Author Topic: Big Gears (Read 4631 times)

starkj73 · « **on:** 18 December, 2012, 03:18:26 pm »

looks like a nice bike but 52 * 13?

Would this only be used as a big sprinters track bike?

http://www.ebay.co.uk/itm/Woodrup-Track-Fixed-531-Vintage-Classic-Racing-Bike-Campagnolo-Record-Pista-/300834215212?pt=UK_Bikes_GL&hash=item460b1dd52c

Sergeant Pluck · « **Reply #1 on:** 18 December, 2012, 03:24:05 pm »

clarion · « **Reply #2 on:** 18 December, 2012, 03:24:41 pm »

I make that about 105".

I wouldn't be confident setting off on that on the flat, never mind uphill (yes, it's set up for the road not track, with a front brake).

rogerzilla · « **Reply #3 on:** 18 December, 2012, 03:41:22 pm »

I've regularly ridden 91" to and from TT starts, and it worked about as well as a normal gear.

Some local guy uses a 125" gear for TTing. You really need a start house and ramp for that one.

Sergeant Pluck · « **Reply #4 on:** 18 December, 2012, 04:15:17 pm »

Quote from: rogerzilla on 18 December, 2012, 03:41:22 pm

I've regularly ridden 91" to and from TT starts

We really need a photoshop expert to combine the above legs with you in that photo, the one with you looking coy under a tree.

LittleWheelsandBig · « **Reply #5 on:** 18 December, 2012, 04:18:53 pm »

I used to turn 92" or 94" from a standing start on the track but only went above 100" when racing the track tandem.

giropaul · « **Reply #6 on:** 18 December, 2012, 04:28:52 pm »

gears are a bit of a secret on the track, but Hoy has said that he uses 52x14 in the team sprint (where he is obviously having a flying start). I seriously doubt anyone is using 52x13 in competition on the track (Derny=paced etc aside).

LittleWheelsandBig · « **Reply #7 on:** 18 December, 2012, 04:32:38 pm »

Hoy still has to do a standing start in that gear, albeit losing a couple of bike lengths.

clarion · « **Reply #8 on:** 18 December, 2012, 04:35:14 pm »

Yeah, but this is a road set up. Even more unlikely.

LittleWheelsandBig · « **Reply #9 on:** 18 December, 2012, 04:40:08 pm »

It has a front brake but I can't see whether it is a drilled track fork or a road fork. There aren't any mudguard eyes.

Agreed, it is a poser's bike but Brit TTers are renowned for thumping big gears. It was good enough for BB!

giropaul · « **Reply #10 on:** 18 December, 2012, 04:55:40 pm »

Quote from: LittleWheelsandBig on 18 December, 2012, 04:32:38 pm

Hoy still has to do a standing start in that gear, albeit losing a couple of bike lengths.

Yebbut - starting 3rd man gets a fair roll down the banking/slope at the start.

LittleWheelsandBig · « **Reply #11 on:** 18 December, 2012, 05:00:56 pm »

When I did Italian Pursuits (what is this Team Sprint nonsense?), you started parallel to the other riders and only got the banking assistance after the first few pedal strokes. Perhaps I should look at how they are doing it now to see what we were doing wrong.

giropaul · « **Reply #12 on:** 18 December, 2012, 05:08:27 pm »

Quote from: LittleWheelsandBig on 18 December, 2012, 05:00:56 pm

When I did Italian Pursuits (what is this Team Sprint nonsense?), you started parallel to the other riders and only got the banking assistance after the first few pedal strokes. Perhaps I should look at how they are doing it now to see what we were doing wrong.

But weren't the tracks pretty well flat in those days anyway?

bikenrrd · « **Reply #13 on:** 18 December, 2012, 05:10:33 pm »

I've got a bike a bit like that - Woodrup 631 track. Not as vintage, though, and the gear is not quite as big - being only a 48-17.

LittleWheelsandBig · « **Reply #14 on:** 18 December, 2012, 05:14:01 pm »

I did a lot of laps on 333m tracks, a fair few on smaller tracks but not that many laps on the big ones. Sweeping up and down the banking is the most enjoyable part of riding the track, apart from the racing, of course.

Exit Stage Left · « **Reply #15 on:** 18 December, 2012, 05:22:48 pm »

Obree was geared at 53/12 for one of his Hour Records.

trumpet · « **Reply #16 on:** 19 December, 2012, 08:19:32 pm »

Quote from: Exit Stage Left on 18 December, 2012, 05:22:48 pm

Obree was geared at 53/12 for one of his Hour Records.

I think Obree used that same gear for 4km pursuits & 10,25 & 50 mile TT's too.

