hollowman

I have a 1993 Gary Fisher Advance Mountain Bike. It came with a Shimano Hyperdrive-C crankset (Shimano Altus C10, 28/38/48 teeth). I need to replace the middle chain-ring (38T). It is mounted with 5 bolts. Can someone please point me to a source (pref. product/part page link) where I can order this chain-ring?
Thx!
BTW: Is there a heavier-duty version of this chain-ring avail.?
Here's a pic of the crankset on my GF:

Bezalel

Those chainrings look like they are not replacable. (The current Altus cranks no not have replacable chainrings.) To get replacable chainrings you will need to uprgade to at least Acera.

hollowman

Thx for your reply.
Can you/anyone suggest a crankset for this bike+BB combo (dunno BB specifics). I don't necess. need a compact crankset (i.e. Hyperdrive C), as on the stock GF bike (shown above). I would like one with a heavier-duty chain-ring set, if possible.
BTW: Why not Alivio crankset? The other stock components on the 1993 GF bike are Aliv
BTW2: Can anyone clue me in on this bike's BB size, and modern (suggested) replacement?
BIG THX!

HillRider

I believe Bazelal is correct that these chainrings are riveted (not bolted) to the crank arm and are not replacable so you will need a complete new crank. Also, IIRC, these chainrings are steel, not aluminum, and therefore are the most "heavy duty" you can get.

hollowman

So a whole crankset it is ... (I really have no choice: the middle CR is missing several teeth, and inner and outer have a few missing as well). Okay, so say I can't find a used OEM off eBay ... and since I'm no loger using the GF as a Mntn Bike (but as a Utility or Hybrid bicycle instead) ... what are the best NEW options? How about these:

Sugino Impel Triple Crankset
$41.25
or how about...

FSA Dynadrive SQ Taper C-Set Crankset
$50.00

Hint: I want to remain a cheapskate with the replacement crankset

mikeybikes

If you get a new crankset, make sure that the existing BB spindle is the correct length, or get a new bottom bracket.

HillRider

Well, before you go any further, is the current crank giving you shifting or skipping problems? I ask because most newer cranks (post about 1990 or so) have "shaped" teeth to assist shifting and, if you don't know what you are looking for, they can seem broken or badly worn.

So, unless the old crank is causing noticable problems, it may be perfectly fine. I.e. If it ain't broke, don't replace it.

hollowman

Yeah, I'm beginning to see that (via user/customer comments on the product pages). I wish every crankset manuf. stated this in their specs/product description. FSA and Sugino don't seem to offer complete data.

hollowman

Hey, folks, what do you think of this crankset for replacement:



FSA DynaDrive Crankset: Sqaure Taper, 175mm, 22-32-44, Black.
Size: 175mm
Style: Mountain
Color: Black
Weight: 945g
BB Thread Type: English
Spindle Interface Type: Square Taper JIS
Spindle Length: 113,110.5mm
Pedal Spindle: 9/16
Bolt Pattern: 4-Bolt
Chainring BCD: 104mm
Arm Length: 175mm
Rings: 22-32-44
Crank-FD Type: Mountain Triple
Crank Intended Use: Mountain
Chain Compatibility: 9-Speed

Can anyone with experience with this model and/or brand of crankset (FSA) comment on its quality, durability and/or reliability?
Thx!

Steev

What are you using the bike for?
That crankset has smaller rings than your current cranks, using that will effectively lower your entire gearing range.
If your chainrings are worn, in what condition are you chain and cassette? They will wear past usability much faster than chainrings.
But, before you go dropping cash, you should read Hillrider's post above. I thought the exact same thing when reading your description of the state of your current rings.

fietsbob

OLD chain has to go, step 1.
you may need a new cassette and perhaps, chainrings, if you let it go way too long.
replace all 3 and you can start afresh.

I get long wear out of steel chainrings, myself. with regular replacement of the chain.
given the wheel rotates multiple times, for every one of the pedals ,
cogs on back wear faster than those on the front.

hollowman

Bike used as util..(see image below) I ride very gently, and all on-road. I don't need bike to go fast.
Cassette is Shimano HG70 7-spd. Current chain, which I replace every 6mos, is Shimano HG91. FYI: Use Conti Top Touring tires and Sun Rhyno Lite rims. Deore hubs. Deore XT rear derail.
As I stated above, the middle CR is missing teeth (at least 6 as of last count). Yes, I have shifting (and skipping / jumping) problems, despite critically aligning gears when chain is new. And, of course (given age and use), all CRs are worn.

hollowman

fietsbob: Cassette is Shimano HG70 7-spd. (in good cond and not very old). Current chain, which I replace every 6mos, is Shimano HG91.

Stokestack

I'm in a similar situation. I have a Trek 920 with the Hyperdrive C chainring set and all other Shimano STX components stock as of 1994. The chain jammed on me yesterday, and now that I look at it, the chainring set is in poor shape. The cassette looks OK, although with some visible wear.

This thread just kind of died without any recommendation. I guess I will replace the crank & chainring set. Is there some advantage to doing the cassette at the same time? Are there entire sets sold at a discount? Any recommendations on what to get?

Also: This bike is a 21-speed, but cranksets often refer to nine- or 10-speed. Does this refer to the number of gears in the cassette, or something else?

I mainly ride the bike around town. I have road tires on it. I might go on trails someday, but it doesn't seem imminent.

Thanks!

Gavin