What size gear?

[Fixedwheelnut]

 Everybody knows don't they?

  I've been riding around even done two TTs thinking I was on 49 x 17  76" gear when infact after fettling my wheels Sunday I discovered and remembered I put a 51 chainwheel on during my winter fettling of the bike, so I have actually been riding 79" gear around "DOH!"

No wonder I struggled more 

[nuttycyclist]

but but but... surely for TT you need a bigger gear to go faster?

[Frenchie]

So far I have only done MG races, so 72''. Am planning to go to 75'' first and 81'' soon after if the weather improves!

[Ian H]

but but but... surely for TT you need a bigger gear to go faster?

79" at 90rpm* gives approx 21mph.

Our club coach sometimes races on 91" fixed, which he thinks is a little too high, but it's the only gear he can get with vertical drop-outs.

*An often recommended normal cadence.

[Jakob]

I did similar early in my fixed career. Went from 67" to what I thought was 72"..except it was 76"!.

[токамак]

Using Sheldon Brown's Grear Calculator my 48/16 on 700/23 comes out at 78.8 gear inches. It's a pretty comfortable cadence when cruising at 20mph and is good for short bursts of speed too - I pushed 35.8mph last weekend and I think my cadence was around 160. Couldn't maintain that sort of effort for long but I'm seriously thinking about doing some proper training and entering a few TT's.

[Chris N]

Using Sheldon Brown's Grear Calculator my 48/16 on 700/23 comes out at 78.8 gear inches. It's a pretty comfortable cadence when cruising at 20mph and is good for short bursts of speed too - I pushed 35.8mph last weekend and I think my cadence was around 160. Couldn't maintain that sort of effort for long but I'm seriously thinking about doing some popper training and entering a few TT's.

To really loosen those muscles, eh?

I'm going the other way - as soon as my new chain arrives, I'll going to about 58".

[токамак]

  now modified - could cause a bit of a nasty headache that could.

[Gus]

Currently riding with 66" and learning to spin. But I'm totally new in this game.

I'm still struggling doing 100rpm 

[Frenchie]

Currently riding with 66" and learning to spin. But I'm totally new in this game.

I'm still struggling doing 100rpm 

A bit low maybe... Or is it windy or hilly in Danemark?

[Gus]

It's low.

I've just spend 3 days on Bornholm. It was the perfect gear for a novice like me there,
it was rolling hills (50m-80m) and windy all over the island.

But in the area I'm riding normally, 76" to 90" will be more appropriate.

I use 89" most of the time on my racingbike.

[Chris N]

Stick at it Gus - it does get easier, honest!  I'll repost this quote, taken from F. T. Bidlake on Matt Chester's blog:

...I am convinced that there is no necessity for anyone, even the strongest riders, to use a gear above 72[inches], for ordinary road riding. I do not speak of those riders whose scheme of cycling includes hanging on to multicycles at record speeds, but for ordinary road riding, more often than not in solitude, and on all sorts of roads. 72 seems to me to be a maximum, but the vast majority of riders will be better suited by a 63, which I would set down as the standard, for normal purposes by the normal human being. It is a gear that works very well with a 6 1/4 inch [~160mm] crank, which I think is the best length for the man of the average height. I know there is a school of believers in a longer crank and a much higher gear, but even within the circle of my own acquaintances I have been noticing a reaction from this combination and a reversion to cranks of 6 1/4 [~160mm] and 6 3/4 [~170mm], and a proportionately lower gear. There is an anatomical reason for the stroke of the crank not being above about this length, except for very tall riders, as the length of the foot available as a lever, measured from the centre of the ankle joint to that part of the foot immediately over the center of the pedal pin, is approximately this length, and a longer crank entails a bigger swing of the shin bone and consequent loss of direct downward thrust of the leg, unless so forward a position is attained that all ankling is impossible. The long-cranked, high-geared man shows the soles of his shoes to any one riding behind him, and digs into his toeclips, or worse, stirrups, with a swimming style neither elegant nor economical of his powers.

http://mattchester.blogspot.com/2008/01/wednesdays-wisdom-of-past-ft-bidlake-on.html

[woollypigs]

Currently riding with 66" and learning to spin. But I'm totally new in this game.

