Baja 5b pinion gear heatsink

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yea, i found anything more than a 3 tooth jump and the motor should be adjusted, though it would work with just a bit more rattle on the maxxs. but for pinion changes of 3 teeth, i usually only took the motor off the motor mounts, was alot easier than yanking the mounts.
now obviously theres more torque tension and such, but for 3 teeth it should be fine imo. i ll keep everyon up to date when i get the 18t.
T
 
I understand what you are saying, but to me, ANY gear change without re setting the gearmesh is just shade tree mechanics. It's that simple. If it works for you, though I can't see how, so be it I guess. Don't kid yourself, though. After Titanic hit the iceberg, it floated, but was still sinking. What may appear to be working (floating) is in reality wearing out(sinking). It's just a matter of time. For myself,I just can't compromise mechanical understanding and integrity for what just "seems to work". I guess it comes down to what is more important to each individual. No matter what though, poorly aligned gears are going to wear prematurely.

Steve Z
 
I think there is too much thinking going on. LOL It is really simple. For every rotation of the motor, an 18 tooth pinion will drive 18 teeth on the spur gear. A 16 tooth pinion will drive 16 teeth on the spur for one rotation of the pinion. You guys are correct that the actual profile of the teeth changes to compensate for the lash between teeth. As long as there is sufficient contact, there should be no problematic wear issues that we all seem to be worrind about. Bad job designing the tooth lobes and it will wear the plastic spur, but a properly designed tooth profile should be able to wear the same. :)
 
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oldschooler said:
I think there is too much thinking going on. LOL It is really simple. For every rotation of the motor, an 18 tooth pinion will drive 18 teeth on the spur gear. A 16 tooth pinion will drive 16 teeth on the spur for one rotation of the pinion. You guys are correct that the actual profile of the teeth changes to compensate for the lash between teeth. As long as there is sufficient contact, there should be no problematic wear issues that we all seem to be worrind about. Bad job designing the tooth lobes and it will wear the plastic spur, but a properly designed tooth profile should be able to wear the same. :)
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LASH is the term i couldnt think of earlier.
Well put. pretty much what i wanted to say but couldnt..lmao.

so far ive burnt one spur gear with the stocker on 8 gals. after i toss on the 18t pinion, if i lose 2 or more spurs not due to landing WOT and smoking them. them i ll agree the idea is crap. until then, i m confident it wont be an issue.
 
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oldschooler said:
I think there is too much thinking going on. LOL It is really simple. For every rotation of the motor, an 18 tooth pinion will drive 18 teeth on the spur gear. A 16 tooth pinion will drive 16 teeth on the spur for one rotation of the pinion. You guys are correct that the actual profile of the teeth changes to compensate for the lash between teeth. As long as there is sufficient contact, there should be no problematic wear issues that we all seem to be worrind about. Bad job designing the tooth lobes and it will wear the plastic spur, but a properly designed tooth profile should be able to wear the same. :)
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My thoughts exactly. The same diameter is the key, the math is done by teeth vs teeth. As long as the profile is done correctly a 3 tooth variation is nothing to be concerned with and the diameter / backlash can stay the same. When you have a fixed position motor this is the only option that works. This makes the need to change the spur gear unecessary. Profile cutting for the same diameter works with no (bad) side effects.
As much thought as the forum has put into this to try and figure that this does not work more time has been put in by engineers to prove it works, and it does...... now stop doubting it and just try it, what have you got to lose?
I have the 18t gear from Germany and it is done right, works, fits and does not cause wear. I'll also be getting the 16t and 18t from HPI. No need for another stock 17t ....
 
This is my last reply to this and I will just let it go. It does not matter how many teeth are on the gears or how they are cut. Going up to 18 teeth from 17 teeth on the pinion should make the pinion gear physically larger in diameter which in effect would lower the leverage factor of the pinion gear to the spur gear. Now, providing the engine has the power to overcome the increased load factor, here is where your increase in speed comes from. It does not come from the number of teeth. The teeth of the gears only provide the "grip" from one gearwheel to the next. It's the circumference ratio between the two gears that you are measuring and the only accurate way for us to be able to this is to have equal reference points(gear teeth) that we can count and divide amongst themselves to obtain useable numbers. The only reason more teeth are needed on the 18 tooth is this. Because the engine cannot move, the teeth have to be made smaller as to be able to engage the spur gear further out towards the tips of the spur gear's teeth. From a leverage point of the spur gear, this is like going to a larger spur which in fact provides more torque and less speed. I'll have to see the performance difference before I will try them. I just can't see any advantage in this setup.

Steve Z
 
When I look at the pics of the pinions/ heat sinks. the Heat sink are always the same size as the pinions, so I find that hard to believe they go in the inside of the pinion. I brought this up in HBF, and I thought if it went on the outside of the pinion how do use our covers? cause look at the size of the heat sinks in the pics?they are almost the size of the pinions...:sleep: unless they just blew the pic size of the heat sink up too show us?I don't know. they really do not explain it... I bought all 3 pinions and plan on trying them...
 
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angus said:
This is my last reply to this and I will just let it go. It does not matter how many teeth are on the gears or how they are cut. Going up to 18 teeth from 17 teeth on the pinion should make the pinion gear physically larger in diameter which in effect would lower the leverage factor of the pinion gear to the spur gear. Now, providing the engine has the power to overcome the increased load factor, here is where your increase in speed comes from. It does not come from the number of teeth. The teeth of the gears only provide the "grip" from one gearwheel to the next. It's the circumference ratio between the two gears that you are measuring and the only accurate way for us to be able to this is to have equal reference points(gear teeth) that we can count and divide amongst themselves to obtain useable numbers. The only reason more teeth are needed on the 18 tooth is this. Because the engine cannot move, the teeth have to be made smaller as to be able to engage the spur gear further out towards the tips of the spur gear's teeth. From a leverage point of the spur gear, this is like going to a larger spur which in fact provides more torque and less speed. I'll have to see the performance difference before I will try them. I just can't see any advantage in this setup.

Steve Z
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I just want to correct you on one thing. The diameter is not the factor but the tooth count is. More teeth on the pinion gear (same diameter) will spin the the spur gear faster, it is just simple math. In order for the diameter to remain the same the tooth profile can be adjusted / cut to compensate. A 3 tooth variation (1 less and 1 more over stock) works and does not complicate wear, mesh or any other problem. This is nothing new and has been used and proven to death. Just don't ask me to prove it, but I know beyond a doubt it works. :)
 
Turtle how many different gearing options are you looking at making? I only really see a need for taller gearing because the motors we have available already accelerate insanely fast.
 
tulz43 said:
Turtle how many different gearing options are you looking at making? I only really see a need for taller gearing because the motors we have available already accelerate insanely fast.
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Well, the majority of people want more speed, but I will go both ways because there are still people that want more power, tight tracks. I like options, so I really like to offer options. That's why I will try to offer plastic & alumnum Spurs too.
 
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