7 or 8 Tooth Speedo Drive Gear??

[tjm73]

Did some '96-'98 T45's in Cobra's come with 7 tooth drive gears instead of the normal 8 tooth drive gear? If all other factors are the same, how much would a speedo differ if a tranny had a 7 tooth from an 8 tooth gear?

I put a '96 Cobra tranny in my '98 GTand my car is showing 1 mile on the trip odometer at almost exactly the sme time I pass a 9/10 mile marker. So I am wondering if my '96 tranny might have a 7 tooth speedo gear since the's odometer is reading faster than the car is actually traveling.

Anyone have any thoughts on this?

 

[RandyStinchcomb]

1996 to 1998 Cobra used a 7 tooth gear, Gt's used the 8 tooth and as a "rule-of-thumb" each tooth is worth @9 mph

 

[tjm73]

That will make life a lot easier if I go through with the gear swap.

 

[tjm73]

....... as a "rule-of-thumb" each tooth is worth @9 mph

Do you know at what speed this would be? 1 tooth difference would have to be X percent off. If it's off by 9 mph at 100 mph,then that's 9% off. Which would confirm my theory of getting 1 mile on the odometer at the 9/10 of a mile, mile marker.

Which I am inclined to think is true at this point.

 

[RandyStinchcomb]

Do you know at what speed this would be? 1 tooth difference would have to be X percent off. If it's off by 9 mph at 100 mph,then that's 9% off. Which would confirm my theory of getting 1 mile on the odometer at the 9/10 of a mile, mile marker.

Which I am inclined to think is true at this point.

no I dont know at what mph that holds true for, in the parts business its always been that when people change-out gears, tires and trans they go thru speedo gears and we have to play wth different drive and driven gears in the trans and it seems that 9 mph was about the average per tooth.