Quote:
Originally Posted by Sparky7B
Hi there
I understand gear ratios and use the www.gearchart.com to calculate my final gear ratio's.
When I use the calculator for say my TC4 with 72spur and 22 pinion it gives me a ratio of 8.18. If i use say a 98spur and 30 pinion I get a ratio of 8.17.
Obviously you get a slightly different gear ratio which could affect
performance. But what other reasons would there be to change say the spur gear as oppossed to just the pinion.....
Thanks
Dwayne

if you calculated 98spur30 pinion and 72/22 to be that close its the same ratio.its a .006 difference spur/pinion ratio(are you talking about wheel to shaft as the final?)Rule of thumb is if you want that ratio, go with the smallest of the 2 possible.Less rotating mass and in alot of rear end motor mounted cars the motor will be closer toward the middle and can make a slight handling differnce as Dave H has pointed out.
But these are very slight in difference and for example,if you are at the track and need to gear the car a certine ratio and you have not the smallest gears possible but have the gears to make the ratio needed,,i wouldn`t go out of the way to get the smallest ones because it wouldnt be worth it.
But if you have an entire strip of pinions and spurs, bust out the calculator and start grabbing for the smallest ones that pop up in the ratio you are looking for.
If you find a ratio that you like the best for a certine track.The next time you go there,show up with the smallest gears possible that makes the same ratio.
Even though it is a slight difference,alot of slight differences add up.Pennies can add up to millions of $ and thats how the pros look at it when it comes to racing.Every difference counts.