chainset ?

Nick@D

Hi All,

i have a "FSA Omega Compact Chainset MegaExo" on my bike & what i would like to know is?
1: what does compact mean, 2: can i change it into a triple by adding a smaller chain ring or will i have purchase a complete new triple chainset? 3: the current set up is for a 9 speed, how will i be affected if i purchase a new 10speed chainset?

I know i ask lots of questions but you guys are the oracle! & i dont know how else i would find out.

thanks

Diogenes

1. Compact essentially means that the rings will be 50 and 34 (ish) which gives a broader gear range and lower gear than the standard 52/39.

2. Unfortunately you cannot simply add another ring , the current small ring will have no means to accept the bolts for a 3rd ring and the bottom bracket spindle probably won't be long enough. You would also near a new front mech and if indexed a new front shifter.

3. 9 speed and 10 speed are not compatible, the chain and consequently the rings for a 10 speed are narrower than the 9 speed.

Why do you want to change, the current gear range you have should be okay unless you are touring or climbing big hills.

D

Nick@D

Hi Diogenes,

thank you for your detailed answers, you hit the nail on the head with the last comment, i plan on completing the jogle & i am not sure my legs can push some of the hills. however, with the info you have helped me with at least i can make an informed decision.

many thanks Nick

Yossie

9 to 10 speed on the front will be fine: I've done this loads of times. Its the back where its completely different.

HTH

Y

tonye_n

I currently use a 10 speed Shimano 5750 compact chainset on my otherwise 9 speed setup.
Works absolutlely fine with no drive-train shifting or noise issues.
On this bike I am also using a 9spd double front mech. With HG-73 9spd chain.
There is no difference in the width of the current 9spd and 10spd chainrings.

The difference is that the 9spd chainset had the chain rings spaced slightly further apart to allow for the slightly wider 9spd chain and avoid excessive chainrub when cross-chaining.
If you do not use the extreme big-front/big-rear and small-front/small-rear chainring/cassette cog combinations this will not be an issue.

I did this because I require 172.5mm crank arms and the Tiagra 9spd chainset comes in 170 and 175mm.
I also did this with my formerly owned 9spd triple setup which I have now sold on. Used 5603 crankset with otherwise 9spd setup.

ugo.santalucia

Someone should really put a big sign on the front page of the Forum, saying 9-10 speed chainsets are interchangeable...

Manufacturers want you to buy the latest development, but really, there is no need... cassettes and chains need to be correct for the number of speed for indexed systems, chainset fine...

Nick@D

It looks like 9 & 10 speeds components are interchangerable, just don't tell anyone ssssssshhhhhhhhhhhh

keef66

Oh no they aren't! (Panto season is still on)

Chainsets yes; shifters, cassettes and chains really need to be the same speed

tonye_n

keef66 wrote:

Oh no they aren't! (Panto season is still on)

Chainsets yes; shifters, cassettes and chains really need to be the same speed

Exactly right... IME
You can actually get 10 SPF shifter to work with 9spd rear cogs and vice-versa. But it involves far too much fettling and the results are often very far from ideal.

Diogenes

ugo.santalucia wrote:

Someone should really put a big sign on the front page of the Forum, saying 9-10 speed chainsets are interchangeable...

Manufacturers want you to buy the latest development, but really, there is no need... cassettes and chains need to be correct for the number of speed for indexed systems, chainset fine...

I assumed that Nick wants to run a 10 speed cassette with his current 9 speed set-up, after all what is the point of changing the chainset for one badged as 10 speed if the rings are the same size. Some 10 speed cassettes cannot be fitted to 9 speed free hubs and even if they fit you cannot get the 9 speed index to cover all the cogs.

If he is thinking of buying a triple chainset badged as 10 speed then it is possible if you have a friction shifter to get the front mech to reach each ring. I took this approach on my road bike and changed a 52/39 for a 52/39/30. The front mech just reaches and being a friction shifter I can get across the rings without worrying about indexing.

Running a 9 speed chain on the "10" speed chainset will be fine, but running a 9 speed chain on a 10 speed cassette will not always work.

I accept that if you know what you are doing you can get some combinations to work (especially just changing the chainset) but for "novice" mechanics I would not recommend it, you can make costly mistakes trying to get it right.

To solve Nicks problem of getting up big hills on lejog then look for a 9 speed cassette with a wide range, this will get close to triple ratios anyway, albeit with bigger jumps between ratios which normally doesn't matter unless you are racing.

D

tonye_n

Diogenes wrote:

ugo.santalucia wrote:

.......................
I assumed that Nick wants to run a 10 speed cassette with his current 9 speed set-up.............
D

No he is wanting to use a 10spd chai set with otherwise 9spd setup.
One must be carefull not to over analyse this one.

veryslowtwitch

Nick, do you know what size cassette you have? You might be able to get much lower gearing with a new cassette for twenty or thirty quid. How many teeth are on the biggest cog on the back?

