50/34 or 52/36 crankset

964cup

God I love the internet. Are we seriously suggesting that age has no impact on joint function, or that torque - in other words the bending moment applied to a joint - has no relationship to injury potential?

So it's OK to suggest that higher power damaged tendons (irrespective of the source of the power) but not that the torque component was relevant? OK. So let's compare doing 1 leg press rep of 1 tonne, 10 reps at 100kg and 100 reps at 10kg. Are we all agreed that that's the same amount of work? We'll assume that no-one is going to claim they can press a tonne; are you seriously proposing that the injury risk from 10x100 is the same as that from 100x10?

Current conventional thinking on cadence seems to be that 85-90 is optimum, with attacks at 100-110 - see Sufferfest, for example, and cycling coaches ad nauseam. So let's agree that "low" is 60-70, "high" means perceived-wisdom-optimum. There's more here on oxygen efficiency versus neuromuscular efficiency at low vs high: http://www.bikeradar.com/gear/article/t ... ers-16394/ with *real science* (unusually for BikeRadar). None of this is to do with knee injury mitigation, note - but see my previous paragraphs; this is an attempt to establish what "low" and "high" mean.

You can do the conversion from output power to torque for a given crank length and rpm easily enough. That'll tell you the equivalent leg press (single-legged, of course). 250W at 80rpm requires 17.4kg of force on a 175 crank (29.9nm). The same power output at 60rpm requires 23.2kg (39.8nm). At 100rpm it's 13.9kg (23.9nm). Push up the power output and of course the difference is magnified - the force required to produce 250W at 60rpm produces 416W at 100rpm. By the same token you need 38.6kg (66.2nm) to produce 416W at 60rpm.

I included a personal example so I wouldn't be accused of talking about things of which I had no experience. That went well, then. I'll go back to science.

springtide9

I've owned compact, semi compact and standard.. in that order.

The reality is that you will rarely spin out a 50/11 unless descending.. in which case relax and enjoy the scenery.

But a semi compact 36/52 I found more useful than 34/50. In fact if it is very flat then 39/53 is more pleasant. The main problem with 34/50 is that I found I virtually never went into the 34 cog unless climbing. For that reason I would suggest 36/52 as a good compromise with something like a 11-25/26. You could always get a 11-28 rear to give you a bit more slack.

But in all honesty... it depends on your riding. Also another note, the newer 11 speed appear not to suffer as much from chain crossover... meaning that you can use all of the cassette gears on each chainring.

There is no right of wrong answer, and I'm sure this thread will still be debated until someone else asks a similar question :-)

imposter2.0

964Cup wrote:

God I love the internet. Are we seriously suggesting that age has no impact on joint function, or that torque - in other words the bending moment applied to a joint - has no relationship to injury potential?

No, nobody is suggesting that age has no impact on joint or neuromuscular function. But you were the one implying earlier that unless you spin a high cadence, you will spend the rest of your life walking with sticks (ffs). And I might add that for someone who claims to rely on science, your definition of 'torque' is a bit odd.

dean7879

When i was riding a 50/34 i very rarely got out the big ring.I thought i was the bees knees.

Next bike i rocked a 52/36 and i found myself in the little ring a lot more. This combination has hardly made me faster either. Riding in hilly Shropshire i find myself missing the 50/34 abit but its not that troublesome. You just have to adapt.

It all depends on how powerful a rider you are and what type of riding you are doing.

StillGoing

Imposter wrote:

964Cup wrote:

God I love the internet. Are we seriously suggesting that age has no impact on joint function, or that torque - in other words the bending moment applied to a joint - has no relationship to injury potential?

No, nobody is suggesting that age has no impact on joint or neuromuscular function. But you were the one implying earlier that unless you spin a high cadence, you will spend the rest of your life walking with sticks (ffs). And I might add that for someone who claims to rely on science, your definition of 'torque' is a bit odd.

