Gearing question

On Sat, 5 Feb 2011 15:05:42 -0800 (PST), "
wrote:

On Feb 5, 5:44*am, john B. wrote:
On Sat, 5 Feb 2011 09:34:07 -0000, "Graham"

wrote:

"john B." wrote in messagenews:ue3pk6llt6sq36mmvo2agrk4b624720u0b@4ax .com...

My current bike is a Giant OCR-2 with a SRAM 12-26 cassette and 50/34
chain rings on a Shimano FC-4550-s crank set with a 110mm bolt circle.

I usually ride where much of the area is flat, or nearly flat, with
some rolling hills, however I'm not as young as I used to be and think
I would be more comfortable with somewhat lower gear ratios.

[snip]

I have success with two low geared 9 speed cassettes running with a 50/34 up front. One is a

standard Shimano mountain bike 11-32 cassette and the other is a
Shimano 12-27 dropping out the 14 and putting a 32 single cog behind
the 27. The second option works best in flat to rolling country where
the 32 is only used as a bailout gear if something steep comes along
near the end of a long sportive for example.

You might have to adjust chain length and wind in the "B" screw on the

rear mech to get it to clear the 32. That will depend on which mech
you have and the length of your rear mech hanger.



Graham.

Thanks. I thought from reading various sources that it is likely that
a mix and match cassette is probably the best solution. I've read
several references to doing this and every one repeated that the cogs
are contoured to match the cogs on either side. and then a remark "but
I didn't seem to have any problem with shifting".

This will work, but does not gain you much. A 12-27 9 speed is
12-13-14-15-17-19-21-24-27. A 11-32 9 speed is
11-12-14-16-18-21-24-28-32. By putting the 32 on the end of the 12-27
and tossing out the 14 cog you end up with a 12-32 cassette.
12-13-15-17-19-21-24-27-32. All you really did is change out the
starting cog on the two cassettes you have to buy to do this. Might
as well just buy the 11-32 and use it. Instead of buying two
cassettes. More cost. The custom cassette is 12-32. Instead of
stock 11-32 cassette. Not much difference. Probably not worth the
extra $30-40-50 needed to buy two cassettes instead of one cassette.


Well, of course I have one cassette, the current 12 - 26 on the bike
so the additional cost is one cassette. The thought about getting rid
of the current 12 T cog is because I never use it as (for me) it would
only be useful for going down a really steep hill and pedaling. So
effectively a 11T cog just converts my 9 speed into an 8 speed :-)

From the answers I have received it seems that the Shimano tooth
contour is not a major problem, at least no one has mentioned it yet.

The other end of the spectrum is whether the shifter will handle the
larger cog, thus my thoughts of a 28 t large cog. I have seen one Tri
bike with what appeared to be a 11 or 12 T small cog and a 34 T large
cog and had a normal appearing "road" derailer, at least certainly not
a MTB derailer. So I'm hopeful that will not become a problem.

On Sat, 5 Feb 2011 23:43:30 -0800 (PST), JG wrote:

Okay, changing the chainwheels is absurd. Harris Cyclery says only TA
makes a 33t and if they have it, it's $45. A standard 48t is about
that much too, unless you go for the $20 BMX oriented Rocket Ring
which they say works. You are still paying about as much as a new
triple minus some cash for the old parts, _and_ you are getting a
minimal change in your range, less than the difference between the 28
and 30 you are considering.

Bashing the cassettes looks like a better bet. If you go with
Shimano, then, as Russel says, you need a 14-25 and the tops cogs from
an 11-32 or 34 (the cheap ones so you have separate big cogs...).
That's about $70.

You could also get a SRAM 11-34, ditch the top cog and replace the 3
lower cogs with your existing 12-13-14-15, assuming SRAM cassettes
work that way... You end up with a 12-30 for about 1/2 the price. You
might want to disassemble your SRAM now and check that everything
works the way you expect (for example the last spacer would need to
be loose attached to the last cog.)

Or buy an SRAM 11-28 and if you can't swap the lower 4 cogs, you still
have an 11-28...


Basically, I was leaning toward the Cassette modification/change.
After a bit of searching it appears that the chain rings is not the
way to go. The question is what is available over here. I've checked
the LBS most likely to have replacement cassettes and "no have" what
I want although they do have the 12-26 which they advised me is the
"standard" cassette for my bike. There are not a lot of shops that
cater to road bikes here, most are either standard family style or MTB
although I'm not ignoring the MTB cassettes.

I'll be in Singapore next week, which has far more bike shops then
Bangkok and will also have a look at what is available there.

