Buying crankset advice needed

[kyap]

Hi,

I wish to get a compact crankset for my Cervelo S2 2012 from online.
Currently on Rotor 3D 53/39.

I don't know which compact crankset will be a direct swap.
How do I check the BB compatibility? After search the S2 BB is English but how do I check what BB I have?

I have a budget of $100-150 can be stretched to $200 but hopefully not.
What kind of crankset can I get? I saw those mentioned BB30 which I think not compatible with my bike.
Wish to get a crankset that can be direct swapped instead of changing the BB too.

Any advice will be appreciated.
Thanks

Note: Need the compact for hill climb. Will switch back to Rotor often.

[usernameforme]

you won't get much better than a rotor 3D for $200... unless you go 2nd hand, why not try a bigger cassette on the rear or a 52/36 chainring? If all else fails and you aren't scared of a little weight, the Shimano Tiagra is more than capable. Have you got the rotor 3D or the 3D+ (one is BB30 and the other is a 24mm spindle)? Also, if its a Rotor 3D then you should be able to swap between any shimano crankset without changing the bottom bracket (I think... not sure)

[nickobec]

if your BB has cups (the part of the bottom bracket that attaches to the outside of a frame) then it is 68mm BSA. If it was BB30 it would be press fit. if you have no idea go to wiggle/ribble/c r c etc look at a BSA BB and you will see the cups.

Value for money wise, c r c have been clearing chainsets at good prices for a few weeks now. Generally only non standard crank length left (170, 175 or even 177.5 ). But worth a look if you go down that path. Some of the cheapest are junior chainset with 36/46 chainrings, not the standard 34/50 compact chainrings.

Changing you crank, will probably require FD adjustments. As compact chainrings are smaller than regular chainrings so you may need to move your FD down and then retune it.

I am with usernameforme get a 38t (the smallest 130BCD chainring available, I have one on my "climbing bike") and a larger cassette (I use a 11-26 for climbing, thinking about an 11-28) It saves you stuffing about with the FD, when you change you crank to go climbing, much easier to change the cassette ( or the the wheel)

[kyap]

Usernameforme> Its a Rotor 3D. I know the it will be worst than Rotor 3D. I love the Rotor but Im entering Fitz Epic that is why I needed a compact for the event. I trained with 39/28 (12-28T cassette) now and pushing hard...my knee not coping well. The smallest ring for 130bcd can go to 38t as mentioned by Nickobec.

Nickobec> you are right...i just checked last night and noticed it has this...grey Rotor BSA thingy look exactly like this

Does that mean I can direct swap with any Shimano (Hollowtech or not) or SRAM (GXP or non GXP) compacts?

I had a chat with a mate that if I get a compact, I have more option on the chain rings and I should be able to sell the Rotor 3D at a good price since its fairly new. I had thought about it and I might be going for Sram Rival or Force compact (my S2 grouppo is Sram Rival). I like the Rival OCT compact (budget yet good review).

I've looked at c r c too but Rival OCT compact no stock

Im trying to swap myself if possible to save some cost. Not sure what tools needed but hopefully the Bike Union toolbox have it.
Thanks

[TDC]

I've looked at c r c too but Rival OCT compact no stock

In stock at Ribble. http://www.ribblecycles.co.uk/sp/road-t ... ramchar260

[nickobec]

That BB looks suitable for Shimano Hollowtech, SRAM GXP and FSA MegaEXO cranks, all are 24mm diameter cranks. Even though different manufacturers use different methods to "join" their cranks and they will argue that you should use their BB with their crank because it is designed to work that way.

Though you can pick up a SRAM GXP BB for less than $30 from Ribble when you grab a SRAM Rival crank with 10% off today. (Meaning you sell your Rotor crank with matching BB or seperately)

If I remember rightly 8mm allen key is all you need for a SRAM GXP crank, though they do recommend a torque wrench to get the required torque, which was a decent amount ( 45 ft/lbs if I remember correctly or was that Campagnolo).

[kyap]

Bought the cranks but the BB no more stock. Well, waiting for it to arrive and hope it fits.
Thanks

[thejester]

save money buy a new cassette with a bigger rear cog count.

[kyap]

save money buy a new cassette with a bigger rear cog count.

I am using 12-28 at the moment

[nickobec]

Well, waiting for it to arrive and hope it fits.

It will fit, do not worry

[Releng]

It will fit, do not worry

Ummmm! maybe not. You may find that the non drive end of the SRAM crank is a smaller diameter than the Rotor crank. 22mm instead of 24mm.

[kyap]

Well, waiting for it to arrive and hope it fits.

It will fit, do not worry

Oh no...i just tried fitting it. It has free play on it while the rotor crank fit nicely.
Did I buy the wrong one?

[Releng]

You probably need this as well:
http://www.ebay.com.au/itm/SRAM-GXP-BB- ... 337c9f5d39

[kyap]

Will the Sram Red GXP bottom bracket english fit into Cervelo S2 and the Rival crank?
Thanks

[usernameforme]

It will fit, do not worry

Ummmm! maybe not. You may find that the non drive end of the SRAM crank is a smaller diameter than the Rotor crank. 22mm instead of 24mm.

+1 it won't fit, I hear that you can get an adapter for this though... not sure