What 964Cup posts is real enough for me? Like nearly all novice cyclists, when I first climbed back on board a bike at 48 having got off aged 17, I got into the bravado of "you've got to push a big gear". My cadence was low 40-60rpm and my knees suffered. Now I'll admit that I have years of Army life in my knees, carrying and running with heavy bergens and jumping out of helicopters that in all probability have given me underlying knee and joint issues, but once I figured out that a high cadence and an easy gear was, well easier, my knee issues disappeared as far as cycling goes. I will never run again due to knee pain, but as long as I cycle in an easy gear with a high cadence, no knee issues. If you undertake any activity that is damaging to the joints, it is bound to impact on your quality of life and ability to perform a given task.

imposter2.0

Here we go again. Can someone please define 'high cadence'..?? Because one person's 'high cadence' is highly likely to be another person's 'normal cadence'. Suggesting that someone pedals with a 'high cadence' without actually putting a number on it is utterly meaningless. A bit like suggesting someone rides at 'high speed'....

All of this completely ignores the fact that cadence is largely self-selecting anyway.

964cup

I thought I had "defined" it, which is to say cited an article comparing the 60/70 RPM they (actual scientists - I'm not one) identified as the typical cadence of a beginner cyclist with the 90-100rpm typical of pro cyclists. 60/70 is "low" or "normal for beginners" and 90-100 is "high". This is for road riding, obvs - track cadence is a different animal for obvious reasons of not actually having a choice of gearing. That said, Wiggins averaged 105 cadence for his hour record, so just above the "normal range" for pro cadence.

In what way is my definition of torque odd? Torque is force applied to cause rotation, conventionally expressed in newton metres; power is the rate of applying that force, in other words for bikes or cars it's torque x rpm. To get the leg-press analogy I just converted from newton metres to Kg/cm based on a 175mm crank.

londoncommuter

Back to the matter at hand.....

What about throwing in relative cog sizes? With the rise of the huge jockey wheels it's been suggested that big/big cogs are more efficient than a chain having to wrap itself round a smaller cog. How does that play out in riding say a 52-15 v's 50-14 (or something with the same ratio).

The wrong chainline can cost you 3W of friction:

http://www.bikeradar.com/road/gear/arti ... ing-44016/

londoncommuter

londoncommuter wrote:

Back to the matter at hand.....

What about throwing in relative cog sizes? With the rise of the huge jockey wheels it's been suggested that big/big cogs are more efficient than a chain having to wrap itself round a smaller cog. How does that play out in riding say a 52-15 v's 50-14 (or something with the same ratio).

The wrong chainline can cost you 3W of friction:

http://www.bikeradar.com/road/gear/arti ... ing-44016/

Just re-thinking that, maybe that means you'd be better having a 50T and not dropping to the small ring rather than a 52/36 forcing you to make more use of your available gears. Tricky.....

964cup

That's a really interesting question. It suggests we might be better off with a 53/39 chainset and some kind of 12-36 cassette (near enough same ratios as 50/34 - 11-32). It might be fun to build something like that and see how it rode. Presumably one could bastardise a couple of PG1170 cassettes to get the ratio mix. Run it with a UCB or Berner cage with 15T jockeys.

Alex99

londoncommuter wrote:

Back to the matter at hand.....

What about throwing in relative cog sizes? With the rise of the huge jockey wheels it's been suggested that big/big cogs are more efficient than a chain having to wrap itself round a smaller cog. How does that play out in riding say a 52-15 v's 50-14 (or something with the same ratio).

The wrong chainline can cost you 3W of friction:

http://www.bikeradar.com/road/gear/arti ... ing-44016/

I've read that with sprockets below 14t, you start to get a drop off in efficiency. Makes sense in that the chain has to go around a tight radius under load. Graeme Obree notes this in his book and suggests getting as large a chainring as possible to minimise time on very small sprockets. Also, anecdotally, Wiggins rode 58x14 in his hour record ride. 50x12 is near as dammit the same ratio. Not sure it's as much of an issue with derailieur jockey wheels as the chain isn't under load. Some folk have measured some effect though, hence the mega expensive big jockey wheels. I think I'd just ask, do the pro's use them?

Alex99

964Cup wrote:

In response to various people:

50+ is nothing to do with performance, or strength (more macho bullsh*t) it's to do with biology. As you age, your connective tissue - ligaments, tendons, meniscii, intravertebral discs etc - age with you; they lose elasticity, accumulate damage and in some cases shrink and dry out. 50-year-old knees cannot absorb the same punishment as younger ones. End of. In fact, younger ones can't absorb the punishment some people think they can, which is why so many competitive skiers end up retiring young with knee problems. So high cadence & low torque is the way to go if you want to carry on walking, never mind cycling.

