Frequently Asked Questions.

Q.  I have never heard of you before. How long have you been cutting chainrings ?

A. I have been cutting chainrings for over Fourteen years and have cut over 30,000 rings in that time. All cut and finished by me one a time.


Q. What material are you cutting the rings from?

A. I cut the rings from 3mm and 4mm  aluminium known as armour plate. This stuff is tough and hard and it does work harden as you use the ring so it "gets tougher" as you use it.

This stuff works insanely well and I back that up by saying that I have never had a chainring come back for warranty in all this time.


Q.  Can you copy an old chainring I have ?

A. In most cases the answer is YES.  I have also "copied" a ring and made it into a different tooth count by adjusting the proportions and details, so just ask .

Q. How long does a custom chainring generally take to receive after I have ordered it?

A. anywhere from a few days to about six weeks depending the workload and the design and details of the ring. I will let you know what the wait at the time you are ordering.

Q. It seems that you only cut chainrings for older crank setups. I have a new set of cranks that I want to use in a custom project, can you help?

A. I do prefer working on older bikes and components, the new generation of bikes are of little interest to me.....BUT.....I can cut a chainring for newer cranks. If it is a bolt pattern I have not cut before you will need to send me the cranks and the ring and I can measure it up my way and cut the appropriate setup in one of my jigs and go ahead get the ring cut. This extra measuring and machining of the jig won't cost you anymore than the normal price of the chainring you are ordering.

Q.  I have an old set of cranks that I want a chainring for,  but I don't have an existing chainring. What is the easiest way to workout what I need ?

A. Easy, just send the cranks to me and I can take care of a ring that will work and you can pick from all the available designs.

Q. I have a project that I am working on, it is not bike related, but I am using a bike chain . Can you help with some extra mounting details that aren't normally on chainrings? Also how do I know that it will work?

A. I have machined plenty of offbeat rings for motorised bikes with custom mounts to ergos with there own mounting bolt yes.

The ring will need to have mounting holes that are commonly used on bikes so that I can hold it down when I am cutting.

Whether the the ring will work or not....I can only cut the ring , remember the project is yours and so are the hits and misses.

Q. Do you cut the old Shimano DURA ACE 10mm pitch?

A. Yes.....I have cut around a 100 or so over the years in a wide number of teeth.  My design11  in the Classic Twelve designs is the closest but I can do it in other designs.

I have also cut conventional chainrings to suit the 120 BCD of the original cranks so you can move away from the 10mm pitch if you cant find a chain or rear sprocket.

Q. If I design a chainring can you cut it?  

A. I can cut you your own design.....BUT....I will not work from CAD designs. I do not send electronic files of my work that people can have cut elsewhere or use my tooth profile.

A quick sketch and some other pictures backwards and forwards usually will get the job done.

Q. Can you cut an chainring with ramps and pins?

A. I do not cut ramps and pins into chainrings. Although I can cut you a ring that will work with your geared setup and I can cut you a size that is not available otherwise from the original manufacturer.

Q. What about the new narrow wide chainrings, are you offering them?

A. I have not had any free time to get to work on those designs so for now that'

Q. Can you engrave some writing on my chainring?

A. Yes I can, in plain capital letters.

Q. I want to polish the chainring myself, can I just buy a plain chainring without any finish and is it cheaper?

A. I can cut you ring and supply it to you "off the machine".  The ring is deburred and ready to go, but I do not finish it, you get to have all the fun.


Cycleunderground has been around for over 22 years.

A lot of customers are surprised to find out that it is a one man machining and fabrication shop.

My name is John Bosevski and I have been servicing, repairing bicycles and building  frames, tools and bits for bikes for over 30 years.

I now concentrate on my components and tools and slowly develop new product and tooling to increase my offerings.

I prefer to concentrate on the bespoke side of bicycles, putting my effort towards products and tools that have been forgotten or overlooked.

 My workshop can be found in Taren Point,  Sydney,  Australia.