In my original post ‘46 is the new 50‘, I talked about why I have changed all my outer rings on my compact chainsets (50/34T) to a 46T. The basic premise is to customise my gearing so I get more use out of more of my cassette sprockets on the big ring. I keep a big gear but I also have a much lower gear too reducing the need to drop onto the small ring so often. For my normal commute I essentially operate a 1×10 setup. I never have to use the small ring despite riding up and over the Lickeys both ways, 3-4 times a week. For really steep stuff the 34 inner gets me out of jail.
My first post prompted me to look back at my original calculations and I believe there is still merit in what I do and I’d even go so far as to say a 44T outer may now be even better!
Let me explain…….
Here is my 10 speed 11-28 cassette laid out with some of the most common outer chainring sizes showing gear inches per combination. Sprockets down the left and right, chainrings top and bottom
**calculated using a 25mm tyre (credit bikecalc.com)
So, lets look at a 50T outer ring first. I’m going to concentrate on the 24 sprocket as I don’t advocate using a big ring with the biggest sprocket, so I’ll go with sprocket number 2 instead, the 24.
Looking at the 50 column, 50×24 gives me a 55.03 inch gear. Thats somewhere in between 34×15 and 34×17. I know 34×16 is 56.35 so we can say its between a 16 & 17.
Looking at the 46 column now, 46×24 gives me a 50.80 inch gear. Well 34×18 is spot on 50 inches so its just a fraction over that. There is my lower gear as expected. This shows that by having a 46 rather than a 50 outer I get (the equivalent of) a couple more sprockets and a lower gear on the big ring which is enough to stay on it without the need to change down.
Looking at the biggest gear 46×11, it gives me a 110.59 inch gear which is pretty much the same as a 50×12 (110.32) or somewhere between a 52×12 and 52×13. I still have a big enough gear.
The 44T outer ring – take a bow
Now take a look at the 44 column. This is interesting. The point of all this is to not have really big gears you will never use just sat there on your bike. We’re swapping them for more useful smaller gears at the other end of the cassette so we reduce the need to change down to the small ring. My 46T outers do this for me. I’ve proved it, but can I make it even better?
44×24 gives me a gear of 44.42 inches. This is equivalent to somewhere between a 34×18 and 34×19. Nice and low(er) as we would expect but do we lose a big gear to compensate? Well 44×11 just happens to be exactly the same size (105.83) as 52×13. Plenty big enough yeah? I rest my case.
Ditch the 50 – impress your mates
I don’t get 50/34. It was a step in the right direction to get away from triples and massive 53/39 and 52/36 chainsets. It may work for you if you race but for me and average Joe, the smallest sprockets just never get used due to the size of the gears. My rudementary look at that proves, to me anyway, most riders would be better off on a smaller outer ring and go someway to explain why 1x setups are becoming more popular. I get to use those smaller sprockets now, all of the time with their nice sequential jumps (11,12,13,14 & 15 sprockets) when riding on those undulating flat roads. If the road goes up I have my small gears on the big ring and a get out of jail inner ring if the shit hits the fan.
Do the maths people. Don’t settle for what you are given. You can get more out of your bike than you think.
…and finally. Blow your mates minds when they see you climbing in the BIG RING. Get ahead of the game. They won’t know unless you tell them!
Bit about me
Here are some basic stats so you can compare yourself with what I do. I’m 45 years old and 65kg. I don’t twiddle gears, I don’t grind them either. 70-85 rpm is normal. I can ride up a 10% climb on my 46 ring quite comfortably using my 24 (or higher) on the back as my lowest gear.