I don't know what kind of club runs you lot go on. We generally average 30kph over 100-ish k with about 1200-1500m of climbing (Herts hills, Chilterns etc). I spend most of my time in 50x15 at 85-90rpm (so 35-37kph); I climb the short punchy bits either in 50x25 (on an 11-28 cassette) or 50x28 (on an 11-32 cassette), and the longer hills in 34x19 or 34x21, with the remaining cogs available for steep things like Swains or Plough Hill (15%-ish). Yes, I can get up Swains in 36x25 (and have to on another bike) but it's not fun. I'm taking the same bike to the Alps on Wednesday, where I expect I'll see rather more use of the 34x32, and will spend plenty of time "spinning out" the 50x11 - but we all know there's no point pedalling on descents once you go past 50kph, right? - because the aero drag of your feet rotating outweighs your small contribution to gravity.

I have another bike with a 52/36 that's only used for flat stuff (Regent's Park, Tour of Cambridge etc). That's so I can sit in the 52x15 at the same cadence, but I can't see any other reason to have the 52 for the kind of riding I do. It's got a 12-25 cassette on it, so it has a lower top-end than the climbing bike.

As for this thing about "gaps". Sure, if you're a finely honed TT machine. But for the rest of us? 52x15 at 85rpm = 52x16 at 90rpm. Turn off your cadence meter and tell me you can tell the difference of 5rpm in your legs. I can't. So when someone tells me 11-speed is better because the cassette now has the magic 16 instead of the "jump" from 15 to 17 (10 whole RPM) I have to laugh. Look at your Strava data. Compare your average cadence to the 25% and 75% quartiles in Stravistix, and to the maximum. For example: 116k @ average 29.4kmh, 1124m climbing, cadence average 79rpm, 25% quartile 73rpm, 75% quartile 90rpm, max 127rpm. So a 17rpm (three cog) variation in normal cadence. Setting us up to believe that we "need" no big jumps is a way to convince us that we "need" 12-speed.

Not pedalling downhill isn't to do with additional drag from pedalling. It's because you're already going so fast, so the extra energy to go X kph faster is better spent to go X+ kph faster on the flat or on a climb.

Regarding gaps, some people are sensitive to this. I do find the 15 to 17 jump a bit big at times. Yes, 10 whole RPM is a bit too big when my legs are telling me that I'm in the wrong gear. I ride 9 speed B TW.

964cup

Alex99 wrote:

londoncommuter wrote:

I think I'd just ask, do the pro's use them?

Yes, they do. Some of them - Fabian Cancellara, Edvald Boasson Hagen, Philippe Gilbert for example.

slowbike

964Cup wrote:

Alex99 wrote:

londoncommuter wrote:

I think I'd just ask, do the pro's use them?

Yes, they do. Some of them - Fabian Cancellara, Edvald Boasson Hagen, Philippe Gilbert for example.

Referrring to the large jockey wheels ...

Alex99

Slowbike wrote:

964Cup wrote:

Alex99 wrote:

londoncommuter wrote:

I think I'd just ask, do the pro's use them?

Yes, they do. Some of them - Fabian Cancellara, Edvald Boasson Hagen, Philippe Gilbert for example.

Referrring to the large jockey wheels ...

OK, sure. Not quite widespread, but they are in use.

davebradswmb

I would say that I am an average 50 (+) rider like the OP, and I currently have a compact 50/34 chainset and a 13-26 9 speed cassette. I find that I never use the smallest two cogs except by mistake when I'm on the small chainring. I would normally use the 34/21 ratio for a 8% climb, reserving the biggest two sprockets for anything over 10%. I can climb most things by getting out of the saddle on the steeps, though I had to walk up the steepest section of Rowsley Bar recently. It seems to me that it would make sense to have a 43/29 chainset which would give me the benefit of a couple more gears at the low end without widening the steps between ratios. The only trouble is Campagnolo don't make a 43/29 chainset :-).

on-yer-bike

As you age your VO2 max drops. Doesnt that make it harder to maintain high cadence? Im 61 and my average cadence on most rides is around the mid 70s. I have tried to increase it but it just doesnt feel comfortable. Mind you, I do ride in a relatively hilly area. I use 11-27 cassettes with 34/50, 36/52 and 39/53. The 34 gets used more as I get tired on a long ride. I like the closer ratio of 39/53 but in all honesty its tough on some of the hills round here. The 36/52 is a new experiment but it still has a 16 tooth difference. A 50 / 36 might be optimum. I never really pay much attention to the ratio spread on the cassette, with 11 speed.

