Thinking of moving back to 53/39 from 50/34

[Andywinds]

You are limited by the bcd of the chainset you have. If it is a double 130 bcd your smallest inner ring is a 38t iirc. Anything smaller would require a 110 bcd compact crank.

I've still got the complete crankset that came with the bike, so swapping back to 53/39 is easy.

 

[Andywinds]

At 50 x 11 and a cadence of 100-rpm you would be doing about 36-mph. Not bad going on the flats! And that's too slow for you?

I just like putting in a lot of power and slowing down the RPM's.

 

[si_c]

I just like putting in a lot of power and slowing down the RPM's.

I think you're confusing power with torque. You can apply the same amount of power at 100rpm or 50. The latter will require more torque.

edit: Halving the RPM = twice the torque for a given power.

 

[Racing roadkill]

Since I moved to the compact I have got a lot more fitter and have lost some weight. I don't really use the lowest couple of gears now. My cassette is 28-11
If I had a new bike I would opt for the semi-compact.
My only question is, how is the big jump from 34/28 to 39/28 going to feel. Probably a daft question!! But has anyone done this back? It's a 12.5% jump.

I swapped one of my bikes to a 53-39, put short cranks on it, and rode the PRLS 100 on it this year. It felt a lot better than the bike with the 50-34 and 172.5 cranks I was using for the hills training.

 

[bpsmith]

I swapped one of my bikes to a 53-39, put short cranks on it, and rode the PRLS 100 on it this year. It felt a lot better than the bike with the 50-34 and 172.5 cranks I was using for the hills training.

What length did you drop down to?

I have a Semi Compact on my newer bike, with 170mm cranks and it feels a lot better than the 172.5mm Compact on the other bike. Not exactly extreme, I know.

They say shorter cranks give the same feeling as bigger gears, but just wondering which is better?

 

[gbb]

Since I moved to the compact I have got a lot more fitter and have lost some weight. I don't really use the lowest couple of gears now. My cassette is 28-11
If I had a new bike I would opt for the semi-compact.
My only question is, how is the big jump from 34/28 to 39/28 going to feel. Probably a daft question!! But has anyone done this back? It's a 12.5% jump.

You're talking the low gears, I assume you're happy with a 50t. A lot depends on your terrain I guess. Ironically I had a 50/34, found the 34 useless in my area and swapped it for a 40 which I found perfect for the rolling terrain of Northants and flats areas of the fens.
At my peak I realised the 50 was holding me back so opted to a 53/39 on my latest bike. That was fine...then I caught TB, lost fitness and now wis he'd I had the versatility of a compact again. Can't win can you ?

It sounds like you could try a larger small ring, the options are plentiful...and relatively cheap.

 

[grellboy]

At risk of hijacking the OP's post, could someone please explain to me the thinking behind the gearing on my two current bikes; although I am a very keen cyclist, I can't pretend to have any technical knowledge at all. I currently have a cross bike - caadx - with 46/36 chain rings and a road bike - Dolan l'etape - with 50/34. Now in my simple mind, the more teeth the faster you go and the ring with fewer teeth makes getting up hill easier and the closer the numbers are to each other then the smoother the transition from one to the other. That might all be nonsense, but its a summary of my understanding. However, what I really want to know is what is the advantage of having fewer teeth on the big ring on the cross bike? Surely the more teeth you have the faster you go - or is it a terrain thing?

 

[Andywinds]

I think you're confusing power with torque. You can apply the same amount of power at 100rpm or 50. The latter will require more torque.

edit: Halving the RPM = twice the torque for a given power.

Yes I did mean torque.

 

[Andywinds]

You're talking the low gears, I assume you're happy with a 50t. A lot depends on your terrain I guess. Ironically I had a 50/34, found the 34 useless in my area and swapped it for a 40 which I found perfect for the rolling terrain of Northants and flats areas of the fens.
At my peak I realised the 50 was holding me back so opted to a 53/39 on my latest bike. That was fine...then I caught TB, lost fitness and now wis he'd I had the versatility of a compact again. Can't win can you ?

It sounds like you could try a larger small ring, the options are plentiful...and relatively cheap.

I'm going to see what gears I use later today/tomorrow on some of the grade 4 climbs. Not done them for a while.

