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Old 01-27-2009, 09:41 AM   #11221
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Due to the design of the TC3, running high wind brushless motors (21.5) can be a challenge. There are many solutions to find the proper gear ratio. The simplest solution can sometimes be the most expensive, which is to buy smaller spurs and/or bigger pinions.

To accomodate the larger pinions, you may have to remove some material if you are running a tub chassis. You may also find that your motor cam may not move as far as you like. Trinity used to make a motor came that allowed for more movement. Here is a link that shows a photo of this cam (http://i245.photobucket.com/albums/g...4/000_2875.jpg)
and photo

Compare the Trinity cam to the stock cam below


I think it would be okay to modify an Associated aluminum cam, but I would avoid removing too much material on the Associated black cam. I have had the stock cam actually break. I'm not sure what material it is made from.

Last edited by IndyRC_Racer; 01-28-2009 at 09:01 AM.
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Old 01-27-2009, 01:52 PM   #11222
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I would strongly suggest NOT tu buy or use this trinity part, because it isn't properly machined. My english is not good enough to explain exactly how, but if you try one of these once you'll see that they cannot hold the motor properly, because the outer edge of the cam is not thick enough (hope it makes sense) . So the motor will more or less be hanging out of the chassis hole, scratching the road and being not parallel to the chassis, ruining your spur gear.


The only solution i've found is to dremel the stock part. Never had a single problem with this, the part seems quite strong to me. Just take your time , use the biggest diameter sand drum on the dremel , and it will be easy.

Just by putting it in the chassis, you'll see where to remove material. If the cam doesn't go as far as you've allowed it by grinding, when you install the clamp, then grind the outer edge of the cam where it collides with the clamp. This way you'll be able to rotate the cam even further.

Have fun !
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Old 01-27-2009, 01:57 PM   #11223
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Quote:
Originally Posted by IndyRC_Racer View Post
Another issue with the TC3 is over time the front bumper tends to droop down due to accidents. Having a turnbuckle mounted to the bumper will help maintain the life (and flatness) of the plastic bumper.

To avoid this very simply, just bend the bumper up with a lighter, gently. The thing you describe will NEVER happen again, I promise
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Old 01-27-2009, 02:29 PM   #11224
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To be more precise

Picture of the bumper : in red I circled the places wher you should put the flame of the lighter to bend it upwards.
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Old 01-27-2009, 02:33 PM   #11225
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Picture of the cam: my ugly drawing shows how it should look like after grinding it.

In red, the outer edge where it hits the motor clamp, you can grind a bit here too.
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Old 01-27-2009, 05:54 PM   #11226
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Thanks for the tip on the motor clamp Heretic.
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Old 01-28-2009, 07:02 AM   #11227
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How much weight do you guys typically need to add to balance the TC3 ??

I put 2 mini scales under the chassis (wheels off) with no battery in the car (21.5 Novak motor). The motor side is about 4 oz. heavier than the empty battery side. My LiPo pack is around 8 oz. (I think?) -- so when I put that in I'm going to have to add like 4 oz. of lead to the motor side ?? Is that typical ?

Thanks.
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Old 01-28-2009, 09:08 AM   #11228
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Heretic, thanks for the info on the motor cam. I was just posting photos of the Trinity cam so that people could get the idea of what to do. Your photo of a modified cam is great.

As far as the front bumper, I've also used the heat/flame/lighter trick on the stock bumper. Personally I think the stock bumper isn't wide enough, so I'm using an RPM bumper (http://www.rpmrcproducts.com/product...ires/80292.htm). THe RPM bumper is made from a little thinner material, so it does benefit from having an extra brace.

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Old 01-29-2009, 06:55 AM   #11229
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didn't know this part existed.. thanks !
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Old 01-29-2009, 09:31 AM   #11230
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Here is another racer's way of increasing the movement of the TC3 cam. (VTA tuning Q&A). This was posted in the USVTA setup thread here on RCTech.

The best part of this post is that there is a good picture showing where to dremel the chassis for larger pinion gears.
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Old 01-30-2009, 11:56 PM   #11231
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Does anybody have a good way to restore stripped out threads in the plastic on these cars?

I know you can just replace some of the plastic parts but a couple of my stripped holes are in the chassis itself.
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Old 01-31-2009, 05:41 AM   #11232
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For stripped screws I've heard that you use a few drops of super glue in the hole as a filler. Make sure to give the glue enough time to completely dry. After the glue dries, if possible use a new steel screw to re-cut the treads in the hole.

The other possible solution is to use longer screws and/or steel screws in the bad hole. The threads on the blue aluminum screws can wear down slightly if they are cross-threaded.
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Old 01-31-2009, 07:27 AM   #11233
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Replace striped 4-40's with 3mm, cheap and easy.
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Old 02-01-2009, 09:16 AM   #11234
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Thanks for the ideas guys.

I'll probably try the glue idea first, I'd prefer not to mix-n-match SAE with metric, but sometimes it's unavoidable.

I wish there was enough material to just use something like a helicoil.
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Old 02-01-2009, 05:55 PM   #11235
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Quote:
Originally Posted by IndyRC_Racer View Post
Here is another racer's way of increasing the movement of the TC3 cam. (VTA tuning Q&A). This was posted in the USVTA setup thread here on RCTech.

The best part of this post is that there is a good picture showing where to dremel the chassis for larger pinion gears.
Not sure I understand why all this Dremeling on the cam is needed.

I run a 76, 80, or 84 spur (64 pitch) and I have no problem getting whatever FDR I want in my TC3.

Why all the grinding on the cam ???
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