f=28&t=24676&start=0
that was laser cut in 2mm stainless - cost about £20. + you might need a longer chain ;^)

It's a good approach, but reduces ground clearance a fair bit. In the case of a folder that's potentially a problem when you fold the bike, as the chainring may well end up bigger than the protector that's used to prop the bike up when folded.

It might be fairly easy to get similar small sprockets laser cut and then internally threaded, though. If the teeth can be turned off a standard freewheel and the hub threaded then a unit like the Regina one could be fabricated.

Jeremy

[Ykick]

Ahh Ykick.. i had a feeling. That is unfortunate.
My solution is a 13t and a single 48t gear in front.

Yeah, that's my ratio F48t/R13t right there - fine for 12S Lipo but 15S begins to run out of leg speed.

What really pisses me off about the DNP part is/was paying premium price for such cheesy metal. Surely, they must know about tool hardening?

Oh well, my next gearing tweak will be fitting road crankset - 52t? Will also keep checking eBay and/or old bikes for one of those decent Shimano 11t's. All DNP had to do was get one of those and clone it's quality. I'd pay $50 for that...

[itselectric]

Now, they are in middle re-design 7, 8, 9 11-tooth freewheel. And I am involved in beta testing with their new freehweel. This is a lot of works, this involve installing 7, 8, 9 speed freewheel on each brand of motor (crystalyte, bafang, mac, bmc, bionx, etc...)

Why so many gears ? A 6 speed freewheel would suffice for the majority of ebikes and there's no drop out width issues. Something like the current 6 speeds but with the smallest gear being an 11t.

Hell, bring back 3 speed freewheels! I'll take an 11-18-28 with a 48t single speed chain ring thanks

It is much easier to maintain the same gear ratio with the shifter during installation, otherwise you purchase addition part and addition parts to changes.

[jbond]

There's a *lot* of Shimano 7 speed freewheels out there fitted to cheap bikes. So a straight replacement that works with 7 speed shimano indexed quickshifters would be desirable. Personally, I'd be looking for an 11t-28t 7 speed or perhaps 11t-30t. The megarange bottom gear is fairly pointless if you have a double or triple front chainset. Having 11t-28t would mean all the gears would get used. However, if you only have a single chainring on the front, then 11t-34t gives you a low granny gear for when the battery has run out and oyu have one last hill to get up before home.

PM sent to the DNP rep.

[auraslip]

itselectric actually isn't a dnp rep, but a store and online business. They have some videos on youtube about how they grease the dnp freewheel before shipping with freewheel grease injector. I'm glad they're taking the first step by contacting DNP. It might be easier just to have an 11 tooth cog made that threads on to a standard shimano freewheel. Those are $10 bucks, plus the price of the custom cog (can't be much if you get 1000 made right?).


I for one am currently watching a 12 tooth NOS sachs freewheel on ebay

[Kingfish]

I went through this study several times and finally resolved to move forward with a freehub; the cheaper Asian freewheels are what they are and the best that one could do is to stock up and prepare for more frequent R&R...

Or change the system over to FWD and go with a freehub (which is what I did with the P1 ebike).

Formerly in the same boat, KF

[auraslip]

A free hub that screws on too a hub motor would be perfect.

OR EVEN BETTER////why not just an adapter that screws on to the threads meant for a freewheel? Should be easy for a machine shop to make,

[Kingfish]

Not made on this planet

~KF

[psycholist]

itselectric;
I think your initial efforts should be focused on just providing a quality 6speed 11t freewheel (11 to 30t). 7 to 9 speed freewheels are not required on e-bikes and 6speed should resolve the majority of spacing issues. As for quality, just find an old Suntour,Shimano,Regina etc.,Present it to DNP and say “build this”.

[Mark_A_W]

I disagree entirely about using 6 speed freewheels (or 3).

I've never seen a 6 speed shifter - what are you going to use it with?
The freewheel needs to match commonly available shifters. So that's 7, 8 and 9.


I personally like a 7 speed 11-34 Shimano, coupled with a twist shifter fitted to the LH handlebar.

An acceptable compromise, to fit into the tight space available with most motors, would be a 5-7 speed freewheel, BUT using 9 speed spacing - this could then be used with the most common shifters = 9 speeds (you lock out the derailleur from the other missing gears with the adjusters).

[Alan B]

At one point I was told that a 6 gear freewheel will work with a 7 speed shifter, just limit it to 6 speeds. Have not verified that myself.

For the record, 6 speeds is sufficient, 11-28 is probably enough range, and compatible with available shifters of some standard type, with the limiter screw preventing overshifting/dumping the chain.

I have a 6 speed 14-34 megarange and the derailleur doesn't like the 34t megarange gear. So 28 is likely to be more compatible.

Thanks for asking!!!!!

[adrian_sm]

The derailer seem to be fairly forgiving. I use a 8speed DNP freewheel with 9 speed shifters no problem. Even though there is technically a 0.5mm difference in cog spacing vs shifter spacing. But I don't typically use the biggest 1 or 2 cogs on the freehweel, so I have no idea if it will play nice with them.

Looks like a similar difference in spacing between 6 freewheel & 7 or 8 speed shifters, so you should be okay.


Here is a link to the common freewheel cog spacings. Scroll down a bit to find them.

[Alan B]

My derailleur problem is a 9 speed derailleur doesn't expect a 34 tooth gear in position #4, so it doesn't clear the gear, but runs into the side of that gear. It would handle a 34t gear is position #1 just fine, it is designed for that. But the 6 gear freewheel is skipping the first three gear positions, effectively.

So that is one danger of making a 6 or 7 gear freewheel. The derailleur may not be opened up enough to clear the largest gear if it is made too large.

At least that has been my experience with mine.

[auraslip]

Not made on this planet

How much would it cost to have one made to you think?