Road Bike Gear Ratio Table

Gear Ratios are Important for Climbing

One of the most common questions I get on the blog relates to gear ratios, most commonly framed around people struggling to get up hills. It can be demoralising when you see people flying up hills and you're panting away - I've been there.  Being 210Ibs in weight, physics tells me that I'll never be challenging for a Polka dot jersey!

What I did learn however is that  you can make it easier on yourself by having a review of the rear cassette on your bike.  It's one of the quickest and easiest things you can do to make things easier when hauling yourself up an incline.

First thing you need to do is establish what your current gear ratio set up is. There are are two ways to check this: -

1.  Look up your bike spec on the web and see what it comes with as standard (quickest way).
2.  Count the number of teeth on the front chainset and on your rear cassette (the teeth on the back wheel - count the largest and the smallest of the rings).

There are three different types of commonly used front chainsets: -

a) Standard - 53 teeth on the biggest ring/39 on the small (53/39).
b) Compact - 50 on the biggest ring/34 on on the small (50/34).
c) Triple - 50 teeth on the biggest ring/39 on the middle ring/30 on the smaller ring (50/39/30).

In terms of rear cassettes, there are a number of different cassettes you can buy and bikes are sold with a range of different cassettes on them, so have a quick look on the web and see if you can find yours.

Next Steps

Once you've established this, you can quickly figure out whether there is anything to be gained from a rear cassette change.  Basically, the higher the number on your rear cassette, the easier it will be to push the pedals when climbing up hills.  When you get stronger and fitter, you might want to change cassette again, it doesn't always have to stay the same as your gearing should match your capability/strength.

I've compiled this table below, showing the gear ratios for all three front chainsets, so you can quickly compare if a cassette change would be advantageous for you (if you click on the image, it will open in a new window).  I've highlighted the row in yellow as many road bikes are sold with a 12-25 cassette on from the showroom.
 

Road Bike Gear Ratio Chart - www.race-pace.net

 What does this show?

Even if you have a bike with a standard front chainset (53/39 and rear cassette of 25) which gives you a lowest gear ratio of 39/25 (1.56), you could achieve a similar gear ratio to a bike with a  compact chainset (50/34 with a rear cassette of 25 - ratio of 1.36) by switching your rear cassette to a 29 tooth (lowest gear ratio of 39/29, giving a ratio of 1.34).

How Low Should You Go?

Basically, the lower you get the ratio, the easier your pedals will be to push.  You have to remember that it's a balance as if you make things too easy, you may end up spinning like crazy and not going very far.

In my experience, a gear ratio of 1.1 or higher should get you up just about anything if you are new to cycling, overweight or just want the capacity to give yourself some breathing space on a bad day in the saddle.

When you are first starting out, you will need lower ratios whilst you build your fitness and stamina up.  My suggestion would always be - if buying your first road bike - to ask them to fit a 27T rear cassette, which will give you more capability. As you get fitter and stronger, then you can change your rear cassette to say a 25T if appropriate.  I run 34/27 on my climbing bike and my winter bike and 39/25 on my speed machine (I steer clear of hills on this one and ride it on flatter, faster routes).

Weight a Minute

One important point to note about gearing relative to hill climbing is your body weight, so it's worth a quick mention.  The lighter you are, the easier you should find it to go up hills on the principle that your weight + bike weight = total weight to haul up.  When combined with your output power (otherwise known as Power to Weight ratio or PWR per Kg) you will quickly realise that someone who is 126Ibs in weight and fit, will always beat you to the top of a hill.

If you are at the heavier end of the scale, selecting the right gear will give you more capacity to keep up.  We can't all be King of the Mountains, but getting your ratio right for your build will make it inherently more enjoyable.  See you at the top!