Author Topic: gearing  (Read 5620 times)

gearing
« on: April 07, 2020, 02:00:26 pm »
Hi Folks,
Probably been asked a 100 times, however, what is the favoured gearing for a single speed audax bike? I've had 2 in the past - 42 x 16 and 48 x 18 and I found little difference between the 2. Am asking now because I am thinking of getting a bike built up and wanted some thoughts/advice etc

Cheers,

Doo
I dunno why anybody's doing this!

Phil W

Re: gearing
« Reply #1 on: April 07, 2020, 02:10:53 pm »
You need to divide front teeth count by the rear count to compare gears for same bike.

They both come out 2.6..., which will be why they don’t feel much different.

bludger

  • Randonneur and bargain hunter
Re: gearing
« Reply #2 on: April 07, 2020, 02:22:14 pm »
I am riding 44/16 at the moment which seems like a very good ratio for mixed terrain cycling for me. Gets you up the hills and through the headwinds ok but still lets you average 30 km/h on the flat without being too spinny.

You can have a wheel built with two sprockets/freewheels on either side so you can have a choice of ratios by flipping the hub over as far as I know.

https://bicycles.stackexchange.com/questions/42712/convert-fixed-side-of-flip-flop-hub-to-freewheel

Preferences are very diverse. There was a feature about the people who did PBP fixed/SS and their ratios varied a lot.
YACF touring/audax bargain basement:
https://bit.ly/2Xg8pRD



Ban cars.

zigzag

  • unfuckwithable
Re: gearing
« Reply #3 on: April 07, 2020, 02:31:53 pm »
my favourite* ss gearing is 48x16, have done almost 7000km on that ratio so far, mostly training and audax rides

*which does not mean it will be your favourite

Re: gearing
« Reply #4 on: April 07, 2020, 02:42:05 pm »
I dunno why you'd want to ride any distance on a SS.  All the disadvantages of fixed with none of the advantages. :thumbsup:

Re: gearing
« Reply #5 on: April 07, 2020, 02:42:28 pm »
my favourite* ss gearing is 48x16, have done almost 7000km on that ratio so far, mostly training and audax rides

*which does not mean it will be your favourite

My favourite fixed gearing is 48*16, but it took me a whole to get there.  Used 48*18 for quite a long time before that.

Re: gearing
« Reply #6 on: April 07, 2020, 02:45:27 pm »
It all depends on how fast you ride and your pedalling speed.

Re: gearing
« Reply #7 on: April 07, 2020, 04:17:16 pm »
Thanks for all the responses thus far.
48 x 18 seemed fine before (as did 42 x 16 and I now know why d'oh). Excuse my ignorance, but 48 x 16 would be tougher, right?
I dunno why anybody's doing this!

Re: gearing
« Reply #8 on: April 07, 2020, 04:41:55 pm »
Thanks for all the responses thus far.
48 x 18 seemed fine before (as did 42 x 16 and I now know why d'oh). Excuse my ignorance, but 48 x 16 would be tougher, right?

Funny you should day that but, in the end, I found it easier.

It is a bigger gear, though.   Circa 12%.

JonB

  • Granny Ring ... Yes Please!
Re: gearing
« Reply #9 on: April 07, 2020, 05:01:43 pm »
I find that using a gear inch calculator is helpful, this one works https://www.bikecalc.com/gear_inches. More inches = higher gearing. My preference for fixed gear over the last 18 months or so has been 68" (49 * 19) for most terrain and I've geared down for longer hilly stuff such as the Brevet Cymru or Bryan Chapman 64" (49 * 20).  Never ridden higher than 69".

Re: gearing
« Reply #10 on: April 07, 2020, 06:30:37 pm »
It's a personal thing, so recommendations from others are only helpful to a certain degree.

My gearing choice depends on my weight, the weight of my bike, my fitness, the general terrain I plan on tackling, and the distance.

Most fun bike ever: lightweight carbon race frame 48/18. For me, the right gear to maintain 18mph +/- 2mph @ 80-100rpm, on rolling terrain with no monster hills. Just been out for a quick 30 miler and managed to descend at 30mph with ease.

Might not work for you though

^fixed, not SS (agree with chris n about SS)

Re: gearing
« Reply #11 on: April 07, 2020, 06:45:39 pm »
I've had a fixed in my stable for over 50 years.  As a teenager I rode 48x20 (72") on clubruns until I learned to pedal and dropped the gear to 48x20 like most of my clubmates.  This was for clubruns around the South Downs and central south coast and for youth hostel touring.  On that gear I toured central Wales and in Normandy and Brittany.  For time trialling and outdoor track I rode 48x16 (81") or 48x15 (86").  Just once I tried 48x14 (92") for a short time trial, a 10.  I went slower than usual because I just could not get "on top of" the gear.  Mind you, I was never fast, 25 minutes being my best 10 time back in 1973.  Longest ride on a 65" was 120 miles which was a regular feature in those dim and distant days.

Re: gearing
« Reply #12 on: April 07, 2020, 07:35:24 pm »
70" for fixed, about 60" for SS.  With a SS you don't need to worry about getting down the hills so you can run an easier gear.

However...I pedal at about 100rpm on a geared bike, so a 60" gear gives me a nice steady 18mph.  if you naturally pedal at 80rpm* then a 70" SS would be more appropriate.

*which is more efficient than 100rpm, although not quite as kind to the knees.
And Darkness and Decay and the Coronavirus held illimitable dominion over all.

