badbanshee509 Posted January 21, 2013 Author Report Share Posted January 21, 2013 makes great sence so you saying the smallest rear sproket will be like a 38 which causes you to have to change front sproket were the biggest fron sproket is a 19, so changing your ratio to like a 2.36 will allow you to be just as fast as using a 19 but on a 17 sproket up front rite, so whats the difference in a 2.36 compaired to a 2.8 ratio, Quote Link to comment Share on other sites More sharing options...
Finch Posted January 21, 2013 Report Share Posted January 21, 2013 2.36 is like going one tooth bigger on the front sprocket Sent from my SGH-T999 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
dajogejr Posted January 21, 2013 Report Share Posted January 21, 2013 2.36 is like going one tooth bigger on the front sprocket I wasn't sure on the exact math, so I didn't offer it up...thanks Finch. But you get the gist of it...509. I think, please don't quote me...the smallest sprocket you can get on a 6 bolt stock banshee rear hub is 38. It might be 39...not sure. I ran a 4 bolt Honda sprocket, so you could run a 36 tooth out back. I never ran smaller than a 44 on my drag bikes, I just got the best deals on the Honda bolt pattern axles. Which, sucked because I had to buy "custom" sprockets bigger than the 44...and I had 43 to 47. Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted January 21, 2013 Report Share Posted January 21, 2013 2.36 is like going one tooth bigger on the front sprocket I wasn't sure on the exact math, so I didn't offer it up...thanks Finch. But you get the gist of it...509. I think, please don't quote me...the smallest sprocket you can get on a 6 bolt stock banshee rear hub is 38. It might be 39...not sure. I ran a 4 bolt Honda sprocket, so you could run a 36 tooth out back. I never ran smaller than a 44 on my drag bikes, I just got the best deals on the Honda bolt pattern axles. Which, sucked because I had to buy "custom" sprockets bigger than the 44...and I had 43 to 47. 38 rear won't work. The chain will hit the hub. 39 is very close but I still wouldn't risk it. 40 is the smallest I would run and have no worries. Quote Link to comment Share on other sites More sharing options...
SlowerThanYou Posted January 21, 2013 Report Share Posted January 21, 2013 I think things have been covered pretty well so far. The text book answer for gearing is: Example motor A makes peak HP at 9,700 rpm. Take motor A & run 1/8 asphalt with a 6 speed transmission. Text book scenerio is to have that combo in 6th gear @ 9,700 rpm at or around the 1/8 mile. Say, that's done with a 2.35 (17/40 sprockets) final ratio; no changes needed. Now, take that same ratio & it only give you 9,000 rpm. You are leaving a lot rpm/power out of the run. So you know you need more rpm. I would go to a 2.41 or 2.44 ratio for more rpm. You would use the opposite scenerio if the rpm was at 10,400 rpm. You need to lower the rpm with a mid 2.20 ratio. To determine Sprocket ratio: rear spocket teeth divided by front teeth. Example: 17/41=1.4117647, that gets rounded down to a 2.41 ratio. You give a good detailed set-up & I can give a recommended sprocket combo. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted January 21, 2013 Report Share Posted January 21, 2013 Slow brings up a good point, in which I mispoke/wasn't clear in my original post. You want to hit the traps at peak HP RPM, not peak RPM. Motor A may make peak HP at 9700 but rev to 11K...you want to be at the peak HP through the traps...after peak HP RPM, you're slowing down. Quote Link to comment Share on other sites More sharing options...
SlowerThanYou Posted January 21, 2013 Report Share Posted January 21, 2013 also seems the gearing was way off also. seems to me at least the bike was all out of gear in way into overrev last bit of the track... that can also lead to a very fast holeshot.. ( with low tq) I'm not going to explain everything to make this work. The gearing might be a little off, but that's the way we would gear for quickest ET. Our background is NHRA drag racing for about 30 years. You will find, MOST heads-up & record setting racer's. Will gear their vehicles so they are hanging there lungs out well before the finish line. We follow the same approach with our asphalt ATV & even use it for 300' sand. We have been very lucky to have our drag racing background help us with our ATV set-up. This is more for Dave to ponder over & not a text book answer to what a gave earlier. We are at our peak HP numbers well before the set distance we are running. You would be surprised were it takes place at. I would gladly give up MPH to gain ET. This technique will do it & if done right you can still salvage the mph pretty well. Quote Link to comment Share on other sites More sharing options...
