xwright

I recently got a 1991 Trek 2300 which needs a new cassette. It currently has a 13-21 7-speed cassette and I'm looking for something to replace it with. The guy at the LBS made it seem very difficult (expensive), is that the case? It has a 53/39 up front and the original Shimano 600 all around.

I'm wondering what my options are here.

Thank you!

RoadGuy

Expensive is a relative term.

You can take your choice of tons of new and used 7-speed cassettes from Shimano or Sunrace or SRAM off eBay with auctions starting at $1. Or, if you don't want to wait for an auction to end, there are tons of "Buy It Now" cassettes going for $15, including shipping.

You will need a tool to remove the old cassette, and it will cost less than $10. Changing the cassette will take you less than five minutes. Remove the rear wheel from the bike, use the tool to loosen the lock ring on the cassette, remove the old cassette, attach the new cassette, tighten the lock ring using the tool, and reinstall the rear wheel. That's all there is to it.

If you decide to change the cassette gear ratios, you need to check the rear derailleur adjustments.

Does that sound expensive or difficult? Sounds like the bike shop just wants to sell you a new bike.

Homebrew01

Are you sure it's a cassette and not a freewheel ? Verify before ordering a replacement.

canam73

I am going to guess that his bike takes the older Uniglide cassette which is no longer made. While they do come up on ebay, they tend to go for much more than the equivalent Hyperglide and certain sizes and models do go for really high prices. It may be that they are unavailable through normal lbs supply chains.

If it is a Uniglide, it doesn't come off in the manner you described, either. The last cog functions as the lock ring and it requires 2 chain whips to remove.

BoSoxYacht

It's nice to see that some people actually know WTH they are talking about.

xwright

I thought it was a freewheel because the 1991 catalogue says "(fw) shimano hyperglide 13-21", but the mechanic at the LBS said it was a cassette.

I believe it is not a uniglide system, because it looks like it'll accept one of those tools to twist and unlock the cassette.

If that is the case, I'm wondering which cassette would work best with the current crankset on there in terms of gearing, since I can't seems to find many 13-21.

Thanks for all the help!

RoadGuy

If the OP's Trek 2300 has the original wheels that it came from the Factory with, it will have an Shimano Ultegra 600 Tricolor 7-speed HyperGlide rear wheelhub. I have a 94 Trek 2300, and I have recently seen others. Mine and every other one I've looked at (91 or newer with the original wheels) has a 7 or 8-speed HyperGlide cassette.

Even if somebody changed the rear wheel, and it has an older Shimano UniGlide wheelhub of some sort, right now there's a used Shimano 7-speed UniGlide 13-23 cassette going for $14.50 on eBay. Two change whips would cost $20-$30, which isn't that much, if he wanted to try changing the cassette himself. He might already even have the chain whips. I've never changed a UniGlide cassette, and I have one chain whip, getting one more is no big deal.

The OP could also choose to replace the rear wheel if it was changed to something that uses a replacement freewheel or cassette is relatively expensive or unavailable. No need to panic.

datlas 

OP, look at Sheldon Brown's page to help you figure out if you need a cassette or freewheel. From that time period, it could easily be either one but the two should NOT be confused.

Once you know what you need, you should be able to find a replacement easily.

xwright

Thanks all, I'm mostly just confused on the gear of situation. Will I have any problems using a 12-28 with my current setup?

RoadGuy

You have your choice of gear ratios. You can get an identical replacement if you are satisfied with what you have. What is best for the rider is an individual choice. 11T is generally the largest small cog you'll see on a 7-speed cassette. Do you spin out the 13T? Would you like a smaller small cog? There are 11T and 12T small cogs available. Do you live/ride where there are hills and do you want/need a larger "granny" gear? There are cassettes with 23T, 25T, 26T, and 28T, large cogs (and I have read that a 30T cog will work with the Ultegra 600 rear derailleur, but have not tried it). You can even mix and match cogs (within brands of cassettes) to assemble a custom cassette with your choice of gear ratios. There are hills where I ride and a 21T low gear is not near low enough for me, I prefer a 26T or a 28T. I'm working on gathering/buying a 8-speed cassette with 13T and 14T cogs so I can assemble a 8-speed 13-28 cassette for my Trek 2300.

I took a quick look and you can get 13-23 and 13-26 Shimano 7-speed cassettes for less than $30, Shimano 13-28 for just over $30, or Shimano 11-28 for less than $15, brand new, "Buy It Now" on eBay.

canam73

Hyperglide is definitely a cassette. Going to a 28 would most likely require a longer chain, which is a good idea when changing the cassette anyway. I don't think the older shimano short cage rear derailleurs were rated for 28, but from what I have heard you can usually make it work. But I have never tried it.

RoadGuy

While Shimano publishes the spec for the 7-speed rear derailleur (105 and Ultegra) at a difference of 15T, I have or have had 12-28 cassettes on my bikes, and they worked fine.

Is the 13T small cog on your cassette too small, and can you spin and hold your cadence above what is comfortable for you? I'm more of a low rpm grinder, and I don't like spinning at what used to be the recommended 90 rpm (I'm more of a 70-75 rpm guy, and always have been). That would indicate that you can power a smaller small cog than you are presenting running.