Elliptical chainring.... suppliers

[cycle tramp]

Hello There,
A couple of years ago i tried hub brakes for the first time and was impressed.. i'm now thinking of trying elliptical chainrings and am currently looking for possible suppliers for a 36 tooth chain ring with a 110 mm bcd. Does anyone know where they may be fot sale?
As ever thanks for reading this

[meic]

Highpath Engineering, formerly of Lampeter now reborn in England, used to sell rings made to all sorts of designs including various ellipticals at very high prices but no longer do.

The common mass produced ones that I heard of were Sugino Cycloid and Shimano Biopace and they aimed for the opposite effect and have the ellipse going the different way to each other.
I dont know if they made 36t versions and the only place I can think to still buy them is on ebay or this forum!
Spa and SJS were selling them a decade ago and may have one lurking on a shelf but not on their webpages.

[gaz]

At 110BCD 34T is the smallest round ring commonly available. 36T doesn't leave much scope for introducing an elipse.

As meic says 38T was a common Biopace ring (Stronglight Bio-Strong, Sakae OvalTech) and you should find something via ebay/cycle jumbles. Modern 38T are also available, most likely at a different rotation to Biopace ,e.g. Wolf Tooth.

[meic]

Ouch.
The Highpath made to order ones were around that price.

[iandriver]

I think rotor do them http://rotorbike.com/catalog/default/ro ... 110x4.html
Not my place to look at what they cost.

[Brucey]

I think I have some biopace rings tucked away somewhere, but some may be 130BCD rather than 110. IIRC I have a 42, 52 pair not sure about the others. I'd suggest you might want to get some like that just to try, before you spend big bucks on (expensive) rings that are better suited to your needs.

BTW you may find that your idea of the best gearing changes once you have oval chainrings fitted, so again trying some (even if they are not your first idea of what is perfect for you) makes sense.

cheers

[cycle tramp]

Thanks for the advice, folks. Its much appreciated. The prices are a little bit more than i imaged, and i'm now wondering if my local lazer cutting firm could do something for half the price.... Does anyone out there know CAD?

[MikeF]

The design of biopace rings was to slow down the rotational speed at TDC and BDC where the leg direction change is greatest. Wolf chainrings seem to be doing the opposite.

[gaz]

... Does anyone out there know CAD?

Previous thread, may have some leads: viewtopic.php?f=5&t=72711

[spider2106]

Try Velotech, Western rd, Stratford upon Avon. 0845 4755339

[Pneumant]

I have a 38T 110BCD alloy ring, not biopace but the Sugino equivalent (I think) so orientated differently. Back in 1988 when I had a bike with these rings I found myself freewheeling at any given opportunity, I also found it hard to maintain an even cadence. The chain 'bob' caused by the rings also wore out my rear mech prematurely too! Anyway OP you are most welcome to this ring FOC

[Bowedw]

http://www.cornant.uk is the information site of the late Chris Bell of Highpath Engineering, scroll down to bottom and there are several sections to open , one being on these rings. you should find it of interest and possibly informative. Chris was a well respected producer of components of this nature.
well worth a read of of his touring exploits as well.

[Gattonero]

Thanks for the advice, folks. Its much appreciated. The prices are a little bit more than i imaged, and i'm now wondering if my local lazer cutting firm could do something for half the price.... Does anyone out there know CAD?

mind you, shifting is not great with those chainrings to boot, and a plain ring with no ramps or pins is going to be a real gamble to get the chain from the small to the outer ring and vice-versa

[cycle tramp]

Thanks very much for everyone's replies to my post. Its deeply appreciated. I'm very grateful for the link to Chris Bell's website. What a Great Gentleman and definayely before his time. I'm also grateful for Brucey's comments about how changing the ring shape may infact alter the size of chainring i need...
I'm especially grateful for Penumant's oval ring offer and a private message is on its way...
...my current thinking is to raise the size by 2 teeth to a 38 size chain ring, and use 10% ovallity (if that's a word) so the chain ring can be used with hub gears and have the ring with lots of mounting holes to allow for timing changes..

[cycle tramp]

Thanks for the advice, folks. Its much appreciated. The prices are a little bit more than i imaged, and i'm now wondering if my local lazer cutting firm could do something for half the price.... Does anyone out there know CAD?

mind you, shifting is not great with those chainrings to boot, and a plain ring with no ramps or pins is going to be a real gamble to get the chain from the small to the outer ring and vice-versa

That's a good point.. however for the moment at least i envisage using a single chsin ring with a rear derailleur... although if i change my mind, you'll be right, the chain"s going yo have diffculty moving from one chain ring to the next.....