On Sun, 06 Feb 2011 00:51:21 -0800, Ronko
wrote:

In article ,
says...


On Fri, 04 Feb 2011 18:40:47 -0800, Ronko
wrote:

In article ,
says...



My current bike is a Giant OCR-2 with a SRAM 12-26 cassette and
50/34
chain rings on a Shimano FC-4550-s crank set with a 110mm bolt
circle.

I usually ride where much of the area is flat, or nearly flat, with
some rolling hills, however I'm not as young as I used to be and think
I would be more comfortable with somewhat lower gear ratios.

For my use the large chain ring ratios work pretty well, except for
the 12 tooth cog, which I would only use pedaling down a steep hill
(which we don't have) but the small chain ring rations really aren't
low enough. With the 34-26 ratio I am really puffing on some of the
smaller hills and some roads I don't even bother to ride. I have it in
my mind that a 48 - 14 high gear ratio and a 33 - 28, or 30 low gear
ratio spread would be more fitting to my physical capabilities.

My questions a

Are smaller chain rings available for the Shimano 110 bolt hole
cranks? So far I haven't found any.

Secondly. I don't see cassettes with, say a 14-28, or 14-30 cog set,
however I have read about people who have combined cogs from two
or
more cassettes to get the ratios that they want.

I do understand that modern cassettes have contoured cogs that work
best in certain combinations, but have also read that people who
combine cogs report few shifting problems.

So - can anyone offer a suggestion where I can obtain a 48/33 chain
ring combination for a 110mm, 5 bolt, circle crank and (2) how much
difficulty will I have combining various cogs in the cassette?


Cheers,

John B.
Sram makes 11-28 cassettes in 8 and 9 speed and they are cheap on
Ebay,
under $30. I use these for 9 speed, they work fine. You may not need
the
11 but the 28 over the 26 will be noticeable and probably work fine with
your existing rear derailleur. Most likely your chain is long enough also.
You can't go smaller than a 34 in 110bdc I believe. If you need lower
then
you'll probably have to go to a triple setup, new crank, chain, front and
rear
derailleur and shifters. Not worth it on the OCR.

Well, let me pose another question. As the 11 tooth cog is of no real
use to me (we don't have hills around here steep enough for me to use
it :-) I wonder whether I can take the 12 tooth small cog off my
existing SRAM cassette and replace the 11 tooth cog on the 11 - 28
cassette?
No. I'm guessing you have an 8 or 9 speed drive train? 8 if you're lucky as
it will be cheaper in a cassette. There are 12-32 cassettes around. You can
use that but will need a longer cage rear derailleur and most likely a longer
chain than what you have.

Going from 34 to 33 in the front is only about a 2.9% lower gear, not
worth it. Going from a 26 to a 32 in the back is 23% lower, you will notice
that and can just stay with the shifters, crank and gears up front.

It is a 9 speed and I agree with you that the chain ring change is not
the best choice. The "the plan" is to change the cassette as it seems
the most bang for the buck. The chain rings were a shot in the dark.

john B. wrote:
On Sat, 05 Feb 2011 16:59:08 -0600, AMuzi wrote:

john B. wrote:
On Sat, 5 Feb 2011 10:59:28 -0800 (PST), JG wrote:

Generally, especially with gearing, you are much better off with off
the shelf solutions rather than the expense and bother of DIY fix.
I'd take another look at a triple set up. You will have smoother
shifting in front, and still have the option of bigger cassettes, if,
for example, you have a chance to ride some different terrain.

A new Tiagra triple crank cost ~$95 and you can probably get about 1/3
back selling the double on Ebay. If you have 4500 or 4503 left
brifter, you are all set (but if not, it can be pricey). You may not
need triple derailleurs, but if you do, you can probably use what you
have until you can get a good price on Ebay. (I just saw a $26
shipped buy it now front on Ebay.)

J
I don't want to be sarcastic, but I did considered your thoughts
before I posted. First, bike shops in this part of the world stock
very few chain rings or cassettes of any sort, as apparently there is
little demand. Second, when you make an offer on e-bay and include a
statement that shipping is from Thailand at the buyer's expense, it
kind of takes the shine off the price, even if it is low. Very few
takers, except in wholesale quantities.

Up to 1.8kg USA to Thailand $22, 6~10 days. Not excessively
pricey.


That just hasn't been my experience. The last items I had shipped was
two bottles of pills, something under a pound a piece, less then 1 Kg.
total including packaging. Shipping cost? US$ 39.00. Another order was
for a marine toilet rebuild kit. $52.00 for the kit, total weight
about 1 Kg. and $51.00 for the shipping. Total $103.00 USD.

