Sprockets

C

Circle track maniac

New member
How do you know what sprockets to run. ex. 14-56, 15-60, 16-64, 17-68 all of these come out to 4.00 to 1 ratio.

me being a beginner how do i know how to pick what clutch sprocket to run?
 
If you use the 'search' function, you'll find a plethora of arguments about gear ratios and which clutch driver to use. If you're on a clone, I like to keep the rear gear in the 61-66 range personally, so given those options, I'd call it a '16' track. Now, in the heat of the summer if the track is really fast, and you're not letting off and want to drop say two teeth, I might go to a 17/65 or 66 in that moment instead of down to a 16/62. The 'rule of thumb' is that you want to be on as high of a clutch gear as possible, without having to run too big of a rear gear. There's a whole thing about a larger clutch gear being faster than the same ratio on a smaller clutch gear, and I have no way of proving it or disproving it, but it seems to hold true. Hope this helps!

-Andy
 
Looking at your gear ratio chart, you'll see that if you're using a 16 or 17 driver, the difference between them is four teeth on the axle. Not exactly, but very close. Now there are those that insist that the bigger the driver, the better. There are even those that will insist that the track can change enough to favor one or the other. Even with the same ratio. I've given up arguing that.

So if you want to raise the ratio, and you want to put on the bigger driver, if you go from a 16 to a 17, which would call for four more teeth on the axle, but you want a higher ratio, instead of adding four teeth to the axle, just add three, or two. If it were me, I would just take off one or two teeth from the axle and leave the 16 driver on the engine.

Every toolbox should have a gear ratio chart in it. No guessing!

From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
 
Al, all these youngsters have high falutin' phones now with calculators...they need some "non-common core" math skills to be able to calculate gear ratios! FYI- my recent tests pretty much confirmed to me that a ratio is a ratio. 14/ 63 and 16/72 produced almost identical laps on pavement for me..the best laps with each looked almost identical on the Mycron .I'm staying with the 14/63 because I need the ground clearance due to a raggeddy turn 2 exit that i consistently drift in to
 
The lap times will be similar, but where you are fastest will change. Lower driver makes you faster low end off the corner, but less on top. It only matters once you have all your other set up near perfect. Trial and error while actually racing is the only way to judge.
 
Doesn't it all come down to the length of the longest straight away or tight turns........................just asking...
 
spotteddawg said:
Al, all these youngsters have high falutin' phones now with calculators...they need some "non-common core" math skills to be able to calculate gear ratios! FYI- my recent tests pretty much confirmed to me that a ratio is a ratio. 14/ 63 and 16/72 produced almost identical laps on pavement for me..the best laps with each looked almost identical on the Mycron .I'm staying with the 14/63 because I need the ground clearance due to a raggeddy turn 2 exit that i consistently drift in to
Click to expand...

Well actually you're hurting yourself at opposite ends of the track, hence the same lap times ( the 14/63 lunges off the corner while the 16/72 pulls the last 1/3 of the straight) you will see a lap time improvement if you used a 15/68. I can say this as I know the track your racing on. quick question though, are you running red vegas or firestone ygf's?
 
apex96 said:
the 14/63 lunges off the corner while the 16/72 pulls the last 1/3 of the straight)
Click to expand...

I'm not arguing or disagreeing at all, but I'm just curious why? I've heard this before but I just do not understand!! But then again I'm not the brightest little lamp!
 
spotteddawg, if you test the 15 I suggest testing it with a 67 and a 68. My suspicion is that if you're fast with the 14/63 you'll be the same or faster with a 15/67.
 
yellows on the right side will be way to soft. I'd suggest using a set of reds or trying firestones. I've run some extremely soft tires there before and they tend to fall away really quickly (around 7 laps into a run) and you'll begin to feel the kart really squirm around entering and exiting the corners. and the reasoning for running the 15 is simple.

