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Old 06-29-2004, 07:49 AM   #361
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I am basing the ratios and various pinion selections on a similar matchup of what AE uses for there vehicle.

These are just suggested starting spots, which wasn't included in the manual but should have been. Till I get to run the motors I have I won't know how it will turn out.
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Old 06-29-2004, 11:08 AM   #362
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Quote:
Originally posted by Cain
Looks like for gearing we are doing about 10 to 11 over the wind? Checking out what they do for the B4 and the T4 ( light vs heavy ) it goes 9 to 8 over the wind, where the 19T motor is geared similar to a 13T motor .

So using what you recommend for a tight bumpy track going with 10 over the wind using the 70T Spur :

Motor Pinion
10 turn 20
11 turn 21
12 turn 22
13 turn 23
14 turn 24
19 turn 23 - 24
24 stock ( torque based ) 24
24 stock ( rpm based ) 23

My only concern is that these selections are even larger in pinion size that what the B4 buggy uses for gearing recommendations, and I would think a 2wd drivetrain would have less drag? If the drivetrain on the Academy is that efficient, no problems here!

If I was gearing this similar in final ratios to say the B4, I would drop all these values by about 2 teeth.

I am going to try them though and see how it goes. Three-Ewes, let me know how it goes for you.

Another racer has a review of the buggy in a race situation, nothing detailed but I will post it here:
Whoa, I guess I'd better buy some higher number pinions... I got like low things like 15,16,17,19, 20.... oh! I do have a 23!
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Old 06-29-2004, 11:21 AM   #363
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Some of your smaller sizes won't even fit on the vehicle with the biggest spur they make ( 70T ) .

If any of you guys call MRC today for whatever reason, just ask them about the kose hopups and if they are thinking about importing them. Sort of keep it in there minds you know?

I am going to setup my vehicle spring wise similar to what I was told they are running on the BJ4x4, silvers up front, greens in the rear and see how it goes. Not sure for oil yet.

Anyone know what the rating is for the kit included oil?
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Old 06-29-2004, 01:01 PM   #364
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To all sb owners-

Last night a good friend (who is a machinist) and myself successfully milled a prototype spur that will work on the sport.

We started with a 78 spur gear for a B4.
Modified it...now it just sits the same way the sb regular gears sits on that hub.

The b4 gear is not as thick so a little bit more of the screws that hold the spur to the hub appears on the other side of the hub but you would see 2.5 milimeters and the screw stubs do not hit the rear gear case.

Taking into consideration that the 78 spur would have to clear the lower chassis and upper chassis. So to run a 78 the decks (slots-above and below ) would have to be milled slightly to allow for the gear to turn undisturbed.

also the rear battery bracket would have to be modified (the curved slope) to allow for the gear to turn undisturbed. I modified mine but I feel you other sb owners shouldnt have to do that.

So my chassis was milled to allow for this gear and IT WORKS!!

You could easily run a 72,74 -b4 modified spur without ANY chassis modifications.

I'll get some 72s , 74s, 76s and let you know how those come out!

regards,
Threeewes




P.S.

Our prototype has vitually no runoff
and less runoff than the molded gears already sold by the big manufacturers.


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Old 06-29-2004, 01:15 PM   #365
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how does the gear sit in the chassis, does it protutrude below the bottom of the Chassis?
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Old 06-29-2004, 01:48 PM   #366
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Da cookie monster-

A 78 would stick out 2.3 millimeters below lower plate. It sits perfectly.

an update- I found a source for 72s-I'm going to pick up a couple to check out the disk/hole pattern -hopefully it doenst have a million mounting holes all over it-If it looks like the b4 style-I'll be happy

I'll check out losi and I get back to you guys.

Also if you guys know of companies other than kimbrough, robinson racing products that make 48 pitch spurs in 72,74, let me know-it doesn't matter which company makes it.
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Old 06-29-2004, 02:13 PM   #367
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Not to pick holes in what you are doing there buddy, but if the spur is sitting below the chassis, one heavy landing could see a lot of damage there as the undertray slams into the spur gear.
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Old 06-29-2004, 02:19 PM   #368
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The 78 is prototype. Just to prove the idea would work.
(i did fashion a spur barrier for the bottom last night)so as I stated before-It does work)
Keeping that in mind If I mill anything smaller than 76-we are in good shape with no modifications.
What I'm finding is the major companies dont make 48 pitch spurs smaller than 78.
Robinson has lots of spurs but there are so many mounting holes all over the disks.
I know I can get the 72's so I will get those done and test them.
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Old 06-29-2004, 02:26 PM   #369
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just curious, but is an Underbody common in 4wd? Never even heard of one until I found this buggy...
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Old 06-29-2004, 02:43 PM   #370
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Quote:
Originally posted by LosiFromHell986
just curious, but is an Underbody common in 4wd? Never even heard of one until I found this buggy...
On cars with moulded tubs like the Losi and Yokomo, they don't need one, cars based on a flat pan need some form of underbody to keep the dirt out.
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Old 06-29-2004, 02:46 PM   #371
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ohhh I get it, yeah, because the SB has a Fiberglass(?) Chassis... unlike the XXX4 and Yoke SD2... Gotcha
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Old 06-29-2004, 03:39 PM   #372
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threeEwes: I believe that the Spurs that work for the TC3 are 48 pitch and around 72 and above. Not sure if that will work though.

Keep us informed on your progress with the gears and if you plan to offer these for sale.
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Old 06-29-2004, 04:42 PM   #373
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spur update-

kimbrough makes a 72 / 48p gear but it has a lot of mounting holes. The inner mounting holes would have to be dealt with.

Robinson has ultra (machined) tc3 72/ 48 spur too, but their mounting holes are in the only area on the spur to place screws. Awesome design though.

I"m going to give kimbrough a call...
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Old 06-29-2004, 07:13 PM   #374
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wow.
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Old 06-30-2004, 05:54 AM   #375
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Tim at MRC posted over at www.rc10b4.com in the general forum area . he said he is looking into getting the 72T spur gear ( still not sure if it will work but he is looking into it ) and that a slipper is on the way. He is also contacting them about the axle shearing off.
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