i dont know what cassete to fit ,,any idea

[jim55]

hiya iv got a good road bike and i cant climb worth a monkeys ,,its 12-20 !!and the front is 30-53 ,the guy i got it from was obv a beast and a serious roadie ,but its wasted on me .
it has shimano 105 hubs and obv i want to just change the cassette for something with easier gears to spin as if its a half decent hill i just cant spin ,,even in the lowest gear available its too big for me ,,when i got the bike i noticed it straight away and wanted to change it but a lot of people said just keep it on and soon ul b powering up climbs ,,er ,,,no ,,thats not happened ,so im gona change it
its as said 105 hub ,dura ace derauiler and id imagine a pretty standard fit ,,its approx 37 mm wide and runs /changes really well ,,can i just buy a reg shimano cassette of ebay ?any thing i need to b aware of ,,is the dura ace changer an issue ,,i think il need a longer new chain as well ,,,its a 105 crankset as well with a campag!!!front mech ,so its all pretty standard ,,as far as im aware its just a cassette and a chain im looking for ,,any links or pointers

 

[jim55]

just took these

 

[Tomba]

Jim, i'm in the process of swapping cassettes.

One thing I was told to watch out for was the sizing of the sprockets. Some rear mechs wont handle over a certain size. From limited time reading I think Shimano is limited to 27 per their own instructions but people have put larger. In fact I saw a bike advertised as having 12-30 with a 105 rear mech.

If you knew exactly which model Dura Ace rear mech is on it you could check on Shimanos site. The latest 7900 model suggest 28 teeth max.

Sorry I couldn't be more help as I'm fairly new to all this

 

[ColinJ]

I'd be surprised if the front isn't really a 39 and a 53! It would be a huge jump from 53 down to 30, or do you have a triple at the front?

Yes - a 20 is pretty tiny 'big sprocket'. You could definitely get a better cassette for yourself. The picture is a bit dark, but it looks like 8-speed. Why not get something like a 13-26? You would need a longer chain. It's possible that the rear derailleur might struggle to take up all the extra slack in the chain if you shifted to the smallest chainring and sprocket at the same time but I'd be tempted to try it and see.

A 26 instead of a 20 would give a 23% easier bottom gear.

 

[jim55]

well iv had a good look at the cassette thats on it and theres no marks other than dura ace ,,any idea what model this is

 

[Fab Foodie]

Looks 8 speed.
Is it a Freehub/cassette or a screw-on freewheel?
A cassette is a set of sprockets, some individual, that slide onto the integrated 'hub' body of the wheel containing the bearings for the sprockets. Whereas a freewheel is a complete set of sprockets joined together complete with their own bearings that screw onto the wheel hub.
Sheldon is your guide:
http://www.sheldonbrown.com/free-k7.html

 

[ColinJ]

If you knew exactly which model Dura Ace rear mech is on it you could check on Shimanos site. The latest 7900 model suggest 28 teeth max.

If it is 8-speed, then it is pretty old - Shimano went to 9-speed Dura Ace in 1997!

 

[jim55]

oops ,,typo ,,its defo (as u pointed out )39-53 up front and 12-20 at the rear ,theres ladsa cassettes on the bay but i really dont know which one to get

 

[jim55]

Looks 8 speed.
Is it a Freehub/cassette or a screw-on freewheel?
A cassette is a set of sprockets, some individual, that slide onto the integrated 'hub' body of the wheel containing the bearings for the sprockets. Whereas a freewheel is a complete set of sprockets joined together complete with their own bearings that screw onto the wheel hub.
Sheldon is your guide:
http://www.sheldonbrown.com/free-k7.html[/quote]
im not really sure ,,i was hoping somebody with better knowledge than me would just say ,,ah yes ,105 hubs ,,,and tell me exactly what i need to get all i know is its bloody hard to climb lol

 

[HLaB]

The main things I've found with cassettes:

• are they Campy or Shimano compatible; You'll want the latter my recommendation would be SRAM its Shimano compatible and I find they do a good gear range and their stuff is light and robust :-)
• The Speed of your existing cassette/shifter, you need to get the same, I think that looks like an 8spd you've got (the last SRAM 8spd cassette I got was an 11-26 (good for downhill speed and good for climbing).
• If its larger than a 27t you may need a new long mech (although I believe the latest short cage shimano's can handle a 28t)
• and you will need a new chain (I use the wrap round big cassette and big ring allowing a link overlap, inner and outer and that seems to be fine)

I'm currently running a 12-25 campy cassette on my 39/53 Bianchi and a 11-26 SRAM cassette on my 38/52 Kinesis and they make climbing a lot easier; the Bianchi still has the original cassette but the Kinesis cassette has been changed about 4 times and there's not much to it, all you need is a lockring tool, spanner and chain whip and a chain tool. If the chain is a SRAM/KMC/Wipperman with a quicklink its a lot easier all you need to do is remove the extra links with the chain tool and close without a tool.

IHTH

 

[TheDoctor]

I'd go for one with a 27 or 28T as the largest sprocket. You can't be sure that anything bigger will work.
Obviously it needs to be the same speed (ie number of sprockets) as you already have.
If it is 8 speed then something like this will fit nicely. The 13-26 will give you a few gears lower than what you have now.

 

[RecordAceFromNew]

Since 8 speed freewheel is rare as hens teeth, and given the age of your other components I am 99.99% certain you have a cassette freehub (which makes it easy to pick new rear sprockets). I also believe you have a Dura Ace RD7700 short cage rear mech, which is able to handle 11-26 at the back and a 14 tooth difference at the chainset.

What that means, is you could get a cassette that has a 26T largest sprocket, and a smallest sprocket that is either 11, 12 or 13T depending on whether you would like a higher or lower high gear (i.e. be able to go faster downhill or have closer ratios between gears), and a new, longer chain (preferably not Shimano, kmc or sram are good).

If you have any other question just ask.

 

[jim55]

so sram would do as well a ?i think 26 or so is enough for now id fit a new chain for the bling factor cos some of those sram cassettes are really clean looking ,,it doesnt seem hard to do ,,i could fit it myself its just buying the bits im not sure of ,,

 

[jim55]

well tbh id like to keep a fairlh high gear (53*11 or something )i just need to make it easier at the other end ,,that link for the tiagra cassette ,,would that work with the present set up

 

[mcshroom]

I'd be tempted to try one of these - http://www.chainreactioncycles.com/Models.aspx?ModelID=6388
I've used 11-32 and 11-28 versions of this cassette and they are very nice - and only £15