Compact to Triple - what to change?

[CharlesF]

I have a Genesis CdF with a compact chainset 50/34 and the cassette is 11-30. My problem is that I am old, weak and battling to get anywhere near spinning up steep hills. Instead I am straining and wheezing up at 2-5mph – not a pretty sight.

My first thought was to change the rear cassette to HG61 which offers 11-32, 11-34 or 12-36. I wasn’t sure if the rear mech could cope with 12-36 and would I get a big enough boost in the low gears.

My next thought was a triple chainset FC3503 which is 50/39/30.

I have just visited my two favourite LBS to discuss the problem and both agreed the triple was a better option but they varied completely on what needed to be done:

LBS1 said new shifter, new front mech, new chain and the triple.
LBS2 said new bottom bracket and the triple; everything else would be fine.

Can anyone say which option is correct and any other thoughts are most welcome.

 

[KneesUp]

If your shifting for the front is indexed, you need a new changer because obviously with only two clicks you can only use two cogs.

You won't need a new chain as the old one is long enough - but perhaps LBS1 noted it was worn, or suggest it so you have a new chain to match your new crankset so it will shift smoother. If your old chain is new it will be fine.

Changer - not sure. What model is on your Croix?

I can't see the need for a new BB - I think I'm right in saying that the chainline will sort itself out as long as the BB is right for the frame. Perhaps LBS2 had a crankset in mind (or in stock) that is a different fitting to the BB you have (e.g. JIS in stock but you have BB30 - no idea of the spec of your bike, but you get my point?)

So in summary:

Shifter - if it's indexed, yes
Mech - possibly - depends on model
Chain - not necessarily but might be wise
BB - no, unless new crankset is a different type than the current one

But then I could be wrong too

Also - new changer cable. I bet none of them mentioned that, but in my experience you'll never get it off the old mech without it fraying

 

[BSRU]

I have a Genesis CdF with a compact chainset 50/34 and the cassette is 11-30. My problem is that I am old, weak and battling to get anywhere near spinning up steep hills. Instead I am straining and wheezing up at 2-5mph – not a pretty sight.

My first thought was to change the rear cassette to HG61 which offers 11-32, 11-34 or 12-36. I wasn’t sure if the rear mech could cope with 12-36 and would I get a big enough boost in the low gears.

My next thought was a triple chainset FC3503 which is 50/39/30.

I have just visited my two favourite LBS to discuss the problem and both agreed the triple was a better option but they varied completely on what needed to be done:

LBS1 said new shifter, new front mech, new chain and the triple.
LBS2 said new bottom bracket and the triple; everything else would be fine.

Can anyone say which option is correct and any other thoughts are most welcome.

I've changed my Croix de Fer to a triple.
I needed the following:-
1) a new left Tiagra triple brifter,
2) a new front Tiagra triple mech,
3) a triple Tiagra crankset, 50/39/30.
4) spacers for the crankset, for some reason they do not come with the crankset.

The new lowest gear would be similar to the old lowest gear. 27 v 30.6, not much easier for so much cost.

 

[RebornBumbler]

You might possibly need a longer cage rear mech. as well

 

[MisterStan]

You might possibly need a longer cage rear mech. as well

Not if the cassette remains the same.

 

[RebornBumbler]

Remember that the rear mech. takes up the slack - if you're going to a smaller chainwheel, there's more of it

 

[Dogtrousers]

Not if the cassette remains the same.

You sure?

If you add on a triple with a smallest ring of 30 (was 34) the difference between big-big and little-little will increase by 4 teeth. Could this extra exceed the capacity of the rear mech to cope with the extremes and call for a long cage one?

Not looking for an argument btw, just askin' I'm not really sure myself.

Edit: Cross post with @RebornBumbler

 

[KneesUp]

It depends on the 'total capacity' of the derallieur.

Total capacity = (biggest chainwheel - smallest chainwheel) + (biggest sprocket - smallest sprocket)

 

[MisterStan]

Well strictly speaking you shouldn't cross chain, so I wouldn't think it would be a problem. If it was me, i'd try with the original first and see what happens....

 

[RebornBumbler]

Actually, it looks like the CdF has the longer cage anyway, so in this case, scrub the rear mech. replacement suggestion

 

[CharlesF]

Thanks for all the help, you can always rely on Cyclechat for expert help. I have just been in to a third LBS (Gear) and they said much of what you all said. They also told me to think about the cost vs results and said a better option would be changing the rear mech and cassette, or just ride harder!

 

[KneesUp]

Yeah, it's changing the shifter that makes it expensive I guess.

There is a lot to be said for friction shifters

 

[CharlesF]

Yeah, it's changing the shifter that makes it expensive I guess.

There is a lot to be said for friction shifters

Quite agree! They are still a good option. And yes, the shifters have to be bought in a pair, plus the chainset is expensive. I'm off to watch the TdeF front my daughter's front garden in York and will think about a new rear cassette and mech when I get back.

Again, thanks to everyone for the information, makes things much clearer for me.

 

[Dogtrousers]

.

There is a lot to be said for friction shifters

There sure is. Somebody stop me before I start!

 

[anyuser]

The friend I cycled the C2C with last weekend had his Croix de Fer fitted with an 11-34 cassette and longer cage rear mech. He had asked the LBS for a triple and they suggested this. He got on fine with it.