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I am due to a new set of chain rings and chain on my bicycle (which I bought second hand).

The current gear is:

  • Front: 53/39
  • Rear: 11/28

I used to be a competitive racer wich made these gears also bearable in the Liege-Bastonge-Liege hills (close to my home). But now several years after "retirement" I am back to biking and having a lot of pain on the hills.

I like to do small races (50k with avg above 40km/h) and I fear that going to a smaller chainring will limit me in these races that are mostly flat.

So my question is can I do these races with a 50/34 in the front with a cadence of 95 rpm? So that I can enjoy both sides of cyling?

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    You sound like you're in a better position then people on this forum to answer your question!! You know your athletic ability, you know your hills, you know your preferred cadence. Together with a bike cadence calculator you should be able to put everything together bikecalc.com/speed_at_cadence
    – user2705196
    Commented Apr 21, 2023 at 11:49
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    You can get 51 and 52T chainrings compatible with a lot of setups so you don't need to make such a big jump. Also, have you considered swapping cassettes (or back wheels) between events to show you to optimise the gearing for each race? Do you know what your RD can handle?
    – Chris H
    Commented Apr 21, 2023 at 11:50
  • What is the rear derailleur on your bike? Try and find the model number, often printed/stamped onto the mech. For shimano, it will likely start with RD-. That will tell us if you can take a larger large cog in teh cassette, like a 32 or 34 tooth.
    – Criggie ♦
    Commented Apr 21, 2023 at 12:19
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    I'll echo the suggestion of a wider range cassette if possible. Even if your current derailleur doesn't support it you could change the derailleur when you next need to do a cassette swap. It could be inexpensive if you are willing to go lower end (e.g. drop from Dura-Ace to the still excellent 105). I assume you are no longer counting grams if you are racing more casually now. You'd have more range and flexibility in chain ring selection, the downside being more difficult to keep a particular cadence (bigger jumps in gears). Though if you are running 2x11 that may be a non-issue.
    – shox
    Commented Apr 21, 2023 at 20:07
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    Have you considered an 11-30 cassette? Will give the lower get same as 50 chainring but maintain the high gears you want with the sacrifice of larger steps between gears. (Could swap cassette for a race as you do not need the lower gears if the step is to much sacrifice.)
    – mattnz
    Commented Apr 21, 2023 at 20:16

1 Answer 1

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I suggest playing around with https://www.ritzelrechner.de/

With 50/34t chainrings and 95rpm cadence you get these speeds (link to the setup):

enter image description here

As you can see, at 40km/h you still have 4 more gears available for a top speed of 55km/h. If you increase your cadence to 110rpm for a short time (e.g. during descents) you can go all the way to 64.5km/h. Perfectly fine in my opinion.

Personally I’ve never understood why so many road bikes are sold with 53/39t chainrings. IMHO it gives you gear ratios which are only suitable for a world class professional, and even for them it’s only suitable for races or flat terrain. For long, easy training rides in even somewhat hilly terrain the gear ratios are way too hard.

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  • It's been a while since I posted the Q but still havent decided what to do. To have a second opinion on your statement I will share this information. "IMHO it gives you gear ratios which are only suitable for a world class professional, and even for them it’s only suitable for races or flat terrain." Pro's will race the big gear in normal mountain stages for sure. You need the 53 in long descends where the speed goes way above 60-70kmph. If you see the actual speed they ride uphill a 39T with 28T or even smaller should not be a issue.
    – Mech_Engineer
    Commented May 22, 2023 at 5:53
  • It really depends a lot on the terrain. IMHO the highest priority is almost always to have enough easy gears for the ascents. On a pure racing day bike those gears can be harder (especially if the race or at least the ascents are short).
    – Michael
    Commented May 22, 2023 at 7:21

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