OBRA: OBRA Chat: Gear Inches Question

.David.Auker.

2004-03-14

Subject: Re: [OBRA Chat] Gear Inches Question

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To subscribe or unsubscribe via the World Wide Web, visit

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or, via email, send a message with subject or body 'help' to

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There's all sorts of helpful stuff there!

David

----- Original Message -----

From: "Luciano bailey" <ride-@hotmail.com>

To: <roger-@speakeasy.net>; <wind-@Hevanet.com>; <mc-@gorge.net>

Cc: <ob-@topica.com>

Sent: Sunday, March 14, 2004 5:41 PM

| I have been a riding flip flop with 42x17 around town and 42x18 Auker Ride

| gear for the last five years in Portland and pity the knees pushing these

| big gears. Half the bike handling workput of riding a fixie is getting

wound

| up down hill while still navigating most climbs.

|

|

| >From: Roger Joys <roger-@speakeasy.net>

| >Reply-To: roger-@speakeasy.net

| >To: wind-@hevanet.com, mc-@gorge.net

| >CC: 'obra' <ob-@topica.com>

| >Subject: Re: [OBRA Chat] Gear Inches Question

| >Date: Thu, 11 Mar 2004 17:38:58 +0000

| >

| > >

| > > There are a number of other concerns, crank bcd, chainline, 1/8 vs

3/32"

| > > etc. which you should work through with a mechanic that does track

| >stuff.

| > > Most shops can handle it, but our local (Portland) experts are:

| > >

| >

| >Yup.. great list of considerations. I'd add a good straight chainline

too!

| >My last 2 cents... If you ride on the road a lot, and in all sorts of

| >conditions, a track hub will probably teach you a lot about hub repacking

| >and general maintenance. Many hubs, and usually better hubs (EG Shimano

| >Dura-Ace track), are built on the assumption of nice dry velodrome

| >conditions. The seals are not as good as most road hubs. Phil Woods and

| >Surly make great sealed cartridge bearing hubs that have road in mind.

| >-r

|

Luciano bailey

2004-03-14

I have been a riding flip flop with 42x17 around town and 42x18 Auker Ride

gear for the last five years in Portland and pity the knees pushing these

big gears. Half the bike handling workput of riding a fixie is getting wound

up down hill while still navigating most climbs.

From: Roger Joys <roger-@speakeasy.net>

Reply-To: roger-@speakeasy.net

To: wind-@hevanet.com, mc-@gorge.net

CC: 'obra' <ob-@topica.com>

Subject: Re: [OBRA Chat] Gear Inches Question

Date: Thu, 11 Mar 2004 17:38:58 +0000

There are a number of other concerns, crank bcd, chainline, 1/8 vs 3/32"

etc. which you should work through with a mechanic that does track

stuff.

Most shops can handle it, but our local (Portland) experts are:

Yup.. great list of considerations. I'd add a good straight chainline too!

My last 2 cents... If you ride on the road a lot, and in all sorts of

conditions, a track hub will probably teach you a lot about hub repacking

and general maintenance. Many hubs, and usually better hubs (EG Shimano

Dura-Ace track), are built on the assumption of nice dry velodrome

conditions. The seals are not as good as most road hubs. Phil Woods and

Surly make great sealed cartridge bearing hubs that have road in mind.

-r

To respond to the whole group send to ob-@topica.com.

To respond to the list manager send to cmur-@obra.org

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JOHN FORBES

2004-03-11

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If you use a large cog, e.g., a 20 or 21 DON'T use one of the shiny, stamped metal ones. If you do you will most likely strip the threads on your hub. Instead, spend the extra few dollars and order/ buy a true track cog, such as those from Sub-11 or the like.

John Forbes

503-331-6658

2126 NE 12th Ave.

Portland, OR 97212

----- Original Message -----

From: mike.m-@obra.org

To: mc-@gorge.net ; ob-@topica.com

Sent: Thursday, March 11, 2004 10:06 AM

Subject: RE: [OBRA Chat] Gear Inches Question

1. 48/20 will be slightly bigger than a 42/18. 48/21 will be a smaller

gear. For riding on the road the 48/20 will be close enough so that if you

are riding with other people in a 42/18 (like Auker) the gear will not be

the thing that makes the difference. 20 and 21 tooth track cogs are a bit

difficult to find though.