Who were you getting a shipping cost of US$ 12.00/Kg from?



Air Post.
By selecting small packet services you're incurring a
relatively high per-packet service fee often including
formal customs entry which isn't strictly necessary for
small value shipments.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

The other end of the spectrum is whether the shifter will handle the
larger cog, thus my thoughts of a 28 t large cog. I have seen one Tri
bike with what appeared to be a 11 or 12 T small cog and a 34 T large
cog and had a normal appearing "road" derailer, at least certainly not
a MTB derailer. So I'm hopeful that will not become a problem.- Hide quoted text -


A short cage road derailleur will clear a 32 cog on the vast majority
of bikes. The shifter does not matter. It will shift up to a 32 or
whatever just fine. Its the rear derailleur. A short cage will not
clear a 34 cog. A mountain bike rear derailleur will clear a 32 cog.
It may not clear a 34. it really depends on the derailleur hanger on
the bike. How low it is. I have a Redline touring bike that will not
let a mountain bike rear derailleur clear a 34. Clears a 32. My
brother cleared a 32 cog with a short cage Shimano 600 rear derailleur
on a 1991 Trek OCLV 5200 frame. Its all about the frame, not the
derailleur.

On 2/6/2011 6:06 AM, john B. slocomb wrote:
[...]
I'll be in Singapore next week, which has far more bike shops then
Bangkok and will also have a look at what is available there.

Watch out for the flying squirrels!
http://www.zoochat.com/243/giant-flying-squirrel-night-safari-47088/

High spoke count wheels to prevent squirrel intrusion are recommended.

--
Tºm Shermªn - 42.435731,-83.985007
I am a vehicular cyclist.

"john B." wrote in message
...

My current bike is a Giant OCR-2 with a SRAM 12-26 cassette and 50/34
chain rings on a Shimano FC-4550-s crank set with a 110mm bolt circle.

I usually ride where much of the area is flat, or nearly flat, with
some rolling hills, however I'm not as young as I used to be and think
I would be more comfortable with somewhat lower gear ratios.

For my use the large chain ring ratios work pretty well, except for
the 12 tooth cog, which I would only use pedaling down a steep hill
(which we don't have) but the small chain ring rations really aren't
low enough. With the 34-26 ratio I am really puffing on some of the
smaller hills and some roads I don't even bother to ride. I have it in
my mind that a 48 - 14 high gear ratio and a 33 - 28, or 30 low gear
ratio spread would be more fitting to my physical capabilities.

John, how long have you been riding? In all seriousness, it gets easier
sooner and faster than you can imagine.

On Sun, 06 Feb 2011 13:17:02 -0600, AMuzi wrote:

john B. wrote:
On Sat, 05 Feb 2011 16:59:08 -0600, AMuzi wrote:

john B. wrote:
On Sat, 5 Feb 2011 10:59:28 -0800 (PST), JG wrote:

Generally, especially with gearing, you are much better off with off
the shelf solutions rather than the expense and bother of DIY fix.
I'd take another look at a triple set up. You will have smoother
shifting in front, and still have the option of bigger cassettes, if,
for example, you have a chance to ride some different terrain.

A new Tiagra triple crank cost ~$95 and you can probably get about 1/3
back selling the double on Ebay. If you have 4500 or 4503 left
brifter, you are all set (but if not, it can be pricey). You may not
need triple derailleurs, but if you do, you can probably use what you
have until you can get a good price on Ebay. (I just saw a $26
shipped buy it now front on Ebay.)

J
I don't want to be sarcastic, but I did considered your thoughts
before I posted. First, bike shops in this part of the world stock
very few chain rings or cassettes of any sort, as apparently there is
little demand. Second, when you make an offer on e-bay and include a
statement that shipping is from Thailand at the buyer's expense, it
kind of takes the shine off the price, even if it is low. Very few
takers, except in wholesale quantities.

Up to 1.8kg USA to Thailand $22, 6~10 days. Not excessively
pricey.


That just hasn't been my experience. The last items I had shipped was
two bottles of pills, something under a pound a piece, less then 1 Kg.
total including packaging. Shipping cost? US$ 39.00. Another order was
for a marine toilet rebuild kit. $52.00 for the kit, total weight
about 1 Kg. and $51.00 for the shipping. Total $103.00 USD.

Who were you getting a shipping cost of US$ 12.00/Kg from?



Air Post.
By selecting small packet services you're incurring a
relatively high per-packet service fee often including
formal customs entry which isn't strictly necessary for
small value shipments.

