Comments on: Which Chain Ring to Use?

By: Karen, Richmond VA

Karen, Richmond VA — Tue, 01 Sep 2009 12:16:59 +0000

Great information.
I recently went from a 3 ring chainring to two and am having problems adjusting. I plan to practice some of this advice this afternoon on a very hilly ride. I have trouble (seems to take extra time) shifting to my small ring. By the time I get there I am screwed. And also, I have dropped my chain twice in this situation. Have been told it is due to excess pressure on the pedals when I try to shirt and also maybe I am in too low a gear in the back when I shift to low in the front. Is any of this true?

By: Alastair Hamilton

Alastair Hamilton — Mon, 17 Aug 2009 09:23:06 +0000

Hi Guys,Yes Paul a triple with 50-40-30 will give a wider range than a 50-34, but it will have more similar gear ratios.mds, personaly I would go for the compact over a 46×27 option.All great comments from everyone, thanks.

By: mds

mds — Mon, 17 Aug 2009 09:18:56 +0000

would a compact chain ring with a strainght block clustwer on the rear wheel be a better option than a 46 chain ring and 27 on the back?

By: Michael B..

Michael B.. — Mon, 17 Aug 2009 07:34:32 +0000

I just wanted to say I am looking into buying a bike and all this information helps me out soo much. Especially that last part by Michael and using the analogy of strength and aerobics and the topic of gearing also helps me out all and all this is a great all around site that I will be using from now on.

By: Mike

Mike — Mon, 17 Aug 2009 07:01:23 +0000

Hi,Just a comment about the compact versus triple chain ring question.I have a trek 7.5 FX with a 48/36/26 triple and a 11-26 cassette. This gives a pretty big top gear and a nice low gear for the many hills around here. It seems to work quite well.

By: Marshall

Marshall — Mon, 17 Aug 2009 07:00:53 +0000

Thank you!! Answered my questions perfectly, and very consistent with some of the answers I have recieved from other cyclists.Thank you very much.Marshall

By: Kurt

Kurt — Mon, 17 Aug 2009 06:59:58 +0000

Here is how I like to explain it.Cadence and RPM’s(revolutions per minute)on a bike is just like a car. The 90 rpm mark is a rule of thumb for being the most efficient for a bike similar to the 2300 rpm for a car.So when riding, keep your cadence at 90, as you find that it starts to decline to 86-88 and you cannot increase your effort to compensate for the drop, shift down. When you find your cadence is at 95-96 shift up. If you watch your car’s tachometer you will see a similar reaction.To answer the shifting using the front chainring vs of the rear sprocket it helps to understand the gear ratios you have available. Set up a table in a spreadsheet one column the number of teeth in each sprocket, one column divide the 1st column number by the number of teeth on the small chainring (39, 42 are common) and one more column divide the 1st column number by the number of teeth on the large chainring (53 is common). The lower the number the harder it is to pedal but the faster you will go while maintaining 90 rpm cadence. The important thing to identify from this exercise is that you will see that there is a range of ratios that are similar in both columns. In your spreadsheet, try to find the crossover point that minimizes the difference in ratios.

By: Paul

Paul — Mon, 17 Aug 2009 06:58:44 +0000

A typical triple crank with 52/42/30 or 50/39/30 will have a wider gear range than a standard compact double with 50/34, not the other way around as stated in the article.

By: Michael

Michael — Mon, 17 Aug 2009 06:57:45 +0000

All good advice but the best cure is simply time on the bike to see what works best for you. On a recent ride with mark Sumner, 2 time New York State road racing champion, he suggested that learning to spin is the key to going fast and saving your muscle strength. Over-straining your legs is like lugging your car in 4th when you should be in second. Its a trade off, spinning taxes you aerobically but saves muscle energy and power, gronking the pedals keeps the HR down but takes your power quickly. I saw in application when riding with Mark side by side when cars approached he was able to immediately jet forward up the hills in an instant, if his gearing were overpowering him he couldn’t do that. Just keep riding, dude, you will get it.

By: Kurt

Kurt — Mon, 17 Aug 2009 06:57:20 +0000

I try to keep the chain as straight as possible. If the Chainring is on the 39T and the 12t sprocket(smallest)the ratio is 12/39 or 0.307. The problem is the chain is under a lot of stress and friction causing drag which requires increased effort from the cyclist to overcome. It is far better to use the large front chainring 53t and the 16t sprocket with a 0.301 gear ratio. The chain will be straighter which means less friction and less work for you.