Gear question

[2006FXDCI]

I have a question for you guys who go to the track allot . I will be finishing up my build soon on my 2006 dyna . I switched it over to chain drive this winter and im wondering with my gearing if it will be possible to launch in 2nd gear instead of 1st . This bike stands up fast and i would like to leave the line a little harder than i normally do plus i put a shinko stealth tire on it so it should grip allot better than before . Obviously i will need to practice 2nd gear launches but im looking for some opinions from you guys . I filled in the particulars of my gearing on the big boyz site and here is a snap shot . Let me know what you think

[prodrag1320]

been a long time since I ran street/strip stuff,but I would not recommend launching in 2nd

[jam65]

I made a gear change last year to enable me to launch in first gear. I was having the same issue that you are dealing with. I still need to get more practice but it is fun while trying.
As I get better at it, the front will come down as the rpms go up and then shift to second. Starting in second will probably be harder on your clutch and have enough power to get your front wheel too high. Just my observations.

[pwmorris]

Yeah, I agree-no second gear launches for me, but your first gear is deeper than I like. I like a longer, lower numerically, first/second ratio.
Less violent, easier to control out of the hole and you can bring your revs up to use the stored energy in your motor with higher rpms.
You are gonna need a lot of seat time to learn your clutch/tire set up and there will be lots of wheel stands and tire spinnin' in the meantime. Without a lock up to let your clutch slip at launch you are going to have to learn to feather that clutch and  what your bike likes to just keep that front tire barely touching the ground without spinnin your rear tire.
You could send your trans to R&D for an full upgrade, and ask for the SP first gear set up.
My street bike 60' ft in the 1.50's and pro no bar racer regularly 60' in the 1.30's to give you some goals. My first 11 Sec pass I think I had a 1.7 60' with an 11.88 @ 112 mph.

Try to keep your front tire down as close as possible to the surface, pulling all your power out of your bike-


But don't let that front tire go to far in the air or you might end up like this-Lol...

[2006FXDCI]

Thanks Kirby , Jay and Paul . I figured i would need to go to a 60 tooth sprocket to launch in 2nd but i was afraid that it would make 1st gear unusable . I am running a bandit sportsman so i can play around with spring pressure some . Maybe i will drop a few teeth off the rear sprocket to make it easier . Above all i know seat time is the most important ! Thanks guys for your input

[kd]

Maybe run the numbers with a 49 tooth clutch hub?

[pwmorris]

Maybe run the numbers with a 49 tooth clutch hub?

Maybe run the numbers with a 49 tooth clutch hub?

It's not necessarily the overall ratio, but how hard those deep first gear gives you that initial hit before you have to bang second. Those high ratio first gears make your bike rev so quick, shift light comes on almost instantly and it's time to bang second gear.
Without an electric shifter, foot shifting 1-2 is hard as hell with your front wheel in the air (forget forward controls lol..), especially when you really hammer it and dump that clutch at launch.
Anything to bring the bike out smoother and more under control works for me.

[Wicked]

Left fingers for optimal rpm and tire temp/pressure for grip or slip....
Non-drivetrain important factors!

[jam65]

One other thing to consider is what gearing with consideration of your build, will pull through the trap at the big end. I was having to shift because I hit the rev limiter about 150 feet before the trap.

[2006FXDCI]

Jay , according to the big boyz chart i should be good for 134 mph in 5th gear at 6700 rpm . I dont think im gonna run out of 5th gear , im hoping to maybe break 120 mph . What gearing are you running on your dyna ?

[jam65]

I am now trying 30,49,25,48.

[bladerunner]

  shift to 5th at the 1/8 mile  and just approach the rev limit at the 1/4 trap . 

[pwmorris]

  shift to 5th at the 1/8 mile  and just approach the rev limit at the 1/4 trap .

Bingo-

One of the first things I learned from former multi world record holder, Dan Baisley.