Converting double to compact - Specialized Allez Sport

Todd Sweeney

Hello all - would any of you please be able to advise on what would be involved, and how easy it would be, to change the 52X39 front chainrings on this bike (Specialized Allez Sport 2007) to a compact (50X34) for getting up hills a bit more easily? Also, what would the costs involved be roughly? It currently has a Shimano Tiagra Hollowtech II 2-piece crankset, and a Shimano Tiagra Hollowtech II bottom bracket.

http://www.leisurelakesbikes.com/produc ... oryID/136/

I am a cycling newbie so don't have much knowledge regarding this type of thing - thanks very much in advance!

bladerider

This is all you should need ...

http://www.wiggle.co.uk/ProductDetail.a ... 20Chainset

If you spend another penny cost is less than £45. Your current bottom bracket cups should be OK.

fosmaal

bladerider is right you should only need the chainset no need for new BB cups.

You may also find that the chain is too long once you have put the compact on. You will need to remove a couple of links from it. So for a shimano chain you will need a replacement chain pin.

Something like this http://www.wiggle.co.uk/ProductDetail.aspx?Cat=cycle&ProdID=5300002616&N=Shimano%20Super%20Narrow%20Spare%20Chain%20Pins

You will probably need to move you front derailer down a little also and it may require some minor adjustments to make sure it changes smoothly.



Hope this helps

Todd Sweeney

fosmaal wrote:

bladerider is right you should only need the chainset no need for new BB cups.

You may also find that the chain is too long once you have put the compact on. You will need to remove a couple of links from it. So for a shimano chain you will need a replacement chain pin.

Something like this http://www.wiggle.co.uk/ProductDetail.aspx?Cat=cycle&ProdID=5300002616&N=Shimano%20Super%20Narrow%20Spare%20Chain%20Pins

You will probably need to move you front derailer down a little also and it may require some minor adjustments to make sure it changes smoothly.



Hope this helps

That's excellent, thanks very much for your help Fosmaal and bladerider!

bladerider

Just seen it for £40 here ....

http://www.chainreactioncycles.com/Mode ... elID=19207

The only 'special' tool you should need is one of these ...

http://www.wiggle.co.uk/ProductDetail.a ... ion%20Tool

If you need to shorten the chain you'll also need a chain breaker.

John.T

Be careful if you shorten the chain. The 50 ring is only 1.5 links (3 teeth) less. Compact seem to run best withj as much chain as you can still get tension with when on the small/small combination. If you are running less than a 12/27 cassette you may be able to run your chain as it is. Also makes swapping chainsets around easier. 12/27 with 50/34 needs careful chain length adjustment as it is at the limit of the rear mechs range with a short cage one..