Can I install Standard Crank instead of Compact?

by Muntasir   March 10, 2014  

Currently I own a Cannondale CAAD10 5 105 which is equipped with a Compact (50/34) FSA Gossamer Crank. Where I live, don't have any climbs of sort hence I'm thinking about changing to a 53/39 or 52/36 standard crank. Can I just buy a BB30 Standard crank and replace my current one or it's dependent on other criteria for which I may not able to upgrade? Your input will be really helpful.

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basically yes, and probably a new chain to account for the extra teeth.

It maybe cheaper just to replace the chainrings assuming you can get the right ones to match the BCD of the cranks

posted by jason.timothy.jones [303 posts]
10th March 2014 - 9:40

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105 53/39 chainset can be had for as little as £45. Do some research on ebay and you will come up trumps.

You will need a new chain too, as already noted, due to the extra teeth.

posted by Martyn_K [32 posts]
10th March 2014 - 10:05

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As per my knowledge, Compact cranks are 110 BCD whereas Standard is 130 BCD..So will it hamper my Front Shifting? If there's no issue then I'll look to upgrade my Crank to FSA SLK 53/39

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posted by Muntasir [12 posts]
10th March 2014 - 10:24

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Martyn_K wrote:
105 53/39 chainset can be had ...

105 isn't a BB30 compatible crank so you'll have to factor in adapters too, along with the possibility of creaking issues.

You can probably find 52/36 chainrings to fit the 110bcd cranks you have which is the cheapest option, or a standard BB30 crank if you prefer. Front shifting should be better in theory to a compact as there's a smaller jump in size between the two rings (14 tooth difference between standard rings compared to a compacts 16).

You'll have to raise your front mech also, and possibly fit a new cable if it's been cut too close.

posted by Nick T [781 posts]
10th March 2014 - 12:26

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I updated my FSA Compact to a 50/38, (from 50/34) spot on for me. 38 Stronglight inner ring approx £15 for a 110 BCD. Majority of standard cranks come 53/39 so my 38 is fine. Then at least any hilly events I can switch back to a 34 ring. Didn't need a chain.

posted by Roberj4 [189 posts]
10th March 2014 - 12:27

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The Gossamer crank on my winter bike is 52/36 with a 110mm BCD. You can probably get the chainrings from an FSA dealer. Might be cheaper to buy a new/2nd hand crank though.

Twitter: @velosam

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posted by SamShaw [252 posts]
10th March 2014 - 12:45

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Roberj4 wrote:
I updated my FSA Compact to a 50/38, (from 50/34) spot on for me.

How is that beneficial, may I ask? You have the same top end but a reduced number of low gears, probably a good few duplicates as well. Seems like the worst of both worlds.

posted by Nick T [781 posts]
10th March 2014 - 13:29

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FSA chain rings are available in 52 & 36 (110BCD) that should be compatible with your Gossamer crank and Shimano groupset.

I know that ChainReactionCycles, UKBikeStore & Wiggle all do them (alphabetical order Wink ... as do others I'm sure, but those are the ones I can remember off hand).

Worth an email to your chosen supplier to confirm the compatibility (I recently bought some and emailed ChainReactionCycles - unfortunately the ones they had weren't compatible for me, but they responded very quickly and confirmed that the ones from another retailer were what I needed - was impressed by that).

posted by d_jp [104 posts]
11th March 2014 - 12:34

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Nick T wrote:
Roberj4 wrote:
I updated my FSA Compact to a 50/38, (from 50/34) spot on for me.

How is that beneficial, may I ask? You have the same top end but a reduced number of low gears, probably a good few duplicates as well. Seems like the worst of both worlds.

Someone who doesn't anticipate riding up steep hills or is a strong climber may not feel the need for the low gearing with a 34 front ring.