2. For racing on the track 48/16 will be OK for the Cat 4/5 group but

probably a bit small. A 48/15 will work any group. That is what Shaun

Wallace uses at Alpenrose and he is going faster than most, although most of

the faster riders are in bigger gears. For beginning track racers you

should not go bigger than 48/15. Although the gear will feel too small,

especially to experienced road racers, it will be safer and easier to

handle. It is important to remember that a bigger gear is not only harder

to accelerate on it is also harder to slow down on. For racing on the track

speed is about turning your legs over quickly, not about grunting along big

gears.

If you are planning on using the bike for both road and track use you will

be stuck with needing to change the chain length regardless of what

chainring you use because it is likely that the fork ends will not allow

enough adjustment to accommodate the 4-5 tooth difference between the gears.

The smaller the chainring the more difference that cog teeth will make so if

you are looking to try to accommodate both racing and road use gears with

the same chain go to as small a chainring as you can fit. For track cranks

(144 BCD) the smallest is 41 tooth. You may still need to have a gear a bit

bigger than what you want to ride on the road and a bit smaller racing on

the track.

Mike Murray

-----Original Message-----

From: martin cohen [mailto:mc-@gorge.net]

Sent: Thursday, March 11, 2004 7:56 AM

To: ob-@topica.com

Subject: [OBRA Chat] Gear Inches Question

Just got my Specialized Langster entry-level fixed gear/track bike,

comes with flip flop hub, came set up with 48 x 16 free, didn't come

with track cog. Two questions:

1. For the road, want to ultimately have 42 x 18 fixed. Since I already

have the 48, would putting on a 20 or 21 in the rear be close enough? I

just have to add more chain links to accomplish this, other than that

does it matter how I get the gear inches, be it big ring/big cog or

smaller ring / smaller cog?

2. What's a good place to start for the track? 48 x 16?

Thanks!

Martin

To respond to the whole group send to ob-@topica.com.

To respond to the list manager send to cmur-@obra.org

To unsubscribe send to obra-uns-@topica.com

To respond to the whole group send to ob-@topica.com.

To respond to the list manager send to cmur-@obra.org

To unsubscribe send to obra-uns-@topica.com

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<DIV>

<DIV>If you use a large cog, e.g., a 20 or 21 DON'T use one of the shiny,

stamped metal ones. If you do you will most likely strip the threads on your

hub. Instead, spend the extra few dollars and order/ buy a true track cog, such

as those from Sub-11 or the like.</DIV>

<DIV>John Forbes 503-331-6658 2126 NE 12th Ave. Portland, OR

97212</DIV>

<BLOCKQUOTE

style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>

<DIV style="FONT: 10pt arial">From: <A

href="mailto:mike.m-@obra.org">mike.m-@obra.org</A> </DIV>

<DIV style="FONT: 10pt arial">To: <A

href="mailto:mc-@gorge.net">mc-@gorge.net</A> ; <A

href="mailto:ob-@topica.com">ob-@topica.com</A> </DIV>

<DIV style="FONT: 10pt arial">Sent: Thursday, March 11, 2004 10:06

AM</DIV>

<DIV style="FONT: 10pt arial">Subject: RE: [OBRA Chat] Gear Inches

Question</DIV>

<DIV> </DIV>1. 48/20 will be slightly bigger than a 42/18. 48/21 will

be a smaller gear. For riding on the road the 48/20 will be close

enough so that if you are riding with other people in a 42/18 (like Auker)

