Quote:
Originally Posted by spiftacu1ar
Wait, ur saying it comes with a 46t spur, not a 48t.... SNAP. I have it setup for use with the neu-castle finned motors (42mm diamter), but the diamter is actually less than that up front at the end bell. I don't remember what diamter I made it, but it is the right diamter for the front of the castle motors. I hadn't orgianlyl desgined it to sell... BUT, if there is enough interest, and my design ends up being much different than mikes, then I may sell them. Let's see what mike has to offer first though.
I did the math,and with the neu-castle motor, the closest mesh you can get is one with 48:9, not 46:9. 46:9 is a tad high for the savage anyways. In fact, 48:9 is a tad high too. 50:9 and 50:10 are ideal ratios.
If I do decide to sell these, I will be fabricating them at the techshop, as it is too expensive for mew to have someone else fabricate them if I sell them (i.e., I have to mark up the marked up price, which will make it insanely expensive). If I fab them myself, I can sell them at a reasonable price. Also, I can change individual ones for different motors and hole patterns, as only the main plat would have to change. The "cup" part would be the same for all of them.
Another cool feature I didn't mention is that the screw hole for mounting the motor is completely counterbored, and the cup goes on top, leaving enough space for your allen wrench, but not allowing the screws to fall out. This means you can easily remove the motor and put it back in without having to reseat the screws. This makes changing motors and pinions easy while leaving the gearbox in the truck.
I don't know if that makes sense, so if it doesn't I'll try and get soem pics of it.
EDIT: It can handle 50:12. An easy way to see if the gearing will work is 48:9 + 6 teeth anywhere. (you can add 2 to one side, and 1 to the other, or 3 to one side, and none to the other). Mod 1 gearing works out such that increasing either the pinion or spur by 1 tooth will increase the distance between the shafts by .5 mm (it increases the mesh diamter of that gear by 1mm). I have my ratios set as follows. Based off the distance for 48:9, you can go in an additional 1.5mm (on only one side, so a total shoaft movement of .75). Round 1.5 down to 1, for a 1 tooth reduction, (but the motor may interfere with the cup). You can go out an addition 6.5mm (shaft movement of 3.25mm), so round 6.5mm down to 6 for 6 additional teeth possible (You will still have about 1mm between the motor and chassis if the motor is ALL the way out to 6.5mm, which it never will be, because it won't be in mesh with anything there.
I made a typo above, which I will fix. The max distance is with 50:13 or 48:15 (both of which are WAYYY too high for a savage). Basically, although I didnt have intentions of selling, I kept speed demons in mind jsut in case I do decide to sell.
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Hmm, good info.
Given your info, it looks like your design will handle 46/16 gearing. Since you have designed it to fit the neu/castle motor, it will fit a smooth can neu just fine. I have a special project that will use a 1527 2y motor (625kv) on 10s lipo, which makes for low motor rpms.
I was going to lock the X tranny locked in second gear, and use 47/23 gearing, but I am not sure if the tranny can handle it. That motor can make some torque, and the vehicle will not be light. Not sure if I would use a std diff, or Mike's slipperential.
As for your question on the bearing to bearing dimension, it should be the same as a losi 8 diff (I think that is the diff with the smallest spacing). Mike made the diff to fit most 8th buggies, and it requires shimming between the bearings and the bulkheads to fit some of the brands. I would make yours to fit a std hotbodies/ofna/kyosho diff, and the slipperential will fit (may need shimming) and will alos allow the largest number of available diffs to fit. I would most likely use a hpi al diff cup with a kyosho plastic spur, as the plastic will provide some shock protection, and run a bit cooler than steel on steel. And I could grease it since your design is sealed.
My other question is are you using stock chassis holes to mount it? Or do you plan to drill the chassis? Either is fine with me, as I would make my own tvps...