Salvatore · « **Reply #17 on:** 19 December, 2012, 08:31:06 pm »

According to this site, Chris Boardman used 56x13 for his 1996 hour record, not quite as big as Tony Romiger's 60x14 or Obree's 52x12 (117 inches)

Old Git · « **Reply #18 on:** 19 December, 2012, 09:36:36 pm »

Quote from: rogerzilla on 18 December, 2012, 03:41:22 pm

Some local guy uses a 125" gear for TTing. You really need a start house and ramp for that one.

That wouldn't be John would it?

rogerzilla · « **Reply #19 on:** 19 December, 2012, 09:58:19 pm »

Quote from: Old Git on 19 December, 2012, 09:36:36 pm

Quote from: rogerzilla on 18 December, 2012, 03:41:22 pm
Some local guy uses a 125" gear for TTing. You really need a start house and ramp for that one.

That wouldn't be John would it?

I don't know, but he's ridden in our area (Wilts/Gloucs).

I assume it was 60 x 13, although 65 x 14 would be more efficient (13T sprockets are best avoided) and you can get 65T rings.

chrisbainbridge · « **Reply #20 on:** 20 December, 2012, 03:34:38 pm »

Hi, sorry for butting in but why are 13T sprockets best avoided? I have been riding fixed on 42/17 to work and Sundays in the winter and loving it. I have been doing hill repeats on it recently to increase my climbing. I was looking at dropping to 42/15 after Christmas with the plan to go to 42/13 by end of february. Should I instead be looking at changing to something bigger at the front?
Chris

Old Git · « **Reply #21 on:** 20 December, 2012, 04:04:28 pm »

Quote from: rogerzilla on 19 December, 2012, 09:58:19 pm

Quote from: Old Git on 19 December, 2012, 09:36:36 pm
Quote from: rogerzilla on 18 December, 2012, 03:41:22 pm
Some local guy uses a 125" gear for TTing. You really need a start house and ramp for that one.

That wouldn't be John would it?
I don't know, but he's ridden in our area (Wilts/Gloucs).

I assume it was 60 x 13, although 65 x 14 would be more efficient (13T sprockets are best avoided) and you can get 65T rings.

John Iszatt rides all over but many Essex/ Herts area.
He rides BIG gears fixed. When you squat 200kgs in training you can ride as big as you like

rogerzilla · « **Reply #22 on:** 20 December, 2012, 07:01:40 pm »

Quote from: chrisbainbridge on 20 December, 2012, 03:34:38 pm

Hi, sorry for butting in but why are 13T sprockets best avoided? I have been riding fixed on 42/17 to work and Sundays in the winter and loving it. I have been doing hill repeats on it recently to increase my climbing. I was looking at dropping to 42/15 after Christmas with the plan to go to 42/13 by end of february. Should I instead be looking at changing to something bigger at the front?
Chris

They're less efficient because of the angle at which the chain has to articulate around the small radius. If 13T sprockets were really good, all road fixie riders would be running 35 x 13 for lighter weight; but they run 48 x 18 instead.

Brompton's choice of a 13T as the standard sprocket is a bit rubbish. Since the bike is overgeared as standard, fitting a Sturmey-Archer 14T (and an extra link of chain) is the cheapest and easiest solution, but Brompton would rather you paid for a smaller chainring (which is swaged onto the RH crank, and therefore expensive). I run 54 x 15, which is even better.

LittleWheelsandBig · « **Reply #23 on:** 20 December, 2012, 08:48:24 pm »

Not all of us pedal our Bromptons at high revs. I use the top 3 gears of my stock B just about every day, 3rd sometimes and the bottom 2 very rarely. I'd miss the train every morning with a top gear around 80".

Crumbling Nick · « **Reply #24 on:** 21 December, 2012, 12:14:29 am »

Quote from: rogerzilla on 20 December, 2012, 07:01:40 pm

Quote from: chrisbainbridge on 20 December, 2012, 03:34:38 pm
Hi, sorry for butting in but why are 13T sprockets best avoided? I have been riding fixed on 42/17 to work and Sundays in the winter and loving it. I have been doing hill repeats on it recently to increase my climbing. I was looking at dropping to 42/15 after Christmas with the plan to go to 42/13 by end of february. Should I instead be looking at changing to something bigger at the front?
Chris
They're less efficient because of the angle at which the chain has to articulate around the small radius. If 13T sprockets were really good, all road fixie riders would be running 35 x 13 for lighter weight; but they run 48 x 18 instead.

Agreed but it's only half the story. Chain tension increases in exactly the same proportion as the extra articulation around the cog.