Replacement 10 speed cassette options?

tonysj

Hi All.
I'm in the process of swapping my worn cassette on my Boardman team carbon road bike and the original fitted cassette states it's a
Shimano Tiagra HG500 10speed.12t 28t.
Now I've checked online and found that I can choose between 4 slightly different cassette toothed! options all the same price..
They are
11t 25t.
11t 32t.
11t 35t .
12t 28t
I'm relatively new to all this and want to know..
What will each cassette give me over my fitted one?.
How much difference and typically where I will notice this?
Having progressed over the last year in all aspects , as I ONLY started to take notes of times for this bike, what would be my best "upgrade to performance" so to speak?
I live in Derbyshire so plenty of hills around and a typical 20 miler round trip will generally cover
1500feet of elevation.
Any help appreciated as I really dont know we're to go with this one....
Tony
.

N0bodyOfTheGoat

You could do with finding out which rear derailleur model you have, smaller ones will reduce the maximum recommended sprocket that can be used with them.

A smaller tooth range on the cassette will mean smaller jumps between gears, meaning it will be easier to find a gear that suits your cadence.

A larger maximum tooth cassette means the odds of you having to grind at a slow cadence, or even get off the bike while climbing a hill are reduced, often at the cost of bigger jumps between gears (because they still often have a smallest sprocket of 11T or 12T).

dj58

If your bike originally came with a 12-28T cassette it will more than likely have a sort cage SS rear derailleur, in which case I would recommend you fit a Ultegra CS-6700 12-30T cassette which will give you a lower bottom gear 34-30T, while still having a good spread of ratios.

Do forget to screw the B-tension screw in to obtain the required clearance between the top RD guide pulley and the 30T cog. You will need to add 2 links to your chain length, better still fit a new chain and size it accordingly.

https://www.jejamescycles.com/shimano-6 ... gJ_Z_D_BwE

Shop around you may find it cheaper.

OnTheRopes

A lot depends on your style of riding and how strong you are.
Seeing as you already have a 12-28 then you know if you have been struggling or not with it, do you feel you need a bigger sprocket than 28? What size chainrings do you have?
If 12-28 has not found you lacking then I would stick with that, you probably don't need an 11 unless you are sprinting or want/need to put the power on downhill.

tonysj

This is the actual bike I have last year's black with yellow and NOT the white model.
Link below that has road . Hopefully! !

https://www.boardmanbikes.com/gb_en/pro ... arbon.html

Will get more info if need tomorrow guys.
Thanks for the replies so far.

Tony.

jameses

If you've only had the bike for a year, I doubt the cassette needs changing yet. I would normally expect to get through 3-4 chains (8,000-10,000 miles) before the cassette needs replacing.

With regards to your original question - an 11t smaller sprocket will give you an extra gear when pushing downhill, at the expense of a much more useful gear in the middle of the range (normally the 15t or 16t) that you would use on the flats.
The larger sprockets at the other end will make it easier (but slower) to get up hills. Worthwhile only if you are struggling with your current lowest gear. 35t seems like overkill, and even 32t will (probably) not work with a short cage (SS) derailleur.

dj58

Well that link to the Boardom site does not actually state which Tiagra group it is, but lets assume it is the latest 4700 10sp. Your rear derailleur could be an RD-4700 SS or GS, Shimano specs state a max low sprocket of 28T for the SS, though will most likely take a 30T with the B-tension screw wound in. A max low sprocket of 34T for the GS if using a double crankset.

Your cassette options (CS-HG500-10) are for SS 11-25T and 12-28T, for GS 12-28T, 11-32T and 11-34T, plus the CS-6700 12-30T I mentioned in my previous post.
Specs. here http://productinfo.shimano.com/#/lc/2.2/tiagra/2x10

The RD of the link to the Boardman site looks like a GS model to me, I could be wrong though but.

birdie23

As has been said, you probably don't need a new cassette yet. If you are buying though, stick with 12-28 unless you have been struggling to get up hills in which case find out which RD you have and maybe get the 11-32t if it will work.

tonysj

OnTheRopes wrote:

A lot depends on your style of riding and how strong you are.
Seeing as you already have a 12-28 then you know if you have been struggling or not with it, do you feel you need a bigger sprocket than 28? What size chainrings do you have?
If 12-28 has not found you lacking then I would stick with that, you probably don't need an 11 unless you are sprinting or want/need to put the power on downhill.

I have taken a couple of pictures and Im fairly certain the derailleur is a SS short model, please correct me if Im wrong.
I have measured the distance between the 2 cage centres on the derailleur and they measure around 6cm ( just under 2 1/2" ) Does this sound right for a SS?
The chainrings are 50t -34t and the info I have found regarding numbers
largest casstte minus smallest + largest chainring minus smallest is this
28-12 ( 16 ) + 50 - 34 ( 16 ) = 32t.
I cant attach the pictures at the mo!!!.
Im at the point of replacing my chain with a new one as its worn and accept that the cassette probably doesnt need replacing just yet.
With all the updated groups sets coming out is it likely that the Tiagra 10speed which I have is likley to become difficult to find?
Or am I safe in thinking I will have no trouble getting hold of a replacement when my cassette eventually needs to be replaced?

Sorry for the idiot questions but Im not that knowledgeable on bikes but trying to find out more.

Thanks.

Tony.

tonysj

birdie23 wrote:

As has been said, you probably don't need a new cassette yet. If you are buying though, stick with 12-28 unless you have been struggling to get up hills in which case find out which RD you have and maybe get the 11-32t if it will work.

I think if I do replace I will stick with the 12t - 28t as Im OK with hills as they say it doesnt get any easier you just get fitter..

Thanks Tony.