Help selecting a speedometer gear

[Burn 14]

I have a toploader 4 speed with a (Black) 7 tooth gear drive and was wondering which speedometer gear to buy. What makes this difficult is that my tires are staggered. 26.1" dia. in the front and 27.1" dia. in the rear...running 3.70 axle ratio. The calculator on this site TCI says 19.99 (20 tooth ?) for the 26.1" and then 19.25 (19 tooth ?) for the 27.1" tires.

 

Maybe I'm analyzing this too much, but do i round up or down, do I take an average between the two numbers and then choose...or should I not round the numbers and since both are 19.??, it would be a 19 tooth? :helpsmilie:

 

Thanks.

[Jayru 17]

Just use the rear tire as that's the driven one from the trans/rear and will determine speed. If it's 19.99 round up to a 20 tooth. You can never get a speedo exact, it's usually just as close as you can depending on the rear gears/trans etc.

 

Make sure you get the right gear for your trans (left or right drive), it depends on which side your speedo gear is on the tailshaft.

[maxum96 32]

You can never get a speedo exact, it's usually just as close as you can depending on the rear gears/trans etc.

 

 

Unless you have an aftermarket electronic speedo. That have provisions for adjustment for gear ratio and tire size.

[Burn 14]

Just use the rear tire as that's the driven one from the trans/rear and will determine speed. If it's 19.99 round up to a 20 tooth. You can never get a speedo exact, it's usually just as close as you can depending on the rear gears/trans etc.

 

Make sure you get the right gear for your trans (left or right drive), it depends on which side your speedo gear is on the tailshaft.

 

Okay, my rear tires are 27.1" so I'll get the 19 tooth. The gear on the transmission is on the passenger side so would that be a right drive?