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Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

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Old 09-07-07, 01:38 PM   #1
danielmramos
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Has anybody tried making a large custom chainring for their folder?

I was looking for a place to buy an affordable large chainring on the web and I found that Giles Puckett (http://www.mozbike.com/giles.html) created a program that allows you to design your own custom chainwheel on the fly. According to what he says it is fairly easy to design your own chainring using his program, print it out, glue it to some flat aluminum, and cut out your very own large chainring. He also states that the only labor intensive part is filing down the teeth after you have cut and drilled out the shape. I think that this may be what I end up doing. It has to be less than the $190 - $200 that some of these companies want for their 68T chainrings. It would probably be a great skill to learn. My goal is to learn how to build my own wheels and cut my own chainrings. That would be awesome!
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Old 09-07-07, 02:36 PM   #2
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Interesting idea. I ran the programme and looked at the output. I'm not that sure what shape I'd have to file the teeth. The printout shows a number of small circles. Maybe I'd have to file around the circles to get the tooth shapes. What do you think?
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Old 09-07-07, 04:27 PM   #3
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Matt Weaver makes his own chainrings. Might be worth an email to him.
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Old 09-07-07, 08:31 PM   #4
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custom chainring

These guys craft all manner of customs chainrings:

http://www.highpath.net/cycles/eggs/01.html
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Old 09-08-07, 08:03 AM   #5
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An alternative to the 'filing it yourself' option might be to take the design you want to a machine shop that has a computer-controlled CNC machine that could run you up a ring in no time at all.
Or look at the range of bigger 'Egg' chainrings by Highpath Engineering (up to 110 teeth!)
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Old 09-13-07, 03:15 AM   #6
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I had a guy manufacturing a 72T chainring for my auto mini folder. Take a look at this post. http://bikeforums.net/showpost.php?p...postcount=1352
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Old 09-13-07, 08:22 PM   #7
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Hey Zepi, I looked at that post. The link to the Auto Mini Folder pictures or what not does not work. Would you please give us another link and some more details on how you got that done?

Thanks
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Old 09-14-07, 05:20 AM   #8
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Originally Posted by danielmramos View Post
Hey Zepi, I looked at that post. The link to the Auto Mini Folder pictures or what not does not work. Would you please give us another link and some more details on how you got that done?

Thanks
here is the link to the auto-mini: http://bikeforums.net/showpost.php?p...3&postcount=23
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Old 09-14-07, 06:26 AM   #9
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Oh, that looks like a sweet setup. How much did it change your top end when you switched to the larger chainring? After the guy cut out the chainring with laser cutter how was the ring refined to completion? What program or pattern did you use for the 72T chainring? That was a hell of a price you got. Good for you.

Thanks
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Old 09-14-07, 07:28 AM   #10
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This thread got me thinking, what chainring size would I want if I were to put a Rohloff hub on my DT Mini? So I went to the trusty gear calculator (http://sheldonbrown.com/gears/internal.html) and came up with: 85 Teeth! That would give me a nice spread of 20 to 105 gear inches.... Now let's see... basic EGGring from Highpath Engineering, $500... and the Rohloff hub, somewhere around $1250... oh, and throw in a rim and some spokes, please....

Uh, right. Someone want to do me a favor, and tell my wife what I want for Christmas?

Makes me appreciate the wonders of the SA8, imperfect as it is.
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Old 09-14-07, 07:46 AM   #11
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Originally Posted by rhm View Post
This thread got me thinking, what chainring size would I want if I were to put a Rohloff hub on my DT Mini? So I went to the trusty gear calculator (http://sheldonbrown.com/gears/internal.html) and came up with: 85 Teeth! That would give me a nice spread of 20 to 105 gear inches.... Now let's see... basic EGGring from Highpath Engineering, $500... and the Rohloff hub, somewhere around $1250... oh, and throw in a rim and some spokes, please....

Uh, right. Someone want to do me a favor, and tell my wife what I want for Christmas?

Makes me appreciate the wonders of the SA8, imperfect as it is.
Try the calculation again, but use the 13t cog available from Rohloff... you should now get the same gear spread with a commonly found 58t chainring.

Bruce
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Old 09-14-07, 08:00 AM   #12
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Try the calculation again, but use the 13t cog available from Rohloff...
Oh, I didn't know that's an option! Sheldon Brown's website says: "It comes with a 16t cog, but 15 and 17 are available."
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Old 09-14-07, 10:05 PM   #13
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Hey there, I am really drunk right now, so I think you should totally go for the 85T chainring. Nah, that is a bit asinine. It probably wouldn't even give you any ground clearance. Gosh, I am sitting here wondering what that would even look like. Is it even possible?
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Old 09-26-07, 02:15 AM   #14
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interesting: http://www.philvarner.com/bikes/blog...eep-on-turnin/
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Old 11-06-10, 11:09 AM   #15
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large custom chainring

i bought a 67 tooth chainring for my greenspeed gto trike last year. the price varies according to size & 67 teeth sounded right to me. my crankset is 44-57-67. the 67 cost $165, from 68 teeth to 110 teeth (the maximum) the price goes up to $500 (egad!). that is understandable because according to sheldons website cnc machining wastes lots of metal. the ring was beatifully finished but not anodized because i think highpath does not the technology to do that. i wanted my chainring weather resistant so i piggy backed my chainring to a order my company was sending out to be anodized. chris was a pleasure to deal with & the product was top drawer though it might shift better if it was cut & pinned. i can without reservation reccomed this company.
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Old 11-15-10, 04:38 AM   #16
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65T handmade

this just came in at our indonesian forum
http://sepedaku.com/forum/showthread...y-Seli-20-quot

this guy just drilled and filed each tooth...

it must be really cheap (if compared to cnc/laser cut)
I am not sure whether or not he is taking orders from you guys
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Old 11-15-10, 09:10 AM   #17
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need to be a member to see that link posted above.
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Old 11-15-10, 10:57 AM   #18
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A Schlumpf high speed drive crankset offers 2 speeds, direct,
and an overdrive planetary gear within the crankset.

that multiplies the chosen chainring by 2.5 X
http://www.schlumpf.ch/hp/hsd/hsd_engl.htm

so gear, in high range, functions much larger than it is, physically .

there is a 1.6 X version also ..
http://www.schlumpf.ch/hp/sd/sd_engl.htm
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