badbanshee509 Posted January 22, 2013 Author Report Share Posted January 22, 2013 I think things have been covered pretty well so far. The text book answer for gearing is: Example motor A makes peak HP at 9,700 rpm. Take motor A & run 1/8 asphalt with a 6 speed transmission. Text book scenerio is to have that combo in 6th gear @ 9,700 rpm at or around the 1/8 mile. Say, that's done with a 2.35 (17/40 sprockets) final ratio; no changes needed. Now, take that same ratio & it only give you 9,000 rpm. You are leaving a lot rpm/power out of the run. So you know you need more rpm. I would go to a 2.41 or 2.44 ratio for more rpm. You would use the opposite scenerio if the rpm was at 10,400 rpm. You need to lower the rpm with a mid 2.20 ratio. To determine Sprocket ratio: rear spocket teeth divided by front teeth. Example: 17/41=1.4117647, that gets rounded down to a 2.41 ratio. You give a good detailed set-up & I can give a recommended sprocket combo. well im currently running a 4 mil 65mm cylinder on alky, 35mm lectrons, 16F 38R sprocket, etended +8 swing arm, lightened all the wAay frame, shaved seat, solid struts all the way round, american racing tires rear, scooter fronts, lockup clutch,1-5 override tranny , do you need more info to tel me what gears i should get, i havent ran on the track yet due to me still being new to this sport and recently put my bike all back together, i astually built my bike from asking alot of annoying question lol lol to people on this site, trying to learn as much as possible befor i go to a 4mil DM. Quote Link to comment Share on other sites More sharing options...
badbanshee509 Posted January 22, 2013 Author Report Share Posted January 22, 2013 i started this website with this: and with all the personal work i did to this: yes im getting new tires lol Quote Link to comment Share on other sites More sharing options...
stroking Posted January 23, 2013 Report Share Posted January 23, 2013 you can get up to a 20 tooth front sprocket and it fits without any cutting on cases i have two sitting on the shelf sandtoys.com sells them Quote Link to comment Share on other sites More sharing options...
stroking Posted January 23, 2013 Report Share Posted January 23, 2013 you can get up to a 20 tooth front sprocket and it fits without any cutting on cases...cheaper than straightcuts i have two sitting on the shelf sandtoys.com sells them tires size and motor size has alot to do with what sprocket to run as well...takes alot of tq to run a 20t and is nomally for a lower rpm motor with high hp and small tires on the rear 18" is what we use alot. Quote Link to comment Share on other sites More sharing options...
badbanshee509 Posted January 23, 2013 Author Report Share Posted January 23, 2013 tires size and motor size has alot to do with what sprocket to run as well...takes alot of tq to run a 20t and is nomally for a lower rpm motor with high hp and small tires on the rear 18" is what we use alot. i currently running a 16t and its pretty quick, once i get to the track i may barrow my mechanics 17t and see how it runs, i will not know untill i make it out their what ill run in the 1/8th with my current set up Quote Link to comment Share on other sites More sharing options...
trae3star Posted May 1, 2013 Report Share Posted May 1, 2013 I think things have been covered pretty well so far. The text book answer for gearing is: Example motor A makes peak HP at 9,700 rpm. Take motor A & run 1/8 asphalt with a 6 speed transmission. Text book scenerio is to have that combo in 6th gear @ 9,700 rpm at or around the 1/8 mile. Say, that's done with a 2.35 (17/40 sprockets) final ratio; no changes needed. Now, take that same ratio & it only give you 9,000 rpm. You are leaving a lot rpm/power out of the run. So you know you need more rpm. I would go to a 2.41 or 2.44 ratio for more rpm. You would use the opposite scenerio if the rpm was at 10,400 rpm. You need to lower the rpm with a mid 2.20 ratio. To determine Sprocket ratio: rear spocket teeth divided by front teeth. Example: 17/41=1.4117647, that gets rounded down to a 2.41 ratio. You give a good detailed set-up & I can give a recommended sprocket combo. well what you guys saying makes since so here is my setup please help lol 22mil dmx 83 bore k&t port shear pipes 2-5 tranny im going 1-6 on tranny motor was used for hills an sand going to asphalt Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted May 1, 2013 Report Share Posted May 1, 2013 Medinas old motor? Quote Link to comment Share on other sites More sharing options...
Ctown208 Posted May 1, 2013 Report Share Posted May 1, 2013 Sounds like it Quote Link to comment Share on other sites More sharing options...
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