London Fixed-gear and Single-speed SJS Cycles

I ride a 44/ 18 set up at the moment. I love it because it makes hills ridiculously easy up, and hilarious down- around richmond park my legs are like- something fast and circular.
But i was wondering if i shouldn't change the rear sproket to a 16 or something to help with the fact i'm moving to a ridiculously flat area.
And or the fron to a 48?

Any help would be loverly.

I live and ride in a pretty much flat area and 48x18 works great for me. I had 48x16 before and didn't complain, but I can see that 48x18 is much easier on the knees. I get to work less tired than I used to, but it takes me a bit more time (probably because I'm not spinning faster).

I think the new ratio is easy enough to pedal around on flat routes, 44x18 would be a bit lighter than ideal, me thinks...

My IRO's set up at 46:17, I find that a bit spinny on the flat but easy-peasy on hills... The other one's 48:17 and that's perfect on the flat, haven't taken it up anything very steep yet tho'...

it is quite light.

i'm running 48x18, seems just right for me, in and around london

That's exactly how my IRO is set up! Was racing my mate up Hamsted Hill after Critical mass (him on gears), and he was shocked how easy I could keep up with him.

I'd go to 48 at the front. 48/18 seems about perfect for nearly all of London. Since I'm an old git, the odd roadie goes past but who cares? I get almost anywhere with virtually no effort. Also, to break rank, I've moved out of clipless and gone to big platforms with allen bolts sticking out - a better match for scrapes with 4x4s.

yeah i'm going to go with 48/18 (17 perhaps - i like odd numbers). Also requires much less tweaking,
Cheers guys.

I know what you mean, it's very satisfying... :D

I ride 46x17 a lot - great up hills, and only starts to feel spinny on the flat once you're trying to keep 25mph ticking over for any length of time. Pretty much the same as 48x18 (well, only an inch in it, init).

Sometimes that extra inch makes all the difference... ;-)

its not the size......

Wider diameter tubes do feel a bit stiffer though :-O

48 20 here!

its too light to be honest but i like it
i do need to get a 19 instead but its fine really, fun and really fun up the hills

48 17... Find it good for everything around town, but should be spinning more...

I have just bought a 44, so will drop to a 16 I think, which will split the difference.

Keep the 17 for more skid patches (and the same gear as me - what a special little club)

48:16 bit of work up big hills, but i've got a few open drags on the way to work (regents and hyde park) and am already spinning a bit

Cheers Hippy...

All I need do now is learn how to skid.

(god love the front brake)

I use my front brake a lot. It's nice.

incidentally i now ride a 44:16.
it is nice.

better, would you say?

muchly.

Is anyone riding a 44 15 ?

In the whole wide world? Yes, probably.

I could.. if I swapped chainring from Raleigh to Soma.. but I wont :P

I've just changed to 48 x 18, more comfortable for fixed than the 48 x 16, which was perfect for single-speeding.

i'd reccomend 44:16, itd about perfect for the town.
44:15 was tempting

15T is a weird size though.

Not as weird as 15.5 T

49x18 on one, 48x19 on the other. i still need to take some effort on spinning faster on the 48x19 but i do really like it, and it's on my conversion frame so it rides really comfortably. the other one is the track frame more like blasting around.

i really liked 48x18 but i'm loving the skid and it gives you only 3 patches. that's why i changed it over to even-odd.

Is that voodoo fixie-maths? It may work as a general rule of thumb, but it's a bit cargo cult. A hypothetical 60-15 would have only one skid patch, despite being even-odd. By contrast, my 49-19 gives 19 skid patches*, and that's odd-odd.

* Or would if I did skid. Which I don't.

Yeah and 53x18 has 18 patches..

Check out these easy to read tables and get that 17T on the back! :)

http://www.fixed.org.au/2006/11/

Weird how? Riding a bike without gears and freewheel with only one brake on the London streets when a hundred years of bicycle development have given us the option of a chainring and sprocket combination for every conceivable occasion...

That's fucking weird.

The Rule is:
If you have the ratio ie mine 44:16, and you divide it down to the smallest possible divisible fraction, then you have the potential numbe of skid patches.
SO 44:16 = 11/4, so 4 possible skid patches.
17 doesn't divide by anything. that is why it is good for your tires (17 skid patches possible).
I would change to 15, which would give me 15 patches, but i love the ratio as it is.

running 48x18 with a half link, normally would be 3 skid patches, seem to have the right length of chain because now got 17, and i like the 72 inch.

i think i know skid patches - does he have a mohican?

This isn't true. If you rode 34/17 or 51/17 you would have only one skid patch.
It's not to do with the primallity of the divisor, bout the co-primallity of the chainring and the sprocket.

no, but the fact remains that it still matters whether the top and the bottom can be reduced in terms of fractions.
i.e. 51/17=3/1
34/17=2/1
so actually it totally depends on the divisor, as all fractions do.

So this is not true.

no 17 Doesn't divide by anything.
51 divides by 17

gear ratios are fractions, if you can work out fractions you're fine- in terms of skid patches.

in order to get gear inches:
multiply your ratio by 26.4 for 700x23c
or by 27.1 for 27x1/1/4"

I think we can agree that 17 is prime. The fact that 17 is prime will not (as stated by you) will not guarantee 17 skid patches.
19 and 23 are better prime nos. anyway. (insert smiley face here)

I agree smiley faces all round,
but I never guaranteed 17 skid patches, unless you had a 44T up front

hth ;)

Yes, I know, eyebrows said "possible". I'm wrong again.

hth?

Hope that helps.

so this does this not hold true then?

ignoring the actual technical factors and going on feel, what makes you choose your gear? i run 52-18/20.

i live in an area with long flats and big hills. i dont like the feeling of spinning out when im trying to keep up with traffic. with my gearing i can comfortably keep up and overtake traffic with enough gear left for me to put in a full sprint.

on hills i dont mind having a big gear as i kind of enjoy the challenge, and having having some resistance to push against feels good. i wouldnt want this if i was riding 100~miles or up a 20mi climb, but for bashing about its great.

so i try to ride a gear that is as close to spinning out on the flat as i can, without actually spinning out.

i recently went out on a 50mi ride with a 22t, and while i could definatly ride longer with it, i missed the top end speed for sprints and the resitance up hills.

i prefer the 52/18 as well, and im in a pretty flat area too.

i dont mind pushing in that gear up hills, as long as the bike can take the pressure and abuse ill keep on pushing. I want a front brake with that gearing though because stopping becomes like manhandling a drunk cow.

currently im cruising on 46/18 while i fix my racer, and that i can easily ride brakeless, but i totally miss the ridicolous acceleration and being able to keep up with all traffic and bomb hills like crazy.

I think im going 53/18 when i fix the bike though. Which apperently brings me from 9 skid patches to 36? is that good or bad? less flat spots? I dont get this at all, anyone care to explain how this is supposed to work?

53/18 will give you 18 skid patches, the max number of skid patches you can have is the amount of teeth on your sprocket (and that's only if the number of teeth on the cahinring doesn't divide into it, which 53/18 doesn't) however if you usually skid with either leg (as opposed to always skidding using the same leg) you can double the skid patches, only when the number of teeth on the chainring is an odd number though (such as 53). Well, that's what I think, if it's wrong feel free to say =D

I never thought my love of numbers and bikes would cross over in such a way =P

this may be a stupid question but
is more skid patches then better or worse?