Sorry to have to ask this, but why couldn't you just not put a lower/higher pinion to get the same result. I have never understood gearing in the way of changing out spur gears instead of just changing the pinion size.
Changing a spur gives you a more refined increment of change. So for instance:
Going from same spur to different pinion
40 / 14 = 2.857
40/ 13 = 3.077
2.857/3.077 = .9327 .... 1 - .9327 = 6.7% Differential
Now going from the same pinion to a different spur
40/14 = 2.857
41/14 = 2.928
2.857/2.928 = .9757 .... 1 - .9757 = 2.4% Differential
(check gear chart below as well)
As you can see it does make a difference just in a smaller amount than a pinion would. Have you ever wanted a little more or less but haven't been able to accomplish that with pinions? Basically you can look at the spurs as splitting a pinion in half like going from a 13 to a 13.5 pinion if one existed.
Hope this helps clerify a little more of what the spurs accomplish
The noise reduction is only an added benefit of the spur but not its soul function. The new spurs are a tuning function not just a noise reducer.
They are more than proven by winning the Jconcepts nats series finals, Jconcepts Clash, OCRC Surf City Classic, and Shortcourse showdown finals. The spurs have been run the whole time with many comments that the truck is unbelievably quick and violently fast when it hits the track.
Try them out you wont regret it.
