Replace inner chainring on 10 speed Shimano 105 Triple with smaller one

I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.

On Jul 25, 9:12 pm, wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.

The 24 to 39 and 39 to 24 shift is "iffy" with an STI front shifter,
IME.

OTOH, 105 RD will clear a 30T cog, that and a 28T inner will give you
a "25 inch" gear.

Another alternative is using a friction shifter for the front (barend,
DT, 'traditional' Campy Ergo). Then, you can do as you wish.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.

On 2007-07-26, wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.

I'm running 9 speed Tiagra/105 with a 52-42-26. Shifting between the
inner and middle ring is not as quick or as smooth as with the stock
30t ring, but it works. My guess is that a 50-39-24 will work as well.
You may need to set the low gear limit stop loose and use a chain
watcher, especially if you tend to shift the front under any kind of
load.

wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.


why??? what's wrong with an mtb crank?

On Jul 25, 9:38 pm, jim beam wrote:
wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.

why??? what's wrong with an mtb crank?-


What's a MTB crank going to do for the OP?

Ozark Bicycle wrote:
On Jul 25, 9:38 pm, jim beam wrote:
wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.
why??? what's wrong with an mtb crank?-


What's a MTB crank going to do for the OP?


give him a lower granny gear without all this messing about?

In article ,
says...
Ozark Bicycle wrote:
On Jul 25, 9:38 pm, jim beam wrote:
wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.
why??? what's wrong with an mtb crank?-


What's a MTB crank going to do for the OP?


give him a lower granny gear without all this messing about?


And when he wants to use the 50 tooth ring?

RBrickston wrote:
In article ,
says...
Ozark Bicycle wrote:
On Jul 25, 9:38 pm, jim beam wrote:
wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.
why??? what's wrong with an mtb crank?-

What's a MTB crank going to do for the OP?

give him a lower granny gear without all this messing about?


And when he wants to use the 50 tooth ring?


for what? how many people /need/ to pedal faster than 30mph?

bottom line, look at the op's question. they're not driven by speed,
they're driven by either touring or lack of fitness. mtb gearing is a
better solution to meet their goal.

On Jul 25, 9:21 pm, jim beam wrote:
RBrickston wrote:
In article ,
says...
Ozark Bicycle wrote:
On Jul 25, 9:38 pm, jim beam wrote:
wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.
why??? what's wrong with an mtb crank?-

What's a MTB crank going to do for the OP?

give him a lower granny gear without all this messing about?

And when he wants to use the 50 tooth ring?

for what? how many people /need/ to pedal faster than 30mph?

bottom line, look at the op's question. they're not driven by speed,
they're driven by either touring or lack of fitness. mtb gearing is a
better solution to meet their goal.- Hide quoted text -

- Show quoted text -

The OP is clearly not interested in replacing the cranks. He's going
to buy the 105 triple bike if he can use a 24-tooth granny he already
has.

Joe Bernard wrote:
On Jul 25, 9:21 pm, jim beam wrote:
RBrickston wrote:
In article ,
says...
Ozark Bicycle wrote:
On Jul 25, 9:38 pm, jim beam wrote:
wrote:
I am about to order a new road bike that comes with a 10-speed
Shimano 105 drive train components: 50-39-30T chainrings, 12-27T
cassette, front derailleur, rear derailleur with long cage, and STI
shift levers.
I would like to replace the 30T inner chainring with a smaller
one, preferably a 24T. Is this a compatible modification? I
recognize that it may not shift up to the middle chainring as smoothly
as stock, but as long as it gets the job done I would be satisfied.
To me, this is a deal breaker -- if I can't get a 24 inch low gear, I
will have to select a different bike.
Are the inner chainrings for 10-speed triples different than
those made for (1991) 7-speed triples? I have an old 28T and and old
24T chainring, each with the required 74 mm bolt diameter, I could try
out.
why??? what's wrong with an mtb crank?-
What's a MTB crank going to do for the OP?
give him a lower granny gear without all this messing about?
And when he wants to use the 50 tooth ring?
for what? how many people /need/ to pedal faster than 30mph?

bottom line, look at the op's question. they're not driven by speed,
they're driven by either touring or lack of fitness. mtb gearing is a
better solution to meet their goal.- Hide quoted text -

- Show quoted text -

The OP is clearly not interested in replacing the cranks.

but that's the point - he should be interested! by the time he's done
dicking about with cogs, and quite likely derailleurs and chain keepers,
he'd have spent less money and less time just going mtb.


He's going
to buy the 105 triple bike if he can use a 24-tooth granny he already
has.