Also, perhaps you haven't noticed others' issues with a typical compact. Lots of people find the jump from 50 to 34 too wide. For me the triple's 39 middle ring is ideal for rolling terrain or steady riding (where I'd be swapping from 50 to 34 and back), while you still have a larger ring for more favourable conditions.

Fitting a 38t or similar inner ring to the existing crankset would save the OP buying a whole new one (and possibly a new BB too). The difference between 50 and 52 teeth is marginal anyway.

I have posted this chart before, it may help this discussion too: triple (50/39/30) vs compact (50/34) with 700x25c tyres.

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posted by Simon E [1940 posts]
11th March 2014 - 14:15

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A quick tap of the set up on Sheldon's gear calculator reveals, with 50/38 chainrings on a 11 speed cassette, 6 combinations duplicated to within 2 inches of another, 4 of which are within half an inch.

Not a great solution in my view, though I do understand the 16 tooth jump - something I pointed out a few posts earlier you may notice.

posted by Nick T [781 posts]
11th March 2014 - 15:16

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So what's the best option for me guys? Should I change the Inner Chainring to 38 while keeping the outer 50 or change both chainrings to a 52/36 to optimize gear ratio and shifting?

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posted by Muntasir [12 posts]
11th March 2014 - 15:25

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You don't live near any hills, so do you ever use your 34? If you don't, you won't use a 36 or 38 either.

Are you running out of gears in your 50? If so, buy a 52, and a 36 to go with it.

posted by Nick T [781 posts]
11th March 2014 - 15:40

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Stupid question time, what is wrong with the setup you have. Why do you want to change it.

Which gears do you use, which don't you use. Do you notice any annoying gaps with the ratios you have, are you consistently changing between chainrings.

There Is no point in changing for the sake of change, understand why you want to change then do it.

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posted by mrmo [1064 posts]
11th March 2014 - 15:51

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Simon E wrote:
Nick T wrote:
Roberj4 wrote:
I updated my FSA Compact to a 50/38, (from 50/34) spot on for me.

How is that beneficial, may I ask? You have the same top end but a reduced number of low gears, probably a good few duplicates as well. Seems like the worst of both worlds.

Someone who doesn't anticipate riding up steep hills or is a strong climber may not feel the need for the low gearing with a 34 front ring.

Also, perhaps you haven't noticed others' issues with a typical compact. Lots of people find the jump from 50 to 34 too wide. For me the triple's 39 middle ring is ideal for rolling terrain or steady riding (where I'd be swapping from 50 to 34 and back), while you still have a larger ring for more favourable conditions.

Fitting a 38t or similar inner ring to the existing crankset would save the OP buying a whole new one (and possibly a new BB too). The difference between 50 and 52 teeth is marginal anyway.

I have posted this chart before, it may help this discussion too: triple (50/39/30) vs compact (50/34) with 700x25c tyres.

Good points here (thanks for coming to my rescue). I've been in & out of cycle racing over 30 years and I'm very much 'old' school 42/52 on my old Cad3 winter bike for training and racing in my early years. Very rare that I use the 52/50 tooth outer ring while training these days, it's 42t all the way for me.

So to find majority of new bikes come with a compact chainset 50/34 is fine if you live in the Alps or the York Dales but (for me) even worse my new purchase (5 years ago) Cannondale has the dedicated BB30 shell so I'm stuck with this system. I like to use of a 34 tooth for hilly Sportifs around the Dales/Lake District but for every day rolling hills a 34 is a total waste of time and I'm not prepared to ride all day long in just a 50t outer ring (can't be that good for my old knees!). I'm not in a position to purchase another BB30 39/52 chainset (expensive, limited choice) that would also mean adjusting my front mech each time I'd change a crankset over.

So to cut costs and hassle I switched to a 38t 110 BCD keeping the 50t which I find more than happy with pushing. 110 BCD 38/50 is great for every day riding and fast training, I've no problem keeping up with the younger lads.

posted by Roberj4 [189 posts]
11th March 2014 - 15:59

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