Changing crankset and cassette - newbie problems!!

[Joffey]

Hello

I have a Carrera Virtuoso Ltd and I'm struggling going up hills. Badly. So I thought about changing the crankset or cassette (or both) to give me a better chance climbing.

My problem - I've never done it before and don't know what is even possible.

Easiest solution in my mind would be change the crankset from a double to a triple. Problem solved. But would my derailleur need changing and would my shifters work still?

Any advice would be appreciated.

The spec currently is:

Chainset: Shimano FCA050 52/39
Front Mech: Shimano FDA050
Cassette: 12-26T
Rear Mech: Shimano RD-2300
Shifters: Shimano ST-2300

Also, I need to do this as cheap as possible... I have Shimano triple on my MTB, could I use this and the front mech on the road bike?

Thanks, and sorry for being thick!

 

[RecordAceFromNew]

Also, I need to do this as cheap as possible... I have Shimano triple on my MTB, could I use this and the front mech on the road bike?

Thanks, and sorry for being thick!

Certainly nothing thick about your question, what is thick is manufacturers/shops continuing to offer gearing on road bikes more suited to professional racers than the vast majority of riders.

The answer is going to be a bit long-winded, but hopefully can also be of some use to others in a similar situation.

Firstly given your front shifter is the ST-2300 rather than the ST-2303, it can only handle two rings up front, and since drop bar shifters tend not to be cheap, that rules out a triple chainset. Secondly because Shimano drop bar road front shifters pull insufficient cable per shift for mtb front mechs, you should not try to use your mtb front mech on the road bike.

So the obvious choice is narrowed down to a) increase the size of the largest rear sprocket and/or b) reduce the size of the smallest front chainring.

Despite the official spec of the RD-2300 (largest cog of 26T and wrap range of 35), most rear mechs work fine beyond their spec to a certain extent, and it is most likely that your setup will work with a 8 speed cassette with a 28T sprocket, and perhaps even 30T, without modification. Further even if it does not, Shimano mtb rear mechs (of 9 speed or below) are compatible and can be bought for not much more than £10 and which can handle cassettes up to 34T. You will likely need a new, longer 8 speed chain however if you are increasing the size of the cassette.

To lower the gearing by modification up front, you can consider replacing the existing 52/39 chainset with a compact chainset (usually 50/34). It is likely that you would not need to replace the front mech, but it should be moved down the seat tube by 4mm (assuming it is perfectly set up currently). If the current bottom bracket is sound (you can feel for any roughness by shifting the chain off the chainset), and if you do not want to change it, you will need to pick a compact chainset that delivers close to 43.5mm chainline with a 110mm JIS bottom bracket, or else you may end up with front shifting problems. You do not have to change the chain, if it is sound, if you are lowering the gearing by only changing the chainset.

If you are picking only one route, apart from the relative economics, it is worth bearing in mind that front shifts are never going to be as easy and smooth as rear shifts, especially when you are going uphill. A 34/26 is just as low as a 39/30.

To figure out how low you need/want, you could use your mtb, and see what is the highest low gear you are willing to accept (by noting the tooth counts front and rear, and taking due account of the different wheel/tyre size with the help of a gear calculator). You will find such a low gear conservative on the road bike, because the mtb's knobbly tyres and additional weight make it a less efficient climber.

Hope it helps.

 

[Joffey]

That is an amazingly helpful reply!! Many thanks!!

 

[RecordAceFromNew]

That is an amazingly helpful reply!! Many thanks!!

 

[Joffey]

Just hope I can put it all back together once I've taken it apart! Haha

 

[Tanis8472]

I'm betting the BB is a really cheap chinese made one. The one on my Virtuoso was.
Changed it to one of these http://www.wiggle.co.uk/shimano-bb-un55-bottom-bracket-british-thread/
Totally agree about the gearing. Sold a compact chainset to the BIL and he is finding it a lot better

Although findind a compact set could be interesting