Chainset/Gear ratios/I don`t understand!!

Page may contain affiliate links. Please see terms for details.
Hi,

I was thinking of entering a sportive but looking at some of the blurb, it says that they a bottom gear of 39 x 25-28 minimum is recommended.

I have a compact chainset (50/34) and the cassette is 11/30. I take it that means my bottom gear is 34x30.

Does that mean that my bottom gearing is easier when climbing than say 39x28?

FWIW, I quite like going uphill, i`m just not very fast at doing it!
 

Mo1959

Legendary Member
Hi,

I was thinking of entering a sportive but looking at some of the blurb, it says that they a bottom gear of 39 x 25-28 minimum is recommended.

I have a compact chainset (50/34) and the cassette is 11/30. I take it that means my bottom gear is 34x30.

Does that mean that my bottom gearing is easier when climbing than say 39x28?

FWIW, I quite like going uphill, i`m just not very fast at doing it!
Yes, quite a bit easier so you should be fine. My lowest is 34/28 and I can get up most hills around here even although I'm getting on a bit! Lol
 

Sailorsi

Recumbents - Exercise whilst lying down
Location
Hants
Sheldon explains all regarding gear ratios should you wish to do some more reading. It gets a little technical but good for comparing different bikes. Here's the link to his calculator:
http://www.sheldonbrown.com/gears/
Good luck on your Sportive, I have yet to attempt one but keep coming up with excuses.....
 
It's complicated, you need to think in terms of 'gear inches' or ratios, rather than discreet 'gears' you'll find there is a fair bit of overlap in the combinations between chain rings and sprockets. Then you have to factor in the actual physical size of the chain rings ( thinking in gear inches addresses this to an extent). So you may find that a granny ring and given sprocket, will have the same ratio as a big ring and different sprocket, but the gear inch calculation will give the reason it doesn't feel the same. I have triple chainsets on 2 bikes, a compact on 1, and a semi compact on another. I have an 8 speed cassette (11-25), on one of the tripled hybrids, a 9 speed 12-27 cassette on the tripled road bike, a 10 speed 11-32 on the compacted hybrid, and an 11-28 10 speed on the semi compacted road bike. I can do all the hills I encounter regularly, on my travels on any of the bikes, but if I know I'm going to be going up a 25% gradient, I'll use the triple 12-27, because I've got more choice, and less gap, between ratios.
 
OP
OP
Sunny Portrush
Location
Musselburgh
[QUOTE 3909632, member: 9609"]your 34>30 will be about 23% easier than a 39<28
if you have a sprocket with 24t, then try your bike in 34>24 this will be very similar to 39>28[/QUOTE]

Well, that`s made my night - 23% easier, if I went any slower uphill, I`d be going backwards lol
 

cyberknight

As long as I breathe, I attack.
I go slower up hills twiddling a low gear than standing and pushing a bigger one , my legs just dont like to spin away .
 
Top Bottom