by chrisguyw » Mon May 14, 2018 12:19 pm
Considering that the majority of folks in the hobby likely use the motor shaft in conjunction with a "slotted" crown to provide gear mesh, this system does offer some benefits, While the benefits are there, they are not massive by any means, and and a switch to this type of new gear will not make you a world beater.
This new Crown will offer some friction advantages due to the 2 "thrust" washers being incorporated, particularly in left hand corners, where the axle shifts due to lateral loads, and the motor shaft contacts the face of the crown centering slot. While this does happen on both left and right hand corners, it is particularly a problem on left hand corners, as in this situation, the motor shaft is spinning in the opposite direction to the Crown....obviously not ideal for a variety of reasons ;)
So, from an engineering point of view, this new design does make sense, and while the benefits are there, they are small.
If you routinely inspect/lubricate your motor shaft/Crown slot, the differences will be very small, but, the differences are there, so, if you are looking to save every 1000th of a sec. possible, the new design makes sense.
That said, if you are really looking to save every 1000th possible, using the motor shaft as part of the gear meshing process is far from ideal.
The following are three levels of inline gear set up....depending on your abilities/patience/tools ,and, willingness to cut motor shafts.
1/ GOOD........Leave the motor shaft as is.....place spacers between the wheels and axle bushings to eliminate lateral axle play, and set the Crown so the slot faces just clear the motor shaft on either side.
2/ BETTER........Trim the motor shaft flush with the end of the pinion........spacers between the wheels/axle bushings, set the Crown with just a hint of lash.
3/ BEST.........Trim the motor shaft.......place spacers between the OUTER edges of the Crown and the INSIDE axle bushing faces.....you will need a bit of patience, and a good variety of spacer widths (several .005"), and add/subtract spacers so the a small amount of lash is present (in both directions)......tighten your Crown, and you are good to go !!
This method eliminates any chance of the mesh going "off" should your wheels happen to move laterally on your car........this happens more than you think, just check the lateral axle play on one of your cars after a race.
For anyone racing enduros etc. this method also allows wheels/tires to be changed quickly without affecting the mesh one bit.
Most high end inline (BSCRA, Eurosport etc. etc ) are run this way, and have run this way for years.
Cheers
Chris Walker
Last edited by
chrisguyw on Mon May 14, 2018 1:53 pm, edited 1 time in total.