Bicycle Mechanics - Help choosing new rear cassette for Trek 370

Ok,

So I have an old (1994) Trek 370 that I am training on (planning to ride a century in Death Valley in October for the JDRF, see my post in charity btw).

Anyways, the chain is slipping at random on the rear. I figure its a good time to replace the oem cassette and chain (bike was given to me so I have no idea how many miles are on them).

I've been looking at this: http://www.amazon.com/Shimano-CS-HG30-I-Cassette-11-28T-Black/dp/B000F5LLVC

Is this a good combination of gears? I'm a bit lost when reading the gear articles. I figure a bit of gear would help as the Death Valley ride has a decent (1500ft elevation change at the end) amount of hills, then again I'm working hard in the gym to get my legs as strong as possible.

The questions:

1. Correct selection for my bike? If not, how can I tell?

2. Gear selection: Better suggestions? Can I convert the bike to 8 or 9 speeds? From what I read I'd need a new rear hub correct? The RD (and front) are the stock Shimano EX components (300EX front/400EX rear).

Thanks for any/all help.

Jason

I assume the chain rings are 52-42 with a 13-28 cassette?

To go to a 8 or 9 speed, you would need a new Free Hub BODY. The 7 speed BODY is about 3? MM shorter than the higher speed bodies.
If you have indexed shifters, they would have to be replaced also.
If 9 speed, a new chain.
Wheel might need a bit of redishing???

Is the "elevation change" up or down? Both? That would have a major impact on my decision, especially for the highest gear.

Front is 40/52 rear is 12-28.

Elevation is up and down (course is there and back with the big elevation change at the half way point).

As for shifters, yep indexed so I'll stick to 7 speed then untill I save up for sti style shifters one day.

So...am I looking at a reasonable choice then? If not, please suggest better. I'm not against spending more money, just want something that will perform and not slip :)

First off, make sure it is a freehub/cassette system and not freewheel. 7-speed could be either, see here to determine if you're not sure: http://sheldonbrown.com/freewheels.html and http://sheldonbrown.com/k7.html

There's nothing wrong with the cassette you found on Amazon. However, you need to make sure the freehub body can accept an 11T cog. See here: http://sheldonbrown.com/k7.html#hyperdrivec (Also, make sure you use the new 11T-compatible lockring that will come with the cassette.)

As far as gearing, an 11-28T vs 12-28T will give you a little faster top gear and the individual cogs may be different (you'd have to compare teeth counts).

How is the current cassette fairing for the route? If you need lower gearing, look at like a 13-32T cassette: http://www.nashbar.com/profile.cfm?category=600087&subcategory=60001109&brand=&sku=6213&storetype=&estoreid=&pagename=Shop%20by%20Subcat%3A%20Freewheels However, you'll need to make sure your rear derailleur can handle that spread and the 32T largest cog. You'd need a long cage MTB type derailleur, like: http://www.nashbar.com/profile.cfm?category=600083&subcategory=60001039&brand=&sku=20855&storetype=&estoreid=&pagename=Shop%20by%20Subcat%3A%20Rear%20Derailleurs

Can you do a trial ride and determine if you have "enough" low gear for the hills?
Also, do you "spin out" on the down hills?
12-28 = 12-14-16-18-21-24-28
11-28 = 11-13-15-18-21-24-28
Going to an 11T top cog will only help on the down hill, IF you are spinning out on the 12T.
However, it's going to make a bigger "gap" on 4th to 5th gears! (3 vs 2 tooth jump)
That's a pretty BIG gap! I know I would hate it.
Your 4 lower gears are the SAME.
Obviously, a 4T "gap" in the bottom gears is fine. You wouldn't consider it in the upper 2 gears, if you get my drift.
There is another option that you "might" explore-
I had the same 12-28 as you.
I bought a 13-26 (13-15-17-19-21-23-26)
I "combined" them to make a 13-14-15-16-17-19-23, for my flat land MB "commuter" type riding.
You might be able to do something similar to "tune" your cassette for various rides.
You pretty much have to make sure your low gear is "low enough:, which doesn't leave a lot of options for the higher gears.
Now if your shifters have a "friction mode", you could upgrade the number of speeds without the major expense of new shifters. Just a new FH Body, cassette & chain.

EDIT:
That was a good catch by Jive Turkey! The 11T requires a Compact FH body. Your bike might have one, but I kind of doubt it.
Go Bulldogs:)

It is indeed a freehub/cassette (see here: http://tilmun.de/rbw/images/3058980.jpg ) with "hyperglide" gears. I'm amazed something is going in my favor on this bike (amazing how a "free" bike winds up costing a decent amount to bring back to life).

I think I'm going to go with a 12T per your suggestion.

Thanks for all your help! Now I'm off to go buy a chain tool and a whip.

It is indeed a freehub/cassette (see here: [pic above])

I think I'm going to go with a 12T per your suggestion.



That freehub is hyperglide and uniglide compatible, but is not compact/11T compatible, so you're on the right track. Let us know what cassette you get.

Go Bulldogs:)

Did you go to West Albany High School?

Just ordered a Shimano HG70 12-28 cassette from Universal Cycles for $25.00. Old cassette was the HG50 so I slightly upgraded.

I am fine with the combo, just sick of the skipping. Thanks for the advice on gears, confirmed my thoughts.

Did you go to West Albany High School?

My friends son plays on the football & basketball teams and also participates in track, so I've "adopted" them.
I'm too old to have gone to West:) Plus I grew up in ID.

My friends son plays on the football & basketball teams and also participates in track, so I've "adopted" them.
I'm too old to have gone to West:) Plus I grew up in ID.

I went to South Albany. But don't worry, I didn't have enough school spirit to buy into the rivalry.