Cassette question - ratios

oh, yes, doh! train harder... buy better seems so much easier *sigh*

aha, why did you not say: sram-red is the nuts!

I am running sram red on my specialized tarmac and 11-28 with 54/39 has got me up most things, even after 70km in my legs

The OEM sram red mechs are good for 28T as you can see here:

http://www.merlincycles.co.uk/Bike+Shop/Road+Parts/Transmission/Deraille...

you can get a much better geared 11-28 here for £55:

http://www.merlincycles.co.uk/Bike+Shop/Road+Parts/Transmission/Cassette...

this will give you better top speed as well as better climbing gears, I would say you are good to go with this upgrade and zero fettling

Could not agree more with first 5 comments, and have thought about last comments as well for one bike (upgrade to apex).

Ultimately, its hard to imagine needing those gears until you are there, but on a long ride, with no glycogen left in the thighs for big gears, for everyone except 8 stone pros as one of above comments said, you will need more gear inches!

Firstly, practically, I take it you are 9 speed shimano, no? so apex is a shift too far? (forgive pun)

if you can get a 12-30 tiagra as above, and it will fit. then do, or 12-27 as a bare minumim.

Other options:

can you swap a 28/29/30 cog from somewhere else? I once did this the other way round, where the casette was 13-x and needed speed - put an 11 in there and took the biggest gear out? some people are doing this with MTB as well, when moving to a double up front, there is a company that makes a 9 speed 36T and you just remove your fastest cog (in mtb that is 11/12 depending on cassette)

I did a search on CRC for road chainrings and the compact rings are not that expensive and add up to around the same as a non standard cassette? however it may depend on your mech and how it is mounted as to whether you can change?

bear in mind the road inches and cost / ease of doing as its easy to get carried away. the best options should be lower inches for least work and least money:

at the moment you have 45" or 45 gear inches (lowest crank / biggest cassette * 29 wheel inches).

The 27 cassette will give you 42 road inches, which is much better, although not great.

assuming you can get and fit a 12-30, then you are in 37 road inches; more like it. You should not need a longer chain as long as you stick to the small chainring with that gear, if you want to use all gears you will need a new chain as above comment.

so, the other options are to change the chainrings, assuming mech can handle it, anyone?

34/ existing 25 rear gives you 39.5 road inches, which is better than a 12-27 cassette. you will need to change both chainrings as the maximum difference is 14 to 16 cogs between chainrings. If you do chainrings and 12-27 you will have every combo of gears you will ever need, and assuming the front mech will take it, the easiest path

having said that, 12-27 will def help, and should not need any fettling; the others will need some playing with / special orders. If you can get the 12-30 and it fits, that would be great. if not consider chainrings as well. hope this helps.

Get an apex rear mech and a 11/12-32 cassette. Just done that myself, £32 for the cassette from chain reaction, picked up the mech brand new £39 off ebay.

The only way I could contemplate getting up there is attaching the back wheel to the chainrings and the pedals to the cassette. Can go vertical with 12/53 set up!!!!

Seriously 34/28 would be my attempt ratio .. and wear my road shoes that are easier to walk in!

Apex rear mech will take a 32T

i used a 50/34 compact and 11-32 cassette for hardknott and wrynose on the fred whitton. needed all the gears to get up 'em

swapping 25 for 27 will make a noticable difference. I don't know many people who'd get up hardknott on a 39/25, and i certainly wouldn't make it on 39/27.

tiagra 30T is a good option if your mech will handle it. technically most road rear mechs are 27/28T max, but then there's a long list of stuff shimano says you shouldn't do that works just fine

And if you want a proper bailout gear, Shimano's new Tiagra 12-30 cassette works fine with a standard cage Ultegra rear derailleur. You'll probably need a longer chain though.

I did a C2C last year. Hardknott is a fantastic challenge, unfortunately I couildn't make it up on a 34/28 compact set up, but as has been said, depends hugely on your levels of fitness.
Will definitely be returning one day to conquer it however!!

I've no idea of your level of fitness but unless you have legs of steel, cavernous lungs and weigh about 8 stone, you'll probably struggle up Wrynose and Hardknott. I have heard of people on the Fred Whitton using mountain bike cassettes.

To answer your question; a 27 will made a noticeable difference but I'd go with a 28 or 30 (if your rear mech can take it). I cant' recall too many places where a 53-11 gearing would be useful (unless you're racing) so 12 as a smallest cog would be fine.

Good luck and I hope you enjoy it. Are you doing it to raise money or just for the challenge?

Not sure if this will help but I have 53/39 and swapped my 25/12 for a 28/12. Easier on hills a bit but not as easy as a compact set up obviously.