the gear will not be the thing that makes the difference. 20 and 21

tooth track cogs are a bit difficult to find though. 2. For racing

on the track 48/16 will be OK for the Cat 4/5 group but probably a bit

small. A 48/15 will work any group. That is what Shaun Wallace uses

at Alpenrose and he is going faster than most, although most of the faster

riders are in bigger gears. For beginning track racers you should not

go bigger than 48/15. Although the gear will feel too

small, especially to experienced road racers, it will be safer and easier

to handle. It is important to remember that a bigger gear is not only

harder to accelerate on it is also harder to slow down on. For racing

on the track speed is about turning your legs over quickly, not about

grunting along big gears. If you are planning on using the bike for

both road and track use you will be stuck with needing to change the chain

length regardless of what chainring you use because it is likely that the

fork ends will not allow enough adjustment to accommodate the 4-5 tooth

difference between the gears. The smaller the chainring the more difference

that cog teeth will make so if you are looking to try to accommodate both

racing and road use gears with the same chain go to as small a chainring as

you can fit. For track cranks (144 BCD) the smallest is 41

tooth. You may still need to have a gear a bit bigger than what you

want to ride on the road and a bit smaller racing on the track. Mike

Murray -----Original Message----- From: martin cohen

[mailto:mc-@gorge.net] Sent: Thursday, March 11, 2004 7:56 AM To: <A

href="mailto:ob-@topica.com">ob-@topica.com</A> Subject: [OBRA Chat] Gear

Inches Question Just got my Specialized Langster entry-level fixed

gear/track bike, comes with flip flop hub, came set up with 48 x 16 free,

didn't come with track cog. Two questions: 1. For the road, want to

ultimately have 42 x 18 fixed. Since I already have the 48, would putting

on a 20 or 21 in the rear be close enough? I just have to add more chain

links to accomplish this, other than that does it matter how I get the gear

inches, be it big ring/big cog or smaller ring / smaller cog? 2.

What's a good place to start for the track? 48 x

16? Thanks! Martin To respond to the whole group send to <A

href="mailto:ob-@topica.com">ob-@topica.com</A>. To respond to the list

manager send to <A href="mailto:cmur-@obra.org">cmur-@obra.org</A> To

unsubscribe send to <A

href="mailto:obra-uns-@topica.com">obra-uns-@topica.com</A> To

respond to the whole group send to <A

href="mailto:ob-@topica.com">ob-@topica.com</A>. To respond to the list

manager send to <A href="mailto:cmur-@obra.org">cmur-@obra.org</A> To

unsubscribe send to <A

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mike.m-@obra.org

2004-03-11

1. 48/20 will be slightly bigger than a 42/18. 48/21 will be a smaller

gear. For riding on the road the 48/20 will be close enough so that if you

are riding with other people in a 42/18 (like Auker) the gear will not be

the thing that makes the difference. 20 and 21 tooth track cogs are a bit

difficult to find though.

2. For racing on the track 48/16 will be OK for the Cat 4/5 group but

probably a bit small. A 48/15 will work any group. That is what Shaun

Wallace uses at Alpenrose and he is going faster than most, although most of

the faster riders are in bigger gears. For beginning track racers you

should not go bigger than 48/15. Although the gear will feel too small,

especially to experienced road racers, it will be safer and easier to

handle. It is important to remember that a bigger gear is not only harder

to accelerate on it is also harder to slow down on. For racing on the track

speed is about turning your legs over quickly, not about grunting along big

gears.

If you are planning on using the bike for both road and track use you will

be stuck with needing to change the chain length regardless of what

chainring you use because it is likely that the fork ends will not allow

enough adjustment to accommodate the 4-5 tooth difference between the gears.

The smaller the chainring the more difference that cog teeth will make so if

you are looking to try to accommodate both racing and road use gears with

the same chain go to as small a chainring as you can fit. For track cranks

(144 BCD) the smallest is 41 tooth. You may still need to have a gear a bit

bigger than what you want to ride on the road and a bit smaller racing on

the track.

Mike Murray

-----Original Message-----

From: martin cohen [mailto:mc-@gorge.net]

Sent: Thursday, March 11, 2004 7:56 AM

To: ob-@topica.com

Subject: [OBRA Chat] Gear Inches Question

Just got my Specialized Langster entry-level fixed gear/track bike,

comes with flip flop hub, came set up with 48 x 16 free, didn't come

with track cog. Two questions:

1. For the road, want to ultimately have 42 x 18 fixed. Since I already

have the 48, would putting on a 20 or 21 in the rear be close enough? I

just have to add more chain links to accomplish this, other than that

does it matter how I get the gear inches, be it big ring/big cog or

smaller ring / smaller cog?

2. What's a good place to start for the track? 48 x 16?

Thanks!

