Converting Frame to Single Speed Chainset

Weir85

Hi all,

I'm hoping to convert my Giant Defy 2 to a single ring on the front. The chain jammed in the front mech and bent the frame and Giant will not replace it under warranty as I can't prove that it have under "normal operation". So the frame cannot be used with a front mech anymore.

So my question; does anyone know what kind of chainset can be used in place of the Tiara 10sp double chainset I currently have?

giropaul

Is grinding off the front changer hanger and using a clip on hanger an option?

Bobbinogs

OP, you could always look for another frameset and simply swap everything across? I picked up a mint Specialized Allez E5 frameset second hand for £180 when the existing frame had an irreparable seat stay crack. I reused everything from the original bike, right down to the bottle cages. If you shop around and can be flexible on frame type (as long as you stick with the right size) then you might be able to resurrect your bike for a lot less than you think. Just be sure that any 'new' frame does not have some features that the seller has not revealed.

timothyw

It might be a good idea for you to take a picture, because right now I'm struggling to picture the issue, and so the solution.

With that said, there's no reason at all that you can't use your existing tiagra chainset in a single chainring configuration - you just need to buy a new chainring which is a bit smaller than your big ring, and larger than your small ring... something like this:
http://www.superstarcomponents.com/en/c ... -style.htm

42 tooth should be fine. Swap it in place of the big ring - I'm assuming you have a 110mm bcd 5 bolt chainset? You can tell this because the existing chainrings will be a 50 tooth and a 34 tooth, and they will be attached with 5 bolts...

You'll probably also want to shorten your chain a bit, to reduce the chance of the chain coming off. This is also why it's fairly important to get a narrow-wide chainring, as they're better at holding onto the chain.

Bobbinogs

I would also be tempted to wind the Lower limit screw so that the bottom (biggest) cog is eliminated. Even with a 42 up front, I wouldn't want to be regularly riding with a crossed chain for all the usual reasons.

The Rookie

Just put a narrow wide chainring in which ever location gives the better chainline, you can use a CX ring, upto 44t is commonly available.

Weir85

Thanks for the replies. I've actually decided to do both - I've tracked down an older Defy frameset in the right size for £140 on eBay.

I've got the frame back from Giant as well and it seems a shame to just scrap it so I'll build it back up with some spare bits I've got lying around and see what I can get second hand - yo can never have too many bikes.

I will try and post some pictures up as it was a pretty unusual failure - never seen or heard of anything like it. It was clearly a failure of the bike but as I had taken the front mech off Giant refused to honour the warranty as the said they weren't able to speculate as to what caused the failure.

Weir85

Bobbinogs wrote:

I would also be tempted to wind the Lower limit screw so that the bottom (biggest) cog is eliminated. Even with a 42 up front, I wouldn't want to be regularly riding with a crossed chain for all the usual reasons.

Yes, agreed, you'd go through chains pretty quickly

dj58

Weir85 wrote:

The chain jammed in the front mech and bent the frame and Giant will not replace it under warranty as I can't prove that it have under "normal operation". So the frame cannot be used with a front mech anymore.

As a matter of interest, which part of the frame bent, seat tube, chain stay or did you bend the FD brazed on mounting bracket?

Weir85

https://twitter.com/weir85/status/819486978425192448

Posted a picture up on Twitter. It actually bent the frame itself. The braze on hanger was ok but the mech was also damaged. Annoying to say the least.