Computer science, but a firm believer that every sphere of knowledge is interconnected. This is just one case: algebra informing athletics. It's too bad our schools and society at large don't know how to resynthesize the disciplines after so many years of fractioning, the Greeks knew a thing or two.

so what you have to do is remove the tire spin it up a notch and your good to go for another so many miles. I always wondered about this stuff but never cared to think it out. Thanks.

slacking the chain and rotating the wheel by a few (rear cog) teeth would probably be easier.

Wow, phew! Thanks, guys! Now, not to be a PITA, but one revolution of my crank sent my rear wheel around only 2.5 times....?

okay, now do me.

i ride 39/14

*hides around a corner to see if that really worked*

You talkin' to me?!?!? HA!

sheesh...where did all the large chainrings go? 39? 42??? WTF!?!?!?!

50x16, minimum....all the way.

good for you.

ok, i'll do it, but only because of the flack you took over in the sXe thread.

you sir, have 14 possible skid spots.

Indeed. I just cannot think that way, but now that you mension it, sure that'll work.

2 5/9 times, to be precise because that's what 46/18 is. That's why ya gots to do the math to figger it right.

forgot about this thread, but thanks much adamkell. 14 is enough for me!

and i like my little chainring, thanks. the 14 tooth on the back is exactly the same size as the hub flange, which i find very nice looking.

How about an odd # of teeth. My fixie is 52/21. How many skid spots is that?

Can somebody do the math? I would but I'm too dumb and lazy!

skidding is fun

summed up nicely here...
https://www.dartmouth.edu/~ccatalan/skid.html
Now if only they made an online calculator to do it for you, like Sheldon's gear calculator.
Is it right that if your highest common factor is 1, then you have a skidpatch for every tooth on the cog?
If so, I guess that's another reason to have a larger drivetrain.

Yep

Sure, and then you'll have people trying to factor PGP keys using your website.

Yes, that's called relatively prime.

Not necessarily. For relative primeness it's better to be 47/16 than 64/16 (or even 48/16).

no, no. Not just a larger chainring, I mean larger all around, chainring, and cog so you can have a decent gear.
With more teeth on the cog, so more skid patches, so longer lasting tires.
I'm seriously thinking about getting a larger chainring and cog (and get below a 75 inch gear, this 77 inch stuff is nonsense!) mainly for this reason.

47/16 is better than 54/18 for that reason. It's all about relative primeness, there's just no shortcutting it, I'm afraid.

Likwise 48/15 is better than 48/16.

" Is it right that if your highest common factor is 1, then you have a skidpatch for every tooth on the cog?"
Then if you were saying I was right in that a highest common factor of 1 means a different skidpatch for every tooth on the cog, then it makes sense to me that a 16 tooth cog would have 16 skidpatches and an 18 tooth cog would have 18. So, the 18 would be better for your tires.
(I think this was discussed at length not long ago on the Fixed gear mailing list. Wished I would've paid more attention now, just like in my math classes!...)

I don't feel like starting a new thread for it, but can you guys skip with regular pedals? I can do it with clipless, but can't get the rear tire off the ground when I switch up pedals so I can go out in normal shoes. Maybe my technique is flawed.

Richmond sprint club does some grass track racing I believe.

What do you mean by "regular pedals"? I have clips and straps on my fixie (because I use it everyday and like to wear regular shoes) and I can skid just fine. I was riding with a bunch of other fixie riders last night and they said that it is EASIER for them to skid with clipless pedals because there is less of a "stretch" to the straps. but since I have always had clips and straps I really dont know the difference. I dont have a problem skidding with clips and straps. If you are talking about flats though, I know its POSSIBLE but difficult since you would have to put a lot DOWN on the pedals.

Yes, if you're talking about increasing the number of cog teeth while still maintaining relative primeness, then it is better to increase the number of teeth in the drivetrain. But if in increasing the number of teeth, you decrease the relative primeness, then it's a net loss. For example, 48/17 is good (17 patches), 48/18 is less good (3 patches), 48/19 is best of all (19 patches).

woohoo! i've got 17 skid patches!