Chainrings and things.

[deanswood]

Hello,

I hope you can help me out with some recommendations on what to do to help me deal with hills. I bought a Specialized Allez sport frame when I was in London last summer. It's been a great bike and the gearing in London was no problem with it being basically flat. I have now moved to Swansea, it is not quite as flat and I am struggling a little bit with the hills. On top of the sudden addition of hills, I am not long out of plaster and just coming back to fitnees(thats a bit optimistic but you get the point). Basically I am running out of gears.

I have got Campagnolo Centaur 53/39 Chain ring with a 23/12 10 speed cassette on the back. I was thinking about changing the chain rings to a 50/36 or even a 50/33 and keep the rear the same.

Does anyone have any thoughts on ratios that I may find useful and suggestions for replacements for the Centaur (not sure but looks like if I want to change the rings I have to change the cranks too).

Thanks very much for any help you can offer.

Dean

 

[RedBike]

Changing the cassette will be cheaper

Having a 26 or even 29 tooth sprocket will make a big difference.

39/29 gives a ratio of 1.3

If you were to swap to a compact chainset you'll have
36/23 a ratio of 1.6, (quite a bit higher )

 

[Steve Austin]

It seems you want a compact chainset, with 50/34 rings on it.

Easiest way is to buy a new chainset with new rings as new rings alone are expensive and as you have said, new rings won't fit. Smallest rings you can run on yours is 39, so you'll need a compact crankset.

Or you could run a triple 'shudders'

 

[fossyant]

You'll be a bit limited in changing the rings as you'll need a compact chainset to get as small as a 33 on the front.

Without knowing your fitness, it's a tad difficult. If you are pretty fit a 39 front and a 25 rear is as much as you'll need anywhere. If you like to spin the gears then you may just need a compact or maybe a tripple.

You've probably got 9/10 rear sprockets, so why not buy a bigger cassette (i.e. has larger biggest sprockets) and see how you go on.

I mix and match my cassettes to the ratio I want best.

 

[Will1985]

If you want a compact, you will certainly have to change the cranks. Have you thought about changing the cassette instead? A cassette change is cheaper and will have more of an impact on your gear ratios. You could get a 12-25, or 13-26 which will take a bit off the top end but add an extra couple of bottom gears.

If you have a medium derailleur, you could even go 13-29 which could reduce your bottom gear by 10 gear inches, at the cost of bigger jumps between gears.

If you prefer closer gaps between gears, then a compact with 34-26 bottom gear will get you pretty much the same gear as 39-29

 

[mickle]

I've got the same ratios and they're a bit of a knee popper when I'm in Bristol. 39t is the smallest you can go on your cranks using Campag rings, however, many Campag chainrings will accept a 38t, Middleburn make one if I remember. Clearly a one tooth difference will have bugger all effect so it'll be a case of either installing a bigger big sprocket at the back or replacing the whole cassette. A jump from 33t to 53t at the front will be more than your front mech can cope with and I expect, more than your rear too as it'll be required to accommodate a big take up of chain. Take a look at some of the 'compact' ratios available, combine this with a slightly larger cassette and you should be able to keep your existing mechs.

 

[deanswood]

Thanks for the advice. I have gone for a bit of both. I am going to get a compact front, 50/34 and change the rear cassette for a 13-26. That gives me the same as getting a 29 on the rear and keeping the front the same. It's probably about time I changed the drivetrain anyway and this is a good excuse. It is a little more expensive but hey, that's what credit cards are for.
I have gone for Campagnolo stuff again as the experience I have had with it so far is quite good.

Thanks again everyone.

Dean

 

[RedBike]

Will a short cage rear mech work with that setup?
(I assume you're currently using a short cage rear mech)

 

[mickle]

Yeah.

 

[Archie]

Or you could run a triple 'shudders'

What's the problem with triples, may I ask?

 

[TheDoctor]

What's the problem with triples, may I ask?

They're heavier and they don't look as cool!!!

Seriously, if you want a triple get one. There's some snobbery and people who think it's 'just not right' to have a triple on a road bike, but it's your bike - do what you want. I think Campag are getting out of doing triples though...

 

[peanut]

What's the problem with triples, may I ask?

pretty much redundant now with compact double chainsets.
You are only likely to need a triple on a heavily laden tourer these days I should have thought.
By changing to a compact 50t 34t x 12-26t it gives the OP an extra 11" (approx equivalent of changing down 4 times on original equipment)

 

[TheDoctor]

pretty much redundant now with compact double chainsets.
You are only likely to need a triple on a heavily laden tourer these days I should have thought.

Erm, no, I don't think so. I wouldn't be without my triple and the stupidly low bottom gear. I don't need it too often, but when I need it, I really need it!

 

[Paulus]

pretty much redundant now with compact double chainsets.
You are only likely to need a triple on a heavily laden tourer these days I should have thought.

Erm, no, I don't think so. I wouldn't be without my triple and the stupidly low bottom gear. I don't need it too often, but when I need it, I really need it!

I would agree with the Doc. A triple gives you that extra bit of insurance should you need it on very steep hills. Grinding away will do your knees in in the end.

 

[porridge]

Can anyone tell me what a chainring is ?- please