Clone Gear torque range.

Krtrcr47

Member
I've looked and did not see this discussion for clone gear selection so here we go. What rear gear range do you motor builders want to see us on? What rpm drop makes you decide to raise or lower the driver gear?For clone only please. My thinking the clone will be similar to the animal in that dont want to gear bind the motor. So my thinking on the clone stay between 61 to 65 rear gear and adjust front accordingly to keep rpm around 68.
 

racing promotor

Moderator
First I'm no engine builder and not sure on proper verbiage to best describe what range your keeping it in, But what I'm hearing and seeing now is for normal racing on tracks with 600 + rpm drop keep rear from 58 to 62 some builders will say even little lower, Of course you need to hit your target RPM, I used to not follow this lower rear logic and a few years ago would of said 62 to 66 but have been testing the waters more and right now what seems to be best for people I'm helping, is stick to as posted above unless the track gets real good and rpm drops are close 300 or less only then go into the 62 to 66 range, AND ONLY with a driver that maximizes momentum close to 100 %.
Also this question is pretty easy to verify for yourself even if all lips are sealed, as long as you venture out to some bigger races, just go to the grid and look at rear gears of all the hot shoes you can easily tell which size range there in ;)
 
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WPaul

Member
Here we go again. LOL. IMHO 64-68. On any race car, Kart any class, Legends car, Street Stock or Late Model, you gear as close as possible to max power at lowest RPM at accelleration point on the track. Many times that will cause an over rev early on the longest straight. But this will race well.
With the late model "crate motor" class we are running today the rev limiter comes on way early on the straight a way but the max power point is matched to the max load point coming off the corner. Keep in mind to pull the tallest gear that's practical and Pit max power against max load. Now there's an exception with road courses with extremely long straights. For most fifth mile ovals gear for max power to max load and you'll be in the ball park.
Best, WP
 

OVALTECH1

Site Supporter
To me 6800-7100 is the norm unrestricted, 5800-6500 for plates... this is run of the mill stuff I’m sure there are unicorns out there that beat these results....as far as gear that’s solely gonna be based on track type and drivers experience and his/her ability to get around it. Keep drivers 12-15 and rear gears 60-65 and that should cover you darn near wherever you go.
 
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alvin l nunley

Site Supporter
One tooth on the driver is worth 4 teeth on the axle. Plus or minus, in the 4.00+/- gear range. At any given track, do you change ratio by that much, one driver tooth? One driver tooth equals about 400 RPM. In other words, add one tooth to the driver and you need 400 RPM on the top to be going the same speed. Not exactly, but very close. One tooth on the axle, gain 100 rpm, same speed.
 
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racing promotor

Moderator
One tooth on the driver is worth 4 teeth on the axle. Plus or minus, in the 4.00+/- gear range. At any given track, do you change ratio by that much, one driver tooth? One driver tooth equals about 400 RPM. In other words, add one tooth to the driver and you need 400 RPM on the top to be going the same speed. Not exactly, but very close. One tooth on the axle, gain 100 rpm, same speed.
View attachment 9205
In dirt oval racing this does not hold true, a front driver change will not get 400 rpm change, maybe 325 change and some only see little over 200 change.
 

alvin l nunley

Site Supporter
I think you might have misunderstood my post, I didn't say you were going to pick up 100 RPM per tooth, I was trying to point out that that's what you need to pick up if you change one tooth. That's if you want to be going the same speed at the end of the straight. It's just math.
What you say might be true, but that makes my point, adding one tooth and you don't pick up the corresponding amount of RPM, you're going slower.
 

Krtrcr47

Member
I have seen with my own eyes on my karts16 63 out run 15 59 I believe is a 3.93 to a 3.94. Both karts rpms near the same both right rears roll out to 34". Both same tires. So as long as rpms stay up the motor has the power to pull the gear. But if the track slows down I see the 15 59 with better lap times. So that torque band or maybe torque curve is what I'm looking for. Maybe. Also just think this a good one for newbies in general. I had the flathead and animals down I will have the clones in a couple races I only have 2 practices and 1 race on a clone engine. So I was hoping to help shorten everyones including my learning curve or debate the diffrent ideas.
 

flattop1

Dawg 89
According to the math . Yes they should go the same speed .
Now the problem is .
Why is one Racing Kart faster then the other ?
Math can not solve that problem .
 

Krtrcr47

Member
According to the math . Yes they should go the same speed .
Now the problem is .
Why is one Racing Kart faster then the other ?
Math can not solve that problem .
Yes more going on corner speed rpm drop. Slow track fast track. Rpm drop is the key. Which would you run and why 15 59 or 16 63?
 

alvin l nunley

Site Supporter
Are you not reading the OP's post???Maybe I'm not understanding it? Obviously getting around the whole track can and does make a difference.
 

Krtrcr47

Member
Are you not reading the OP's post???Maybe I'm not understanding it? Obviously getting around the whole track can and does make a difference.
I love you al . road course guys wont get this right off , if at all. I was driving not second hand . Fast track means higher average rpm not only peak rpm.
 
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I can tell you at the biggest kart races in the country, and what most Pros do, 58-62 is spot on. A 56 or 57 can be used, as with a 63, but anything other is very rare. Not saying a 64 is never on, but rarely on. Some are still using the smaller rear gears too, but 58-62 is the most common range, and also the most common range of gears i sell.
As for when to change according to RPM drop, thats all depending on the bite in the track and what you expect the track to change to speed wise.
 

Krtrcr47

Member
I can tell you at the biggest kart races in the country, and what most Pros do, 58-62 is spot on. A 56 or 57 can be used, as with a 63, but anything other is very rare. Not saying a 64 is never on, but rarely on. Some are still using the smaller rear gears too, but 58-62 is the most common range, and also the most common range of gears i sell.
As for when to change according to RPM drop, thats all depending on the bite in the track and what you expect the track to change to speed wise.
This is the info I'm looking for this what I was thinking also until I ran 16 63 and picked up. I think it was track getting faster not so much gear but it sucks cause I was testing gear change lol. I'm basically making sure I still know what I think I know lmbo. Thanks everyone
 

Krtrcr47

Member
I know it was track getting faster corner speed was way up I know I'm answering my own questions but I think this more important than most realize.
 

racing promotor

Moderator
I would point out that yes going to bigger than a 62 depends on the grip ( some say bite ) in the track, but during the transition period track gaining grip ( bite ) goes hand in hand with RPM drops going lower in number, lower RPM drops is a gauge for track getting faster. I only point out the terminology of grip VS bite because when I think " TRACK " I thing GRIP, when I think " TIRE " I think BITE, so I'm thinking some others do as well so I'm just hoping to make it more clear that were all on the same page.
 
If we are talking bull rings and differences between bearing and non bearing driver would you not do what you could to stay on the bearing?
 

Krtrcr47

Member
I would point out that yes going to bigger than a 62 depends on the grip ( some say bite ) in the track, but during the transition period track gaining grip ( bite ) goes hand in hand with RPM drops going lower in number, lower RPM drops is a gauge for track getting faster. I only point out the terminology of grip VS bite because when I think " TRACK " I thing GRIP, when I think " TIRE " I think BITE, so I'm thinking some others do as well so I'm just hoping to make it more clear that were all on the same page.
Yes also I mean fast track as in track gripping up. But you all answered my questions. Thanks for the feedback.
 
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