Crankset/Cassette Comparison

burly

Hi all, currently running on a 20-speed road bike, ultegsa 34/50 crankset, with 11/32 cassette.

Currently looking at an upgrade but the bike I like is a 22-speed, 39/53 crankset with 11/28 cassette.

My cycling is a mix of all gradients really, typically a mix of sportif cycling, but mostly adventure racing type races with mountainous cycle sections.

Can someone who maybe has experience of both set ups offer some advice on whether the 39/53 crank with 11/28 cassette will suit my needs?

Obviously the power in the legs is ultimately the most important thing assuming that's ok, what are the main differences between the two set ups?

Thanks in advance.

sullzz

burly wrote: »

Hi all, currently running on a 20-speed road bike, ultegsa 34/50 crankset, with 11/32 cassette.

Currently looking at an upgrade but the bike I like is a 22-speed, 39/53 crankset with 11/28 cassette.

My cycling is a mix of all gradients really, typically a mix of sportif cycling, but mostly adventure racing type races with mountainous cycle sections.

Can someone who maybe has experience of both set ups offer some advice on whether the 39/53 crank with 11/28 cassette will suit my needs?

Obviously the power in the legs is ultimately the most important thing assuming that's ok, what are the main differences between the two set ups?

Thanks in advance.

You'll certainly notice a difference changing from a 50/34 to a 53/39.
But i wouldn't let this be the deciding factor on whether to buy the bike or not, you could always change out the crankset if you find yourself struggling on the climbs.

coastwatch

In simple terms, you will be loosing your current two lowest gears and gaining two gears at the high end. So the new setup would be less suited for climbs than your current setup.


As Sullzz says, you could always change the crankset to a compact 50/34 and cassette to 11-32 or even 11-34 ( might require a new rear derailleur too). If you're buying new, in a shop, they might change it as part of the sale.

Cee-Jay-Cee

Is the bike your buying new? Can you not ask for a 50/34 chainset on it? If the shop really want the sale I’m sure they can swap it out for one better suited to you??

Eamonnator

https://www.bikecalc.com/gear_ratios

By my reckoning, the lowest gear on 39/53 with11/28(39-28) equates to approximately 34/25 on your current setup.
That's quite a lot to lose.

burly

Thanks for your replies.

So if I'm losing the two lowest gears which I could miss on steep climbs, does it follow that I would gain two extra gears at the other end which could benefit me on flats and downhill?

One other thing I should mention is that I would be upgrading from aluminium frame to full carbon, so is it possible that what I would lose in terms of the lowest gears could be somewhat mitigated by the fact I'll be pushing a lighter bike??

burly

Not buying new from a shop, nearly new private sale so don't have the option of swapping out the crank without paying extra for it

ED E

burly wrote: »

Thanks for your replies.

So if I'm losing the two lowest gears which I could miss on steep climbs, does it follow that I would gain two extra gears at the other end which could benefit me on flats and downhill?

One other thing I should mention is that I would be upgrading from aluminium frame to full carbon, so is it possible that what I would lose in terms of the lowest gears could be somewhat mitigated by the fact I'll be pushing a lighter bike??

Its generally way more aggressive. Each "set" of gears is harder that the counterpart.


Is it a TT bike or something? That gearing is suitable for dead flat terrain at high speeds OR strong riders.

53x11 on 700c/25 is 55KM/h at 90rpm. At 100RPM is 61KM/H. Thats fast bar descents but climbing on 39x28 will be hard prior to that for non beasts.

Eamonnator

If you live up to your user name, you'd probably miss those two gears on the climbs.

burly

@eamonator: very funny :-) but thankfully no, I'm lean as a whippet these days

coastwatch

burly wrote: »

Thanks for your replies.

So if I'm losing the two lowest gears which I could miss on steep climbs, does it follow that I would gain two extra gears at the other end which could benefit me on flats and downhill?

One other thing I should mention is that I would be upgrading from aluminium frame to full carbon, so is it possible that what I would lose in terms of the lowest gears could be somewhat mitigated by the fact I'll be pushing a lighter bike??

You'll be gaining one extra gear at the high end ( 3 extra teeth at the front, same 11 tooth sprocket on cassette, so 6% higher gearing). You'll have smaller jumps between gears overall.

Try doing some hills without using the two lowest gears on your current bike to see how it feels.

I dont think the change from aluminium to carbon will offest the gearing change, depends on how much lighter, might feel like "half" a gear difference.

Cee-Jay-Cee

burly wrote: »

Not buying new from a shop, nearly new private sale so don't have the option of swapping out the crank without paying extra for it

If that’s case budget for a new 50/34 crankset, going from 50/34 with 11/32 to 53/39 and 11/28 is a big jump regardless of the bike being carbon/lighter.

burly

Thank you all, some great advice above. Really appreciated

CantGetNoSleep

I once sold a bike I loved purely because I wanted a 50/34 and bigger cassette on the back (it had an 11-25). TBH it was going to cost a bit to get a new chainset, cassette and maybe chain or derailleur.

If you're riding is anything like mine, unless it is a really a fantastic deal I'd wait to find something with a compact chainset at least. I don't think you see any benefit from a 53/39 or shorter steps between gears unless you are racing

C3PO

I currently run 53/39 and an 11/27 on one of my bikes. It’s fine for my local regular spins but wouldn’t fancy it for a long day’s cycling particularly with significant climbing! I’m pretty fit!

burly

Hi all, thanks for the excellent advice above. Spoke to my local bike-mechanic who recommended changing out the inner crank from a 39 to a 36, therefore having a modified 53/36 on the crank. Question is, would the 11/28 cassette be ok with a 53/36 crankset, or would it need to go to 11/32?

magicbastarder

my concern there would be you'd have too much of a difference between the big ring/big ring chain length and the small ring/small ring length, thus leading to potential issues if you weren't careful with gears.

burly

magicbastarder wrote: »

my concern there would be you'd have too much of a difference between the big ring/big ring chain length and the small ring/small ring length, thus leading to potential issues if you weren't careful with gears.

Could you expand a bit on your concern? Is you concern with the difference between the 53/36 or, is your concern having using an 11/28 cassette with the 53/36 crank?


Mechanic pointed out there is not much difference (one tooth) between a modified 53/36 and a semi-compact 52/36, and there are plenty of bikes out there running 52/36 with 11/28 cassettes.

Eamonnator

If your chainset is 130BCD, it won't accept a 36 inner chain ring.

magicbastarder

burly wrote: »

Could you expand a bit on your concern? Is you concern with the difference between the 53/36 or, is your concern having using an 11/28 cassette with the 53/36 crank?

it was more to do with your comment re a 32 tooth on the cassette.
the larger the tooth difference you create on the front, the smaller you can have on the back.

i'm no expert in this, but from what i understand, the issues relate to the rear derailleur - how much 'swing' it has (i.e. how much slack it is able to take up in the chain) dictates how big a gearing difference you can accomodate.
so you could in theory have a chain which is long enough to go from the big ring at the front to the big ring at the back, but if you change to small/small, the slack that creates in the chain is too big for the RD to take up.