Author Topic: Gear choice for fixies  (Read 3127 times)

'breff

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Re: Gear choice for fixies
« Reply #25 on: September 01, 2018, 12:01:50 am »

IanDG

  • The p*** artist formerly known as 'Windy'
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Re: Gear choice for fixies
« Reply #26 on: September 01, 2018, 12:09:01 am »
I'm a low 60s (inches) rider for every day use currently 42x17. Have done a 58 minute 25mie TT on 81" in my day.

Re: Gear choice for fixies
« Reply #27 on: September 01, 2018, 10:06:46 am »
A question , is there any theoretical advantage and or actual advantage to riding larger chainring / larger sprocket , as in 51/19 etc...
Yes, it feels smoother due to lower chain tension and is less sensitive to things being not quite round.  Weighs slightly more.  Actually, all this is in the OP.
Never tell me the odds.

Re: Gear choice for fixies
« Reply #28 on: September 03, 2018, 12:42:44 pm »
43x17

Best gear ever.  The combination of two primes makes for even chain and tyre wear and a beautifully smooth ride.
(click to show/hide)

Re: Gear choice for fixies
« Reply #29 on: September 03, 2018, 06:56:24 pm »
I'm warming to 47 x 18.  I liked 52 x 20 a lot, but 20T EAI sprockets are no longer imported, it seems.  I have 42 x 16 on a bike at the moment and it's a bit harsh for my liking.
Never tell me the odds.

Re: Gear choice for fixies
« Reply #30 on: September 12, 2018, 12:12:18 pm »
Currently on 44 x 17 but it's a tad high for Morth Mcr so I have a 46 x 18 to try. Originally started with 48 x 19 which seemed spinny but comfortable. Interestingly I can now hold a slightly bigger gear uphill on my road bike as a result of the 44. Might try 43 x 17 and never thought about odd/even numbers and wear

simonp

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Re: Gear choice for fixies
« Reply #31 on: September 12, 2018, 12:47:53 pm »
I have a 47T chainring, which is nice because it's a prime number. I typically either use 65" or 69" gearing which are 19T and 18T respectively.

Re: Gear choice for fixies
« Reply #32 on: September 12, 2018, 12:58:05 pm »
I have a 48 tooth ring on my new crankset. I have 15, 16, 17, and 18 tooth cogs - I figures 18 was probably a reasonable all round gear and the smaller ones would be good for TTs next year. Stupidly, I'm supposed to be doing a hillclimb in a couple of weeks, and I reckon 48x18 might be pushing it on that.  Maybe 48x19 would be fine. Means I need yet another sprocket!  ::-)
I used to ride 40x16 everywhere, which matches up reasonably well to 48x19.

Re: Gear choice for fixies
« Reply #33 on: September 16, 2018, 03:16:12 pm »
43x17

Best gear ever.  The combination of two primes makes for even chain and tyre wear and a beautifully smooth ride.
(click to show/hide)
I'm due to replace 42 x 16 on my Pompino soon.
I'm tempted to give this a try.

Re: Gear choice for fixies
« Reply #34 on: January 19, 2019, 03:54:11 pm »
The street fixie nerds in the US swear by a 19T rear cog because you nearly always get 19 skid patches and no coincidence of teeth (at least, not unless you pick 57 x 19, which would be unlikely and expensive).  Prime-numbered chainrings are better than prime-numbered cogs, though, because they absolutely guarantee no concentrated wear.
Never tell me the odds.

Re: Gear choice for fixies
« Reply #35 on: January 19, 2019, 05:23:21 pm »
I now have a 48 tooth chainring, and sprockets from 14-20 teeth for my TT/hillclimb fixie.
In order to get it to work properly on the turbo trainer, I'm going to have to get a lower gear than 48x20 though. I have seen 22 tooth Sturmey Archer freewheels, I assume they would fit on a regular flip/flop hub? Are there any better ways of going lower while retaining the same chainring? I don't want to have to switch chainrings to change between turbo and race - I can live with switching wheels (and chains) just about!

Re: Gear choice for fixies
« Reply #36 on: January 19, 2019, 11:02:12 pm »
Sturmer Archer sprockets for geared hubs are not compatible with the usual ("regular" matches my understanding) threaded flip/flop or double fixed hubs. FWIW I fitted a 22t (biggest that would fit in the chainguard) sprocket to youngest daughter's Shimano 8-speed hub (caution... that was 6 years ago). It seems odd, but I'm sure that those components were 3/32", rather than the traditional 1/8" chain width for fixed gear & single-speed transmissions (I use 3/32", but that's not normal). It's possible that you're referring to freewheels that would fit on a threaded hub. I think that's unlikely, but ICBW.

I've tried to find threaded cogs with more than 22 teeth in the days when Will was still running HubJub. By now, I can't remember who made the 23t, probabaly E.I.A. or Andel. However Will seemed unable to obtain them (on reflection, he might have been able to, but not on terms which would have kept his business solvent). I'm not up to date with Hubjub's offerings (E.A.I. are no longer supplied in 3/32" width), but 22t seems the limit.

