adding chainring to Trek 400

In article <[email hidden]>, [email hidden] says...

Quoted message said:

On an old Trek 400 series sport-tour bicycle, I want to install an additional chainring (somewhere
in the low 30t range) so the bicycle can be used for moderate touring. Is installing only one
chainring to the existing rings possible or will installing a whole arrangement be necessary? If
possible, what type of technical issues do I need to be cognizant of? For instance, will the front
derailleur be of concern? bottom bracket? gear cluster?

If it is possible, the following will need to be considered:

1. Is there holes (threaded?) to mount the new inner chainring?
2. Is there room between the existing inner chainring and the frame to put another chainring? You
may need to install a longer bottom bracket.
3. Will your front derailleur move inward enough to shift to the new chainring (assuming you use the
existing BB)?
4. Will your rear derailleur handle the extra chain that will be spooled off when shifting to the
new chainring?
5. Will your current shifter handle the extra cable needed to swing your front derailleur the
extra distance?
6. Will your current front derailleur handle the difference in chainring size without dragging along
it's crosspiece?

--

Remove NOT from email address to reply. AntiSpam in action.

In article <[email hidden]>, alonzo lewis

Quoted message said:

On an old Trek 400 series sport-tour bicycle, I want to install an additional chainring (somewhere
in the low 30t range) so the bicycle can be used for moderate touring. Is installing only one
chainring to the existing rings possible or will installing a whole arrangement be necessary?

It is probably not possible/practical to add a third ring to the existing crankset.

Quoted message said:

If possible, what type of technical issues do I need to be cognizant of? For instance, will the
front derailleur be of concern? bottom bracket? gear cluster?

I think what you'll need are a crankset, a bottom bracket that matches it, a front derailleur
designed for the size chainrings you intend to use, derailleur cable. If the rear derailleur is a
short cage design, you'll probably need to replace that as well. Chain is a possible requirement as
well depending on the gearing you end up with and the rear derailleur.

You're probably looking at around $125 in new parts at the very minimum (ie, discount mail-order
purchase) and probably over $200 if you have a bike shop supply all necessary parts and labor.

--Paul

Guys, thanks for your input. The information is very helpful.

Alonzo

"Dan Brussee" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

In article <[email hidden]>, [email hidden] says...

Quoted message said:

On an old Trek 400 series sport-tour bicycle, I want to install an additional chainring
(somewhere in the low 30t range) so the bicycle

can be

Quoted message said:

Quoted message said:

used for moderate touring. Is installing only one chainring to the

existing

Quoted message said:

Quoted message said:

rings possible or will installing a whole arrangement be necessary? If possible, what type of
technical issues do I need to be cognizant of?

For

Quoted message said:

Quoted message said:

instance, will the front derailleur be of concern? bottom bracket? gear cluster?

If it is possible, the following will need to be considered:

1. Is there holes (threaded?) to mount the new inner chainring?
2. Is there room between the existing inner chainring and the frame to put another chainring? You
may need to install a longer bottom bracket.
3. Will your front derailleur move inward enough to shift to the new chainring (assuming you use
the existing BB)?
4. Will your rear derailleur handle the extra chain that will be spooled off when shifting to the
new chainring?
5. Will your current shifter handle the extra cable needed to swing your front derailleur the
extra distance?
6. Will your current front derailleur handle the difference in chainring size without dragging
along it's crosspiece?

--

Remove NOT from email address to reply. AntiSpam in action.