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Old 12-28-2011, 09:41 PM   #1
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Default gearing to low, a bad thing?

I am new to this and was wondering if I would harm a 10.5 BL LRP by gearing it to low. I have this motor in a Slash my son is racing, we are running a technical indoor track with one front stretch that is probably 70' or so long. The track is tacky not muddy with one large double, with a 15/90 he can make the double fine. I kinda need to slow him down and that is the reason for the gearing it down idea. Temp runs around 125* after 7 mins. He only has a simple radio with no epa, the truck also has a LRP ssx tc speed control that after I get the link up cable I could adjust things but not sure what they would be yet. Please keep it in simple english if you have any ideas, I am new and learning. I do know this motor is probably to hot for a young novice driver but I don't mind repairs and broken parts due to FAST. He is a quick learner and does really well running against the grown ups he has to race against. Is going lower (15/90) on the pinion going to hurt the motor, heat seems to be ok at this point. Thanks in advance.
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Old 12-28-2011, 10:08 PM   #2
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The USB link cable is only to update the ESC firmware. The LRP SXX is programmed through the mode button. Check the users manual, you want setting #3 (throttle profile) to be zero. Under-gearing can cause the motor to generate more heat because it is spinning at max rpm more. just keep an eye on temps. Somebody may have more on this, but you could probably turn down the motor timing for less rpm and more torque.
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Old 12-29-2011, 04:26 AM   #3
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The motor should keep accelerating until 3/4 of the straight. A little less won't hurt, but you should avoid that the is spinning at the top RPM's in the infield.
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Old 12-29-2011, 04:59 AM   #4
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Deffinitly could back down the timing thats a good idea there. It may end a up a trade off in gears though? But at 125 its not a bad temp. Sounds close to under geared though, it may be 125 cause he hasn't pushed it yet. Make sure he puhes it to gear correctly. 130/135 would be safer. LOL then it may be over gear till he pushes it? Its a happy Medium temp between to high and to low at Fastlane. I run 4x4 and am running 145 10.5 Sonic LRP. What motor you running? What radio? You can tweak the radio settings. I tried gearing the 75% down the strait method but these brushless motors have to much get up and go on a short straight. Brushless change my method there, and its all trigger in put now. I'm at Fastlane this Friday and Most Saturdays now. Look me up if you make it out. They call me Racer-X. We probably have met? BTW what is your ESC temping at? My motor at 145 the ESC hovers 85/95. Never hit 100 yet. My ESC Stock Spec. allows you to check temps and will tell you how close your coming to shut off values. If the seeedo is cold you probably don't have a worry.
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Old 12-29-2011, 07:24 AM   #5
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Quote:
Originally Posted by UN4RACING View Post
Deffinitly could back down the timing thats a good idea there. It may end a up a trade off in gears though? But at 125 its not a bad temp. Sounds close to under geared though, it may be 125 cause he hasn't pushed it yet. Make sure he puhes it to gear correctly. 130/135 would be safer. LOL then it may be over gear till he pushes it? Its a happy Medium temp between to high and to low at Fastlane. I run 4x4 and am running 145 10.5 Sonic LRP. What motor you running? What radio? You can tweak the radio settings. I tried gearing the 75% down the strait method but these brushless motors have to much get up and go on a short straight. Brushless change my method there, and its all trigger in put now. I'm at Fastlane this Friday and Most Saturdays now. Look me up if you make it out. They call me Racer-X. We probably have met? BTW what is your ESC temping at? My motor at 145 the ESC hovers 85/95. Never hit 100 yet. My ESC Stock Spec. allows you to check temps and will tell you how close your coming to shut off values. If the seeedo is cold you probably don't have a worry.
Hey X, only "seen ya" as far as I know on heartlandrc but have read a few of your posts over there. We have not been up to fastlane yet but were always looking for a reason to try out a new track. Thanks for the answers and here goes.

Radio is a stock AM traxxas
ESC is SXX TC SPEC Modle #80950
Motor is a LRP 10.5 VECTOR sensored X11 stock
Batts Gens ace 5000 MBA 40C 2S
15/90 stock slash gear box
Motor runs 120-130* and the ESC is so cool to the touch I don't bother checking it.
I had it geared up to a 21/86 but motor did run hot 180* after 4-5 mins. Tried combos until settling on this one but nothing lower geared yet.
I got this motor/esc setup second hand an I see on the instructions they are marked like this..
Mode 2 power profile #8
Mode 3 initial brake #4
Mode 4 automatic brake #3
These are past the defaults and I am going to check manualy, this is what is writen down as his settings. Mode 2 the power profile has the timing real high if I understand this correctly, I will back it down to 1
Thanks again everyone
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Old 12-29-2011, 07:32 AM   #6
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The best way to achieve this would be to gear the motor appropriately, but turn down the throttle EPA to limit the car's speed.
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Old 12-29-2011, 07:40 AM   #7
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Quote:
Originally Posted by turners dad View Post
Hey X, only "seen ya" as far as I know on heartlandrc but have read a few of your posts over there. We have not been up to fastlane yet but were always looking for a reason to try out a new track. Thanks for the answers and here goes.

Radio is a stock AM traxxas
ESC is SXX TC SPEC Modle #80950
Motor is a LRP 10.5 VECTOR sensored X11 stock
Batts Gens ace 5000 MBA 40C 2S
15/90 stock slash gear box
Motor runs 120-130* and the ESC is so cool to the touch I don't bother checking it.
I had it geared up to a 21/86 but motor did run hot 180* after 4-5 mins. Tried combos until settling on this one but nothing lower geared yet.
I got this motor/esc setup second hand an I see on the instructions they are marked like this..
Mode 2 power profile #8
Mode 3 initial brake #4
Mode 4 automatic brake #3
These are past the defaults and I am going to check manualy, this is what is writen down as his settings. Mode 2 the power profile has the timing real high if I understand this correctly, I will back it down to 1
Thanks again everyone
Be sure to look me up if you make it. See ya.
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Old 12-29-2011, 07:56 AM   #8
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Cut a small sliver of that anti fatigue foam mat stuff and tape it behind the trigger since you dont have epa on your radio. it is just firm enough to stop him but but can be full throttled if hes got the muscle.
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