Gear ratios and hills - halp

by TomvanHalen   August 14, 2012  

So, I'm new to this road cycling business, having come from MTB, and I'm having a bit of a headache with gear ratios. The bike I've picked up has early 90's Chorus and Mirage kit, 8-speed, and is currently set up with 53/42 on the front, 175mm cranks, and a gnarly 11-21 cassette. I'm reasonably fit but I'm carrying a fair amount of weight for 6ft, and that 42-21 gear isn't cutting it for many of the hills and hillocks around here.

I've just ordered a new 39t chainring and a 13-26 cassette to rectify this, but I'm now having second thoughts about the back. Should I stick to a 12-23 instead? I don't especially want to lose the 12t, especially with such long cranks, and it's hardly mountainous in Norfolk, but I'm used to being able to spin up any hill on a MTB triple and grinding up even small hills is knackering me. Any thoughts?

TL:DR, sacrifice climbing versatility or top speed for new-ish road rider?

5 user comments

Oldest firstNewest firstBest rated

there are hills in Norfolk? Thinking

53-39 is more conventional 'double' gearing anyway I think -> I.e. what today's off the shelf double bikes tend to come with.

I'd just fit the chainring to start with and see how it goes for two weeks.. then change the cassette if you need to.

posted by ALIHISGREAT [109 posts]
14th August 2012 - 18:06

like this
Like (1)

Keep the old cassette as a spare. You can swap it back on if you find that you never use the lower gears once you've got used to the new bike and gearing. Given that loads of people ride compact double chainrings of 50/34 because the majority of new road bikes are supplied with them as standard you aren't losing much by ditching that 12 tooth sprocket. 53x13 gives you 107.1 gear inches whereas 50x12 would give 109.5 which isn't a great deal of difference at all. Either one will get you well past 30mph before you spin out. If you are new to this game I'd suggest that's plenty fast enough and would take a big effort to sustain on the flat. 39x26 will definitely help on the bumps.
Enjoy the new bike!

Ah! Condor

posted by Bedfordshire Clanger [307 posts]
14th August 2012 - 19:43

like this
Like (0)

there are hills in Norfolk? Thinking


My favourite casette ATM is 11-28.

NB. The tour of Britain comes through my local suffolk roads, and they've managed to find a KOM hill (!!).

I looked it up, and it turn out to be one of my Strava segments (that I have the KOM on Big Grin ) so lets hope that noone who uses strava turns up.

Sir Velo

Raleigh's picture

posted by Raleigh [1728 posts]
14th August 2012 - 20:15

like this
Like (0)

Thanks folks; I'll do as alihisgreat suggests and just stick the chainring on first, and not worry too much about the 12 cog in any eventuality. I can put off buying a chain whip and lockring tool at least Tongue

posted by TomvanHalen [33 posts]
14th August 2012 - 20:48

like this
Like (0)

53/39 with a 12/25 cassette is really standard but 50/36 (or 34) compact with 11/28 give a bigger top and much smaller bottom. Better unless you need a 90+/-1 cadence and need a cog with 16 teeth!!

posted by veseunr [279 posts]
18th August 2012 - 9:37

like this
Like (0)