Shimano Double to Triple Crankset

bianchibob

My winter bike is a Specialised Allez with a Sora Compact double crankset , 9 speed. I went out cycling this weekend with a friend who has a similar bike but with a triple crankset. We are both getting on a bit now, and his climbing ability was far superior to mine. We swapped bikes and I found the lower gear on his triple a revelation.
I would now like to convert my double set up to a triple.
I obviously need a new triple crankset and a new front derailleur, however would I still be able to use the existing left hand lever, the reason I ask this, as although the levers are indexed I have seen left hand levers advertised as double/triple.
I only want to replace the bare minimum so if I could use the existing levers, this would be a bonus, plus I wouldn't have to disturb my handlebar set up !
Thanks

martinperry

Need a triple specific shifter, and a new BB as well
Sorry

arlowood

martinperry wrote:

Need a triple specific shifter, and a new BB as well
Sorry

Correct to say that you will need a triple specific LH shifter but I fail to see why you will need to change the bottom bracket. A Sora triple crankset (or Tiagra, 105, Ultegra) will be compatible with the BB that your Sora compact is running with at the moment.

What you will have to consider is changing your rear derailleur to a long cage version. The standard derailleur that is probably currently on your bike will not cope with extra tension you need to cover the 30 tooth inner ring on the triple.

Have a look in the classified section on here. You will see cranksets and rear mechs on offer fairly regularly. Failing that have a chack on Fleabay - currently someone selling an Ultegra long cage rear mech which you could try bidding for:-

http://www.ebay.co.uk/itm/Shimano-Ulteg ... 2c757d8a8a

bianchibob

Thyanks for the replies, good point regarding rear derailleur...hadn't thought of that one !

desweller

You'll need a new front mech as well. Double/compact mechs do not extend far enough around the chainrings.

martinperry

The BB is triple specific - longer shaft to accommodate the extra cog - 3mm difference - see choices on theis listing for example
http://www.chainreactioncycles.com/shim ... -prod38998

slowbike

Before you go down the expensive route of changing cranksets & shifters - look at the gear ratios on your mates bike to what you can get on yours ..

www.gear-calculator.com has been posted up before and it's a good way to visualise the options.

My wifes Dolce is a triple and has a lowest combo of 30-26 which = 30.3". My bike has a compact double (34/50) and has a 28-12 cassette - the 34/28 combo gives me 31.9" - so nearly the same as a triple - if I changed the cassette to a 30-12 then the 34/30 combo would give me 29.8" - so easier than the triple lowest combo ....
You may need a long cage derallieur as well - but that and a new cassette could be less than the triple crankset alone ...

The Mechanic

I agree that you should look at the actual ratios you have before spending a lot of money. I believe that the latest 10 speed Shimano mechs in some series have a capacity to go to a 32 tooth rear spocket. That would entail a new rear mech and cassette and, perhaps, a new chain. Much cheaper that chainset and shifters etc.

BTW, my Allex Comp as a triple with 27/30 being the smallest gear of around 30 inches.

My new Felt Z4 has a compact double with a 30/34 smallest with gives a gear of, you've guessed it, approx 30 inches.

francis666

Listen to Slowbike and The mechanic.

Your probably running a 11/25 rear cassette
a simple cassette change to a 12-27 will make a noticeable difference.

Changing the front end will be expensive.

A solution I have on my 10 speed Ultegra is to have a MS (medium cage but a long cage in old money) derailleur on the back and fitted a 12/30 rear cassette. My inner front ring is still a 39 and I manage (with loads of effort) to get up a 15% hill (Whitedown in the Surrey Hills) and two rcassette gears left going up Boxhill with an average gradient of nearly 7 % and a max of 15%.

Bear in mind I’m 48 and weigh 18 stone!

I went one step further and made a hybrid 11/30 out of two Ultgra cassettes using the 11/25 and a 12/30 by using/mixing the two sets of cogs for a better stepped set.
I did this because I couldn’t get a 11/30 out of the packet.
This works really well, as I still have the low 11/55 tooth for the flat and the 30/39 for the hills.

The medium cage (they don’t make a long Ultegra cage, only short and medium) handles the long length chain.

Costs:
New: chain, cassette and rear mech.