wi.flash

I am looking at a 18 speed road bike and I am afraid I would not have enough top end speed. I know when it comes to the hills I can htfu, but I dont want to outgrow my bike.

I am looking at 36/50T Chainring. Then the range is a 12-24t. Thanks in advance.

LowCel 

The number of speeds has nothing to do with top end speed. If you want more speed you can get an 11t small on the rear cassette, an 11/27 will give you more high end speed and a lower gear for climbing.

Most people have "20 gears", 10 on the back, 2 on the front but that doesn't mean they have more top end speed gearing.

wi.flash

is there a big difference from the 11t to the 12t and then from the 24 to the 27? If I am correct. The smaller the number the top end speed and the higher is for climbing? Sorry if I make no sense.

55/Rad

A 12/24 cassette with a 50/36 crank will render the same range whether you have 10 gears or 2. What changes is what is between the 12 and the 24. As mentioned, you can change the range to make it harder, easier or both by either changing the gears on the cassette or the crank.

wi.flash

I do understand that you can change gears in between, but if I am following you correctly. The low and high are still going to be 12/24 and 50/36 and all the other gears are mixed within. I do understand that it all depends on ability level, but what are the chances of spinning a top gear in this setup?

55/Rad

As Lowcel mentioned, you can add the 11t cog if you are spinning out your 12 in the 50 ring. Or you can change the cassette to the 11/27 to give yourself both more low and top end. Or if you are finding everything too easy, change to a 53/39 standard crank.

big chainring 

I ride 12 speeds total. 6 speed freewheel and double chainrings. Why get so complicated? I rarely have the need for more gears. And I ride a 40/54 with a 14-21 freewheel. I spun out the 54 by 14 once - tailwind in a group ride. Really dont want to ride that fast. Gets a little hairy.

FactVord

Low would be 36-24 and high would be 50-12. I'll give you two months - if you haul 50-12 for longer than 15 minutes on a flat, my hat's off to you.

DScott

You'll be fine. I'd worry more about the low end than the top...

Where do you ride? Do much climbing?

rm -rf

It's pretty common for experienced riders to spin the cranks between 80 and 100 rpm. For instance, I like to stay between 90 and 95 rpm when I'm on flat roads.

Here's a chart of a bike with 50/34 and 12/25, so it's very similar to your bike's gears. (It's from Mike Sherman's gear calculator) The 50 chainring is in black, and the 34 chainring in red.

You can see that the high gear, 50-12, is for riding at 30+ mph. (That would be downhill for most recreational riders!) So you won't be maxing out your high end gears.

Actually, many riders are more concerned about having a low enough gear for the hills.

Shimagnolo

Agreed. We all know speed is directly proportional to how much money you have in your bike.

dahut

Thats me.

Im not a young rider in the peak of condition. I'm 54 and glad to be riding at all. I dont ride for flash, or to leave flames behind as I blast down the road. Some people live for that - I'm not in that big of a hurry.

Hills are the challenge I live for. Getting up the steepest in one piece, without falling over in a heap, is my thrill.
Triple chain rings are for me, with 9-10 cassettes. All the numbers and subtle differences between gears are lost on me. Again, I know some guys live for all this stuff, and I welcome them to it.

For me, there is high range, mid-range and hill grinding range.

wphamilton

Not likely.

LesterOfPuppets

Average? Lemme see.

2 single speeds
1 sixteen speed
2 twenty-one speed
1 twenty-four speed.

84/6 = 14

My average at the moment is 14 speeds.

My 16 speed bike is a 14 speed bike when I put the sewups on, so maybe I should call that one a 15-speed?

LesterOfPuppets

I'm with rm -rf, though. 50x12 is a downhill or stiff tailwind gear.

wi.flash

Thanks everyone for the replies. I think have a pretty good grasp about gearing now. Makes MUCH more sense now.

bbattle

Even Alberto Contador had a 32T sprocket at the Giro this year. (52-39 and 11-32) David Miller went with a 52-42 and 11-36. Mechanics must've been pulling their hair out.

OP, you can swap the 36T chainring up front for a 34T and swap the cassette in the back for a 12-27 if you want lower gears for the climbs. Or you could gear up and go 52-36 with an 11-24.

It's not recommended but you could swap both chainrings and have a 52-34 up front. Put an 11-28 SRAM cassette on the back. If wide range is what you want, you can have it.

tyson387

I read an old bicycle maintenance book by an American- don't remember the name but I remember the cover had a picture of a guy working on an old Condor road bike. He said he had a set up that was something like 60-30 up front and 13-24 on the back. People always use to give him a hard time for it but he said it worked for him. My question is whether a set up like that would even be possible on today's bikes, and would it really be that terrible? I was playing around with the gearing calculator on the Sheldon Brown site and it was a perfect layout in regards to keeping the same RPM's and moving right up the latter from the 24 to the 13 in the 30 gear and then switching to the 24-13 on the 60 gear if that makes any sense. You would only have to shift between the large gears once because you wouldn't have duplicate gears.

Just for the record- I know that if I ever used this setup I'd probably only use 10 of the gears, however, I was just curious

Gear chart using MPH @ 80 RPM

For 700 X 25 / 25-622 tire with 170 mm cranks

With 9-speed "Classic 9" 13-14-15-16-17-18-19-21-24 Cassette


6076.5 %341329.0
16.47.7 %1426.9
15.27.1 %1525.1
14.26.7 %1623.5
13.36.3 %1722.2
12.65.9 %1820.9
11.95.6 %1919.8
11.210.5 %2117.9
10.214.3 %2415.7
8.9

tyson387

That didn't transfer over quite right

here it is again

60

tyson387

Darn tab button.
Here's another try

@80 RPM
GEAR gEAR
60 30
GEAR
13 29.0 MPH 14.5MPH

14 26.9 13.5

15 25.1 12.6

16 23.5 11.8

17 22.2 11.1

18 20.9 10.5

19 19.8 9.9

21 17.9 9.0

24 15.7 7.8

reshp1

Definitely not recommended. You would be comprising shifting on the front with such a big gap between the gears and you might also need a new rear derailluer with a longer cage to take up the chain length differences

lol headwind

Basically you shift the entire cassette when you change chainring? That's pretty nuts, but I guess it's less nuts if he (presumably) had downtube shifters.

Reynolds 

60/30 rings? How would that shift?

EdIsMe

I ride an Sram Apex 53/39 in front and Sram Apex 11-23 in the rear.

I also live in Florida which is pretty much flat. I have used both the very low range of my gearing, as well as the very high range. The gearing does have some overlap, but the range of overlap is actually welcome in some circumstances.

For example:
In the small front ring, my max speed without crosschaining and without exceeding 105rpm cadence, is something like 24mph. In the big front ring, my minimum speed without crosschaining and without exceeding 70rpm cadence is something like 16 mph. The overlap allows me to choose a particular front ring depending on the riding I'll be doing and ride in a good number of situations without having to shift on the front derailleur. If I know I will be riding in a more suitable range for one ring or the other, that's when I shift.

If anyone cares, 105rpm cadence at top gear (53x11) puts me just under 40mph.
I also have a fixie with a 46 front and 13 rear.

kf9yr

If you live in Port Edwards get a 53/39 with a 11/25 cassette.

I lived just south of you for many years and there aren't enough hills anywhere near you to worry about ever using even the 39/25 combination.