Cycling UK Forum

kendrick57

hi
james I have designed a chainring to the specifications you asked for, pm me to see where we go from there.

kendrick

kendrick57

Hi
Will have a look at that later when at home should be interesting to look at.
Kendrick

kendrick57

hi
natural post an example of your files to make the chainring, compress them all into a zip file,these can be posted on the forum.

kendrick

kendrick57

bobc wrote:
It

OK I just tried to attatch a dxf file to this post but the system wouldn't let me :^(

Hi
From the look of the way you have the ring set up at the moment the angle between the major axis and the cranks is wrong with the chainring as it is in the picture reposition the crank to about 2 o'clock I'd say 2 or 3 holes.

As for loading up dxf files try compressing it into a zip file

Kendrick

kendrick57

Hi
A good guide to what is a suitable chainring on what bike is to check with Highpath's web site.
From what I read you can have a maximum of 15% ovality with hub gears without a chain tensioner.
Bobc's chainring would be no good it has an ovality of about 23% fine for what he is using it for but too much for a hub gear setup on its own.

Kendrick

kendrick57

Hi
I'm not sure what bobc used but the stainless steel that geoffs chainrings are made of is a high grade automotive type. i have had torque arms for electric bikes made by the same company and checked on the strength first.

Kendrick

kendrick57

Hi
To add to Geoff’s comment sprockets would be better made out of laser cut 2nn stainless steel with maybe a bit of milling on the teeth if it is for a 9 or10 speed drive train, the important bit would be custom width spacers would be needed, for that a milling machine would be required. It would work and can be done but the cost of the finished item may well be more than most want to pay.

Kendrick

kendrick57

Hi
What bike was the chainring to go on? It looks too big for an offroader maybe a road mainly hybrid MTB or a road bike?

kendrick

bobc wrote:my brother asked me to knock up a 48 tooth elliptical chainring. I'll get this made (laser cut) in 2mm stainless

the major & minor radii are 107mm and 87mm. The ring of holes near the middle are 110mm PCD so the thing will bolt straight onto most 5hole crank spiders.
Weight will be 200 grams.
lotsa holes so you can play with angles and swapping right/left or rotating 180degrees both give a stack more options.
They will probably cost about £15 including postage, maybe less so if anyone wants to try one, leave a reply on here by tuesday lunchtime - that's when I'll be round at the laser place.
It's as easy for me to get 5 cut as one...... ;^)
You will have to chamfer the tooth sides (file or grind) and clean off any flash. There are none of the "easyglide" ramps and bumps to aid front deraillieur changing.

kendrick57

hi
As asked for a picture of a tooth bulit around the golden length of 12.7mm.

kendrick

kendrick57

hi
sprockets were mentioned at the start of this thread, its correct eliptical sprockets are not wanted but having round sprockets made of hard to get sizes might get some interest, custom spacers will probably be required as well.

Kendrick

kendrick57

Hi
I am the nephew.
A CNC milling machine is being made capable of making oval chainrings any size required, I intend to use aircraft grade aluminium 3 and 4 mm thick depending on the application.
The tooth shape I will be using is the same as was used on eggrings including derailleur gates if required.
Kendrick

kendrick57

Hi
I would prefer the aluminium route not carbon fibre, with carbon fibre one damaged tooth and the chainring may well be a right off with aluminium a file would fix the problem. I have had EGGrings from Highpath before but production has stopped on health grounds not to start again.

Kendrick

kendrick57

Hi
Is there anyone still making custom chainrings made from top quality materials, both round and oval?

Kendrick

Cycling UK Forum

Search found 13 matches

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: eliptical chainring - want to try one?

Re: Custom chainrings

Custom chainrings