Maracski

I live in hilly hilly San Francisco and am new to fixed gear riding. For right now I'm only riding on the street but am aiming at getting back into shape and going down to the hellyer v-drome on Saturday mornings. I'm a heavy girl but super strong from 25 years of biking, skiing, and soccer (I'm only 29).

My set up is 46x16 (75.6 gear inches) and I'm having a real hard time stopping (skidding). I can control my speed fine but can't get enough back pressure on the pedal to skid. I want to swap out my cog for something larger, my questions is: how large should I go? Initially I was think 18, but I'm afraid that's still going to be too high. I'm afraid to go to 20 because I don't want to spinout and bounce all over the place. Again, my main objective is to be able to skid stop in hilly hilly San Francisco.

Please let me know what you think. Any advice is most welcome.

endo shi

There's no skidding in the velodrome; ask at fixed gear/singlespeed forum

ultraman6970

46x16 isnt that heavy gear anyways, talking as ex track racer... to tell you the truth thats what a 14y/o kid uses for track racing... In my oppinion your problem is that you aren't that strong as you think you are to start with... secondly you havent master the technique of lifting the rear wheel... Probably thats what you mean with skidding?... lift the rear wheel thats all you have to do to stop. isn't that hard to do anyways but it requires practice.

Wonder if you can lift, make the bike jump completely out off the ground with you seated in it. Standing in the pedals is even easyer to do anyways...

46x18 is similar to 42x16... thats ok for riding in the street. If you have problems (jumping over the seat) riding with 46x18 it means that you arent that fast also. In another thread I told how to master racing pace...

Btw... you should be able to move a gear similar/near to 50x15 at least at 90 rpms all the time for at least 30 mins in a regular per points race, so think in sprints, attachs, counter-attachs and stuff also. Gtg... i started to talk s...t again....good luck

Dubbayoo

Do you have brakes?

Mike T.

Only Skidiots skid. Locked wheels slow a vehicles slower than unlocked wheels that's why cars have ABS systems (antilock braking system). Skids wear out tires really fast.

tjsager

To save some wear on your tires, use an even number toothed ring and an odd number toothed cog or vice versa. This will allow your tire to wear a patch on 2 opposite points. If you use even numbered ring and cog or odd numbered ring and cog, you will have only 1 wear point on the tire.

As for skidding, you'll just have to develop the strength. It won't take that long if you ride daily. Of course skidding on the flat should be easier to practice than up or down hill. Good luck.

fixedpip

Read either of:

Fixed Gear 101:
https://www.63xc.com/gregg/101_1.htm

or Puma's fixed gear book:
https://www.pumaville.com/downloads/book101.pdf

Then go and search fixed gear/single speed forum:
https://www.bikeforums.net/singlespeed-fixed-gear/

nexus6

I read a chart somewhere that showed if you use a 17t cog, you get the most skid patches on a tyre.

andre nickatina

Skid patches=Reduce your gear ratio down to the lowest fraction it can go (48x16=3x1)- the denominator is how many skid patches you'll have. I run 49x19 which doesn't reduce down, so that's 19 skid patches. 48x16 would make 1 skid patch, so a very bad gear ratio if you plan on riding brakeless in the streets.

oldsprinter

There's some really dodgy mathematics going on here. Tyre wear is not linked to even or odd chainrings, it is linked to roll-out distance. For example 44 x 18 and 32 x 13 will cause near indetical wear to a tyre.

piwonka

yeah, but they are talking about number of skid spots given certain gear combinations.
17 is prime so you always have 17 skid spots.
skid spots matter not one bit if you don't skid though.

75 gear inches isn't bad on the street. work on your technique.

if the OP will search the SS/FG forum there is tons of talk about this already...you don't skid on the track.

Mr. Clean

To initiate a good skid, you need to unload the rear wheel by shifting your weight to the front of the bike. The best way to do that is to straddle your stem, with your legs touching the flats of your handlebars. The farther forward you lean, the less weight there will be on your rear wheel, the farther you will skid.

Start out slow to learn the timing, and get comfortable enough to commit to throwing your weight forward.

Also, get on youtube and watch some videos. Pay close attention to the riders' motions, not just watching the skid.

Richard Kennedy

Close, but not quite the full story.
Just because 17 is prime doesn't mean you'll get 17 skid spots. Consider the gear 51x17. 51/17=3 , so assuming you skid with your pedals in the same place each time you'd only get 3 skid spots. What you're looking for are a ring and sprocket combination which are, technically speaking, relatively coprime. That means the 2 numbers have no common factors.
17 would be a good sprocket to use but, as already shown, you'd have to avoid the 51 ring (3x17) and the 34 ring (2x17).
There are plenty to choose from. eg. any odd size chainring with a 16 sprocket.