Martin

To respond to the whole group send to ob-@topica.com.

To respond to the list manager send to cmur-@obra.org

To unsubscribe send to obra-uns-@topica.com

Roger Joys

2004-03-11

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There are a number of other concerns, crank bcd, chainline, 1/8 vs 3/32"

etc. which you should work through with a mechanic that does track stuff.

Most shops can handle it, but our local (Portland) experts are:

Yup.. great list of considerations. I'd add a good straight chainline too!

My last 2 cents... If you ride on the road a lot, and in all sorts of conditions, a track hub will probably teach you a lot about hub repacking and general maintenance. Many hubs, and usually better hubs (EG Shimano Dura-Ace track), are built on the assumption of nice dry velodrome conditions. The seals are not as good as most road hubs. Phil Woods and Surly make great sealed cartridge bearing hubs that have road in mind.

-r

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<html>> > There are a number of other concerns, crank bcd, chainline, 1/8 vs 3/32" > etc. which you should work through with a mechanic that does track stuff. > Most shops can handle it, but our local (Portland) experts are: > 

Yup.. great list of considerations. I'd add a good straight chainline too!

My last 2 cents... If you ride on the road a lot, and in all sorts of conditions, a track hub will probably teach you a lot about hub repacking and general maintenance. Many hubs, and usually better hubs (EG Shimano Dura-Ace track), are built on the assumption of nice dry velodrome conditions. The seals are not as good as most road hubs. Phil Woods and Surly make great sealed cartridge bearing hubs that have road in mind.

-r 

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Roger Joys

2004-03-11

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Martin,

I ride a 47x20 on the road. It's as big as I want to go when riding up the likes of NW 53rd etc here in Portland. That's a 63.5. Your two choices (20 or 21) are 64.8 and 61.7 respectively. So yes they are close, and about 1/2 way in between. If you want to ride 20+ on the flatter stuff, go 20, hilly rides (and a whole lot of spin on downhills) may lean towards the 21.

The gear ratio is the same no matter how you get it, in a frictionless world. Some folks feel that the small\small gears make the chain wrap more, and as such create drag, and the shorter chain required will wear faster. Others feel that with bigger\bigger ratios, the more contact on the chain ring and cog will create drag.

Honestly, I think eating a large burrito before a ride has more effect on this than subtle friction differences, so I would recommend, go with whatever you can afford at the time. Riding the bike is the end goal anyhow.

I ride gobs of fixed miles every year, and have road ridden on gear inches from 67-61. I like the 63-64. Happy riding.

-r

-----Original Message-----

From: martin cohen [mailto:mc-@gorge.net]

Sent: Thursday, March 11, 2004 03:55 PM

To: ob-@topica.com

Subject: [OBRA Chat] Gear Inches Question

Just got my Specialized Langster entry-level fixed gear/track bike,

comes with flip flop hub, came set up with 48 x 16 free, didn't come

with track cog. Two questions:

1. For the road, want to ultimately have 42 x 18 fixed. Since I already

have the 48, would putting on a 20 or 21 in the rear be close enough? I

just have to add more chain links to accomplish this, other than that

does it matter how I get the gear inches, be it big ring/big cog or

smaller ring / smaller cog?

2. What's a good place to start for the track? 48 x 16?

Thanks!

Martin

To respond to the whole group send to ob-@topica.com.

To respond to the list manager send to cmur-@obra.org

To unsubscribe send to obra-uns-@topica.com

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<html>Martin,

I ride a 47x20 on the road. It's as big as I want to go when riding up the likes of NW 53rd etc here in Portland. That's a 63.5. Your two choices (20 or 21) are 64.8 and 61.7 respectively. So yes they are close, and about 1/2 way in between. If you want to ride 20+ on the flatter stuff, go 20, hilly rides (and a whole lot of spin on downhills) may lean towards the 21. 

The gear ratio is the same no matter how you get it, in a frictionless world. Some folks feel that the small\small gears make the chain wrap more, and as such create drag, and the shorter chain required will wear faster. Others feel that with bigger\bigger ratios, the more contact on the chain ring and cog will create drag.

