Shimano Cassette Upgrade

I currently have an old (late 80s) frame with Shimano 105 groupset from the same era. I need to upgrade the close range 7-speed cassette I have (13-21) with something in the 13 - 28 range. The cassette is an old Regina Synchro (hub being a 105) and I know I will need a Park Tool FR4 to remove the cassette. I am not sure, however, whether I can just go straight to a Shimano Hyperglide cassette or not? I have a reliability trial coming up soon and could do with the 28 for the hills I am likely to face. Any advice?

 

I don't know the hub, but, if it is 7 speed spin on, Shimano now have 11-28 and 14-28 7 speed spin-ons available. Part numbers, MF-HG50 11-13-15-18-21-24-28 and MF-TZ07 14-16-18-20-22-24-18, page 113 of the 2006 Shimano Book.

 

Thanks. I will take a look at these.

If I do manage to get a Shimano cassette to work, which chain should I use as I have been advised that if you change the cassette you need to change the chain as well. The drive crankset is 105 with SG 53 and 39 chainsets.

 

Any 7 or 8-speed chain from Shimano, SRAM or Wippermann/Connex will do. Even a 9- or 10-speed chain would work too, actually.. but they're more expensive and less durable, so why bother.

If you are changing your cassette, make sure you double check the chain length, and that it'll be long enough to handle the big ring/big cog combination without overstretching the derailleur (while not being so long for the chain to be slack in the small ring/small cog combination)

The general rule about changing the cassette with the chain is to do with wear: the chain and cassette wear together, if they're both worn over the threshold and only replace one half of it, you'll get terrible shifting and/or a really low lifespan out of whatever it was you just replaced.

If you pay attention to chain wear, you can get a cassette to last a few chain-replacement intervals. A rule of thumb is to measure 12 inches worth of chain from one of the rivets; on a new chain the rivet at the 12" point should be bang on 12 inches. If the 12-inch rivet on the chain is:

* under 1/16" past the 12" mark: the chain isn't considered worn out yet.
* 1/16" past: you should replace the chain, but you can still keep your cassette.
* between 1/16" and 1/8" past: it's pot luck if you need to change both or not.
* over 1/8": you really need to replace both.

You can also get chain-wear measurement tools to make the job a little easier.

 

Thanks for the advice.

I have now sorted out the dilemna of the Shimano 105 hub. Turns out to be a Freewheel hub and not a 'Freehub' (Sheldon Brown website solved the issue here). Luckily there are still places that sell these so I am looking at a Shimano HG37 with a 14 - 28 ratio. Also looking at a Sedis PC48 or a Shimano HG50 chain. Will be having a go at changing these over at the weekend so will let you know how I get on.

 

The nice people in Evans cycles changed my Regina freewheel for an HG37 7 speed freewheel free of charge (the freewheel was £15.99 - and they were going to charge £12.50 to swap the freewheels over until I asked them to give me the tools and I would do it myself in the shop ).

Tracking down the tool to undo the Regina freewheel (Park Tool FR4) was more of a challenge.

So I now have a 14 - 28 range freewheel for the North Downs in Southern England as well as an almost 'corn-cob' freewheel if I choose to go into a time trial again.

The only issue I can see is that the spacing of the cogs is slightly different on the shimano freewheel to those on the regina. I guess I have to re-index the gears to ensure that the cable tension is set up right for the top gear and that the STIs (Sora's) work on this freewheel. Given that they are both Shimano I would hope that they do.

Also got a new Sachs chain which I will fit on when I get home from work.

Cheers

 

There is also Shimano HG 50, a 7 speed hub ranging from 11 to 24 throughout 6 gears, plus a "bailout" of 34 teeth for the hills. That's 11-34.