Tommygunn Posted January 9, 2013 Report Posted January 9, 2013 What is the best gear ratio to use for 300ft dirt drags? Motor is making aboout 75hp. Doubt i'll be running drag pipes Quote
Nightmare Posted January 9, 2013 Report Posted January 9, 2013 What size of tires u running? Sent from my SGH-T679 using Tapatalk 2 Quote
Tommygunn Posted January 9, 2013 Author Report Posted January 9, 2013 Haven't got tires yet. maybe 20inch? Quote
JayCLL Posted January 9, 2013 Report Posted January 9, 2013 How much do you weigh? Your bike weight? Tire size? Alot of different factors to calculate. But your not going to get an exact answer you will have to test and tune some. I would start around 2.8 ratio as a guess not know your numbers Quote
Tommygunn Posted January 9, 2013 Author Report Posted January 9, 2013 Bike should weigh pretty much close to stock i would guess. maybe 50 lbs les. I weigh 190. What sprocket size would 2.8 be? Quote
Nightmare Posted January 9, 2013 Report Posted January 9, 2013 Haven't got tires yet. maybe 20inch? Not enough tire with that much hp imo. Sent from my SGH-T679 using Tapatalk 2 Quote
JayCLL Posted January 9, 2013 Report Posted January 9, 2013 If your running 20's I may start out at 15/41 that is a small tire for 75 hp Quote
Nightmare Posted January 9, 2013 Report Posted January 9, 2013 I'm running 15/43, 22x11x8, 12 paddle stags with 86hp. A 21 will help a lot. I would say a 21x11x8 10 to 12 paddle hauler will be good. Sent from my SGH-T679 using Tapatalk 2 Quote
Colby Posted January 9, 2013 Report Posted January 9, 2013 22x11x8 extremes.. 15 tooth up front, stock rear would be a good start Quote
tedd1 Posted January 9, 2013 Report Posted January 9, 2013 Divide the big one by the small one. 15 x 45 = 3.0 Quote
bigboybanshee Posted January 11, 2013 Report Posted January 11, 2013 There is no "right" answer for this kind of question, too many variables (rider weight, chassis weight, tires, track conditions, engine tune, etc. etc.). The only way to find the correct gearing is to start with something and fine tune from there. You want to be at the top of fifth gear when you cross the finish line. Whatever combination gets you there is what you go with...not trying to be a smartass, just being straight forward and honest. Quote
Tommygunn Posted January 11, 2013 Author Report Posted January 11, 2013 I guess I could have been more descriptive. The gearing that was on the bike when I took it apart was WAY too low (not even sure what it is, I’ll have to look). It would wind out just way too fast. 1st gear was just useless. Since I need to buy new chain, sprockets, and tires, and 60% of the bikes time will be spent drag racing I figured I would see what would be best to put back on there. I believe stock is what?..14-41? Quote
bigboybanshee Posted January 11, 2013 Report Posted January 11, 2013 Yes, stock is 14/41. Depending on track conditions with tire choice, it could be what you need. Just remember, if you're tuning for 300' specifically, don't bother with 6th gear, tune for the top of 5th at the finish line. If you're leaving in first, use it only to get you moving then immediately shift to second. 1 tooth on the front is somewhat equivalent to 3 teeth in the rear. If you're close, fine tune your gearing with the rear sprocket. If you're far off, change the front. Also, if you're using a strut for the rear suspension, adjusting that can increase or decrease traction to help utilize your gearing. LOL, lots of factors Quote
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