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.

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.

"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:

http://www.sheldonbrown.com/k7.html

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.

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.