7-8-9 speed

Matthew said:

How do I determine if I can upgrade a bike to 8 or 9 speed
from 7 speed? I have two bikes I like a lot, but would
like to upgrade if possible -- a 96 TREK 7000 (mtn bike)
and an unknown year TREK 7900 (a carbon/aluminum hybrid --
OK, you can stop laughing now). They are both 7 speeds
with mid grade Shimano lever shifters.

If more information is needed, I will try to help. I will
be out of contact for a couple of days, back around
Thursday.

Any advice would be appreciated.

Matthew

Mountain bikes and derivatives usually have 135mm between
the rear dropout faces, and this didn't change from 7 speed
to 9 speed. If you're unlucky and you have 130mm, you have
little choice apart from springing the rear end out every
time you fit the 9 speed hub. This isn't a terribly good
thing to do but carbon/alu can't be cold set to the right
dimensions.

"Matthew" <[email hidden]> wrote in
:"]news:[email hidden]:

Quoted message said:

How do I determine if I can upgrade a bike to 8 or 9 speed
from 7 speed? I have two bikes I like a lot, but would
like to upgrade if possible -- a 96 TREK 7000 (mtn bike)
and an unknown year TREK 7900 (a carbon/aluminum hybrid --
OK, you can stop laughing now). They are both 7 speeds
with mid grade Shimano lever shifters.

If more information is needed, I will try to help. I will
be out of contact for a couple of days, back around
Thursday.

Any advice would be appreciated.

Matthew

You could definately upgrade these bikes to 9 speed. The
real question is how much will it set you back? In order to
answer this you need to find out what needs upgrading and
what can be kept. The first thing you should look at is your
rear wheel. Is the gear mech a cassette or a thread-on
freewheel? If it is a freewheel, you will most likely need
to replace the wheel (or at least the hub). If it is a
casette, you need to find out if the casette body will
accomodate a 9-speed casette.

For more on this subject, go here:

sheldonbrown.comk7.htmlOpen ↗

and scroll down to the following section:

-> Upgrading From 6-/7-speed (126 mm) to 8-/9-speed (130 mm)

Next, you have to worry about weather your chain (most
likely), deraillers (likely rear, front not so likely), and
shifters (won't index properly) need replaced. This is
another can of worms all together.

With these components I say this: Try it!!! If it doesn't
work, then upgrade.

You might learn something in the process 🙂

- Boyd S.

Zog The Undeniable <[email hidden]> wrote in
news:40949fdf.0@entanet:

Quoted message said:

Matthew said:

How do I determine if I can upgrade a bike to 8 or 9
speed from 7 speed? I have two bikes I like a lot, but
would like to upgrade if possible -- a 96 TREK 7000 (mtn
bike) and an unknown year TREK 7900 (a carbon/aluminum
hybrid -- OK, you can stop laughing now). They are both 7
speeds with mid grade Shimano lever shifters.

If more information is needed, I will try to help. I will
be out of contact for a couple of days, back around
Thursday.

Any advice would be appreciated.

Matthew

Mountain bikes and derivatives usually have 135mm between
the rear dropout faces, and this didn't change from 7
speed to 9 speed. If you're unlucky and you have 130mm,
you have little choice apart from springing the rear end
out every time you fit the 9 speed hub. This isn't a
terribly good thing to do but carbon/alu can't be cold set
to the right dimensions.

Last time I checked, all modern road bikes have 130mm
between the rear dropouts. So your 9-speed upgrade shouldn't
be a problem. In fact, most of these 130mm road hubs can now
also accommodate 10-speed cassettes.

- Boyd S.

Boyd Speerschneider said:

Last time I checked, all modern road bikes have 130mm
between the rear dropouts. So your 9-speed upgrade
shouldn't be a problem. In fact, most of these 130mm road
hubs can now also accommodate 10-speed cassettes.

I think his bikes will be MTB-based. Virtually all 7 speed
road bikes were 126mm - the 130mm came in with 8 speed.

Matthew said:

How do I determine if I can upgrade a bike to 8 or 9 speed
from 7 speed? I have two bikes I like a lot, but would
like to upgrade if possible -- a 96 TREK 7000 (mtn bike)
and an unknown year TREK 7900 (a carbon/aluminum hybrid --
OK, you can stop laughing now). They are both 7 speeds
with mid grade Shimano lever shifters.

I'd leave both bikes at 7 speeds, and focus on improving the
gearing with that. For the mountain bike, I'd put a
"compact" 22-32-46 crank on, with a 12-28 or 13-30 cassette.
Or find an adaptor for your current crank, to allow a
smaller inner chainring. For the road bike, there are many
good combinations, depending on your local terrain. You
might try a 110mm BCD 34-48 or 34-50 crank if you're stuck
with two chainrings (because you lack a triple shifter).

IMO, 7 speeds was enough, especially for road bikes. 8-9
speeds were better for mountain bikes, but mostly because 8
speed drivetrains came with better chosen gearing than
because of the extra cog. If you deviate from stock gearing
a little you can do just as well.

So really, you should figure out specifically what you'd
like to improve with your current gearing. Do you need lower
gears for the hills? Taller ones w/ smaller gaps for the
flats? Post back with your current gearing, and gearing
problems. There are easier and cheaper solutions than
converting your whole drivetrain. Even a custom cassette can
be well worth doing.

The exception is if you're hell-bent on replacing your
shifters, because you want STI/RF+ instead of levers. In
that case the shifters are the main expense, so doing the
rest may be worth it.

Those old lugged-and-glued aluminum and aluminum/carbon
Treks were very nice bikes -- sweet handling, and decently
light and stiff -- well worth keeping. They were much better
than the similar Vitus and Alan ones of the same vintage,
which may have had more snob appeal. If I had to choose
between a Vitus 979 and a Trek 1400 for a mountain century,
I'd definately pick the Trek. The carbon Trek was
essentially the same thing, but a few ounces lighter. So I
won't laugh at your old bikes!

Matt O.