So got a new Bike Specialized Roubaix, which is a great fit for my build. Only when I was riding it I realized I am on a 50 34 chain ring. Looked on line and lots of bikes are being fitted with this even racier bikes like the Madone, Now:
Is this an issue? Having ridden 52 36 for ever, this feels weird. Looked at gearing tables and it’s not an issue, the question I have is other than big climbs what is the purpose of the 34? Also it seems to be a waste of gears as most of the time I’m only using 5 to 6 gears most of the time?
So I think I’m deluded and just need to get on with it?
Let’s assume that watts are not a concern (going down hill), the difference 52/11 and 50/11 at 90 rpm is 2km/h (51.6 vs 53.6). https://www.bikecalc.com/gear_speed
So it all depend on how often you above 55km/h and if you need to push every watts when you do… or if you work at a lower cadence.
Using the default values of the Gribble Interactive Power Model, and an arbitrary maximum comfortable sustained cadence of 95 rpm, the grade range where you’ll be spun out in a 50/11 but still could be putting power to the rear wheel with a 52/11 is -6.15 to -6.6. Any more decline than -6.6, and you’ll be spun out in either. Now, there are a lot of variables there (.cda, crr, mass, wind vector) which would change the actual grades where you spin out in either chainring. Regardless, the result is always a similarly narrow grade window where you’re coasting with a 50T ring up front when you could be going a touch faster powering a 52T ring.
I went from the standard setup many years ago to the compact 50-34 as I got older and hills got harder…it was fine except I was often spun out on the 50-11. Not enough that I worried about it all that much (I no longer race), but it was annoying.
I bought a new bike a few years ago (BMC Team Machine) that came with the semi-compact 52-36 & 11-30 cassette. For me, this is the PERFECT set up. I spend 90% of the time in the 52, don’t have any issue spinning out the 52-11 and still have better climbing gearing that I did with the compact set-up (could have changed the cassette I know).
Two things I won’t change now - Di2, won’t buy a bike without it and 52-36 / 11-30 is better (for me) than a compact setup.
like most, I got into the 50/34 game about 15 years ago. When comparing gear ratios, there isn’t much more you can do on 52 that you can’t do with a 50 and most of that time would be better spent tucking and free wheeling downhill. The 50/34 combo is a great triathlon setup. You don’t want to be mashing the biggest gears as often as you can when you have to run afterwards. The 34 saves your legs on those uphill sections.
If you’re talking about road bike gearing when you might have to chase someone going downhill, I could see your point. But in a tri, you usually have no idea about the running ability of the guy that just passed you. If you decide to put the hammer down and chase you could be burning up your legs to catch someone that tows an anchor when running. You’d be wiser to race your race and hope for the best. Both my road and tri bikes are on 50/34 to deal with the hills we have in the northeast.
Thanks, I will go out for a better hit out tomorrow and see how I go, when I looked at the ratios could see that I’ll be fine as I can’t recall too many times I was munching a flat road at over 50 going oh man I need a bigger gear
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I got a synapse 18 months ago and whilst I did swap the stock 50/34 for a Quarq I retained the mid compact gearing. FWIW then I’m an experienced and fairly strong rider, road and tri. Nothing spectacular but normally just inside the top 10% in the bike leg and top 20% in the road racing I do. FTP is about 320w from 85kg at 6’4", last ironman split was 5:12 on a rolling course, around 2:10 on a flat and fast 70.3, on an argon e-114 and S80 wheels.
This was the first time I rode anything other than a 53/39 on tarmac other than my touring bike that had a compact on for fully laden epic climbs. And I absolutely love it and it created a huge step change in my riding. Perhaps it’s size dependent, but means that I can stay seated and spin up all but the steepest climbs which at my size and power means that I am way way more efficient than I used to be. I’m now regularly challenging at the top of climbs and not blown up and dropping back. I am also very very very comfortable sitting on the front of the bunch at 40-55kph spinning at 97.
Now I can see some people being concerned at the descending. However, i am an absolutely huge pussy and my bowels give up before my legs on descents. I did keep the 53/39 in my TT bike but rarely find myself using the 12t (12-25 10speed). I would almost certainly replace the chainrings with 50/34.
Oh, as for the cassette on the synapse, I’ve left the stock on there with the bail out gear. And yes, I’ve used it and been hugely grateful. I don’t use it in normal riding, but I live half way up the road that our cycle club uses for the hill climb for the annual club champs, so after a 140km of the club ride if I’ve emptied the tank then having that granny gear to get home is awesome. I also use it when I’m tail end charlie as it lets me stay seated and climb next to some of the weaker riders who are struggling up some of the steeper gorges we have around here (15-20%).
I have zero care if anyone thinks less of me because of my chainset. Mainly as I can’t see or hear them for very long as they are too far behind… But equally I wouldn’t tell anyone to change to one if they were happy with what they are using. I’d suggest they consider it if they’ve never tried, as I tried it and loved it. But if someone didn’t get on with it, then fine.
Engage some logic.
36/34 is a 6% difference.
Going from say a 17 to 19 cog at the back is a nearly a 12% change.
