# Biggest SS cog?



## mikesee (Aug 25, 2003)

I have an Endless 25t. Looking for a 28 or 30t. Does such a thing exist?

Need über low gear for fatbikepacking off-piste. 

Wide base preferred. Essentially just want something really durable. Weight and aesthetics are waaaaaaay down the list of priorities.

Any help appreciated.


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## slowride454 (Jan 11, 2014)

couldn't you use the 40T or 42T range extender cogs with spacers?


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## Slash5 (Nov 27, 2011)

Be tough to make it strong enough not to fold. What about changing the front chainring? There are some interesting 64bcd chainrings now. Some are dished to help the chainline.


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## bikeny (Feb 26, 2004)

Don't know of anyone making anything that big. Bit I do remember back in the day, Spicer used to sell an adapter that would allow you to mount a chainring (58 or 74 bcd, don't remember) and use it as a cog. Maybe you can find one of those?


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## mikesee (Aug 25, 2003)

bikeny said:


> Don't know of anyone making anything that big. Bit I do remember back in the day, Spicer used to sell an adapter that would allow you to mount a chainring (58 or 74 bcd, don't remember) and use it as a cog. Maybe you can find one of those?


Interesting. I have one. But I can't seem to find a 58mm BCD ring to bolt to it in bigger than 26t. Anyone have any ideas on where I might find a 5 bolt, 58mm ring in 28t or 30t?


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## Andy74 (Dec 11, 2011)

Surly MWOD chainring 33 tooth 58 BCD ???


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## register (Jun 25, 2011)

I have always wondered why they do not set bikes up like cars a ring and pinion or the way motorcycles are set up with the smaller gear up front and larger in the back. It seems like having the smaller gear up front would be easy to spin and maintain cadence.


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## mikesee (Aug 25, 2003)

Andy74 said:


> Surly MWOD chainring 33 tooth 58 BCD ???


I like the idea but having only 4 of the 5 bolts engaged would be a deal breaker in this application.


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## ScaryJerry (Jan 12, 2004)

register said:


> or the way motorcycles are set up with the smaller gear up front and larger in the back. It seems like having the smaller gear up front would be easy to spin and maintain cadence.


hey man if you can maintain a 4-6,000 RPM cadence, then yeah, definitely set it up like that.


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## Andy74 (Dec 11, 2011)

mikesee said:


> I like the idea but having only 4 of the 5 bolts engaged would be a deal breaker in this application.


Can't say that I blame you
Surly has a new narrow / wide chainring
Stainless, 28 tooth, 58bcd 
But they don't seem to be available yet


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## NonConformist (Nov 19, 2004)

I've made a couple chainring to freehub spiders for people, if that helps the situation. I can make most any combination of bcds you'd like. Or if a custom cog suits your needs better I could handle that as well. DG's Custom Machining: Chainring to freehub adaptor


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## bikeny (Feb 26, 2004)

Andy74 said:


> Can't say that I blame you
> Surly has a new narrow / wide chainring
> Stainless, 28 tooth, 58bcd
> But they don't seem to be available yet


Yeah, that one looks like it would be perfect once available. Best I found right now is a Surly 26t 58 BCD ring:

Universal Cycles -- Surly MWOD Stainless Steel Chainrings


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## Saul Lumikko (Oct 23, 2012)

I'm in a similar position: I want a bigger cog.

So far the best idea I've come up with is to drill a 20t cog with a 58 mm 5-bolt pattern and bolt a chainring on it. I have a Surly MWOD 58 BCD 26t inner chainring and all five bolts are used for attachment. The benefit would be to run dual cogs and dual chainrings for a dinglespeed setup: really low gear for crawling and a low gear for general use.

There's also an age-old ghetto modification to bolt a 64 BCD ring on a 16t cog directly. I would not recommend it for any serious use.

Middleburn makes 58 BCD chainrings up to 28 teeth: 58 BCD 5 Arm products from SJS Cycles

Another idea I've had is to butcher a (worn-out) high-end cassette, as I've noticed they often have a 5-arm structure supporting the largest few cogs. It shouldn't be a complicated task to drill them to install a chainring, perhaps even with a larger BCD like 94 mm. Then it would be mated with a Surly 30t chainring.