No, certainly not in Thailand. All incoming goods are subject to
customs, however you are correct that for small packages it is common
for them to be delivered with opening.

But, this "Air Post"; I'm not arguing, but I have, in the last 4 or 5
years, for example, had air freight shipments made to me and in no
case was shipping as cheap as you mention.

Again emphasizing I'm not trying to argue but to gain knowledge, can
you point me at some reference for "small package services". Is it a
part of the US Postal services? The pills I mentioned that were
shipped for.$39.00 were by "USPS Express (Outside U.S)".

If I can discover a shipping method as cheap as you mention it will
put a completely different face on obtaining US good over here.

On Sun, 6 Feb 2011 15:39:07 -0600, "MikeWhy"
wrote:

"john B." wrote in message
.. .

My current bike is a Giant OCR-2 with a SRAM 12-26 cassette and 50/34
chain rings on a Shimano FC-4550-s crank set with a 110mm bolt circle.

I usually ride where much of the area is flat, or nearly flat, with
some rolling hills, however I'm not as young as I used to be and think
I would be more comfortable with somewhat lower gear ratios.

For my use the large chain ring ratios work pretty well, except for
the 12 tooth cog, which I would only use pedaling down a steep hill
(which we don't have) but the small chain ring rations really aren't
low enough. With the 34-26 ratio I am really puffing on some of the
smaller hills and some roads I don't even bother to ride. I have it in
my mind that a 48 - 14 high gear ratio and a 33 - 28, or 30 low gear
ratio spread would be more fitting to my physical capabilities.

John, how long have you been riding? In all seriousness, it gets easier
sooner and faster than you can imagine.

I started riding "road bikes", excluding the riding I did as a young
lad, in about 1980 something and (if I remember correctly) changed
from a 50T chain ring to a 52T because the 50 was too slow. However as
the years go by I don't do that anymore :-)

john B. wrote:
On Sun, 06 Feb 2011 13:17:02 -0600, AMuzi wrote:

john B. wrote:
On Sat, 05 Feb 2011 16:59:08 -0600, AMuzi wrote:

john B. wrote:
On Sat, 5 Feb 2011 10:59:28 -0800 (PST), JG wrote:

Generally, especially with gearing, you are much better off with off
the shelf solutions rather than the expense and bother of DIY fix.
I'd take another look at a triple set up. You will have smoother
shifting in front, and still have the option of bigger cassettes, if,
for example, you have a chance to ride some different terrain.

A new Tiagra triple crank cost ~$95 and you can probably get about 1/3
back selling the double on Ebay. If you have 4500 or 4503 left
brifter, you are all set (but if not, it can be pricey). You may not
need triple derailleurs, but if you do, you can probably use what you
have until you can get a good price on Ebay. (I just saw a $26
shipped buy it now front on Ebay.)

J
I don't want to be sarcastic, but I did considered your thoughts
before I posted. First, bike shops in this part of the world stock
very few chain rings or cassettes of any sort, as apparently there is
little demand. Second, when you make an offer on e-bay and include a
statement that shipping is from Thailand at the buyer's expense, it
kind of takes the shine off the price, even if it is low. Very few
takers, except in wholesale quantities.

Up to 1.8kg USA to Thailand $22, 6~10 days. Not excessively
pricey.

That just hasn't been my experience. The last items I had shipped was
two bottles of pills, something under a pound a piece, less then 1 Kg.
total including packaging. Shipping cost? US$ 39.00. Another order was
for a marine toilet rebuild kit. $52.00 for the kit, total weight
about 1 Kg. and $51.00 for the shipping. Total $103.00 USD.

Who were you getting a shipping cost of US$ 12.00/Kg from?


Air Post.
By selecting small packet services you're incurring a
relatively high per-packet service fee often including
formal customs entry which isn't strictly necessary for
small value shipments.

No, certainly not in Thailand. All incoming goods are subject to
customs, however you are correct that for small packages it is common
for them to be delivered with opening.

But, this "Air Post"; I'm not arguing, but I have, in the last 4 or 5
years, for example, had air freight shipments made to me and in no
case was shipping as cheap as you mention.

Again emphasizing I'm not trying to argue but to gain knowledge, can
you point me at some reference for "small package services". Is it a
part of the US Postal services? The pills I mentioned that were
shipped for.$39.00 were by "USPS Express (Outside U.S)".

If I can discover a shipping method as cheap as you mention it will
put a completely different face on obtaining US good over here.


I do this all day every day, including Thai shipments.
Try he
usps.com
Use flat-rate packets where possible

Let's get a second opinion on that:
fedex.com
ouch!
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971