I'm still struggling doing 100rpm 

A bit low maybe... Or is it windy or hilly in Danemark?

Plenty of wind, as it says under Gus' avatar "in Denmark the wind are our mountains" and that is pretty darn right.

[border-rider]

I don't think 66 is low.  I did my first PBP on 67". 

63 is a good winter or commuter gear, 67 the classic CTC summer touring gear.  For around town 63-70 is fine depending how spinny you are.

edit: pretty-much what F. T. Bidlake said

[Wendy]

I'm on 66", 48x19.  Not a believer in brute-forcing massive gears, it's much better to learn to spin IMO.

[Frenchie]

For the record I am a nominal 72'' rider which I found ideal for pretty much anything bar some of the Peak District short and nasty hills. I have ridden as low as 63'' I believe, but it is too low for me I'm afraid! And no I am not a brute! 

[Ian H]

I don't think 66 is low.  I did my first PBP on 67". 

I don't think 67 is too low.  I did my second PBP on 68".

 

[Gus]

I'm sticking with 67" until I can master the bike, but doing PBP on fixed
that must be a long term project 

[Chris N]

I'm sticking with 67" until I can master the bike, but doing PBP on fixed
that must be a long term project 

You've got over 3 years.

[Fixedwheelnut]

I'm sticking with 67" until I can master the bike, but doing PBP on fixed
that must be a long term project 

You've got over 3 years.

  I thought it was 90 hours, if only I had known   

 I use 68 for Audax, PBP 2003 73" to Brest and 68 back, 68 for LEL 2005 

[Paul Smith SRCC]

Well for what it's worth I rode Herne Hill Monday Comp track league and TimeTrials on 86", on my winter club run commute bike I used only a 62", all on 165mm cranks.

The 62" was fine for me as I like to spin gears plus ride in the surrey hills, although I used the 'Cyclo' made sprockets, as it was only those I could get at the time as large as 21t, they were in fairness not the highest quality, neither very round making chain tension a bit of a lottery, plus they could strip the hub occasionally as the threads on some were not exactly that accurate either! Back then the sprockets from the higher quality manufacturers were not as readily available as they are now.

I rode fixed for about twenty years, I have a bad back and a bit of a dodgy ticker now, which didn't seem to like me spinning down hills, I would get a pain down my arm especially on a long quick descent which scared me a bit so I reverted to gears; a real shame as I always loved riding fixed.

Paul_Smith
www.bikeplus.co.uk

[Lonewolff]

I ride 74" gear on my fixed. So long as you don't mind going very slowly up some hills then its fine. Anything smaller and I would quickly spin out on down hill and be wanting more speed on the flat.

[giropaul]

I read the original post as being about riding timetrials on fixed.

From that point of view I go along with Paul Smith - 86 ish to 90 ish depending on the course.  I used to use this sort of gear for fixed 10s (only ever rode 25s etc Track racing is done on similar gears, and 10 mile events take about 21-24 minutes so that would make sense.

As for anything else; it's got to be "it all depends" - with fitness, distance, terrain, wind etc etc all taken into account.

[Fixedwheelnut]

 I made the post in the first place as I just didn't realise what size gear I had been running for the last few months 

 Generally I ride 68" or 67.5 as it works out 48 x 18 thats good from 0mph-40mph
 well 37mph, 37 - 40 is just scary  but fun.

 I'm still experimenting with gear sizes for TTs allthough I am a spinner more than a grauncher I can't seem to spin in the aero position so it's a gamble between being able to push the biggest gear possible and still get up any hills on the course.

All though one guy on todays Catford Open 10 TT at Harrietsham rode 114" gear for a 21.20 something, I don't think I could have pulled away on that 

[Paul Smith SRCC]

All though one guy on todays Catford Open 10 TT at Harrietsham rode 114" gear for a 21.20 something, I don't think I could have pulled away on that 

If that were me it would have been 3-2-1 "away you go good luck"; then after a defeated groan and veins in forehead a popping it would just be the inevitable timberrrrrrrrrrrrr

Paul_Smith
www.bikeplus.co.uk