Snapped chainring

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Peanutt
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Joined: Tue Apr 08, 2008 13:44 pm

Snapped chainring

Postby Peanutt » Mon Jan 14, 2013 12:01 pm

Don't ask me how I managed it, maybe I need to loose a few pounds or I just have incredibly powerful thighs but I've managed to shear a chainring bolt and snap my lower chainring in two.

Does anyone know where I can get hold of a shimano biopace chainring, think it's a 36t
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mitchgixer6
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Re: Snapped chainring

Postby mitchgixer6 » Mon Jan 14, 2013 12:26 pm

You don't need to get the sepcific Shimano chainring. As long as you get the same BCD (bolt circle diameter) measurement then you can use virtually any ring as long as it's Shimano compatible.

Have a look here http://www.spacycles.co.uk/products.php?plid=m2b0s149p0

Peanutt
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Re: Snapped chainring

Postby Peanutt » Mon Jan 14, 2013 12:45 pm

Ooh I didn't know that, top tip!!!

Thanks
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Me-109
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Re: Snapped chainring

Postby Me-109 » Mon Jan 14, 2013 12:59 pm

Although if you want a Biopace it will have to be Shimano ;-). Not sure they have so much effect in the lower ratios so probably nothing missing by just getting a standard ring.

mitchgixer6
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Re: Snapped chainring

Postby mitchgixer6 » Mon Jan 14, 2013 13:03 pm

Sorry, excuse my ignorance. Just done a quick search and realised that the Biopace is an elliptical ring?

If so then you will have to search for exactly the same kind as mentioned above. Although I'm sure the Rotor Q rings or O Symmetric rings would do the same job and I'm sure they'd be easier to get hold of (if at a premium).

Peanutt
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Joined: Tue Apr 08, 2008 13:44 pm

Re: Snapped chainring

Postby Peanutt » Mon Jan 14, 2013 15:26 pm

I'm guessing it's not going to be that easy finding an exact replacement, toying with the idea of putting spacers in there and just running the top ring until I can get one. It's for my commuter bike, at least it would make winter training a bit tougher!!!
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Rolf F
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Re: Snapped chainring

Postby Rolf F » Mon Jan 14, 2013 16:49 pm

Biopace is far less pronounced than modern eliptical rings. I can't really tell the difference riding them though it maybe more obvious if you are on the flat (which I don't have access to up here!).

As mitchgixer6 said, Spa Cycles is always good for a look. Can't recall though if the inner rings of Biopace were elliptical anyway. Might only be the outer.
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Monty Dog
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Re: Snapped chainring

Postby Monty Dog » Mon Jan 14, 2013 17:30 pm

Biopace is 20+ years old so your chainring has had a good life and likely needed replacing anyway. Whilst it was elliptical, unlike Rotor rings, the high spot is not aligned to the crank. Expect your chainring is 110mm BCD as it's a 36 and Stronglight make cheap, suitable replacements. You'll only likely find a Biopace ring on ebay.
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Rolf F
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Re: Snapped chainring

Postby Rolf F » Mon Jan 14, 2013 19:19 pm

Monty Dog wrote:Biopace is 20+ years old so your chainring has had a good life and likely needed replacing anyway.


That assumes that time ages chainrings rather than useage. The lovely drilled chainrings on my 32 year old Raleigh show no signs of wear yet. You certainly can't assume it would have been due for replacement!
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Peanutt
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Joined: Tue Apr 08, 2008 13:44 pm

Re: Snapped chainring

Postby Peanutt » Wed Jan 16, 2013 11:10 am

Thanx chaps, looks like stronglight is a good contender and in my price bracket too, doubt I'll notice much difference in the lower ring.
No matter where you are, that's where you've been


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