I'll use a bike as an example say I have a 3 speed chain ring on my bike crank-set (rear sprocket doesn't matter at this moment), and I try to accelerate my bike in 3rd (really large) instead of 1st (really small) now its gonna take some serious effort to get the bike moving in 3rd but once she's rolling I'll be making some speed while not peddling super fast. with 1st gear I'll accelerate really quickly with little effort but to make any good speed I'll really have to pedaling fast and hard. but if I use 2nd i'll use a little more effort to get moving than using 1st but less than 3rd and I'll be using a little more pedal power once at speed than 3rd but less than 1st.

now does that make sense, as far as the drivers go?
 
apex96 said:
now does that make sense, as far as the drivers go?
Click to expand...
that is such a ridiculous analogy I can't believe you use it to explain gear ratios. I hope everybody can see how ridiculous it is. To call it ridiculous might be an understatement.

From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
 
This discussion comes up every two to 3 weeks. It's just amazing we still can't agree to disagree one way or another. Lol. I think last time it came up we were at 100+ posts. In 20 years no one, not one person has proved it one way or another. Not to my knowledge anyway...Those on the side of a ratio is a ratio including me get its the way it is because it is!!! Oh and Ill lap you in 5 laps.

I'm just blown away with this!

Circle Track-I hope you get something out of this. It really is an interesting debate. Pick something that works for you that's really what counts! Good luck my friend!!!
 
Yeah...it's a bit deep. I RACED bikes too, and to disregard the rear ring in the discussion is crazy because bike guys recognize that a ratio is a ratio and 24 speed bike will have several duplicate raios that work the same for them.- more of an issue there is "cross chain"- run the most similar ratios with the straightest chainline.
As far as my yellow vegas: it's the tire every winner has used, until they came up in short supply and a few went with whites because they were the only ones available. Those whites are back to getting smoked by yellows. I've won 7 features on them (yellows) this year myself, and lead in points- all also with 14/63. My 12.55 at KGS is considered pretty fast-
That said, I'm open to experiomentation, I love to drive even at my "advanced" age, and I'm usually consistent enough to be able to tell if a change works or not. The Pools are real good about mid-week track time, so I've learned a pile about kart racing this year! Definitely going to try the 15's...but I'll prob stick with my yellows!
 
it's not ridiculous in the sense of the driver, you're asking why change the driver I gave you an analogy as to why, you change the final drive ratio with the rear gear obviously but in this case even if you did change the rear sprocket gear to match up the ratios between the bikes crank-set gears you'd still notice the the difference in pedal power needed and efficiency at speed. And yes I do understand the your concern with the bike analogy but stew on it as it does warrant some thought. And I know from my own experience that the revolutions one will have to pedal through to attain a certain speed while using different gears but the same ratio will mean I'm working a lot harder in some gears rather than others.

Oh and Al I'm in the camp that a ratio isn't a ratio so you can go pound sand if you disagree. Seeing as I was only going for the reference in acceleration and top speed using only the driver as an example I'd say it was accurate.

And I just took a look at the vega page since I'd never once seen or heard of the white being used. There's a good reason it's not been used in the big races, it's a control tire or spec race tire if you may, and i doubt it has anywhere near the performance potential of the reds or yellows.
 
What method do you guys use to determine what ratio to be on? When you look at a track what tells you hey I think I should be on this ratio? And the only information you have is the length of the tack.
 
royslsbry said:
What method do you guys use to determine what ratio to be on? When you look at a track what tells you hey I think I should be on this ratio? And the only information you have is the length of the tack.
Click to expand...

Ask around in pits! Saves a bunch of guess work. At least your close then make changes from there.
 
No You asked in pits and listened to lieing Larry and finished a lap down.I see the argument all the time on here about the gear ratios I want to know how they come up with the ratio numbers.
 
Lots and lots of testing. Most of the knowledge gets passed down at the track as it speeds up the trial and error process. And once you've raced on a certain length track you can usually use that gearing for a baseline at a different track of equal length. If you didn't have the knowledge to begin with you'd have to devote a lot of time to testing and watching the tach and lap times until you got it right.
 
You must log in or register to reply here.
Back
Top