SS/fixed gear ratios. what do you use?

nicklouse

thinking of raiding the scrap bikes out the back of the shop to put a fixed pub bike together as will most likely get some cogs made (sell the rest) to fit on the disc mount..

thats the back ground. the bike will be running 700c x 24 tyres and will be a sit up position.
currently on the SS MTB i run a 32:15.

and the run to the pub is flat and not to far this more of finding a reason to build another bike :oops: and i have some tyres i need to use.

vorsprung

I live in Devon where it is hilly

My old single speed used to be 42:16 which with 700c x 28mm tyres gave about a 70" gear

Kiblams

I use 36x16 for my commute, could be better for the flats but I am in no hurry and the hills are still easily manageable (this is on 26x1.75 wheels/tyres though)

asprilla

48:16 but there are very few hills in London.

Canny Jock

48:15, again in London so not much in the way of hills on the commute.

stickman

46x16 on 650a wheels.

ex-pat scot

42 x 16 on my 700 x 23 tyres.

Gets me up the local hills (1 in 5 / 1 in 6) and bowls along the flats nicely 18-22mph

Sleepycol

48:16 on 26" wheels and 1.5 tyres. Works fine for me, but will probably depend ho how long you stop at the pub.

Matt.K

48x18 on 700x25c

9 miles on fairly flat route (a couple of very small hills).

It's what came with the bike.
On good days I think about changing down to 17 at the back, but then I hit a headwind and change my mind.

Oddjob62

Alternate between 51x15 and 51x18 every few weeks.

DevUK

42:16 on 700x28c on a partially hilly commute. Also 48:16 on my other fixed for the same commute if I'm feeling up to it

Harveytile

48:18. Works out at 72". One real bump, otherwise pretty flat.

Enough to bring a bead of sweat to the brow and keep my scalp in tact most of the time :shock: !
.

biondino

48:18 with 165mm cranks and 23mm wheels. Just about perfect for commuting in flat London, though the most fun bits are often the short sharp hills!

lost_in_thought

46/14, soon to be 48/14. But I'm in London, it's v flat.

Oh and 170mm cranks + 26mm tyres. But I don't know why you need to know that!

wgwarburton

lost_in_thought wrote:

46/14, soon to be 48/14. But I'm in London, it's v flat.

Oh and 170mm cranks + 26mm tyres. But I don't know why you need to know that!

Leverage, LiT, leverage: shorter cranks reduce the leverage your legs apply to the cranks, so increase the effective Gear Ratio. If that doesn't make sense there are various ways to describe it better, but I don't know which would help you most...

Similarly, the tyre size affects the wheel diameter- if you go from 23c slicks to 37c knobbies on a CX bike you increase your GI.

The tyre size will be factored in already if you calculate & quote Gear Inches properly, but not the crank length. If you want to be able to include that then you can use Sheldon's "Gain ratio" number... but no-one will know what you are talking about down the pub. :-)

Cheers,
W.

redvee

700*25 on 46/16 tyres, not had any issues around bristol with the gearing other than being spinny at 28mph+

asprilla

redvee wrote:

700*25 on 46/16 tyres, not had any issues around bristol with the gearing other than being spinny at 28mph+

Your frame must be an odd shape.

andy83

44:17 running on 700x25c quite hilly but i just see it as good training

lost_in_thought

WGWarburton wrote:

lost_in_thought wrote:

46/14, soon to be 48/14. But I'm in London, it's v flat.

Oh and 170mm cranks + 26mm tyres. But I don't know why you need to know that!

Leverage, LiT, leverage: shorter cranks reduce the leverage your legs apply to the cranks, so increase the effective Gear Ratio. If that doesn't make sense there are various ways to describe it better, but I don't know which would help you most...

Similarly, the tyre size affects the wheel diameter- if you go from 23c slicks to 37c knobbies on a CX bike you increase your GI.

The tyre size will be factored in already if you calculate & quote Gear Inches properly, but not the crank length. If you want to be able to include that then you can use Sheldon's "Gain ratio" number... but no-one will know what you are talking about down the pub. :-)

Cheers,
W.

Ahhhhhhh. I do factor in wheel size, but not tyre size - the one I use is a simple table.

