A couple more 105 "cassette swap" questions (10 speed)


Legendary Member
Thanks again for the advice already given.
Just a "heads up" & a couple more questions.

My LBS will fit
a new Tiagra 32 (or the new 34 which is out in August)
New KMC chain
New Mech
£100.00 all in.

I called in at Decathlon who tell me......................
a) It wont need a new mech if I am sticking to a 10 speed cassette...... (many on CC plus LBS tel me I definitely will)
b) they offer Sun-Race cassettes but are happy to fit Shimano if I buy from Wiggle/Chain Reaction.

Decathlon prices are.................
KMC chain...........£8.99
Sun-Race Cassette £17.99 (or my own from Wiggle)

I'm interested to know your thoughts on these points.


Man or Moose!
I have never heard of Sun-Race. As such, I'd personally avoid unless I could be arsed to look it up, which I can't.

KMC is a brand, they makes chains of various qualities, the one the LBS quote included might not necessarily be the same as the one Decathlon did (you provide no specifics as to the model).

The number of sprockets will not influence the need for a new mech. The range of gears is has to accommodate will. As such, it is likely you will need a new rear mech if you fit some sort of a weird massive cassette.
Loch side.
What is the model number of the derailer you want to fit i.e. the Shiman RD-XXX number.
Further, what chainring combinations do you have on the crank?

When we have this info, we can look up the maximum capacities for that derailer.
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