Changing the gearing on a crankset?

Hello,

I'm trying to put together a road bike. It's my first attempt at building a
bike from the frame up.

For gearing, I'm looking at using a 32-42-52T crankset, or something in
that area.

Right now, I have two cranksets. Both are geared for a mountain bike. One
is a Shimano Altus 24-34-42T; the other is a Shimano Hyperdrive-C. The
Hyperdrive is installed on my mountain bike right now, and it's covered
with grime, so I didn't want to touch it but it looks to be nearly the
same size as the Altus.

I was wondering if it's possible to take either of these apart, use the
large and middle sized chainrings, discard the small one, and add a big
52T ring. It doesn't look like they can be taken apart, but I haven't
tried prying/pulling/twisting anything, as I don't really know what to
look for, and I don't want to break or bend either of these.

Any advice you can give would be appreciated.

Thanks,

---
Sean Cunningham

On Sun, 24 Oct 2004 16:34:58 -0400, Sean M. Cunningham wrote:

I was wondering if it's possible to take either of these apart, use the
large and middle sized chainrings, discard the small one, and add a big
52T ring.

No. the smallest one uses a smaller circle of bolts to attach it.

It doesn't look like they can be taken apart, but I haven't
tried prying/pulling/twisting anything, as I don't really know what to
look for, and I don't want to break or bend either of these.

Well, some cheaper MTB cranksets indeed are impossible to take apart
(don't bother with it in that case), but most have 4 or 5 bolts holding
the bigger two rings on, and the same number, accessible from the inside,
for the smallest ring.

--

David L. Johnson

__o | Accept risk. Accept responsibility. Put a lawyer out of
_`\(,_ | business.
(_)/ (_) |

There's no visible bolts on either, so I'm assuming they can't be taken
apart. I thought that might be the case, but I'm new to all this and just
wanted to see if there was something I was missing.

Thanks for the help.

---
Sean Cunningham


On Sun, 24 Oct 2004, David L. Johnson wrote:

On Sun, 24 Oct 2004 16:34:58 -0400, Sean M. Cunningham wrote:

I was wondering if it's possible to take either of these apart, use the
large and middle sized chainrings, discard the small one, and add a big
52T ring.

No. the smallest one uses a smaller circle of bolts to attach it.

It doesn't look like they can be taken apart, but I haven't
tried prying/pulling/twisting anything, as I don't really know what to
look for, and I don't want to break or bend either of these.

Well, some cheaper MTB cranksets indeed are impossible to take apart
(don't bother with it in that case), but most have 4 or 5 bolts holding
the bigger two rings on, and the same number, accessible from the inside,
for the smallest ring.

--

David L. Johnson

__o | Accept risk. Accept responsibility. Put a lawyer out of
_`\(,_ | business.
(_)/ (_) |

On Sun, 24 Oct 2004 23:21:33 -0400, Sean M. Cunningham
wrote:

There's no visible bolts on either, so I'm assuming they can't be taken
apart. I thought that might be the case, but I'm new to all this and just
wanted to see if there was something I was missing.

Thanks for the help.

---
Sean Cunningham


On Sun, 24 Oct 2004, David L. Johnson wrote:

On Sun, 24 Oct 2004 16:34:58 -0400, Sean M. Cunningham wrote:

I was wondering if it's possible to take either of these apart, use
the
large and middle sized chainrings, discard the small one, and add a
big
52T ring.

No. the smallest one uses a smaller circle of bolts to attach it.

It doesn't look like they can be taken apart, but I haven't
tried prying/pulling/twisting anything, as I don't really know what to
look for, and I don't want to break or bend either of these.

Well, some cheaper MTB cranksets indeed are impossible to take apart
(don't bother with it in that case), but most have 4 or 5 bolts holding
the bigger two rings on, and the same number, accessible from the
inside,
for the smallest ring.

--

David L. Johnson

__o | Accept risk. Accept responsibility. Put a lawyer out of
_`\(,_ | business.
(_)/ (_) |






What he said. Actually there is more to it than meets the casual eye.
There are 2 different sizes of bottom bracket with the newer ones
being the smaller. The smaller ones will allow a super granny gear,
like 22 teeth to be mounted. It should also be obvious that the one
piece cranks are the Chinese crap and to stay away from the whole bike.
There are many variations on the changeable chainring also, with some
having the larger two rings riveted together, the cheapest kind.
Then you have the issue of 4 bolts or 5. I use a 5 bolt that allows
for changing each ring to whatever will fit. The two large ones use
one set of bolts and the small one its own. I have a 40-48 combo for
the large right now but did have a 40-56 for a while. It is kind of
fun playing with the gearing until you are happy with it. Just make
sure that the chain is the right length for what you settle on.
Last but not least is the mount to the bracket itself. I use the
square taper and found out that even those are not standard. Some
have the square sides parallel to the crank and some are rotated
45 degrees. There are also some star pattern mounts, and there is
a variation on the square ones in that some use a shoulder nut and
some use a allen screw.
Simple questions sometimes get complicated results.
I found out by buying a few hundred dollars worth of bike stuff
on E-bay.
Best of luck
Bill Baka

On Sun, 24 Oct 2004 23:21:33 -0400, Sean M. Cunningham
wrote:

There's no visible bolts on either, so I'm assuming they can't be taken
apart. I thought that might be the case, but I'm new to all this and just
wanted to see if there was something I was missing.

Thanks for the help.

---
Sean Cunningham


I forgot one thing. You will need a puller to get the crank off if you
want to change it for some extra versatility, like 170mm or 175mm crank
lengths or 4~5 bolts.
Bill Baka