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Old 06-20-2008, 07:06 PM   #4996
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Hey guys is it possible to reach the rollout needed for a Hacker 17.5 with the 88T spur or do I need to swap in the 76T?
You should shoot for a 81 to 86mm rollout. I run either a 76, 78 or 80T spur and 47 to 51T pinions depending upon the tire size.
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Old 06-20-2008, 07:20 PM   #4997
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If you look at the centerline you'll see that the motor is not exactly centered in the car but is just very slightly off to the clamping side. That makes up for it, but as I said it was'nt exactly perfectly balanced in this configuration. I tried it with the esc on the other side but it was worse that way so this was as close as I could get.
I hadn't thought of that...the off-set is right for the center of mass for a brushed motor but not for a brushless. I planned on rewiring my car after this weekend's race. I think I'll try moving the ESC over to the other side for balance but put the reciever and servo on the left side and see how it balances.
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Old 06-20-2008, 07:38 PM   #4998
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Hey All - FYI!

The 4th Annual Midwest Carpet On-Road Championships has been announced!

Hope you can make it to "The Plex"...!


http://www.rctech.net/forum/attachme...9&d=1213690177



-Todd
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Old 06-20-2008, 08:39 PM   #4999
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You should shoot for a 81 to 86mm rollout. I run either a 76, 78 or 80T spur and 47 to 51T pinions depending upon the tire size.
Much appreciated
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Old 06-20-2008, 10:11 PM   #5000
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Here is a pic of mine, not the best angle but the only one I have right now. It balanced out really close like this.
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I hadn't thought of that...the off-set is right for the center of mass for a brushed motor but not for a brushless. I planned on rewiring my car after this weekend's race. I think I'll try moving the ESC over to the other side for balance but put the reciever and servo on the left side and see how it balances.
chris thanks bud i appreciate it and i will try it that way. im also going to run a FASST reciever and it should be a little bit more wieght than that tiny spectrum one. and good point about the motor being a little more offset i didnt really think about that. thanks

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Old 06-22-2008, 03:18 AM   #5001
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I showed a mate of mine my newly finished DB12R today...... can any one say green with envy
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Old 06-23-2008, 12:26 AM   #5002
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Another great day for BMI at our local race. Our local hot shot just got into 1/12th with a 12R5 and smoked us all but BMI came in 2nd and 3rd I believe. I brain farted and only was able to pull off a 3rd but that was good enough to bump me up to finish 2nd place overall in our championship series that just finished. Not bad considering the first few races I was driving a different car and finishing poorly in those races. The strength of the BMI impressed one driver enough to buy one on the spot so you got mail Jason Got another order
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Old 06-23-2008, 02:00 AM   #5003
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On a side note to InspGadgt's post the 2nd place BMI DB12R was my car But of course it was not driven by me I loaned a fellow racer my DB12R for this race because I wanted to see how he felt about the car?

He had no previous experience with this car and did'nt change anything but some radio adjustments. Qualified 2nd for the A-Main and ran a very good race in the Main and as mentioned finished 2nd!

Needless to say he was very impressed with the DB12R and I think now is on the look out for one
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Old 06-23-2008, 11:52 AM   #5004
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Well if he wants to order one have him contact me
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Old 06-23-2008, 04:18 PM   #5005
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Man If I can ever put together enough $ for a second honeymoon I'll go back to the islands and race with you guys.
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Old 06-23-2008, 05:47 PM   #5006
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The more the merrier


Our little race is growing fast. We had 84 entries in the last race and had up through an F main in the GT class. We had 12 1/12th scale cars and still had some normal racers that did not race.
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Old 06-23-2008, 06:15 PM   #5007
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Quote:
Originally Posted by tbeardmore View Post
Hey All - FYI!

The 4th Annual Midwest Carpet On-Road Championships has been announced!

Hope you can make it to "The Plex"...!


http://www.rctech.net/forum/attachme...9&d=1213690177



-Todd
Todd, That link dose not work
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Old 06-24-2008, 02:17 AM   #5008
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Another great day for BMI at our local race.
going well in the UK also

keep up to speed with what's going on over the pond here
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Old 06-24-2008, 05:12 AM   #5009
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Originally Posted by chris moore View Post
If you look at the centerline you'll see that the motor is not exactly centered in the car but is just very slightly off to the clamping side. That makes up for it, but as I said it was'nt exactly perfectly balanced in this configuration. I tried it with the esc on the other side but it was worse that way so this was as close as I could get.
Hey Chris,

Some may have issue with this, but when I brought it up a while back, either here or on the 1/12 thread (or both), most seemed in agreement. I've taken to balancing the main plate of the chassis with the electronics on it and ignoring the rear pod and motor. Unlike a T(axi) C(ab) we use a solid axle--regardless the weight side-to-side both tires are flat on the "road" and the rear axle is as level as your tire size is even. An extreme example would be that you could tape another motor on top of one rear tire and you wouldn't affect tweak.

What WILL affect tweak, though, is putting electronics onto the main plate in an effort to balance the rear pod out. Yes you can get the tweak to even out, but you will have different pressures on the tweak screws/springs (and this should show up even more on the "tweakless" BMI) and can manifest itself as different ride heights side-to-side. We're not talking about anything enormous here, but a difference.

In a perfect situation the rear pod would balance too but, as Brian Bodine found when he experimented with a mass-centered motor pod, it wasn't worth the effort. There was no effect on handling, it only evened up the VERY modest difference in tire wear across the rear. This wear is more easily compensated for by rotating the tires side-to-side every run or two.

When balancing I've gone on the theory that the stuff that's symetric (front suspension, hardware on the sides (hockey sticks, etc), body mounts (anything you install equal numbers of on both sides) can be left off. I've done it both ways now and obtained the same result. I do install the antenna mount as it affects placement. The IRS buttons work perfectly inserted in the rearmost hole for the battery brace. I sure wish the buttons didn't have the hole in the face--it cuts their "sensitivity" enormously. I've almost found it easier in this regard to have the front suspension mounted, etc, just to help overcome the "flat face" the hole creates on-center.

Using this method I've built 3 DB12R's now (and a CRAPLOAD of 3.2R's, a Darkside, etc, but you have to drill your holes for these) and these cars all track dead straight on or off the power as long as the diff is adjusted properly. A fact I attribute to using the Niftech alignment tool is that every time I throw a brand new car on the track I never have to adjust the trim and it drives perfectly straight hands-off every time. I've taken to counting on that--it just does. On to worrying about something else.

Now if I could just learn to drive...
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Old 06-24-2008, 12:04 PM   #5010
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Here's my ride in a slideshow

Nosram 2007 esc
Nosram 6.5s bl
Sanwa 141
MRT PTx transponder
Spektrum Micro receiver
VXR regulator & rx li-po
Jaco Prism's
Stromfoce Racing EnerG SC4600
Blackart Audi R10

the rest, oh it's pure BMI DB12R

weigths in @ 920g

Last edited by radio_car_racer; 06-24-2008 at 12:37 PM.
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