I'm also appalled that I've been working for american hedge funds so long that my brain now reads 'leverage' as 'LEV(rhymes with kev)er-idge' rather than 'LEE-ver-idge'

Grrr.

jonginge

lost_in_thought wrote:

WGWarburton wrote:

lost_in_thought wrote:

46/14, soon to be 48/14. But I'm in London, it's v flat.

Oh and 170mm cranks + 26mm tyres. But I don't know why you need to know that!

Leverage, LiT, leverage: shorter cranks reduce the leverage your legs apply to the cranks, so increase the effective Gear Ratio. If that doesn't make sense there are various ways to describe it better, but I don't know which would help you most...

Similarly, the tyre size affects the wheel diameter- if you go from 23c slicks to 37c knobbies on a CX bike you increase your GI.

The tyre size will be factored in already if you calculate & quote Gear Inches properly, but not the crank length. If you want to be able to include that then you can use Sheldon's "Gain ratio" number... but no-one will know what you are talking about down the pub. :-)

Cheers,
W.

Ahhhhhhh. I do factor in wheel size, but not tyre size - the one I use is a simple table.

I'm also appalled that I've been working for american hedge funds so long that my brain now reads 'leverage' as 'LEV(rhymes with kev)er-idge' rather than 'LEE-ver-idge'

Grrr.

Et, voila! http://www.appbrain.com/app/org.bikecalgary.fixedgears

lost_in_thought

JonGinge wrote:

lost_in_thought wrote:

WGWarburton wrote:

lost_in_thought wrote:

46/14, soon to be 48/14. But I'm in London, it's v flat.

Oh and 170mm cranks + 26mm tyres. But I don't know why you need to know that!

Leverage, LiT, leverage: shorter cranks reduce the leverage your legs apply to the cranks, so increase the effective Gear Ratio. If that doesn't make sense there are various ways to describe it better, but I don't know which would help you most...

Similarly, the tyre size affects the wheel diameter- if you go from 23c slicks to 37c knobbies on a CX bike you increase your GI.

The tyre size will be factored in already if you calculate & quote Gear Inches properly, but not the crank length. If you want to be able to include that then you can use Sheldon's "Gain ratio" number... but no-one will know what you are talking about down the pub. :-)

Cheers,
W.

Ahhhhhhh. I do factor in wheel size, but not tyre size - the one I use is a simple table.

I'm also appalled that I've been working for american hedge funds so long that my brain now reads 'leverage' as 'LEV(rhymes with kev)er-idge' rather than 'LEE-ver-idge'

Grrr.

Et, voila! http://www.appbrain.com/app/org.bikecalgary.fixedgears

Duly downloaded!

georgee

42x14 700 23c

one hil but generally flat London commute.

Oddjob62

WGWarburton wrote:

The tyre size will be factored in already if you calculate & quote Gear Inches properly, but not the crank length. If you want to be able to include that then you can use Sheldon's "Gain ratio" number... but no-one will know what you are talking about down the pub. :-)

Rabbit calculates them all

http://software.bareknucklebrigade.com/ ... pplet.html

supersonic

Nick, if you a going to ride a fixie you must grow a beard and start wearing braces to hold your slacks up.

:twisted:

DevUK

Oddjob62 wrote:

Rabbit calculates them all

http://software.bareknucklebrigade.com/ ... pplet.html

This is the one I use. Very comprehensive

wgwarburton

DevUK wrote:

Oddjob62 wrote:

Rabbit calculates them all

http://software.bareknucklebrigade.com/ ... pplet.html

This is the one I use. Very comprehensive

+1

Cheers,
W.

nicklouse

supersonic
one word Fivefingers.

cheers for the feed back and the calcs. yes i know about them but it was not the question.

now to build 2 front wheels.

Clarion

I have 46x18 on my Carlton. With 700x32c it's about 69". I'm thinking about lowering it.

Oh - cranks are 170mm.

My Rudge is also 46x18 (46t is awfully common on cottered chainsets), on 26x1 3/4", which still works out at about 69". And that definitely needs lowering. No idea of the crank length. But I don't commute on the Rudge (haven't as yet, anyway )

Clever Pun

48-15 and there hills of sorts that require MTFU
50-17 but only one brake

nicklouse

cheers all. think i will be starting with 16T as it seems to give the most future options.

now to make some mods to a fork and some bars. must find a suitable frame though as the other fixed build on here has got me thinking.