Dr1Gonzo

I've got a 46/18 at the moment.
Edit: meant moving from 16t to 18t
It's perfect for the way down but on the way back up home, there is some very gradual incline and 2 steep sections. I can just manage it on my 46/18 but my left knee hurts a bit and it's slow going.
Wondering if swapping to an 18t would help or is there not going to be much difference?

oouellette

ggpepper

Maybe you meant going to a 20t? If so, going up will be easier but going down won't be as much fun....if that's possible

ThermionicScott 

Try standing when you climb.

Blylan

Does OP think 18 and 18t are two different things?

Dr1Gonzo

oops. meant 16t to 18t

Co1Ev

A change of two teeth on the rear cog makes a massive difference - there are some hills I struggled with when first riding 48x16 in my local area but after popping an 18 on the back they were breeze. Just gotta get used to the higher cadences when coming down the hill.

Track cogs can be had for fairly cheap, pick up an inexpensive 18T cog to see if you like it. if you do, great. Ride the hell out of it and then replace it with a better quality cog further down the line. If not, try a different ratio then rinse and repeat.

Dr1Gonzo

If I want on the freewheel / single speed side rather then the fixed side, is there a freewheel as part of the cog in these or can I use the existing one and just fit a new cog onto it?

TimothyH

Freewheels and cogs are two different things.

You can use two freewheels, one on each side of the wheel and coast all the time. Or you can use two cogs, one on each side of the wheel and ride fixed all the time.

Or you can use a freewheel on one side and fixed-gear cog on the other, any number of teeth you want, in any combination. The threads for freewheels and cogs are the same. there is no fixed/freewheel side. The wheel doesn't care.

The only thing to watch out for is that some freewheels can't be removed once they are installed without diassembly. You have to punch out a part of the freewheel, disassemble it and remove it with a vice and pliers.

seau grateau

Not necessarily. On many hubs, one side lacks the reverse-threaded section needed to use a lockring for a fixed cog.

Dr1Gonzo

At the moment, I have a flip flop hub on a Fuji feather.
So if I get a 18T it can go on either side. I suppose there is an existing freewheel mechanism that I can just unscrew the existing cog from?

Blylan

I have a 2012 Feather and the stock freewheel attached requires a bit of dismantling to remove it, for the Fixed Cog you just need a lock ring tool and a chain whip.

TimothyH

First of all, and again, freewheels and cogs are two different things. You can't unscrew a cog from a freewheel mechanism - freewheels and cogs are completely different things. You replace a freewheel with a cog and lock ring, and vice versa. If your bike can coast then you have a freewheel. If your bike can't coast (AKA fixed gear) then you have a cog with lockring.

Second, as @seau grateau pointed out, some wheels don't accept a freewheel on both sides. You have to check your wheel, make sure your wheel has the capability to accept a lock ring on both sides. If you see two sets of threads on both sides then you can put freewheels or cog/lockring on both sides. If one side has only one set of threads then you can only put a cog/lockring on one side and the other has to be a freewheel.

In your case, if you can see two sets of threads on the side that currently has nothing on it then you can just buy a cog and lockring. You will need tools (lock ring tool and possibly chain whip) to install it and grease to lubricate the threads. If you don't understand all this or if you don't have and can't buy the tools then it is probably best to go to a shop. Five minutes in the local shop is going to answer all your questions.

McBTC

There is ~10% change in gear inches when you increase the rear cog by 2 teeth...

Dr1Gonzo

My terminology is all messed up then. On a MTB, what do you call the 6 or 7 rings around the back freewheel/cassette - not cogs?
How do I change the size of the ring on the freewheel side?
Pics of the fixed side and pics of the freewheel side.
I don`t really mind either but since freewheel is probably easier downhill then I should probably put the 18T on the fixed side. How many extra chain links would be likely?

Flatulentfox

On a modern mtb, you have a free hub with a cassette. The ratcheting mechanism is built into the hub. On a flip flop hub like you have, the ratxheting mechanism is built into the removable freewheel. The hub is just a solid chunk of aluminum. You change the entire free wheel to change gears.

Do your self a favor a visit sheldon brown. That should clear most of this up.

