Replacing Crank Set

cobra46 said:

I am about to replace the Bontrager Race crankset and BB on my Trek
2100 with Shimano Ultegra cranks and BB. Can anyone advise me on the
tools I will need to do this and also if there are any pitfalls to
watch out for?

Many bottom brackets require a specific tool to fit the splines of the
bottom bracket. You may or may not need two such tools, one for the
Bontrager and the other for the Shimano. Check with either a website or
your LBS to be sure. But you will certainly need one. The good news is
that they are cheap.

The right cup is left-hand thread, and the "cup" will be very tight. The
left side has right-hand (normal) threads, and will be less difficult to
remove.

I assume that your new bottom bracket is a cartridge type. These
typically have the right-side threaded cup attached to the bottom bracket
itself, with the left side cup loose. But the other popular type, with
more separate sides, is similar. If you have a loose-bearing cup and cone
system, it takes a few more steps.

Wrap teflon tape (used for
plumbing) around both threaded portions of the cups.
When putting the new one in, start with the left side cup -- or holder.
Put it in loosely, just engage the threads. Then, the right side will
slide in, bottom bracket and all, and the shaft will fit through the left
side holder. Begin tightening the right side (backwards), making sure the
threads are properly engaged. Then tighten each side, alternately,
tightening down the right side first, with some force, then the left.

You should make the bottom bracket quite tight, and it should be easy to
do until the very end. If the pieces do not easily thread onto the frame,
either the threads are bad, or you have it improperly threaded. The
latter is very easy to do, so take care with that part.

--

David L. Johnson

__o | Let's be straight here. If we find something we can't
_`\(,_ | understand we like to call it something you can't understand, or
(_)/ (_) | indeed even pronounce. -- Douglas Adams

Thanks David. That is very helpful. Can you give me an idea of how
long it should take assuming I have all the right tools and compnents?

David L. Johnson said:

cobra46 said:

I am about to replace the Bontrager Race crankset and BB on my Trek
2100 with Shimano Ultegra cranks and BB. Can anyone advise me on the
tools I will need to do this and also if there are any pitfalls to
watch out for?

Many bottom brackets require a specific tool to fit the splines of the
bottom bracket. You may or may not need two such tools, one for the
Bontrager and the other for the Shimano. Check with either a website or
your LBS to be sure. But you will certainly need one. The good news is
that they are cheap.

The right cup is left-hand thread, and the "cup" will be very tight. The
left side has right-hand (normal) threads, and will be less difficult to
remove.

I assume that your new bottom bracket is a cartridge type. These
typically have the right-side threaded cup attached to the bottom bracket
itself, with the left side cup loose. But the other popular type, with
more separate sides, is similar. If you have a loose-bearing cup and cone
system, it takes a few more steps.

Wrap teflon tape (used for
plumbing) around both threaded portions of the cups.
When putting the new one in, start with the left side cup -- or holder.
Put it in loosely, just engage the threads. Then, the right side will
slide in, bottom bracket and all, and the shaft will fit through the left
side holder. Begin tightening the right side (backwards), making sure the
threads are properly engaged. Then tighten each side, alternately,
tightening down the right side first, with some force, then the left.

You should make the bottom bracket quite tight, and it should be easy to
do until the very end. If the pieces do not easily thread onto the frame,
either the threads are bad, or you have it improperly threaded. The
latter is very easy to do, so take care with that part.

--

David L. Johnson

__o | Let's be straight here. If we find something we can't
_`\(,_ | understand we like to call it something you can't understand, or
(_)/ (_) | indeed even pronounce. -- Douglas Adams

cobra46 said:

Thanks David. That is very helpful. Can you give me an idea of how
long it should take assuming I have all the right tools and compnents?

Well, in theory it shouldn't take long at all, but things always take
longer than they should. Assuming no hassles, an hour? plus time to
re-adjust the front derailleur, which depends on change in chainline,
chainring sizes, etc.

Worst-case, maybe it will take time and penetrating oil to remove the old
bottom bracket. Maybe you will get something cross-threaded and need to
take it to a shop to have the threads chased. Maybe the new chainline
will be terrible (this you usually avoid if the parts are meant for
the application) and you will need to add spacers.

But usually none of this will happen.

BTW, I forgot, you will also need a tool to remove the
cranks from the shaft, if you don't already have that. And there is a
possibility that you need a new one for the new cranks, though that won't
prevent you from installing the new cranks.

--

David L. Johnson

__o | "Business!" cried the Ghost. "Mankind was my business. The
_`\(,_ | common welfare was my business; charity, mercy, forbearance,
(_)/ (_) | and benevolence, were, all, my business. The dealings of my
trade were but a drop of water in the comprehensive ocean of my
business!" --Dickens, "A Christmas Carol"

cobra46 said:

I am about to replace the Bontrager Race crankset and BB on my Trek
2100 with Shimano Ultegra cranks and BB. Can anyone advise me on the
tools I will need to do this and also if there are any pitfalls to
watch out for?

If my recent experience is in any way typical, the splines on the cranks are
made from cheese. Be very careful to get 'em lined up properly with those
on the BB axle.

That machine now has a Campag chainset...

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
The entire population of Uxbridge has no idea that it actually doesn't
exist.

David L. Johnson said:

cobra46 said:

I am about to replace the Bontrager Race crankset and BB on my Trek
2100 with Shimano Ultegra cranks and BB. Can anyone advise me on the
tools I will need to do this and also if there are any pitfalls to
watch out for?

Many bottom brackets require a specific tool to fit the splines of the
bottom bracket. You may or may not need two such tools, one for the
Bontrager and the other for the Shimano. Check with either a website or
your LBS to be sure. But you will certainly need one. The good news is
that they are cheap.

The right cup is left-hand thread, and the "cup" will be very tight. The
left side has right-hand (normal) threads, and will be less difficult to
remove.

I assume that your new bottom bracket is a cartridge type. These
typically have the right-side threaded cup attached to the bottom bracket
itself, with the left side cup loose. But the other popular type, with
more separate sides, is similar. If you have a loose-bearing cup and cone
system, it takes a few more steps.

Wrap teflon tape (used for
plumbing) around both threaded portions of the cups.
When putting the new one in, start with the left side cup -- or holder.
Put it in loosely, just engage the threads. Then, the right side will
slide in, bottom bracket and all, and the shaft will fit through the left
side holder. Begin tightening the right side (backwards), making sure the
threads are properly engaged. Then tighten each side, alternately,
tightening down the right side first, with some force, then the left.

Remember to grease, both inside the left cup and inside the BB shell.
Much more essential than teflon tape, which I seldom use....

Quoted message said:

You should make the bottom bracket quite tight, and it should be easy to
do until the very end. If the pieces do not easily thread onto the frame,
either the threads are bad, or you have it improperly threaded. The
latter is very easy to do, so take care with that part.

--

David L. Johnson

__o | Let's be straight here. If we find something we can't
_`\(,_ | understand we like to call it something you can't understand, or
(_)/ (_) | indeed even pronounce. -- Douglas Adams