50/34 crankset to 53/39

BMKN

Currently I have a 50teeth crank set, I am considering upgrading to a 53 crank set for harder sprints and races, Is it worth my while doing so or the usual minor gains argument and depends? I would be sticking with shimano range, Would I need to upgrade the rear also or would I get away with my current set? I ride mainly on flat and the odd time I like to do a long climb every so often, I am pretty slow on hills but fast on flats, I used to own a TT bike with the 53 ring and loved it, I did hills wit the TT bike but found it tough on hills, but climbing in a TT bike sucks anyway, I assume the road bike wont be as bad? 90% of my riding is flat with rolling hills on my long rides.

markhewitt1978

Are you spinning out (i.e. 110+) on 50/11? If so yes, otherwise no.

bernithebiker

Using a 53/12 at 90rpm (cadence), will put you at 50km/h, i.e. quite fast.

Whereas a 50/12 gives you 47.3km/h. Still quite fast.

A half-decent amateur TTer can do 40km in one hour so you're most likely to be using 50 with the 16/15/14/13/12, i.e. 35.5 to 47.5km/h.

You don't say what cassette you currently have, but if you went to 53, it would be wise to go 25/12, whereas, if you stick with the 50, you could go tighter with 21/11. The 50/11 gets you 51.6km/h, which should be plenty.

Not sure what the 53 brings to the party?

BMKN

Im running 11/25 rear, If I do upgrade crankset what else will need replacing?

markhewitt1978

Your front mech will need moving upwards, other than that, nothing.

ai_1

markhewitt1978 wrote:

Are you spinning out (i.e. 110+) on 50/11? If so yes, otherwise no.

This^^^

BMKN wrote:

Im running 11/25 rear, If I do upgrade crankset what else will need replacing?

You may need to add some links to your chain and tweak your front derailleur. I think that's it.

BMKN

Great Ill think a bit more about the upgrade, I do find I could use more gears on downhill or even harder gears on the flat, I think the main reason I felt so fast on the TT bike was the 53teeth set up as I got PB's when mainly on the hoods as I hated the aero position.

bernithebiker

BMKN wrote:

Great Ill think a bit more about the upgrade, I do find I could use more gears on downhill or even harder gears on the flat, I think the main reason I felt so fast on the TT bike was the 53teeth set up as I got PB's when mainly on the hoods as I hated the aero position.

If you need a harder gear than 50-11 on the flat then you should give Dave Brailsford a call.

Grill

No point. If you really think you need more gear (and it's unlikely you do) then just swap the rings to 52/36.

imposter2.0

BMKN wrote:

Currently I have a 50teeth crank set, I am considering upgrading to a 53 crank set for harder sprints and races, Is it worth my while doing so or the usual minor gains argument and depends?

Not sure why you think it's an upgrade - and you will almost certainly not see any 'gains' from it. Unless you are routinely spinning out on the flat in 50/12 or 50/11 - in which case give Sir Dave a call, as mentioned.

rafletcher

markhewitt1978 wrote:

Your front mech will need moving upwards, other than that, nothing.

We'll the chain may need 1 or 2 extra links depending on how short it is at the moment.

dennisn

BMKN wrote:

Im running 11/25 rear, If I do upgrade crankset what else will need replacing?

Money in your billfold.
I've got to admit that I'm with most of the other posters in the belief that you can't spin out a 50-11 or even need the 11 tooth for that matter.

banditvic

I prefer a 53/39 and run a 11 28, which is very similar to a 34 25. I run 11 tooth because I love descending.

cycleclinic

I run 53/39 because I don't have to change rings as much. I can be riding at 25mph on 39/14T at 110 rpm which is comfortable for a while. If your advise is that a sprint at 50 kph is fast enough for racing then consider the average speed is 24mph is cat 3/4 race round here sprints will be in the high 30's mph or faster . 47 kph on a sprint is not a sprint that is just normal pace on the flat. Compact work fine for most riders but you power output increase and so long as the terrain you are riding is not mountainous then a racing double becomes more viable.

53/12 will allow you to get to high 30's to 40 mph without spinning out. 40 mph can be achieved at 115 rpm which optimal. Also you get closer ratio's on the cassette which is good in my book. Never seen the point in 11-28t cassette's that is an MTB range from the 90's

pilot_pete

thecycleclinic wrote:

47 kph on a sprint is not a sprint that is just normal pace on the flat.

47kph=29.2mph

Normal pace for who might I ask?

PP

Monty Dog

IME 50 kph is not sprinting unless it's uphill - I've been in vet races where flat speeds have been in excess of 65kph. 50kph on the flat is commonplace on a flat circuit and you need to be able to hold it quite comfortably - it's not about the size of the gear but how easily you can spin it. Those who often talk of spinning-out and the need for bigger gears often barely muster 90rpm - it's simply a case of adapting the pedal stroke to spin faster. IMO, 160rpm is spinning-out with gears and 180rpm with a fixed gear.

maltloaf_df

^^^^

Do people really spin at 160rpm ? I like spinning gears but 160 ? Jeez

Monty Dog

maltloaf_df wrote:

^^^^

Do people really spin at 160rpm ? I like spinning gears but 160 ? Jeez

My 'spin' record is 224rpm on a fixed gear on rollers, but I was bouncing a bit in the saddle! :P

bernithebiker

maltloaf_df wrote:

^^^^

Do people really spin at 160rpm ? I like spinning gears but 160 ? Jeez

I would say it's just for a very short time - in a dash to the line sprint or a breakaway.

110 is already quite high for extended periods. (I like to ride around 90 to 110 if I'm pressing on!)

cycleclinic

When I say normal pace it not an average but possible on the flats. I did hold 160 rpm for a mile or so once 39/16T and I was going some I had to slow down though cannot sustain that I am not a track rider.

FransJacques

OP, don't worry about some of the mean-spirited posts effectively saying you're too big for your britches (or chainrings). If you want bigger rings, go for it, it's only a few tenners cost. Google "TA" of "FSA" or "Stronglight 110 chainrings" or some combo thereof to see what they have. There are 100s of 50 tooth 110 rings fewer 52 or 53 tooth 110 rings are less common.

It's good advice to go for a 52, less of a gap to your small ring and better-feeling to my diesel legs than a 53. You don't necessarily need to change your small ring, I'd go in steps first.

Depending on how worn your chain is you don't really need to do anything apart from move your front mech up a few mms and that's it. Takes about 10 mins.

I agree that the feel of a 52/53 is nicer than a 50. I once tried a compact but sold it b/c it didn't work for me.

jibberjim

I ride a 52x36, I have spun out a 50x11 (which doesn't mean I still couldn't put out watts at that cadence but that I couldn't put out the number of watts I wanted at 76kph down a mountain) , I would never have optimised that situation though, that would be foolish (especially as I'd just been undergeared in 34x28 moments before going up the same mountain)

The thing to optimise for is the minimum gear inches between gears at the speeds you normally ride at. The smallest jumps in gears are in the 14/15/16/17 (and higher if you have a straight through block, but most people don't) The difference between 16 and 17 is 6%, between 11 and 12 it's 9% - so you are much less likely to find yourself between gears.

If you do go for 53 or above on a 110 BCD getting "aero" chain rings can be a good idea as they tend to be considerably stiffer which can help with shifting.