Alex99

davebradswmb wrote:

I would say that I am an average 50 (+) rider like the OP, and I currently have a compact 50/34 chainset and a 13-26 9 speed cassette. I find that I never use the smallest two cogs except by mistake when I'm on the small chainring. I would normally use the 34/21 ratio for a 8% climb, reserving the biggest two sprockets for anything over 10%. I can climb most things by getting out of the saddle on the steeps, though I had to walk up the steepest section of Rowsley Bar recently. It seems to me that it would make sense to have a 43/29 chainset which would give me the benefit of a couple more gears at the low end without widening the steps between ratios. The only trouble is Campagnolo don't make a 43/29 chainset :-).

That would be a road triple with the big ring removed.

drlodge

I recently bought a groupset with 52/36 crank on the basis the bike would be used for dry/summer/fast rides only. I then realised that I might want to use it on some big hills to for which I would need the 34 chainring. I've since bought replacement 34/50 chain rings so I should have gone for the 34/50.

I would ask yourself one simple question - what's the lowest gear you want. Then work out what combination of cassette and chainrings will give you that ratio. I'm 50 next year, fairly fit and run 34/50 and 12-29 cassette. I wouldn't want to drop to a 36 chainring or 12-27 cassette, the ratio just isn't low enough when doing a steep hill or on a century+ ride and knackered.

I went out at the weekend with a friend on his new bike, equipped with 34/50 and 12-32 cassette. That's a very low gear, he's pretty fit too but he used that 34-32 bottom gear when we hit the 20% slopes.

apreading

I was happy with 50/34 and an 11-28 (10 speed) cassette. Now I have a bike with 50/34 and 11-32 (11 speed) cassette. I regularly find myself using the two smallest cogs on the cassette and never using the 32 on the rear with the 34 on the front - I have been wondering about moving to 52/36 on the basis that with the 32 rear would make up for the bigger ring up front and I would be running nearer the middle of the cassette more of the time.

Thinking I might just swap the 34 ring for a 36 up front first because they can be bought for about £20 and only switch the 50 for a 52 if I find that sufficient. I assume that I can switch to a 36 without changing chain length or anything else, but will need to consider these things if I change the big ring. If I change the big ring can I just put a couple of missing links into the chain to compensate?

slowbike

drlodge wrote:

I recently bought a groupset with 52/36 crank on the basis the bike would be used for dry/summer/fast rides only. I then realised that I might want to use it on some big hills to for which I would need the 34 chainring. I've since bought replacement 34/50 chain rings so I should have gone for the 34/50.

I would ask yourself one simple question - what's the lowest gear you want. Then work out what combination of cassette and chainrings will give you that ratio. I'm 50 next year, fairly fit and run 34/50 and 12-29 cassette. I wouldn't want to drop to a 36 chainring or 12-27 cassette, the ratio just isn't low enough when doing a steep hill or on a century+ ride and knackered.

I went out at the weekend with a friend on his new bike, equipped with 34/50 and 12-32 cassette. That's a very low gear, he's pretty fit too but he used that 34-32 bottom gear when we hit the 20% slopes.

yup - so what I said earlier - get the gear to suit your riding... if you want an example - the Pro's won't be riding the same gear selection for the whole of the TdF - they'll have hard-arse gears for the flat stages then swap to pansy gears for the mountains ... why? Because they can select what is going to give them the best advantage for the race. I know we're not racing - but I fail to see why you wouldn't select the best range of gears to suit the riding you do.

super_davo

To me the biggest problem with either 50/34 or 52/36 is the big gap of 16 teeth. A compact is great for big hills but not so good for a false flat into the wind.
I'm currently using a compact where I've changed the inner to a 38. Biggest benefit is that on rolling terrain you're in the middle of the cassette where the increments between gears are smallest.
Large cassettes eg 11-28 and above tend have a bail out gear or two, but are the same through the rest of the cassette. That means you can still get up hills but have the close ratios for the majority of your riding.
I'm changing my groupset soon, and am going for 53/39 11-28 for this reason.