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## Cotharyus (Jun 21, 2012)

What about direct mount single rings? I know you can get down to 26 teeth up front like that. Also, here's a thought: Wolftooth (who makes good quality products, as far as I'm concerned) has a stainless steel SS cog that they sell in 16 18 and 20. They seem like the sort you might be able to call and talk to, and have them knock you out a few one offs. Yes, there's cost involved, but if you can't find them anywhere else, maybe you can show them there's a demand for it, and they start making them. Just a thought.


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## Saul Lumikko (Oct 23, 2012)

If there's a direct mount interface that matches Shimano HG freehubs, you have my attention.

One-offs are certainly possible. My chainring (33t 58 BCD + additional holes to mount 104 or 110 BCD bash guards or chainrings) was custom made from stainless steel, there's only two of them.


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## Saul Lumikko (Oct 23, 2012)

Just thought of something: Problem Solvers makes an adapter that allows you to run 6-bolt cogs on a HG-splined freehub. This would make a custom cog far easier to manufacture, because you only need to cut the cog from 2.3 mm sheet - no need to mind wide base: it comes with the PS part.


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## ScaryJerry (Jan 12, 2004)

Very smart idea!


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## bikeny (Feb 26, 2004)

Just came across this, Middleburn makes 28t 58 BCD chainrings:

Middleburn 58 PCD 5 Arm Inner Chainring - £20.99

And Warhawk makes up to a 32t, if they are still making rings that is:

5 Bolt 58mm Chainring


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## teamdicky (Jan 12, 2004)

As seen on FaceBook yesterday:


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## unabashedlypro (Nov 14, 2014)

I ride 34-13. I DEFINITELY have the biggest co...OH..you said COG..nevermind.


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## Saul Lumikko (Oct 23, 2012)

Looks good!

I've got stuff coming up as well. It'll be thin all the way and have holes for light weight, but will require the Problem Solvers IS-adapter for HG freehub use.


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## Saul Lumikko (Oct 23, 2012)

Here we go:



The next step is to put them on a lathe and make the teeth narrow, because I don't intend to run 1/8" chains. Times have evolved. The material is austenitic CrNiMo. I don't expect to see any rust on it even after exposure to salt water - unless the chain leaves stains on it of course.


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## ScaryJerry (Jan 12, 2004)

Impressive!


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## mattbyke (Jan 14, 2015)

Great thread. So many SS threads are about tough gearing. I run a 30/23 for my terrain. Not enough for you. But there is a need for super low gearing.


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## NonConformist (Nov 19, 2004)

7075 28t SS cassette cogs. 3/16" at the base. Compatible with 10sp chain. Reversable. Drilled with IS standard for use as a fixed cog.

I've got two more of these on hand if anyone is in need of them. $40 plus postage.


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## Keener (Feb 25, 2005)

This is the biggest cog that I have had use for









As my cogs need to bigger because my wheels are bigger I am used to adding a 9 spline to BMX sprockets. 
I have found some are not even close to being on pitch diameter. Excuse me I digress.

I use up 25, 28, 30 tooth cogs for "regular" gear inch out put.








a kind of done 28 tooth

For my last lot to modify I bought from Rennen design.









This cog has a home made 9 spline.









However between me spending my money and getting the sprockets in my hand I called the people at Rennen, turns out that if you call them that 9 spline can be yours in the size you want.:thumbsup:


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## Velobike (Jun 23, 2007)

This may do the trick. It takes a chainring.

I use it to get a 22/32 and 32/22 dinglespeed setup. I use the ultralow gear for mud and deep snow, other wise I'm on the 32/22. I've got over 2 years use out of it with no problems.

Pinion Spider Hinterrad - Spider Rear Wheel - P8200 | eBay












Right now I'd like to get my hands on steel 23 and 24 tooth cogs. (Alloy wears out too fast in our gritty mud)

I'm looking at getting a granny ring adapter made so I can use granny rings. Only problem is they don't make 24 tooth grannies in steel AFAIK.


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## Saul Lumikko (Oct 23, 2012)

Oh, the Pinion rear wheel spider is precisely what I was looking for! Oh well, you live and do things the hard way: here's how my own project went on.

I used an old hub to attach the cog to a lathe. Before bolting on the cog I shaved a bit off the front surface to square it.


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