Gearing UP my touring bike

I have a touring bike that I would like to "gear up" a bit -
temporarily -
so it can perform more like a road bike. It came with rather low
gearing
48/36/26 crankset (Shimano Deore) and 11-32 cassette (SRAM PG 950).
I bought a Ritchey wheels and put 9spd 12-23 (?) Ultegra cassette on
it.
And I am thinking about changing crankset/chainrings.

I have never tried anything like that so I really could use some
advice.
The idea is get higher top speed and but still preserve some climbing
ability
(I am rather heavy) so I think I would prefer triple in front. And I
would like
to be able (with that new crankset) to still use old wheels with 11/32
cassette
for more hilly rides.

Is it doable?
What are my options - as far as decent quality but affordable
crankset?
What sizes would be a reasonable step up?
Is it possible to just swap the chainrings? Or would it be prudent to
go for
different crank lengths for diff chainrings?
Any idea what to expect from new chainring? - I do not want to "gear
myself up and out" of my favorite hills to climb. Is there any way to
compute force or power that new crankset would require.

TIA for any pointers/info.

JT

Woland99 wrote:
I have a touring bike that I would like to "gear up" a bit - temporarily -
so it can perform more like a road bike. It came with rather low gearing
48/36/26 crankset (Shimano Deore) and 11-32 cassette (SRAM PG 950).
I bought a Ritchey wheels and put 9spd 12-23 (?) Ultegra cassette on it.
And I am thinking about changing crankset/chainrings.


Your current 48 x 11 is a pretty high gear! It's almost the same as a
53 x 12. So you're top speed isn't going to change with any of any of
the changes you mentioned. What gears do you use on your steep hills?

I would suggest trying the 12-23 cassette with your existing cranks,
and see how it works out. The resulting low of 26 x 23 gear would
still be very low. If necessary, you could go to a 12-25 or 12-27
cassette. Any of those options would give you a good range of closely
spaced gears without having to mess with a new crankset.

Art Harris

On Nov 24, 9:26*am, Woland99 wrote:
Is there any way to
compute force or power that new crankset would require.


http://sheldonbrown.com/gears/

On Nov 24, 11:26*am, Woland99 wrote:
I have a touring bike that I would like to "gear up" a bit -
temporarily -
so it can perform more like a road bike. It came with rather low
gearing
48/36/26 crankset (Shimano Deore) and 11-32 cassette (SRAM PG 950).
I bought a Ritchey wheels and put 9spd 12-23 (?) Ultegra cassette on
it.
And I am thinking about changing crankset/chainrings.

I have never tried anything like that so I really could use some
advice.
The idea is get higher top speed and but still preserve some climbing
ability
(I am rather heavy) so I think I would prefer triple in front. And I
would like
to be able (with that new crankset) to still use old wheels with 11/32
cassette
for more hilly rides.

Is it doable?
What are my options - as far as decent quality but affordable
crankset?
What sizes would be a reasonable step up?
Is it possible to just swap the chainrings? Or would it be prudent to
go for
different crank lengths for diff chainrings?
Any idea what to expect from new chainring? - I do not want to "gear
myself up and out" of my favorite hills to climb. Is there any way to
compute force or power that new crankset would require.

TIA for any pointers/info.

JT

Leave the crank alone. If the 12-23 cassette is not tall enough, then
buy a 11-21 or 11-23 9 speed cassette. 48x11 is 116". At 90 rpm you
are going 31 mph. And the 26x23 or 26x21 would still give you plenty
of low gears. Or you could swap the 26 inner for a 24 tooth inner
ring and get a bit lower.

On Nov 24, 12:09 pm, Art Harris wrote:
Woland99 wrote:
I have a touring bike that I would like to "gear up" a bit - temporarily -
so it can perform more like a road bike. It came with rather low gearing
48/36/26 crankset (Shimano Deore) and 11-32 cassette (SRAM PG 950).
I bought a Ritchey wheels and put 9spd 12-23 (?) Ultegra cassette on it.
And I am thinking about changing crankset/chainrings.

Your current 48 x 11 is a pretty high gear! It's almost the same as a
53 x 12. So you're top speed isn't going to change with any of any of
the changes you mentioned. What gears do you use on your steep hills?

I would suggest trying the 12-23 cassette with your existing cranks,
and see how it works out. The resulting low of 26 x 23 gear would
still be very low. If necessary, you could go to a 12-25 or 12-27
cassette. Any of those options would give you a good range of closely
spaced gears without having to mess with a new crankset.

Art Harris

Thanks Art - is there a rule of thumb for that?
Sth like "1 tooth in back is 3 in front"?
Gears I use... it depends - biggest hill I ride - it says
it is 8% on the sign there but I think there is some 10%
stretch there. I cannot get up that one in anything higher
than 26x28 - sitting. Maybe 26x24 if I stand up. On smaller
hills maybe 36x24?
So I guess (if I understood correctly) what you are saying
is that it does not make much sense to sense (in order to
create speed) to go from cassette that is 11 at the smallest
to casette that is 12 and compensate with larger chain ring
for that.

