Anyone ever made a chainring?
Thick Mike
Posts: 337
I have a Dura Ace triple crankset (7803). The 39t middle ring has worn, but Shimano don't make the chainring any more and there don't seem to be any aftermarket suppliers. Pretty annoyed really.
So I was considering getting a sheet of 7075 T6 aluminium and having a go at making a chainring. Does anyone have any experience? Am I foolish? Is there anywhere with advice etc?
All comments gratefully received :-)
So I was considering getting a sheet of 7075 T6 aluminium and having a go at making a chainring. Does anyone have any experience? Am I foolish? Is there anywhere with advice etc?
All comments gratefully received :-)
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Er, this isn't a great idea.
It certainly isn't a great idea compared to buying any other 39 tooth triple chainring and using that instead.
I replaced my 105 9 speed middle chainring with a current Sora one. It's a bit of a pain to shift into it out of the granny ring, but I found I could just double shift the front (so as if changing to the big ring) then drop down the shifter once it engages with the middle ring.
I think it cost me a tenner. I dread to think how much it'd cost me in time to handmake a chainring, and anything I made would be terrible.0 -
Thick Mike wrote:I have a Dura Ace triple crankset (6703). The 39t middle ring has worn, but Shimano don't make the chainring any more and there don't seem to be any aftermarket suppliers. Pretty annoyed really.
So I was considering getting a sheet of 7075 T6 aluminium and having a go at making a chainring. Does anyone have any experience? Am I foolish? Is there anywhere with advice etc?
All comments gratefully received :-)
Great idea if you have a CNC lathe. Stupid idea if you don't.0 -
6703 isn't dura-ace0
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The 6703 middle ring is a "special" design. The granny ring attaches to the middle ring, not the spider, so there are ten holes, not five. If it was as simple as taking a middle ring from another crankset, I would have done it already!
Sorry, 7803 (just been looking at replacement crankset and had 6703 in my mind).0 -
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darkhairedlord wrote:
If it will fit, I certainly will. Is it a drop in replacement?0 -
I assume you mean 7803? 6703 is Ultegra, and you can buy replacement chainrings from Chain Reaction for £13.50.
http://www.chainreactioncycles.com/shim ... prod117407
7803 39T chainrings are available from:
http://www.jensonusa.com/Shimano-Dura-A ... -Chainring
https://www.walmart.com/ip/Shimano-Dura ... g/31985102
(both in the US, but they should ship to here).
And there's eBay, and I would be surprised if you couldn't just fit any 39T ring designed for a triple. DA 7800 is a standard five-arm design, after all, so try a TA or Stronglight ring, e.g:
http://www.spacycles.co.uk/m2b0s113p196 ... dle-38-40T0 -
Ah, 7703. OK:
http://www.cheapbikeparts360.com/produc ... chainring/ (penultimate option)
Or the TA ring above. You will need a ring designed as a middle ring so that it will lift the chain properly from the granny.0 -
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964Cup wrote:I assume you mean 7803? 6703 is Ultegra, and you can buy replacement chainrings from Chain Reaction for £13.50.
http://www.chainreactioncycles.com/shim ... prod117407
7803 39T chainrings are available from:
http://www.jensonusa.com/Shimano-Dura-A ... -Chainring
https://www.walmart.com/ip/Shimano-Dura ... g/31985102
(both in the US, but they should ship to here).
And there's eBay, and I would be surprised if you couldn't just fit any 39T ring designed for a triple. DA 7800 is a standard five-arm design, after all, so try a TA or Stronglight ring, e.g:
http://www.spacycles.co.uk/m2b0s113p196 ... dle-38-40T
I can only see the 30t inner chainrings on the links above.
I tried at my local Shimano dealer today, they rang round TA and a couple of others who said they didn't do a direct replacement.0 -
964Cup wrote:Ah, 7703. OK:
http://www.cheapbikeparts360.com/produc ... chainring/ (penultimate option)
Or the TA ring above. You will need a ring designed as a middle ring so that it will lift the chain properly from the granny.
The TA one was the one the LBS ordered in for me...but it's not right.
The one on your link looks right, but the website doesn't seem to work (on iPad anyway).0 -
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Paul Onabike wrote:
Might do, thanks for searching it out. I've ordered the Ultegra 6703 39t middle ring from CRC. Going to see if that fits first. If it's NOK, then I'll have a look at that one you linked to.0 -
Stick the old one in a lathe and cut the teeth off. Do the opposite with an ultegra and glue it on with araldite, job done.0
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darkhairedlord wrote:Stick the old one in a lathe and cut the teeth off. Do the opposite with an ultegra and glue it on with araldite, job done.
Noticed there's a spacer between the discs, so not a totally bonkers idea if I'm desperate!0 -
Back in the 70's/80s at British Areospace at Brough East Yorks folk often made cyclo cross chain guards and chain rings. Someone once made a copy of Campag Super Record chain set. In terms of materials and man hours it was rumoured to have cost several thousand pounds0
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Haha, I can imagine...I only pay myself minimum wage for shed time.
I made a Rickenbacker guitar because I couldn't afford one, so why not a chainring that Shimano don't make any more? I think it's pretty crap of Shimano that they don't support this chainset.
Anyway, I got the 6703 39t ring and the bolt holes line up...but the ring is thinner, so I'll have to shim the disc with a spacer of some sort. Anyone got any suggestions? Material? Source?0 -
No, no one.0
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Buy some shim-stock. Have a look in engineering supplies shop or even ebay, I last bought some from RS components.0
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darkhairedlord wrote:Buy some shim-stock. Have a look in engineering supplies shop or even ebay, I last bought some from RS components.
Cool, thanks for the help. Hopefully the Ultegra ring you linked me to will be a goer!0
