FINAL GEARING CHOICE

[ricochet]

Looking for feedback and choices for final gearing for a 73 ironhead.  Stock tranny, 74 " stroker.  What's good for overall performance both in town with an occasional blast down the highway @ 70 or so.  This is sprockets/chain.

ricochet

[olpigiron]

ricochet,

I Am Currently Running A 51 Tooth Rear Sprocket,... I Believe This Is Standard With A Drum.
And A 24 Tooth Front... (Needed Minor Cutting and Grinding On Sprocket Cover, Due to Size).

OPI

[nibroc]

ricochet,

I Am Currently Running A 51 Tooth Rear Sprocket,... I Believe This Is Standard With A Drum.
And A 24 Tooth Front... (Needed Minor Cutting and Grinding On Sprocket Cover, Due to Size).

OPI

same here- 24 front w/77" stroker-stock trans.

[ricochet]

Thanks guys.

ricochet

[ricochet]

Am I correct in thinking what we're realy going after is a ratio with the sprocket choices?  If so and a 24/51 combo is .4705 can I get at that ratio using any other set of sprockets?  For instance 23/49 = .4693 or 22/47 = .468.  This opens up possibilities with sprocket selection and fit issues.  I've got to check what I have with my tranny now.  Is there something I'm not considering here?

ricochet

[saltcaveminer]

the tranny gears can be changed to close or open gaps in the power curve (ex close the gap between third and fourth).its a lot easier and less expensive to stick with the sprocket gears.my 70 stroker has a 19t and my 73 barn my bike has a 24t.the cover will have to modified as stated above for the 24t.big difference. also what size rear tire are you running?Salty

[ricochet]

I'm running a 120/90-18 GT501 in the back and it's a tight fit with the swingarm being within maybe 3/8 ths on each side.  Looks good under later model fender.  Some challenges there with fitting fender struts outboard of frame mounting rather than inside.  But after some massaging it looks good fitwise.  Had to remove the shock mounting spacers on the frame and the spacer/nut plate on the inner side of the strut for a nice solid mounting.  Salty, on your stroker with the 19 tooth sprocket, what was the rear tooth count and what kind of riding or performance did that get you?  Am I thinking correctly about how to get at a ratio?

ricochet

[olpigiron]

ricochet,
If U Are Running The Stock Drum That Comes On A '73 Ironhead, And The Sprocket Is Riveted To the Drum,
I Don't Think U Can Go With A Smaller Sprocket, As U Drop Teeth The Circumference Is Less and I Don't
Believe It Can Be Changed. I May Be Wrong, If I Am... Sorry For The Bad Info.

OPI

[saltcaveminer]

with an 18in rear tire and a 24t front sprocket you should find the highway riding better.around town and between street lights the 19t works well.Salty

[ricochet]

It's a new 18 inch 60 spoke wheel that will take a rotor and any size sprocket leaving the sprocket size wide open.  I'll fit up caliper and mounting some how.

Thanks,

ricochet

[twincamzz]

To figure your final drive ratio you also need to account for the primary gearing. For instance, on my '61 Pan I'm running a BDL belt drive primary with 31 tooth front & 47 tooth rear, 24 tooth on tranny & 50 tooth sprocket at wheel leaving me with a 3.15 final drive ratio ... great for all around riding.

Here's an excellent gear ratio calculator : http://www.nightrider.com/biketech/calc_gearratios.htm