 

[Hugh Manatee]

At risk of hijacking the OP's post, could someone please explain to me the thinking behind the gearing on my two current bikes; although I am a very keen cyclist, I can't pretend to have any technical knowledge at all. I currently have a cross bike - caadx - with 46/36 chain rings and a road bike - Dolan l'etape - with 50/34. Now in my simple mind, the more teeth the faster you go and the ring with fewer teeth makes getting up hill easier and the closer the numbers are to each other then the smoother the transition from one to the other. That might all be nonsense, but its a summary of my understanding. However, what I really want to know is what is the advantage of having fewer teeth on the big ring on the cross bike? Surely the more teeth you have the faster you go - or is it a terrain thing?

You'll be right I reckon; it's a terrain thing. Cyclo X races are usually short, 1 hour plus one lap sort of thing and top racers spend a lot of time in the big ring. Climbs may be steep and loose though so more of a jump between ranges will be the difference between staying on the bike or having to run with it. I suppose you could think of it as their "granny ring" as per mountain bikes of yore.

Interestingly, your chainring ratios of 36/46 are exactly the same as are on all my mountain bikes. Along with a 24 tooth small ring, I have never felt the need to upgrade to any of the new ratios. It is getting harder to do though!

 

[Andywinds]

It's clearly the compact that has got you fitter.
If you change it your fitness will desert you and your weight will go up. Like Samson when he got his hair cut.

Ha ha, maybe. I had no choice but to go to compact, with what what the bike came with 53/39 25/12 I could not get up any incline. I had to replace rear cassette as well as the chain ring. I'm happy with the 28/11 rear, but I would like to try a semi-compact on the front, but I don't have one.

 

[KneesUp]

At risk of hijacking the OP's post, could someone please explain to me the thinking behind the gearing on my two current bikes; although I am a very keen cyclist, I can't pretend to have any technical knowledge at all. I currently have a cross bike - caadx - with 46/36 chain rings and a road bike - Dolan l'etape - with 50/34. Now in my simple mind, the more teeth the faster you go and the ring with fewer teeth makes getting up hill easier and the closer the numbers are to each other then the smoother the transition from one to the other. That might all be nonsense, but its a summary of my understanding. However, what I really want to know is what is the advantage of having fewer teeth on the big ring on the cross bike? Surely the more teeth you have the faster you go - or is it a terrain thing?

CX races are in mud. This means you don't go as fast, so you don't need as high a gear. Mud can also be clingy, making pedalling harder, ergo lower gears are better. But as well as being clingy, it also can exhibit low friction - i.e. it's slippy too. Weird stuff, mud. It's probably got that property that means you can run on custard if you slap your feet hard enough. Anyway, a big gear means you have to generate lots of torque, which will make the wheel spin on mud. A lower gear means you are less likely to get wheelspin, I reckon.

 

[Venod]

There must be some fast people out there, as a younger person I rode 52/42 with a 13 to 24 6 speed freewheel, I use 50/34 with 12 to 30 cassette on 2 bikes and 46/36 on the cross bike with an 11 to 32 cassette, I like the CX bike ratios even on the road 46/11 at 100rpm gets you 32mph its a higher ratio than the 52/13 I used when younger, are you all spinning the big gears at these speeds? I don't seem to have a problem keeping up even on the CX

 

[S-Express]

I like the idea of the 53T for the flats and some downhills.

Logical fallacy. Let's say you ride at 25mph avge on the flat with your current gearing. A 53t ring is not going to help you ride any faster. The limiter for most riders is their sustainable aerobic power, not their gearing.

 

[Racing roadkill]

There must be some fast people out there, as a younger person I rode 52/42 with a 13 to 24 6 speed freewheel, I use 50/34 with 12 to 30 cassette on 2 bikes and 46/36 on the cross bike with an 11 to 32 cassette, I like the CX bike ratios even on the road 46/11 at 100rpm gets you 32mph its a higher ratio than the 52/13 I used when younger, are you all spinning the big gears at these speeds? I don't seem to have a problem keeping up even on the CX

Since Power meters have become easily available, I work with Power primarily. I tend to go with a low Cadence, high torque bias where possible.