weight and balance

T

taylorteamracing

Member
we scaled the chassis today to help get this twister chassis to turn left, and after 5hrs with a dressed driver we ended up lowering the rf, and lf, and jacking the rear axle, a bit and of course moving the seat around a bit as far as the calculator is concerned we hit all the number fairly well, so now we half to see what the track condition is, and play with tire pressures, what would be a good start its a dirt oval short track 600 feet high bank here are our numbers. lf= 60 target 60.2 rf=59 target 58.8 lr=70 target 69.8 rr=68 target 68.2 total 257 front 119(46.3%) rear 130 (50.6%) wedge 129 (50.2) cross weight 129 (50.2%) target 50.0 % the numbers show this kart should handle well in the corner i would think
 
Sounds like you are in the ballpark. Tires and preps should be the tools used to adjust to track conditions, not relying on chassis adjustments. My old Twister did well at just about any track we took it to and never did we need to turn wrenches on the chassis. Tire sizes and pressures plus preps were all we needed.
 
taylorteamracing said:
we scaled the chassis today to help get this twister chassis to turn left, and after 5hrs with a dressed driver we ended up lowering the rf, and lf, and jacking the rear axle, a bit and of course moving the seat around a bit as far as the calculator is concerned we hit all the number fairly well, so now we half to see what the track condition is, and play with tire pressures, what would be a good start its a dirt oval short track 600 feet high bank here are our numbers. lf= 60 target 60.2 rf=59 target 58.8 lr=70 target 69.8 rr=68 target 68.2 total 257 front 119(46.3%) rear 130 (50.6%) wedge 129 (50.2) cross weight 129 (50.2%) target 50.0 % the numbers show this kart should handle well in the corner i would think
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To run which class and weight. ?
 
he was running 420 open but he is 108lbs he just couldn't keep it straight not even on the straight it would just spin the tires lol so he is now on open 212 and I have him a 212 tillotson cam carb pipe rod flywheel no gov the total weight is 257 no weight class limit
 
i started on our other car the last race a seat support broke slipped off the frame on to the nerf bar and pole vaulted the kart end over end so a new seat new supports 1 axle 1 spindle bearing and a steering wheel, i also was wanting to set and scale it with new parts and a new set of Burris 11 tires but none are available oil shortage they recommended Hoosiers new 12x9x6 d20 i have a set of those coming in the sizes i need for the open kart and I will get those results when I get everything done
 
Assuming you know the tire diameters and stagger you want, put something else on with the same measurements to scale. The scales dont care what tires they are.
 
mike97760 said:
Assuming you know the tire diameters and stagger you want, put something else on with the same measurements to scale. The scales dont care what tires they are.
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Actually they do with say cross, You scale on Burris staggered at whatever, You switch to Maxxxis staggered the same same air, cross will be higher AVG 3% to 4 % higher.
 
mike97760 said:
Assuming you know the tire diameters and stagger you want, put something else on with the same measurements to scale. The scales dont care what tires they are.
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You've definitely never scaled with Maxxis, Vegas and Burris all in the same session! Cross does in fact change pretty significantly with each tire!
 
wouldn't a different size Tire be different weight ? I am going from (11 7.10 6) to (12 9 6) and (11 710 6) to (11 8 6) and (11 5.5 6) to (11 6 6) they are physically larger so they would weigh more I am looking for good balance as close to 43/57 and 50/50 cross weight this kart will be running 420 heavy
 
tires will be here tomorrow, and the rest of the replacement parts by fri I believe, but just for curious minds I will weight what is coming off and what is going on just to see the difference
 
I had my sons car scaled last week for the first time. Numbers were horrible. Previous owners had the rear axle jacked the wrong way, and we didn't know how bad it all was. It surprised me how much changing the axle had an effect on cross. I only had to add 5 lbs or so, mainly because our seat isn't adjustable, and we were a little light. Hoping for good weather to see what he can do now
 
okay I have the open 420 heavy weights on the rage chassis made adjustments to tire pressures and spindle height it real close with no added weight anywhere
 

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I'd never try to get the correct scale weights with tire pressure. That should always stay around 4 left side &5 right side, maybe 3.5 and 4.5psi with an open engine. And personally I'd try to have 44% nose, idk man I just don't believe 40% is enough, maybe I'm wrong.
 
mike97760 said:
Assuming you know the tire diameters and stagger you want, put something else on with the same measurements to scale. The scales dont care what tires they are.
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So a Burris, Maxxis, and Vega, all the same diameter and air pressure, will scale differently? Not doubting you, just surprised.
 
no tires I took off was a 1" shorter and close to a inch narrower the Hoosiers are taller and wider plus the take off tires was a Burris 33 and the Hoosiers are D20
 
hotelcalifornia said:
I'd never try to get the correct scale weights with tire pressure. That should always stay around 4 left side &5 right side, maybe 3.5 and 4.5psi with an open engine. And personally I'd try to have 44% nose, idk man I just don't believe 40% is enough, maybe I'm wrong.
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im not sure either so i am taking what is supposed to be optimal percentages and getting close as possible and just go from there
 
mike97760 said:
So a Burris, Maxxis, and Vega, all the same diameter and air pressure, will scale differently? Not doubting you, just surprised.
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Absolutely will, tire carcass is completely different. The more interesting thing is a new vs used set of tires. New tires show higher cross than a used set. Just like air pressure, stiffer sidewalls or tire carcass will change cross. A set of 20 duro Vega vs a set of 40 Vega are different as well. The amount of prep to get a Vega to 20 will affect the carcass of the tire more.
 
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