Need an overview on gears

tc1992

I'm looking to get a road bike, having been riding a Giant Cypress hybrid for 9 months.
My main concern is with the low gear. I'm not going to get into really serious
riding . I'm not too bothered about the top gear.
I can just about do anything hill wise where i live, which is hilly (Glossop),
so would definitely want a low gear on my new bike that is as easy, as the
low on my Cypress. if it can do any easier then great.

So from what i've read it pretty much comes down the teeth numbers.
What are the ratios i should be looking for / avoiding.
What other factors, specifically related to gears should i consider,
and what does compacted mean?

arran77

Take a read of this...

http://www.bikeradar.com/forums/viewtopic.php?f=40020&t=12583566

A 'compact' is a double chainset with a 50 tooth outer chain ring and either a 34 or 36 tooth inner ring as apposed to a 'standard' double chainset which is generally 52 tooth outer with a 39 tooth inner.

tc1992

thankyou aran, will take a look at that thread

markhewitt1978

You will want a bike which either has a compact chainset (front cogs) which is 50/34. Or a triple chainset which can be say 50/39/30. The bigger the front chainring the harder the gear.

Then look at the cassette on the back, the bigger the cog there the easier the gear, for hills you'll need at least 28T on the back, you can get 30T too.

For comparison purposes just divide front by back. So a compact with 28T would be 34/28 = 1.21.

simon_masterson

If you want the same lowest gear you have now, you either want a triple (standard is 30/39/53) with 26t (biggest rear cog), a compact (50/34) with 28t, or a standard double (usually 53/39 these days) with 32t.

To be honest, I think a triple might be the best choice for you. If you want gearing that low and aren't bothered about high gearing, with a triple you have the whole range of the 39t.

tc1992

thanks mark and simon. I have a triple chainset on my hybrid. So would you say that if i have a double chainset on my new bike there is no way that it will have the lowest gear will be as low as the one i have at the moment

simon_masterson

Not at all. If your lowest gear is the one on the website (28x24), the examples I gave above are the same or lower. Compact with 28t at the back is a common configuration, but using a triple, as well as giving the full range of the middle ring, also allows a smaller cassette range for smaller jumps between teeth. Both options work.

markhewitt1978

You don't really need the same bottom gear on a road bike as you would on a hybrid, apart from anything else the road bike will be lighter, so easier to get up hills, plus the drivestrain will be more efficient etc. I went from a Trek FX 7.1 hybid which did have very low gears to a road bike with 34/30 and even though that bottom gear is a lot higher I felt it was much easier to climb than my hybrid.

Initialised

It's probably simpler to explain this way, a higher number means easier pedalling

R/F = Gear Ratio
24/28 = 0.875 (Your current lowest gear)
32/34 = 0.941 (A compact with 50-34 x 11-32)
28/34 = 0.824 (A compact with 50-34 x 11-28)
32/39 = 0.821 (A standard double 53-39 x 11-32)

So a compact double with a 34T on the front and a 32T on the rear is going to be slightly lower geared than your current bike, the other two are slightly higher but so close you probably wont tell the difference as a road bike will most likely be lighter and have tyres with lower rolling resistance.

tc1992

ok, thanks all, think i've got it now. The ratio thing is very helpfull.
And as Mark said, i was thinking would be the case, the bike is going to much better and more effficeint.
My Hybrid is about £350 new, and i'll be looking to looking to buy a bike in the above £700 price range,
so i can't believe it will be a harder bike to use.