4zn_balla

Hello, i should first off apologize for all my previous "tarck" posts about barspins and hope that you guys have it in your hearts/minds to forgive me.

being focused on speed more lately, I've had the typical urge to up my ratio, as a brakeless rider i ask you to respect this choice, and understand that I ride this way because it has become second nature, and would not like the discussion to sway this way, but rather on the gear ratio.

I'm 48/17 right now.

On flats when i have the cruising speed of "blank" mph. Would i tend to keep the same cadence and thus go faster with a higher ratio, or work the same amount and have a slower cadence?

also, maybe i should just go by the "pedal faster/go faster" mentality.

bigbris1

Your question seems to focus on the "once you're moving" aspect & not the overall picture. So you wanna be a monster? You have to make sure you can handle all aspects of a higher gear ratio especially when riding sans brake.

4zn_balla

Yes, a very intelligent response, but it's not so much a "can i handle" but more of a "is it an advantage"

EatMyA**

To try and answer you; if that gear fits you fine for your physical ability/riding style,and you get a bigger chainring or smaller cog, you will SPIN SLOWER. You will have a SLOWER CRUSING SPEED because youll be using more force and getting tired more. That will give you LESS ENDURANCE on a longer ride ("long ride" depends on your definition of it, for some its 10miles for some its 100). You will have a SLOWER ACCELERATION. That will give you LESS CONTROL at slower speeds like you might encounter in heavy traffic. You will get a HIGER TOP SPEED at the same rpms. The question is can you hit the same rpms?

If the top speed outweighs everything else go for it. But maybe the gear you have doesnt fit you is that why? Is the gear you're on too advanced for you? You cant spin fast enough to keep up with it?

If thats the case, with time and practice your legs will get a bit stronger allowing you use the gear ratio you have now. With more practice, as you get faster you can upgrade to a smaller chainring or a bigger cog, because speed is more easily gained than strenght in cycling, your first upgrades will actually be downgrades in ratio to let you spin faster. Once you hit your peak for your rpm range (again it depends on you) then the upgrades start becoming higher ratios (wich you will already have the parts for).

Are YOU too advanced for that gear? Are you already out spinning that gear combination?

I ride 39/17 and I regularly have to get 140 rpm. Once I can get 160 rpm and sustain it I am going with a smaller cog maybe 39/13.

if you can hit 48/17 with a high top end of about 140rpm and sustain it, I think you are very impressive. You should probably get a bigger chain ring, or maybe a smaller cog might be cheaper.

GOOD LUCK! Let us know what you choose!

stryper

it's all about your ability like the above poster stated. But to directly answer what you asked about cadence and and cruising speed: If you get too large a gear ratio your cruising speed will decrease cause you won't have the strength to pedal it at high rpm with any sustain, so will actually go slower. Wether that will happen in your case nobody can tell you.

I would get a computer to help you figure out if you need to change. See if you can't barrow a smaller cog from a friend or even a lbs and ride it for a week or so and see how it effects your average speed (using the computer) and how you feel with it.

Another thing to consider riding breakless is your ability to stop. Is it ever a struggle for you now? I know that I have been riding a 52/17 breakless for 6 months and when I get too tired it can definitely be hard to slow quickly. If you ever find it hard to stop now, I would probably not up your ratio cause it would become harder to stop and then you really risk the chance of hurting your knees.

europa

Mate, fire up this applet: Rabbit (stolen shamelessly from the Gearing Primer at the top of this sub-forum) and get some figures to work from. With your gearing, you should be cruising at something over 20 mph. I say 'should be' based on a cadence of 90 being a pretty useful standard cadence, even for fat old phart's like me. If you're not cruising at 20mph or greater now, yes, you need to be spinning faster.

The thing about fixed gear is that YOU make the changes in the speed of your legs. Because the real world rarely lets us ride as we wish, this means that sometimes you will be pedalling slower than is desirable (and that places a lot of pressure on knees and muscles) and at other times you will be pedalling frantically. The thing about riding fixed is that you need to pedalling skills to be able to handle those high revs and quite frankly, if you can't pedal at 120, you are not going to be able to ride undulating terrain on a fixed gear bike - with your gears, that's greater than 26mph.

Now don't get excited and try to bluff yourself with inflated speeds, there's a world of difference between hitting a speed and holding it. Quite frankly, it's your legs that are going to be complaining long after other people have stopped admiring your gearing. Gear up too much, and you will stuff up your knees and legs - young blokes can do that for a long longer than us old wombats but it catches up to all of us in the end.

I wouldn't up my gearing unless I regularly found myself pulling a cadence of greater than 100 on the flats. Down hill, it's a non-issue, just teach yourself to spin faster and believe me, the thrill of spinning smoothly at 140 is pretty awsome (it feels like you're part of a turbine if you get it right).

You don't use brakes. Every time you up the gearing, you make it harder to control your speed and you increase your stopping distances. Make sure you have a ton of stopping clearance BEFORE increasing your gearing.

The real world is rarely straight, flat and devoid of things to slow you down. Increase your gearing and you will make accelerating harder and once again, it's them leg thingies that will complain first, not the bike.

Real world urban warfare usually means that you don't get to pull your preferred cruising speed for long and that you spend more time slowing down and accelerating than anything else. Increasing your gearing will make that harder and you will probably find that you don't get many opportunities to use the bigger gear.

Then there are the issues discussed above.

BUT all of that is bulldust. Just go out and buy yourself a 16 tooth cog, spin it on the back and try it. If it's still on there in a month's time, you made the right choice. If the 17 is back on, well you won't lie awake at night wondering about whether you want the higher gear.

Richard

jdms mvp

so if u can climb and stop with the "upped" ratio. go for it.

stryper

ya, try it out. Great thing about a new cog is it's only like $20 so if you don't like or can't handle it, it's not gonna burn a hole in your retirement.

europa made a good point about cities not always being flat and wide open. I started on 86 gear inches, moved to 82 so sliding and stopping was easier, and am moving down again to 80 gear inches just because it is a more practical gearing for around town with all the stop and go

adriano 

17 to 16 seems to be a a good sized jump. changing the chainring, while more expensive, would be a less drastic adjustment in that direction.

westokyo

^Well he says he is brakeless so 48/16 will suck. Why not get a 49 or 50 up front?