Freewheel crank resources

[spinningmagnets]

Thanks to wildharemtbkr for the link. http://durgendesigns.com/ddfwadapters.htm

durgendesigns.com has a $35 adapter that makes a non-freewheeling crankarm accept a FW, intended for bolting onto beefy trials cranks. I do not know the central hole ID, I assume its for a well-known beefy BB-shaft.



IRD was mentioned as a very strong CroMoly $60 FW (not flanged), available as 16T, 17T, 18T.
http://store.interlocracing.com/irdsispfr.html

 

[lbz5mc12]

I don't know if this site was posted earlier in the thread but here goes:

http://www.ebkit.com/accessories.htm

On the picture for the one chainwheel crank set, I can't tell if those are mounting holes or indentations because of the blurry pic. It looks like you could attach another chainring to it by bolting another one on, say a smaller one for the motor to run to. Of course then you would need a freewheeling gear on the motor to avoid drag during non-motor pedaling. I contacted aforementioned seller about buying a set of 3 chainring freewheel cranks from him but he said I would have to buy it from the link supplied below:

Then there's this seller in Taiwan but the shipping is the same as the cost of the cranks:

http://www.cyclone-tw.com/order-chainwheel.htm

As I said I apologize if this is a re-post.

 

[Qarsten]

Hello alltogether,

I have constructed am HF-bike (hand-and-feet-bike). It is an usual bike where additional power is submitted by an additional hand drive. Right now I am using the Because Forged Square Taper (see Because Forged Square Taper) with an standard 16T freewheel.

This works fine, but I feel the need to mount a freewheel with less than 16 T. Unfortunately, all the 13, 14 and 15 teeth freewheels have the M30 threads, but I cannot find any 175 mm cranks with this threads.

So: Does anybody know a solution for this?

 

[Miles]

Hi Qarsten,

There are still a few places that have these in stock:
http://riderschoicebikes.com/AC-15T-888-Freewheel-FW08001/

 

[Qarsten]

Hi Miles,

thanks for your reply. I know about this, but I did not find any shop until now which would ship it to Germany. I would like to test this freewheel, but I also read that they should not be the most durable freewheels...

And: I would also like to try 13T and 14T also....

 

[spinningmagnets]

Luna Cycles now has a dual-bearing freewheel, but the only chainrings it currently accepts are 4-arm 68-BCD

https://lunacycle.com/luna-tic-freewheel-for-mid-drive-ebikes/

edit: although the 68-BCD is not a common interface, I googled Ebay and found a variety of sources for chainrings using that bolt pattern.

 

[amberwolf]

A shame--if they had just left the full circle of metal on there, anyone with other numbers of holes could have easily redrilled it to work with their stuff, as long as it was the same diameter.

Doing it the way they did means less people can use it (without making a whole adapter ring/plate), so less customers to buy it, and probably weakens the structure, too (the full ring would better resist twisting loads from off-center chains, etc.

 

[Ecyclist]

Thanks to wildharemtbkr for the link. http://durgendesigns.com/ddfwadapters.htm

durgendesigns.com has a $35 adapter that makes a non-freewheeling crankarm accept a FW, intended for bolting onto beefy trials cranks. I do not know the central hole ID, I assume its for a well-known beefy BB-shaft.



IRD was mentioned as a very strong CroMoly $60 FW (not flanged), available as 16T, 17T, 18T.
http://store.interlocracing.com/irdsispfr.html

Assuming that the thread diameter on this adapter is 1.375x24, I calculated that the hole through is .875".
Wouldn't that mean that this adapter is intended to be used with BMX type of spindles and cranks?
This leads me to next two questions. Can I install BMX BB with BMX spindle on a typical 78mm BB shell? Also, can I get a BMX spindle long enough to fit the adapter with a FW on it?
If the answers are YES and YES, then we have a very good option for a strong and esthetic freewheel crank.

 

[panurge]

yes it is possible indeed, and profile, gusset and a pair of other BMX parts manufacturers produce extra long bmx spindles. But this would be an expensive setup, and anyway the part have to be custom made because it was only available a couple of years ago and the durgendesign website seems even offline right now.
It is In any case an attractive alternative for who has the right tools to make an adapter on the same lines.
A different approach I've explored before, that also uses the BMX single bolt pattern, is to have a freewheel with a flange of that shape.
This would allow to install over that egg-style flange, any of the zillions bmx spiders available on the market, for almost any standard from BMX and MTB till speedtrack rings, at least after a small work on the lathe enlarging the spindle hole in the BMX spider matching the freewheel body diameter.
I Do not remember the PCD of the BMX spider/ring mount but should be a bit more than 64, so should be feasible, and probably such a single hole could be made even over a standard 5 hole electric pattern flange, probably should be in that range.