Alan

caad-expert

Hi, first post here, but long time reader. i have Truvativ Elita triple 10-speed chainset (50/39/30 from 2008, gxp, 130 BDC).
My question is: Is it possible to switch big ring from50 to 52 or 53, and ,if yes, from wich manufacturer, because i don't see many Truvativ rings on the market, thank you!

tonye_n

caad-expert wrote:

Hi, first post here, but long time reader. i have Truvativ Elita triple 10-speed chainset (50/39/30 from 2008, gxp, 130 BDC).
My question is: Is it possible to switch big ring from50 to 52 or 53, and ,if yes, from wich manufacturer, because i don't see many Truvativ rings on the market, thank you!

It certainly is. Just make sure that the selected chainring is for 130BCD, and that you front mech will cope with a max 52t or 53t.
Stronglight make very good after market chainrings.
E.g. http://www.bikester.co.uk/15823.html?_c ... -road-5130

caad-expert

tonye_n wrote:

caad-expert wrote:

Hi, first post here, but long time reader. i have Truvativ Elita triple 10-speed chainset (50/39/30 from 2008, gxp, 130 BDC).
My question is: Is it possible to switch big ring from50 to 52 or 53, and ,if yes, from wich manufacturer, because i don't see many Truvativ rings on the market, thank you!

It certainly is. Just make sure that the selected chainring is for 130BCD, and that you front mech will cope with a max 52t or 53t.
Stronglight make very good after market chainrings.
E.g. http://www.bikester.co.uk/15823.html?_c ... -road-5130

Thanks !

Nick@D

hi,

thanks to all you advise! (worm & can spring to mind ) in answer to veryslowtwitch question,

the cassette is a 12-26, i am not sure how large i can go without changing the rear mech.

Thanks

Nick@D

hi,

think i may have found the solution, SRAM PG 950 PowerGlide Road Bike Cassette 9 Speed 11-34; if i fitted this would i need a longer rear mech??

Nick

Nick@D

TTT, to the top!!

hi all, any thoughts on swopping my current 12-26 cassette & if i would require a longer rear mech to accommodate the 11 -34 cassette??

cheers

Diogenes

What cassette do you currently have? Assuming your new one is the same make or compatible then the change should be straightforward, capacity may be issue for the mech.

The capacity of the rear mech is a simple calc, (teeth on largest front - teeth on smallest front) + (teeth on largest rear - teeth on smallest rear).

So the capacity of your current mech is likely to be 50-34+26-12=30.

Your suggested set up will require 50-34+34-11=39

Both of the above assume your compact is a 50/34, if its not just put the right numbers in an recalc.

Typical capacities are
Shimano long = 45T; medium = 33T
SRAM long = 43T; medium = 37T; short = 30T

Looking at the capacity you need for your suggested setup then you will need a long cage rear mech, not sure what you have but my guess (don't shoot me down for wrong guessing) is that you will have a medium.

D

Nick@D

That is Fantastic Diogenes,

it is not that i am easily pleased but i do like solutions & learning, i best go & get my abacus

all the best

Nick D'

John.T

Nick@D wrote:

TTT, to the top!!
hi all, any thoughts on swopping my current 12-26 cassette & if i would require a longer rear mech to accommodate the 11 -34 cassette??cheers

Assuming you have a Shimano road mech now the largest sprocket you can safely fit (in spec) is a 27 or a 28 with the latest ones. I think Sora now go to 30. Using a long or short cage mech makes no difference to this. It only affects total capacity for use with a triple. The answer is to use a 9sp MTB mech.

tonye_n

John.T wrote:

Nick@D wrote:

TTT, to the top!!
hi all, any thoughts on swopping my current 12-26 cassette & if i would require a longer rear mech to accommodate the 11 -34 cassette??cheers

Assuming you have a Shimano road mech now the largest sprocket you can safely fit (in spec) is a 27 or a 28 with the latest ones. I think Sora now go to 30. Using a long or short cage mech makes no difference to this. It only affects total capacity for use with a triple. The answer is to use a 9sp MTB mech.

+1 What he said.

Diogenes

John.T wrote:

Nick@D wrote:

TTT, to the top!!
hi all, any thoughts on swopping my current 12-26 cassette & if i would require a longer rear mech to accommodate the 11 -34 cassette??cheers

Assuming you have a Shimano road mech now the largest sprocket you can safely fit (in spec) is a 27 or a 28 with the latest ones. I think Sora now go to 30. Using a long or short cage mech makes no difference to this. It only affects total capacity for use with a triple. The answer is to use a 9sp MTB mech.

Thanks John, you are of course right, need to consider max number of teeth as well as range of teeth.

If Nick is using Shimano then I know that Sora and Deore are compatible.

D

Nick@D

Hi all,
i went with the SRAM & then found out it didn't go with shimano brought a new shimano 105 "long" (as advertised) & the code on the side says "GS" is this the longest they make? :?: on the box it says "wide gear ratio 11 to 28"

my current set up is 50-34+32-11 = 37

will have to try again? does shimano make a rear mech to suit my set up?

thanks

Nick

John.T

As I said earlier the answer is a 9sp MTB mech. The GS mech is for road triple. SS for double.
I can't remember the models but you can get medium cage MTB mechs which will do you fine.

Nick@D

thank you very much Mr John T, i will have to learn to "remember" good advise when it is offered!

Cheers Nick