Good/bad gear combinations

[toby123]

Hello, can you advise which combinations below I shouldn't use?
It's in gear inches.

Chainring
-----48----38---28

Cog
11--120--95---70

13--102--80---59

15--88---70---51

17--78---62---45

20--66---52---39

23--57---45---34

26--51---40---30

30--44---35---26

 

[Fab Foodie]

The basic rule is pretty simple...

Big Chainring... don't use the 2 to3 biggest rear cogs
Middle chainring... use what you like!
Smallest chainring, don't use the 2 to 3 smallest rear cogs

Otherwise... use what you like!
The above is really to prevent a poor chainline causing premature cog and chain wear.

 

[TheDoctor]

Wot 'e sed.

You could get a 70' gear using 28*11, but you'd be better off in 38*15. A 24 gear bike only ever has about 20 usable gears, and a good few of those are near-duplicates. TBH, if I had that range, I'd end up only ever using the middle ring...

 

[PpPete]

I've a triple nine speed set up that is not too different in range.

40 through 80 - use the middle chainring.
wouldnt bother with the bigger ring until the 88"
wouldnt bother with the granny until I want the 34"
(or if the front change is sluggish under load I might get ready for a big hill early by going to the 45")

 

[jimboalee]

Going 26, 30, 34, 40, 45; the steps are 4, 4, 6 and 5.

Going 26, 30, 34, 39, 45; the steps are 4, 4, 5 and 6.



Which is better?

 

[TheDoctor]

Ermmm....there's bugger-all difference?
Seriously, I've been riding for 30 years, and I couldn't tell you if I was riding a 39 or 40 inch gear. I don't ever remember thinking 'Oh, if only I had a gear that was a gnats-cock lower'.

 

[toby123]

So it's OK to use any cog with the middle ring? Hmm..

OK, now let's say I have the following:

Chainring
-----50----34
Cog
12--110--75

13--101--69

14--94---64

15--88---60

16--82---56

17--77---53

19--69---47

21--63---43

24--55---37

27--49---33

Now, which ones are good/bad?

 

[byegad]

Avoid Big big and small small and the next one on the rear.