Honestly, I think eating a large burrito before a ride has more effect on this than subtle friction differences, so I would recommend, go with whatever you can afford at the time. Riding the bike is the end goal anyhow.

I ride gobs of fixed miles every year, and have road ridden on gear inches from 67-61. I like the 63-64. Happy riding.

-r

 

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Peter & Laural

2004-03-11

Martin,

Cool, I'll expect a review in a few weeks, as well as a few kind pimpin'

words for the LBS that hooked you up.

48x16 is 81 inches, a honkin' big gear for the road, 42x18 is 63 which is

almost perfect around here. You may go smaller eventually if you really

want to work on leg speed. The 20 or 21 should be fine, 64.8 or 61.7

inches.

It does matter a little bit how you get the gear inches, but I think it only

counts when you're racing against the kids from the deep end of the pool.

Or if you're a geek concerned about things like moment of inertia...

For starting on the track I think a 48x15 is a better bet, 86.4 inches, and

it makes it easier to set up an 88 inch gear later.

Here's a gear chart:

http://www.obra.org/track/track_racing/times/gear_chart.html

There are a number of other concerns, crank bcd, chainline, 1/8 vs 3/32"

etc. which you should work through with a mechanic that does track stuff.

Most shops can handle it, but our local (Portland) experts are:

Dean - Bike Central

Molly - Velo Shop

Jack - EnSelle

Good Luck,

Peter Drake

FMCT

--- Original Message -----

From: "martin cohen" <mc-@gorge.net>

To: <ob-@topica.com>

Sent: Thursday, March 11, 2004 7:55 AM

Subject: [OBRA Chat] Gear Inches Question

Just got my Specialized Langster entry-level fixed gear/track bike,

comes with flip flop hub, came set up with 48 x 16 free, didn't come

with track cog. Two questions:

1. For the road, want to ultimately have 42 x 18 fixed. Since I already

have the 48, would putting on a 20 or 21 in the rear be close enough? I

just have to add more chain links to accomplish this, other than that

does it matter how I get the gear inches, be it big ring/big cog or

smaller ring / smaller cog?

2. What's a good place to start for the track? 48 x 16?

Thanks!

Martin

To respond to the whole group send to ob-@topica.com.

To respond to the list manager send to cmur-@obra.org

To unsubscribe send to obra-uns-@topica.com

eri-@fusium.com

2004-03-11

Find a gear chart and see for yourself. Here's one:

http://home.i1.net/~dwolfe/gerz/

48x16 is an 81, which I think is a fine gear to start with, especially if

you ride for Phil ;) Get a comfy seat and spin your butt off.

You'll eventually want to move up to an 84 or 86, maybe even 90 if you are a

masher and can't spin. By the time you're ready, I reckon you'll know for

yourself.

-Erik

-----Original Message-----

From: martin cohen [mailto:mc-@gorge.net]

Sent: Thursday, March 11, 2004 7:56 AM

To: ob-@topica.com

Subject: [OBRA Chat] Gear Inches Question

Just got my Specialized Langster entry-level fixed gear/track bike,

comes with flip flop hub, came set up with 48 x 16 free, didn't come

with track cog. Two questions:

1. For the road, want to ultimately have 42 x 18 fixed. Since I already

have the 48, would putting on a 20 or 21 in the rear be close enough? I

just have to add more chain links to accomplish this, other than that

does it matter how I get the gear inches, be it big ring/big cog or

smaller ring / smaller cog?

2. What's a good place to start for the track? 48 x 16?

Thanks!

Martin

To respond to the whole group send to ob-@topica.com.

To respond to the list manager send to cmur-@obra.org

To unsubscribe send to obra-uns-@topica.com

martin cohen

2004-03-11

Just got my Specialized Langster entry-level fixed gear/track bike,

comes with flip flop hub, came set up with 48 x 16 free, didn't come

with track cog. Two questions:

1. For the road, want to ultimately have 42 x 18 fixed. Since I already

have the 48, would putting on a 20 or 21 in the rear be close enough? I

just have to add more chain links to accomplish this, other than that

does it matter how I get the gear inches, be it big ring/big cog or

smaller ring / smaller cog?

2. What's a good place to start for the track? 48 x 16?

Thanks!

Martin