On Nov 24, 11:26*am, Woland99 wrote:
I have a touring bike that I would like to "gear up" a bit -
temporarily -
so it can perform more like a road bike. It came with rather low
gearing
48/36/26 crankset (Shimano Deore) and 11-32 cassette (SRAM PG 950).

I can go over thirty miles an hour easily with such gearing, no
problem, on my "tourer". If you're a masher, learn to spin--cheap and
you'll go faster. ;-)

On Nov 24, 12:36 pm, "
wrote:
On Nov 24, 11:26 am, Woland99 wrote:



I have a touring bike that I would like to "gear up" a bit -
temporarily -
so it can perform more like a road bike. It came with rather low
gearing
48/36/26 crankset (Shimano Deore) and 11-32 cassette (SRAM PG 950).
I bought a Ritchey wheels and put 9spd 12-23 (?) Ultegra cassette on
it.
And I am thinking about changing crankset/chainrings.

I have never tried anything like that so I really could use some
advice.
The idea is get higher top speed and but still preserve some climbing
ability
(I am rather heavy) so I think I would prefer triple in front. And I
would like
to be able (with that new crankset) to still use old wheels with 11/32
cassette
for more hilly rides.

Is it doable?
What are my options - as far as decent quality but affordable
crankset?
What sizes would be a reasonable step up?
Is it possible to just swap the chainrings? Or would it be prudent to
go for
different crank lengths for diff chainrings?
Any idea what to expect from new chainring? - I do not want to "gear
myself up and out" of my favorite hills to climb. Is there any way to
compute force or power that new crankset would require.

TIA for any pointers/info.

JT

Leave the crank alone. If the 12-23 cassette is not tall enough, then
buy a 11-21 or 11-23 9 speed cassette. 48x11 is 116". At 90 rpm you
are going 31 mph. And the 26x23 or 26x21 would still give you plenty
of low gears. Or you could swap the 26 inner for a 24 tooth inner
ring and get a bit lower.

Hank and Russell - thanks - I looked up Sheldon's gear calculator.
It should be easy to figure out rest of the numbers - you can get
required power to maintain 31mph, then from power and RPM get the
torque.
Or I can look up some fastest rides (from Edge 305) and figure
what is the max power I can sustain and related torque and play
with those and Sheldon calculator.

On Nov 24, 12:53 pm, landotter wrote:
I can go over thirty miles an hour easily with such gearing, no
problem, on my "tourer". If you're a masher, learn to spin--cheap and
you'll go faster. ;-)

Well Brother Otter - you are better than me - if you can go
"miles and miles" at 30mph. For me it would require 500W -
piece of cake ;-)
You are probably right - 90rpm is pretty much high cadence
for me - perhaps I need to use my trainer to learn how to spin.

Woland99 wrote:

Thanks Art - is there a rule of thumb for that?
Sth like "1 tooth in back is 3 in front"?


Gearing is usually expressed as "equivalent gear inches" which relates
to the wheel diameter of the "high wheelers" of old. Back then, there
were no gears but the bigger the wheel, the more ground you covered
for each turn of the cranks.

Today:

Gear = (front teeth / rear teeth) * tire diameter.
e.g., (53 / 12) * 27" = 119 inches

For a typical 700c tire, your speed (mph) = 0.002913 * gear *
cadence.
e.g., pedaling a 75" gear at 90 rpm gives:

0.002913 * 75 * 90 = 19.7 mph (Where 0.002913 is a fudge factor)

From that you can figure out your speed for any combination of gear
and cadence. It's good to check that for your highest and lowest
gear.

When climbing, you need to maintain about 3.5 to 4 mph to keep the
bike balanced.


Gears I use... it depends - biggest hill I ride - it says
it is 8% on the sign there but I think there is some 10%
stretch there. I cannot get up that one in anything higher
than 26x28 - sitting. Maybe 26x24 if I stand up. On smaller
hills maybe 36x24?

So, it sounds like a 12-27 cassette would work well with your current
crankset. That would give you a 26x27 low gear.

So I guess (if I understood correctly) what you are saying
is that it does not make much sense to sense (in order to
create speed) to go from cassette that is 11 at the smallest
*to casette that is 12 and compensate with larger chain ring
for that.

Right. A 48x12 is identical to a 52x13 which used to be the standard
high gear on road bikes in the early '80s.

Art Harris

Woland99 wrote:

What are my options - as far as decent quality but affordable
crankset?

Look for a 52/42/30, i.e.
"http://www.icyclesusa.com/catalog/truvativ-elita-triple-road-crankset.htm"

Keep the 11-32 cassette.

This won't be low enough for fully loaded touring on steep climbs, but
48/11 isn't high enough for a road bike in some situations.

If you want something that works for both, go 52/40/26 for the crankset
and 11 13 15 17 20 23 26 34 cassette for the rear, though you may find
too much overlap as well as too many gaps in the 20-124 gear-inches range.