Changing the size of my chainrings?

[Joe24]

Yep, 10 speed Shimano 105. I don't fancy spending on a whole new cassette! I will look out for a 2nd hand one ...

Look in the exchange section. There was a sprocket swap thing going o, might be able to swap a sprocket or get one free if your lucky..........

 

[montage]

I have a 12-25 cassette ... the 11-tooth solution makes perfect sense! Thanks Chris and peanut.

I am going at an indicated speed of about 40 mph when I spin out - and trust me, my legs are going like the clappers! Note the use of "indicated" ... I bought the cheapest speedo I could find! Sometimes it doesn't show any speed increase when I know full well that I am accelerating. When I spin out I am keeping up with cars.

you can speed up more by altering your position....if you are feeling daring, hit 40mph, put your hands either side of the stem on the bar, chin touching your knuckles and elbows in.

If you crash...dont blame me

Pro riders wont really have more than a 53 x 11 .... and they can get up to 55+ mph easy on a decent

 

[peanut]

Yep, 10 speed Shimano 105. I don't fancy spending on a whole new cassette! I will look out for a 2nd hand one ...

your better bet is to buy a brand new 9x speed Deore cassette for £13 and just use the 11t and the special locknut from that. It doesn't have to be from a 10 speed cassette.
Don't be put off by the picture the spec says it is a nickle finish
http://www.ribblecycles.co.uk/productdetail.asp?productcatalogue=SHIMCASM300

 

[gbb]

I currently ride with 34/50.

I find that I never use the lowest gear (34 ring with the chain on the biggest sprocket). Conversely, when I'm booting down a hill, I find that I run out of gear!

I would like to go bigger ... what kind of size and ratio would be good?

I notice that you can get 39/53 quite easily ... how much more gear would that actually give me on the top end?

Would it be sensible to go really huge and use a 56? If so, what size of smaller ring should I put with a 56?

Or is 56 too big?

Will I need a longer chain?

For example, I could make up a 39/53 with a couple of these: http://www.chainreactioncycles.com/Models.aspx?ModelID=35784

I dunno, I dunno! Help! Help!

Simple on the bottom end...change the 34 chainring for a 39 or 40. If it's 110bcd, you can fit up to a 40...cost me £15 for a 40T Stronglite from my LBS two years ago. The other advantage is a much much smoother change from the small to large chainrings. No change in chainlength needed when i changed my Campag setup.

On the top end...i dont know what sizes are available above 50t to fit a compact....and whether you'd then need to change the chain length.

 

[Will1985]

With TA chainrings you can get up to 42t inner rings and 53t outer rings.

This is the beauty of compact cranks. I'm not too sure if the larger outer rings might flex more, but 3 teeth can't make too much difference surely?

 

[peanut]

if you are going to change both chainrings you would be probably be better off replacing the chainset completely. it would be cheaper and you'd have a spare compact that way, to sell or keep.

 

[e-rider]

so, can a 10 spd 105 chainring be replaced by any old chainring or does it need to be made specifically for a 10spd chainset. (I know the bcd will need to be the same ie. 110)

 

[peanut]

so, can a 10 spd 105 chainring be replaced by any old chainring or does it need to be made specifically for a 10spd chainset. (I know the bcd will need to be the same ie. 110)

well its not such a good option as adding the 11t sprocket
You'll need to change both chainrings because the drop between 53t and your compact 34t would be ridiculously big .
Basically the 10 speed chainrings are set closer together because the 10 speed chain is narrower . You'll need a matched pair really but I expect 9 speed chainrings will work well enough.