Cute Boy Horse

You just answered your own question, as a whole unit they are either a freewheel or a cassette. Each individual toothed wheel is called a sprocket.

When you are talking about non-geared bikes you talk of freewheels, which are lone sprockets that can coast because they have a freewheel type clutch mechanism built in, or you talk of cogs, which are lone sprockets that can't coast.

When you talk about (dérailleur) geared bikes, then a freewheel is the same but with more sprockets attached. Cassettes are multiple sprockets with no clutch, because it's inside the hub instead.

Dr1Gonzo

And no need for a longer chain with a 18t? ie moving from 46/16 to 46/18.

SquidPuppet

Each tooth increased or decreased will force you to move your axle 1/8 inch. So swapping from 16 to 18 and vice versa will require you to re position the wheel 1/4 inch (6.35mm) forward or rearward in the dropouts.

You'll need to look at your current set up to see if that will work, based on where your axle sits now. Also check tire/seat tube clearance.

Why I care

Well it make a difference because the more tooth you get like 14T and 18T the 18T will have more torque than 14T but 14T have more Horsepower.Here is the simple explanation:More torque=faster acceleration and easier to climb any hill,More Horsepower=faster Top speed but if you want to climb any hill it will be tougher

Rolla

In general, it's cheaper to replace cogs than chainrings, but cogs make a more drastic change in the gearing. As already noted, going from 16 to 18 is a pretty big jump. You might try a 17.

As an avid singlespeeder, I have amassed a pretty large collection of thread-on freewheels, individual cassette cogs, and chainrings over the years. I consult gear inch charts and try to put all of my singlespeeds within the same range -- I like the low 60s for the kind of riding I do, which includes some fairly stiff climbs. As I've aged, I've gone to easier ratios -- my glory days of 74 gear inches are well behind me!

Point is, it's all about experimenting and finding what works for your fitness and terrain. Cogs that you buy and don't use can be installed on future projects; there are lots of combinations that yield similar gear inches. It's all part of the fun, IMO.

79pmooney

You just answered a 6 year old thread. I've been here a while and I don't recall seeing Dr1Gonzo at all. Not a big deal. I'll confess to being guilty of the same from time to time but some posters here have big issues with old threads being dragged up and will almost certainly come onto this thread to tell you of your sin.

And minor correction - horsepower isn't what you are talking about. Horsepower is applied force times speed. The higher gear reduces the applied force. (No, it certainly doesn't feel that way! but that high gear means the enormous force we apply at the pedal is reduced big time at the cog/freewheel/cassette.) Horsepower is not directly dictated by the gearing other that the fact that at too high or low a gear we cannot push the pedals or spin out and therefore fail to produce one part of that force times speed. (And that force is the average force over the entire pedal stroke, not the crank-busting effort we can do when the crank is at 3:00.)

Of course, on a singe speed or fix gear, the game is to best match the gear with the available range of pedal speed and strength we have (and not either do damage to ourselves straining knees, etc. uphill or over-spinning downhill - brakes can be very useful in that second scenario). One of the gifts of riding fix gear is that it opens up our usable range of RPMs a lot.

So, yes, I am continuing the presence of a long dead thread but as many here know, fix gear is my true love. And riding fix gear has changed very little in the past 140 years. Flip-flop hubs were raced more than a century ago (and are seen at the velodrome to this day - no the big races are all won on single sided hubs but at the Thursday evening races, a guy might have a 14 on one side and a 15 on the other for the next different type of race). (My avatar photo is a custom fix gear that I have used to ride 5 week long - and mountainous) Cycle Oregons. Yes, I cheat. Flip-flop hub, fixed on both sides, the chainwhip you can see on the top tube and all the 1/8" cogs between 12 and 24 teeth. Stops to flip the wheel or unscrew cogs. All stuff they did or could have done 100 years ago. And I plead guilty to being 61 years old when that photo was taken. That day I rode 42-17 with a 23 on the other side and the little 12 to make the descents a blast. Photo taken in the hills south of Mt Hood riding toward the Sisters. We'd already ridden over a pass and lunched at a dam. Pass to lunch was fun!)