Meanwhile I'm untroubled by the fuss about co-prime rear cog & chanring teeth. I ride 50x20 & have yet to observe any wear patterns corresponding to that simple 2½ ratio, though I do rotate the chainring when I renew the chain. Also at 73 I'm a long way past it.

Re: Gear choice for fixies
« Reply #37 on: January 19, 2019, 11:10:28 pm »
Sturmey Archer make bog standard single speed free wheels - nowt to do with their gear hubs. I believe they fit standard threaded hubs.

zigzag

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Re: Gear choice for fixies
« Reply #38 on: January 20, 2019, 11:22:23 am »
my new build ss is 58x19 which is very similar gear to 48x16* which i currently ride. the reason for change was the need for higher gears (e.g. 58x16) if i do an occasional tt on it.

*works well everywhere with exception of 15%+ hills and 50kph+ sprints

Re: Gear choice for fixies
« Reply #39 on: January 21, 2019, 05:56:36 pm »
Freewheels tend to have a slightly greater chainline than a fixed sprocket.  This doesn't usually matter as they are less fussy - there's a bit of wobble in most freewheel bearings.  Optimise chainline for the fixed sprocket, if you swap betweenthe two.
Never tell me the odds.

Re: Gear choice for fixies
« Reply #40 on: January 21, 2019, 08:35:00 pm »
I guess I can live with a 22 tooth fixed sprocket on the trainer. I hadn't seen any until I checked out Hubjub. Might get a bigger (53 tooth?) chainring as well so that I have the gearing to get a good 10 mile time if I have the legs! Zigzag - where did you get your 58 tooth chainring from?
Is there any difference between the 1/8 chains? They range from £5 to £63. I guess I would pick one of the mid price Izumi chains as my race chain given no further information.

Re: Gear choice for fixies
« Reply #41 on: January 21, 2019, 09:15:32 pm »

Is there any difference between the 1/8 chains? They range from £5 to £63. I guess I would pick one of the mid price Izumi chains as my race chain given no further information.

I have in the past broken two cheap 1/8th chains.  Both were sideplates cracked across the hole for the pin, and not where I had joined them.

Re: Gear choice for fixies
« Reply #42 on: January 21, 2019, 09:19:55 pm »
I usually buy KMC 1/8" chains.  I would avoid Taya or unbranded ones.
Never tell me the odds.

Re: Gear choice for fixies
« Reply #43 on: January 21, 2019, 09:39:53 pm »
General consensus I think that fixed is hard on chains, so cheap ones are A Bad Idea. I'd look to spend up to £15 and buy a recognised brand - KMC or something, as rogerzilla says. Not to important though what brand.

Re: Gear choice for fixies
« Reply #44 on: January 21, 2019, 09:56:34 pm »
I just buy Sachs/SRAM PC1s or KMC chains and rarely spend more than a fiver.

Re: Gear choice for fixies
« Reply #45 on: January 22, 2019, 08:36:47 pm »
Ideally get a chain with non-peened pins, so they can be taken apart and rejoined without special links or pins.  The PC-1 is peened, annoyingly.  if you never alter chain length this is tolerable because you can just use a master link, but if you want to add a couple of links for a different gear combination (e.g. I want to use 52 x 17 on the track), this means having two master links, and that looks stupid.
Never tell me the odds.

Re: Gear choice for fixies
« Reply #46 on: January 22, 2019, 09:21:50 pm »
I figured I'd just have 2 chains - one for TT gears (53x15  or 53x16) and one for the turbo (48x22). So long as they are obviously different (eg one black, the other silver), and I remember which way around they go, I should be OK just using the master link. I won't buy cheap chains, but it sounds like there's no need to spend lots on a chain either...

Re: Gear choice for fixies
« Reply #47 on: January 23, 2019, 11:48:44 am »
You should be able to use the same chain length for all those, unless you have unusually short dropouts.  Just set it up so 48 x 22 has the axle as close to the front of the slot* as possible.

*I mean the front of the bike, in case you have track ends
Never tell me the odds.

Re: Gear choice for fixies
« Reply #48 on: January 23, 2019, 03:26:30 pm »
It's not a track bike, so it has short forward facing dropouts. However, I shall experiment once I have the bigger chainring/sprocket.

Re: Gear choice for fixies
« Reply #49 on: February 01, 2019, 09:23:03 am »
I ended up ordering a 24 tooth sprocket and a 54 tooth chainring. They were basically the biggest I could get for an affordable price.
The sprocket arrived and I've installed it and used it on the turbo. I had to put an extra link in the chain to make it fit (compared to the 20). The chainring hasn't arrived yet - I'll probably wait until the weather improves before I start switching them around - will discover what chain length I need for 54x16 (or 15 if I'm feeling fast) at that point.