Re: gearing
« Reply #13 on: April 07, 2020, 10:33:27 pm »
I've had a fixed in my stable for over 50 years.  As a teenager I rode 48x20 (72") on clubruns until I learned to pedal and dropped the gear to 48x20 like most of my clubmates.  This was for clubruns around the South Downs and central south coast and for youth hostel touring.  On that gear I toured central Wales and in Normandy and Brittany.  For time trialling and outdoor track I rode 48x16 (81") or 48x15 (86").  Just once I tried 48x14 (92") for a short time trial, a 10.  I went slower than usual because I just could not get "on top of" the gear.  Mind you, I was never fast, 25 minutes being my best 10 time back in 1973.  Longest ride on a 65" was 120 miles which was a regular feature in those dim and distant days.

72" is nominally 48x18 (could be closer to 48x17 with 700x23 tyres). 48x20 is from memory about 65". My touring gear when I was young, strong (and stupid) was 49x19, changed to 49x20 for the winter. Now I have trouble with 42x17, the winter gear was 42x18 when I last rode fixed in winter. It's a bit low but on ss it was fine (freewheel for going down hill!).

I also tied 49x14 in a 10. Same result as you, couldn't get on top of it, beaten by a clubmate for 10 seconds

LittleWheelsandBig

  • Whimsy Rider
Re: gearing
« Reply #14 on: April 07, 2020, 10:38:59 pm »
44/16 (700x32C) is my standard commuting/ audax fixed ratio. There is a 17t on the other side of the hub but it hasn’t been used for a while. I ran 42/17 fixed for a roughstuff weekend last year but there was a fair bit of walking required on the steep stuff.

I’m not strong enough to run much bigger gears for long rides. 48 or 49/14 were normal track gears for me back in the day but I wouldn’t like to turn them for any distance on the road nowadays.
Wheel meet again, don't know where, don't know when...

Re: gearing
« Reply #15 on: April 08, 2020, 06:47:14 am »
I used 48 x 14 for a couple of seasons of "10"s and went faster than on 48 x 15.  This was because the start of the course had a gentle downhill (which you didn't need to ride back up) and it was impossible for me to get power down with a lower gear. 48 x 15 would have been better on the flat bits but it was a trade-off.

Riding to the start and back on a 90" gear was oddly fun.  Everything happens very slowly!

But SS is a completely different animal to fixed, so I shouldn't confuse the OP!
And Darkness and Decay and the Coronavirus held illimitable dominion over all.

Bernster

  • ACME (Herts Branch)
Re: gearing
« Reply #16 on: April 08, 2020, 09:31:41 am »
I dunno why you'd want to ride any distance on a SS.  All the disadvantages of fixed with none of the advantages. :thumbsup:
Interestingly I think the opposite is correct - SS has many of the advantages of fixed without the main disadvantage: ease of maintenance, cheaper/fewer components and not having to make any decisions on which gear to be in, but with the ability to freewheel when required. It's clear that quite a few will not agree with this, but I thought I'd offer the counter argument  O:-)

FWIW I usually use either 43x17 or 43x18 on my SS bikes.

Re: gearing
« Reply #17 on: April 08, 2020, 09:45:28 am »
I'm with chris n on this.  Fixed gets you up hills in a way SS can't, by pushing the cranks over the dead centres for you.  There is also less to go wrong; unless you buy a really expensive White Industries one or flush it with oil regularly, a freewheel can easily stick and give no drive. 

Also, you can throw away the rear brake, rear brake cabling and most of the LH brake lever, so it's measurably lighter.
And Darkness and Decay and the Coronavirus held illimitable dominion over all.

Re: gearing
« Reply #18 on: April 08, 2020, 11:07:30 am »
I did the Mersey Roads 24 on 47*14 and ride faster courses on 50*14.  I can ride at 35mph on the bigger gear.

zigzag

  • unfuckwithable
Re: gearing
« Reply #19 on: April 08, 2020, 08:13:28 pm »
we are veering off topic, but ime ss is vastly superior, just as quick up the hills (if there are dead spots, one should improve the pedalling technique), you can descend any long hill in relaxed manner, without a speed limiter, in a very aero position (=much faster), bunny hop over obstacles easily. safer in case of unexpected situation on the road. it's very reliable too, no problems with good freewheels in my ~14yrs of riding different ss bikes. my "summer" ss bike is light enough with two brakes - 6.55kg without the w.weenie parts.

fixed bikes belong to velodrome, too many compromises/drawbacks for the road use.

Re: gearing
« Reply #20 on: April 08, 2020, 08:26:41 pm »
Yeah, but they’re cool. 

LittleWheelsandBig

  • Whimsy Rider
Re: gearing
« Reply #21 on: April 08, 2020, 08:31:34 pm »
Also, fixed is more fun than SS.
Wheel meet again, don't know where, don't know when...

zigzag

  • unfuckwithable
Re: gearing
« Reply #22 on: April 08, 2020, 08:33:02 pm »
Yeah, but they’re cool.

they were, 15y ago ;)

Re: gearing
« Reply #23 on: April 08, 2020, 09:10:38 pm »
Yeah, but they’re cool.

they were, 15y ago ;)

I have never been comfortable being cool anyway. 

What I liked was a French lad on PBP telling me that riding the event on fixed was folly.

Re: gearing
« Reply #24 on: April 09, 2020, 03:17:53 pm »
How I like to open a can of worms.
FWIW - I'll most probably go flip - flop and have both a ss and fixed in one. Ha!
Thank's for everyone's thoughts, comments, etc
I dunno why anybody's doing this!