Having said all that, I tend to agree with those who've argued that you really don't want to be skidding on the road in the first place. I've ridden fixed on the road for 15+years, if you're in a situation where you need to skid then you're in trouble!

Ceya

Just no need to do it. Sometimes it is good to practice it to learn to get better control of the bike.

RK states " I've ridden fixed on the road for 15+years, if you're in a situation where you need to skid then you're in trouble!"

I disagree.

S/F,
CEYA!

dutret

This doesn't belong in this forum but since there have now been two misinformative posts on the topic it deserves to be pointed out. 51/17 gives you 1 skid patch. Since the every time the pedal is in skidding position the wheel is in the same one. To calculate otherwise you find the largest common factor of the CR and cog and divide the cog by that number. If you have a prime chainring then you will have exactly as many skid spots as you do teeth on the cog.

If you actually care about this which there is no reason anyone in the track forum should do a search over in ss/fg.

oldsprinter

I still don't know how to skid.

fixed_ROCH

just lean forward and lock your legs the more weight off your back tire the better, then you can lean back after you start the skid.

lwtrower

skipping usually stops you fast than skidding. put your crotch on the stem and lean forward

Yoshi

No, 51x17 gives you 1 skid patch assuming the pedals are always in the same location, or 2 for two pedal locations. 51/17 = 3 means the wheel spins three times for each crank rotation, so every full rotation of the crank results in the tire being in the same exact position as at the start of the revolution. However cause half a rotation of the cranks moves the wheel 1.5 times, you get two skid patches for each half revolution.

tjsager

https://www.sheldonbrown.com/fixed.html

Skid Patches

If you make a habit of doing "skip stops" you will wear your rear tire out considerably faster than if you use your front brake. This problem is exacerbated by certain gear ratios, because you may tend to repeatedly skid on the same section of the tire.

Riders who plan to do a lot of skip stops should consider the ratio when selecting their chainring and rear sprocket. The mathematics of this is actually fairly simple:

* Simplify the gear ratio to the smallest equivalent whole number ratio.
* The denominator of the resulting fraction is the number of skid patches you will have on your rear tire.

Examples:

44/16 simplifies to 11/4, so there would be 4 skid patches.

45/15 simplifies to 3/1 so there would only be 1 skid patch.

42/15 simplifies to 14/5, so there would be 5 skid patches.

43/15 can't be further simplified, so there would be 15 skid patches.

This is based on the assumption that you always skid with the same foot forward.

If you are an ambidextrous skidder, and the simplified ratio has an even numerator or denominator, your number of skid patches will be the same.

If you are an ambidextrous skidder, and both the numerator and denominator are odd, the number of possible skid patches will be doubled.

diff_lock2

Im running 69 gear inches (42-16, 700c). I don't skid so much, i have a front brake. But i do skid some times, and what i do is hop a little to start the skid every time. But it really doesn't slow you down, its incomparable (un?) to a front brake (+kool stops)... How can you spin out?!

Once i reach my limit, (50kmph) i just stay there, no point of spinning out of control. I checked, it looks like a bit more than 120rpm. Keeping at that speed is crazy, i poop out too fast (less than one min).

Six jours

Just to elaborate on the first reply in this thread, if you skid at the velodrome, people will think you're an idiot. If you skid ON the velodrome, you will likely fall over, at least if you are anywhere near the banking.

Not that I have anything against the fixed/road/messenger guys; I just don't want you to think that knowing how to skid is a prerequisite to going to the track.

SugarKnuckles

Try learning to push more of your weight onto the front wheel by leaning forward. (practice this somewhere safe, like the DMV parking lot @ oak and broderick) Skidding requires a little confidence, but once you've learned it'll become second nature. also, don't get a bigger cog, get a smaller one and a bigger c-ring if you want better leverage. skidding is not for idiots, there WILL come a time where you need to skid if you're riding brakeless.

Six jours

Never mind the argument that if you're riding brakeless on the street you're an idiot.

To reiterate: skidding is a technique that is unnecessary, unused, and foolish AT THE TRACK. I dunno what the street/fixie/messenger types are doing, but this is the track forum.

Six jours

But being as there's nothing else going on around here...

That sounds counterintuitive. Comments?