 

[Ecyclist]

panurge, thank you for replying. In the end I think that using this durgendesigns adapter will not work well after all. Attaching the bracket to the arm with single screw will most likely tilt the bracket. In order to have minimum axial run-out, the adapter should be press fit. With all that thinking, I arrived with a new idea. Till now I was thinking about attaching FW to crank arm, but securing it to the spindle is a way to go. When using extra long ISIS spindle, I will make a sleeve with threaded OD to fit the FW. I will bore ID to be light press fit. Then, I will install it on the ISIS spindle and secure it with two cross pins. The pins will be just below the threaded surface. This way, I will be able to screw on FW, and after installing the crank, I will back the FW to it. I will use Excess FW. By now I have three of them and find them to be consistently very good quality. They are $22.00 each on DansComp. Dan's is my first choice for spokes as well.

panurge, I really like your FS bike build. I'm shooting for something similar but without custom frame and a more compact drive train. I have almost all my ducks in the row, and, in a few weeks, after I make some parts, I will be putting everything together. I'm sure that not everything will be perfect from the get-go, but that's what it is all about.

 

[panurge]

yes that's another way to go if you have enough room in the spindle...plenty of speculation in these lines in this same thread. The BMX adapter (and my speculation about a freewheel with bmx spider pattern) certainly need at least a light interference in the center bore, exactly as bmx style rings are, with such a radius levera, a fixed center and the bmx crankset itself keeping the assembly in place it should be strong and reliable exactly as BMX cranks are, IMHO.

 

[Ecyclist]

The ultimate way to go is to make ISIS shafts with thread that will work with 1.375x24 FW thread. That should be easy.

 

[panurge]

The ultimate way to go is to make ISIS shafts with thread that will work with 1.375x24 FW thread. That should be easy.

Mhh, that does not sound a good idea....first, to produce an hardened ISIS spindle, is not an easy job, second, in any case this way a standard freewheel does not fit at all in the engaged direction, while a freewheel with pass thru threads (like a dicta) would fit reversed, but with the unscrewing issue and with problems when you want to mount/dismount the unit because the prongs would be unaccessible. The only convenient way to eventually use a threaded freewheel directly on a spindle is in a 2pcs (fictional) Crankset, but I do not see any advantage over a standard 3pcs threaded crank-arm (well, probably a more centered assembly).
The Ultimate way is to avoid threads for splines, than you will have a natural born reversible unit, whatever way/place you decide to use it :wink: . A splined interface allows even a slightly adjustable chainline....

 

[Ecyclist]

I appreciated your constructive criticism. It helps me to make the final decision which way to go.
If comes to spindle, 7075 alloy should be strong enough for our application - if not, than titanium for sure. In the end, too much effort for not enough gain. I will go with modifying existing 148mm shaft, after all.
Standard FW can be used if installed from inside out. I was struggling with assembly sequence, but I worked it out. Once I make it, this will all make sense.
Two piece cranks are a no go because you can't get them with a shaft long enough to fit a FW. You need about 19mm space between BB and crank to fit a FW.
Splined FW is a good idea, but you will still need special, more time consuming attachment. They are more expensive and not readily available.
Unless you change the plan altogether and go with the splined trails crank that accepts a specially made splined freewheel. It is an expensive option, and, unfortunately, splined trail freewheels are very loud. That's the way they like them.
I want my bike to be as quiet as possible that's why I'm going with Excess Pro Series Freewheels.
You can read my review of these freewheels here:
https://endless-sphere.com/forums/viewtopic.php?f=28&t=47618&start=325

 

[panurge]

Not a criticism, just sharing years of experience about freewheels in any form :wink: .
Yes I know the excess units, pretty good ones....I have a 22T sitting somewhere, Its wide blank toothed flange could be useful to drill out a custom pattern...
Still, from my perspective, having to customize something, or to fabricate adapter parts for a freewheeling crankset, I would certainly try in any way to use a different approach rather than threads. The Excess has an eventually useful prong shape that could be used for custom interfaces....