StillGoing

super_davo wrote:

To me the biggest problem with either 50/34 or 52/36 is the big gap of 16 teeth. A compact is great for big hills but not so good for a false flat into the wind.
I'm currently using a compact where I've changed the inner to a 38. Biggest benefit is that on rolling terrain you're in the middle of the cassette where the increments between gears are smallest.
Large cassettes eg 11-28 and above tend have a bail out gear or two, but are the same through the rest of the cassette. That means you can still get up hills but have the close ratios for the majority of your riding.
I'm changing my groupset soon, and am going for 53/39 11-28 for this reason.

One reason why I suggested a 36/50. For me it's finding what your comfortable average is and selecting a chainset to suit your needs. I'm not someone that will spend most of a ride down in the 12/11 on the big ring and more towards the big end and centre of the block. The 36 allows me to spend long periods in the inner and centre small end of the block at high cadence (95-100rpm) with relative ease without sacrificing speed. With the restricted flow of blood to the left arm, it also benefits when I lose feeling in the left hand on long rides and struggle to change gear on the front. If there's a steep ramp coming up, last thing I need is being stuck in the big ring.

Tiesetrotter

If you are comfortable go with the same ratios. I ride on average about 115km on a Saturday between 27 and 29kmh and we do around 1,500m to 1,800m of climbing.

I start thinking I can do this in a semi compact, I end up coming up some nasty liitle incline on the north downs thanking myself that I never put that 11 - 25 back on after last years Etape du Dales. Rarely do i chase our mountain goats up these things and just taking it easy on a 34 - 29 really makes sense.

Also it leaves my legs freshish for the thrash back into Lndon

cycleclinic

Gearing also has everything to do with leg strength. Even 50+ riders can handle tall gearing it just depends on what you are used to.

There is no right answer. I like 52/42T or 53/41T and rides for me have 100m of climbing per 10km. Everyone is different and if you prefer spinning up a hill then go with a lower gear. No point in struggling in a taller gear if you don't have the leg strength to sustain a steady low rpm. No shame in that we are all different.

imposter2.0

thecycleclinic wrote:

Gearing also has everything to do with leg strength. Even 50+ riders can handle tall gearing it just depends on what you are used to.

There is no right answer. I like 52/42T or 53/41T and rides for me have 100m of climbing per 10km. Everyone is different and if you prefer spinning up a hill then go with a lower gear. No point in struggling in a taller gear if you don't have the leg strength to sustain a steady low rpm. No shame in that we are all different.

You are confusing leg strength with aerobic capacity. Cycling has very little to do with leg strength as the pedal forces involved are very low already.

dag_on_a_bike

keef66 wrote:

Imposter wrote:

I don't really see what being '50+' has to do with it either way. There's no metaphorical cliff that you fall off when you hit 50. You either have fitness, or you don't, regardless of age.

Annoying though it is, you do lose muscle mass as you age. There's no sudden, cliff edge drop off, it's all very gradual. But inevitable, sadly. Which means a loss of power, and you have to accept that you'll be going a little slower with each passing year, especially uphill. So easier gearing becomes more attractive / useful.

While that may well be true, I'm certainly more powerful and quicker than I was 3 or 4 years ago, and I'm going to be 60. Soon. Very soon.

And I prefer to ride 50-34 and 11-32. The 34/32 certainly comes in useful, to me, when going up at 14-18% over 3kms+.

DeVlaeminck

I can happily ride 50*34 50*36 or 52*39, I just get a cassette to suit. At the moment I use a 50*34 because that's what came on the bike - I stick an 11 or 12 - 23 on for racing and a 12 - 28 or so if I go to the Alps or the Lakes. I find anything lower than that I'm just spinning my legs faster and expending as much energy for less speed - ymmv.