79pmooney

And related but important enough to warrant a new post IMO - cog quality for running fix gear:

If you ride the hills, run velodrome quality chainring (if possible, often it's not) chain (easy) and cogs (well, they do cost more). I strongly recommend running 1/8" for everything. Reason? Downhill, RPMs can approach the ridiculous. I've done high 40s MPH in gears like 42-17. (For brain dead easy math, 100 RPM in that gear is 20 MPH. So, 40 is 200 RPM, 50 is 250 RPM.) Pedaling smoothly at those RPMS? Yeah, right! If your chain can possibly come off at the loosest part of the pedal cycle, sooner or later, it will. And the consequences will be excessively exciting. That's a given. Might end your ride, your rear tire, your frame's paint, some spokes. some frame integrity, some intact skin, maybe the integrity of a bone or two.

Two ways to prevent this from happening. 1) run a tighter chain. (This could be expensive. With less than velodrdome quality cranksets, the wobble in the chairing circle - not an issue at all with gears - may mean the chain goes full tight momentarily at one point of the several pedal revolutions chain cycle. This will act to put forces on the BB and hub bearings they were never intended to see. Or 2) put the proper slack in the chain and use running gear that is as resistant to derailling as possible. (Basically you are trying to go as far from a modern derailleur chain and cogs as you can get. Those nice rounded teeth that run so quiet (and shift so nicely on cassettes? Bad!)

I run: EuroAsian 1/8" cogs. ~$35 last time I looked. Expensive, yes. Quality steel and they last a long time. Square cut teeth and noisy. Popular at the velodrome for the racers without deep pockets. Isuzu Eco 1/8" chains. $25-30 depending on color. Quality the same for all colors and very high. Again, square and noisy. Also velodrome popular among those on a budget. (And the guys riding the good stuff don't mind seeing the Isuzu and EA on the bikes of the wallet strapped because they know it's good good and they won';t behind a chain throw crash.) My chainrings are all 1/8" but from a variety of sources. For my 110 BCD bikes the Mojo rings are good, round and OK for wear. Haro BMX rings are excellent but I haven't seen one in many years. That bike of my photo has a sweet Sugino 75 crankset with rings as good as they come (and that crankset is so round, setting chain tension is a joy!)

The cheaper you go with your crankset, the more important having chain-throw resistant chain and cogs becomes. Also the more attention you have to pay to setting chain slack right. I have a couple of Surley cogs with a nice gold finish and rounded, quiet teeth. Scares the **** out of me on my bikes with 110 BCD road cranksets. I'll only use them with that sweet Sugino 75 where I can set the chain minimum slack at a proper 1/2" and it never goes beyond 5/8" (I feel much more comfortable with the EA cogs and gold doesn't fit the color scheme so those Surley will last my remaining lifetime plus!)

The money spent on the Isuzu and EU is money well spent if you keep riding fix gear because they wear so well. I do track chain stretch and replace when needed but I keep them. The day may come when all or enough of my cogs have worn past being good fits with new chains and I should be able to start a "new life" with both for most of the miles it took to get past the original "life". That original has been well over 20,000 miles with several replacements of my most used 16 and 17 tooth cogs. Another 10-15,000 miles should have me covered a long time! (This personal aging issue being a friend here.)

Rolla

D'oh!

Bianchi pc

Quote

I run: EuroAsian 1/8" cogs. ~$35 last time I looked. Expensive, yes. Quality steel and they last a long time. Square cut teeth and noisy. Popular at the velodrome for the racers without deep pockets. Isuzu Eco 1/8" chains. $25-30 depending on color. Quality the same for all colors and very high. Again, square and noisy. Also velodrome popular among those on a budget. (And the guys riding the good stuff don't mind seeing the Isuzu and EA on the bikes of the wallet strapped because they know it's good good and they won';t behind a chain throw crash.) [/QUOTE]

Im all for reserection of dead threads if they are as interesting or informative as live ones ( &, or could be with a contribution like this ) this place has been a ghost town as of late...

I also have Izumi eco chains and EIA deluxe cogs on both my bikes and have been doing so since I read in the bike forums track racing section experiences from people who have run the gold cog and the super toughness chain - no measurable performance difference at all between them and the deluxe/eco combo I'm not looking for bling - just quality components...