Gearing 17/56 or 18/59

Zepracer

New member
Would love to hear the different theories on gearing.

Son is racing Briggs Jr at GoPro. Right now he's running 17/56 (3.29) and seems about right. My question is would you pick up more top speed at the end of the straight with a 18/59 (3.28) but sacrifice some bottom end coming onto the straight? I know there's a .01 difference in the ratio which would indicate a higher top speed anyway but I'm thinking an apples to apples comparison. What if the 17/56 & 18/59 netted the same ratio. What would the difference in performance be?

Thanks for being kind to my first post
 
First thing we need to find out is; with the 18/59, can you manage the identical RPMs at the end of the straight. It's not a gimme. Let's say you do. If you do, you'll be going .17 mph faster. Assuming 5000 RPM and 34 inch tires. Maybe that will help your lap times, maybe not.
 
Hi Billy
There are unaccounted for variables in different driver sizes but they are minor and they aren’t going to get you where you need to be. Colin is getting the driving part down. You can help him best by getting into the minutia of setup (Tire pressure, clutch maintenance tire wear, tire pressure, axle and wheel spacing, tire pressure)

You guys are close. When you were running in the back you had the luxury of taking big swings. Now, you don’t. Now, you have to concentrate on doing the little things exceptionally well.
If you haven’t already, take the time read Gary10’s post “the Real epidemic“. Gary is one the most accomplished 4cycles racer around. Take what he says as gospel

Bruce J
 
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^ Great advice from someone who appears to be seeing your progress 1st hand at the track.
Hey, if it were easy, more people would be racing (or stick with it longer.)
Those that continue to work hard at it, are successful over time.

Don't sweat the "gear ratio is a gear ratio" argument at this point. It's a "phenomena" that seems exclusive to momentum dirt ovals (and it is real btw,) but it doesn't seem to make much difference on technical road courses. More importantly, focus on corner exit rpms and end of straight speed (prior to braking zones.)
Break the track into segments and work on improving lap times in those segments as well as overall.
Don't get caught up chasing theoretical "best" lap times as they are never achievable -- speed is a trade-off: if you gain speed in one area of the track, generally you will give up speed in another. ie earlier vs later apex of a turn, technical sections vs. long straights, etc.

When you first start out, you'll be able to make big gains in a short amount of time.
As you get closer and closer to your peak ability, those gains become smaller and smaller and take much more time to achieve. What once was considered a big gain (2 or 3 tenths) is now a tenth or even half a tenth and is worth celebrating. :)

-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
31 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
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Would love to hear the different theories on gearing.

Son is racing Briggs Jr at GoPro. Right now he's running 17/56 (3.29) and seems about right. My question is would you pick up more top speed at the end of the straight with a 18/59 (3.28) but sacrifice some bottom end coming onto the straight? I know there's a .01 difference in the ratio which would indicate a higher top speed anyway but I'm thinking an apples to apples comparison. What if the 17/56 & 18/59 netted the same ratio. What would the difference in performance be?

Thanks for being kind to my first post

ditto what was given for an answer in post #2. Basically YES

But try as we did >>> taking many years <<< to not only understand but to believe after dealing with and understanding fuel, ignition, air density, timing, gearing and clutch the truth be told >>> 99% of the time the difference in your ability to have speed at the end of the straight is about how well you did in the turn before the straight<<> . Become a believer in the last sentence and it will cure a lot of ills.

The FIRST thing needed to be fast at the end of the straight is good exit speed because you efficiently got thru the last turn. The rest of all of everything you can mechanically adjust is to make use of good exit speed. If all is perfect mechanically the only difference between the quick and the fast is how well they got thru the corner.

Do a search for information on Gary10 who is one of the best while both sitting in the seat of a kart and as a kart driving coach.

If there's a slight difference between you and another or others which the gearing can solve it won't be solved unless your equal or better >efficiently< getting thru the turn before the straight in question. IMHO, I think you can take that to the bank. period
 
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Don't let yourself get caught up in the "self-evident truths" of karting. My favorite; "torque off the corners, horsepower down the straights". It sounds so reasonable, to the uninitiated, but to someone like me, with 50+ years experience, it makes no sense at all. Engines make torque and RPMs, horsepower is a calculation, how much torque at what RPM = HP.
I started karting in 1966 and one of the first things I heard was, (from Gary Emmick) "fast off the turns, fast down the straight". To this day I don't believe it. "Fast down the straight", compared to what? What if I have the wrong gear on and I run out of engine before the end of the straight, it would help me off the turns, but not down the straight. That's a simplification but it's true. I have many other examples, some from experience, some from just dead reasoning.
 
I started karting in 1966 and one of the first things I heard was, (from Gary Emmick) "fast off the turns, fast down the straight". To this day I don't believe it. "Fast down the straight", compared to what?

Compared to the kart next to you which will kick your butt because they are able to get thru corners better then you. period !
 
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