I have no idea...

Unfortunately I have drawn a rather big blank, despite reading through reams and reams of sheldon browns thoughts, and searching many many forums I cant find a rough guide to gear ratios, not how to calculate them but rough recommendations for terrain. I know that everyone is different but i'm just looking for a rough recommendation of what might be good. Cause atm i wouldn't know the difference between a ratio of 3 and a ratio of 6 (though i am aware that its quite a big difference)

Please help

are you cycling round London?

i think a gear ratio of 3 would be where the chainring divided by sprocket = 3, i.e 48x16 = ratio of 3.

eventually i will be around london, but atm i'm out in somerset, a little bit hillyer then london, but in town n around town so pretty level still

well it depends. you should get a spinny gear if its hilly - just get a sprocket with a lot of teeth i.e 17, 18, 19, and you'll be fine.

what size chainring is that based on though (48t?) I was thinking of getting a 44t (is that too small?) as i need a 3 pin chainring my options on chainring size are pretty limited atm.

Why bother with ratios? Just know your inches and you'll be fine. 70" is a good starting place for hills and flats, less is easier, more is harder.

nicked this off 63xc

            Road 700c
    16t 17t 18t 19t 20t
40t 67.5    63.5    60  57  54
44t 74  70  66  62.5    59.5
48t 81  76  72  68  65

Offroad 29incher
    16t 17t 18t 19t 20t
36t 63  59  56  53  50.5

Offroad 26" MTB
    16t 17t 18t 19t 20t
36t 58.5    55  52  49  47

Fit a gear, if it's too hard, drop it, if it's too spinny, raise it.
Starting point is always suggested around 70" but if it's hilly maybe 65-70 would be better.
Remember you have to spin down the hills too so fit a brake too.

Use this to work out what chainring/cog combo you can get away with: http://www.sheldonbrown.com/gears/

Do you have a roadbike? Try cycling around in a single gear for a couple of hours and see if you like it. Will give you some idea of a starting ratio to try.

However, gearing is a very personal choice and when you have hills you'll probably need to compromise (need to be able to get up and get down).

When I lived in San Francisco (pretty damn hilly), something around 70" worked out fine (as ImOnCrank has already suggested).

If you've got a fair few hills, go for a ratio of something like 42:18. It's quite low, but it's good for the hills and I found it to be a good transition to singlespeeding/fixed.

on the topic of gears etc...

if i wanna run a free wheel on the flop side of the bianchi pistas flip flop hub, can i use a 1/2x3/32 inch freewheel, whatever the hell that means (something to do with the chain yeh?)

1/2" is the chain pitch, gap between links. 3/32nds of an inch is the width of the teeth. Yes, you can use this.

thanks mr. hippy. is this the standard or is 1/8 the standard for most bikes?

3/32 is the road/mtb standard. 1/8th is the bmx/track standard.
What is your fixed side? If it's 1/8th get a 1/8th freewheel, if it's 3/32 get a 3/32 freewheel.
You can use 3/32 cogs with 1/8th chains, also.

well long story short i'm thinking of purchasing the bianchi pista, but it doesnt come with a freewheel on the flip-flop hub (i only run singlespeed, think i should keep a freewheel cog to fall back on at least till i'm used to fixed.

the thing that was confusing me is this: the bianchi pista is primarily a track bike yes? so i thought maybe it'd be 1/8 standard.. so i looked for freewheel cogs, found mostly ones saying bmx in the auction on ebay but with 3/32.. so i got confused.

actually i still am confused :(

Dunno if the Bianchi comes with 3/32 or 1/8th kit. But, if you buy a 3/32 freewheel it will work with both anyway.

ok, good to know. didn't want to stick summat on that would a) not work or b) fucuck my sparkly new bike. thanks hippy

lpg i think a gear ratio of 3 would be where the chainring divided by sprocket = 3, i.e 48x16 = ratio of 3.

48x16 is quite high.

I used this gear ratio of 3 as well when i was in Brazil and used to ride 39x13. Now i know why i used to feel so tired after riding my fixie :)

Don't forget about the crank length - I think Sheldon is on the right track with his 'gain ratios'. I just switched from a road crankset with, I would guess, 172.5mm cranks, to a track crankset at 165mm, and I was amazed at how much difference it made - my good old 44/16 (=2.75) just feels too high now.

I would say for riding around London (lots of stop-start, not too much flat out top speed) you want a medium-lowish gear, certainly less than 3. That 44/16 was low enough to get up the steepest roads in Brighton and high enough to get up to 40 kph on the flat.