So you’re bothering about a half a gear shift at the back.
It’s mostly a problem in your head really, not in the bike.
@Slowman said it best. You never wished for a bigger gear but always wished you had a smaller one. I love a compact crank and specified if on my Road and Tri bike.
Now it is standard issue - it’s what the masses want.
John
I was going to sell mine when I got it but was talking to a friend who is a cat1 and he was winning hilly road races and flat crits on the thing, so good enough for me.
I do like the 39 for noodling along, it’s a tall enough gear, where the 34 is just for the hills. I have a 46*34 on my cross bike for the summer and really like it
I see no reason to go past a compact gear unless you frequently cycle in groups, have little elevation gains or rarely spin past 90rpm for any extended period of time.
My most commonly used gears are 50/21 and 50/19. Spinning between 90-100 rpm on solo rides, I can maintain 21-25mph with these two gears depending on elevation and wind. On TT rides where cadence is emphasized, I can get up to 21-23mph on 50/21 at 110-120rpm. When wind or hills hit, I drop down to my 34 and a 34/15 or 34/14 can do 17-20mph within that range. If a long climb hits, I simply don’t run out of gears to keep high cadence. I can spin up to 42 mph on my biggest gear. There’s really no need to go past 40mph whilst training, ever, in my opinion.
Seeing people with 53/39 tells me that they misunderstand the importance of cadence with respect to aerobic power and efficiency. A high cadence on a lower gear has greater ability to produce more power with less fatigue over a period of time. It’s just part of the new ideology in cycling which has been producing successful results for over a decade now. Hence Froome’s ‘washing machine’ cadence on climbs.
Theres a reason most new, top of the line bikes are being seated with compact gearing. Hell, the Madone, Trek’s flagship aero road bike, comes stock with a 48/35 on all sizes.
My most commonly used gears are 50/21 and 50/19. Spinning between 90-100 rpm on solo rides, I can maintain 21-25mph with these two gears
What kind of wheels are you using?
With a 25mm 700c tires, 90-100rpm on 50x19-21 is a range of about 17mph to just under 21mph. Even on 2.6" 29er MTB tires, pedaling 50-19 at 100rpm only gets you to a little over 23mph.
My most commonly used gears are 50/21 and 50/19. Spinning between 90-100 rpm on solo rides, I can maintain 21-25mph with these two gears
What kind of wheels are you using?
With a 25mm 700c tires, 90-100rpm on 50x19-21 is a range of about 17mph to just under 21mph. Even on 2.6" 29er MTB tires, pedaling 50-19 at 100rpm only gets you to a little over 23mph.
I use 700c 25mm tires. According to the calculator, a 50x19 at 115rpm is about 23mph
I suppose from my context, those would be the average speeds I see whilst using that gear over a period of time. I also live in the Northeast so I may see more frequent elevation changes than many people and vary my cadence based on that
My most commonly used gears are 50/21 and 50/19. Spinning between 90-100 rpm on solo rides, I can maintain 21-25mph with these two gears
What kind of wheels are you using?
With a 25mm 700c tires, 90-100rpm on 50x19-21 is a range of about 17mph to just under 21mph. Even on 2.6" 29er MTB tires, pedaling 50-19 at 100rpm only gets you to a little over 23mph.
I use 700c 25mm tires. According to the calculator, a 50x19 at 115rpm is about 23mph
I suppose from my context, those would be the average speeds I see whilst using that gear over a period of time. I also live in the Northeast so I may see more frequent elevation changes than many people and vary my cadence based on that
I’d be pretty surprised if anyone was spinning at 115 RPM for any kind of extended ride. Even 100 RPMs is a very quick cadence.
50-34 is my least favorite chainring combo for a road bike. I agree on the 34t- and find it almost useless aside from very steep climbs. I’d only recommend 50-34 to folks that are very much a beginner or of low fitness level
Crap.
I’m a fairly decent cyclist, 4w/kg ish FTP, and find myself in 34 front 28 back pretty often and spinning <70 rpm. Why? Because I live in West Yorkshire by the Peak District which is all valleys and moors. I’m either climbing or descending 80% of the time, often well above 15%.
But people on here have always struggled to look further than their own experiences. You may not be in Kansas any more, Dorothy.
I have a 50/34 on my road bike, but that was put on when I was planning on doing the Mt Washington hill climb. I never got around to doing the race and was planning for it this year. Maybe next year… I have an 11-32 in the back with the long-cage Force derailleur. On my tri bike I have a 54/42. For anything under 32 mph or so the 50/34 is perfectly fine. I feel that over that speed I start to spin out a little - or at least a higher cadence than I’m accustomed to riding at.
I’d only recommend 50-34 to folks that are very much a beginner or of low fitness level
Ha. I love to climb and my ftp sits in the high 340/low 350 range putting me at 4.5 w/kg. I appreciate a 34 tooth chainring when I’m hitting routs with lots of 12+% pitches as well as at the end of rides where I’ve put in 5K+ of climbing. I don’t often spend time in the 34/30 gear, but it never hurts to have an easier gear so you don’t end up up with the sad click.