Limitless Need some schooling on reverse Pinion spur gearing

[Jeppyjep]

Does having a bigger pinion than your spur help reduce voltage drops and cut offs because the motor has to work less ?

What’s a good reverse gearing on a V2 limitless to achieve 130 ish on 6s without needing a country mile?

Thanks

 

[Diem Turner]

What kind of gearing you need for a particular speed will depend largely on the KV rating of your motor. If you're running a higher KV motor such as a Castle 1721, you're probably always going to have a pinion smaller than the spur at 6S power. If, on the other hand, you're running a Castle 2028 1100KV motor, your pinion will, probably, be larger than your spur.

I just ran a quick calculation, just for comparison. Running on 6S, to reach 130mph, you would need the following gearings (pinion/spur):

1721: 27/37
2028: 46/31

So, tl;dr...you need to gear for the speed that you want to achieve in relation to the motor that you're running (taking factors such as voltage and KV sag into consideration). There's really no way to go about this in another fashion.

Hope this helps. If not, please return fire

 

[Cereal_killer]

What kind of gearing you need for a particular speed will depend largely on the KV rating of your motor. If you're running a higher KV motor such as a Castle 1721, you're probably always going to have a pinion smaller than the spur at 6S power. If, on the other hand, you're running a Castle 2028 1100KV motor, your pinion will, probably, be larger than your spur.

I just ran a quick calculation, just for comparison. Running on 6S, to reach 130mph, you would need the following gearings (pinion/spur):

1721: 27/37
2028: 46/31

So, tl;dr...you need to gear for the speed that you want to achieve in relation to the motor that you're running (taking factors such as voltage and KV sag into consideration). There's really no way to go about this in another fashion.

Hope this helps. If not, please return fire

+1 if it wasn't for @LicketySplit @Diem Turner @vwturbowolf @LibertyMKiii i wouldn't be where I'm currently at. I'd listen to any input they say..

But your post is very vague. Without any context of what esc/motor. That would help.

 

[SrC]

What kind of gearing you need for a particular speed will depend largely on the KV rating of your motor. If you're running a higher KV motor such as a Castle 1721, you're probably always going to have a pinion smaller than the spur at 6S power. If, on the other hand, you're running a Castle 2028 1100KV motor, your pinion will, probably, be larger than your spur.

I just ran a quick calculation, just for comparison. Running on 6S, to reach 130mph, you would need the following gearings (pinion/spur):

1721: 27/37
2028: 46/31

So, tl;dr...you need to gear for the speed that you want to achieve in relation to the motor that you're running (taking factors such as voltage and KV sag into consideration). There's really no way to go about this in another fashion.

Hope this helps. If not, please return fire

+1

 

[LibertyMKiii]

Does having a bigger pinion than your spur help reduce voltage drops and cut offs because the motor has to work less ?

What’s a good reverse gearing on a V2 limitless to achieve 130 ish on 6s without needing a country mile?

Thanks

Not aware of any method to speed run at speed above 100 mph without needing a long road to avoid massive voltage drop.
Voltage drop is avoided by a slow throttle pull and appropriate gearing for the speed and abilities of the lipos.

 

[SrC]

Underdriving (under gearing) versus Overdriving (over gearing) the spur gear with a pinion is relative as descibed above.
Hope your radio has the range you will need. Drag running doesn't require much range, different venue altogether compared to long distance speed running at 130+mph. Slow and deliberate max throttle pulls of 4-5 sec duration ( @ 100% power) is common at those speeds. Or you will amp cut at some point no matter what. Raz's Perfect Pass solution will help in this regard.
Start by crunching the numbers on a Gear calculator, like @Diem Turner stated above.
Similar to how you set up for Drag running, but just for a shorter distance Drag Trap speed.
You want to tweak/ turn down ESC Punch/Start Power for Speed running. The opposite of what you do for Drag pulls.

 

[Jeppyjep]

Underdriving (under gearing) versus Overdriving (over gearing) the spur gear with a pinion is relative as descibed above.
Hope your radio has the range you will need. Drag running doesn't require much range, different venue altogether compared to long distance speed running at 130+mph. Slow and deliberate max throttle pulls of 4-5 sec duration ( @ 100% power) is common at those speeds. Or you will amp cut at some point no matter what. Raz's Perfect Pass solution will help in this regard.
Start by crunching the numbers on a Gear calculator, like @Diem Turner stated above.
Similar to how you set up for Drag running, but just for a shorter distance Trap speed.
You want to tweak/ turn down ESC Punch/Start Power for Speed running. The opposite of what you do for Drag pulls.

What kind of gearing you need for a particular speed will depend largely on the KV rating of your motor. If you're running a higher KV motor such as a Castle 1721, you're probably always going to have a pinion smaller than the spur at 6S power. If, on the other hand, you're running a Castle 2028 1100KV motor, your pinion will, probably, be larger than your spur.

I just ran a quick calculation, just for comparison. Running on 6S, to reach 130mph, you would need the following gearings (pinion/spur):

1721: 27/37
2028: 46/31

So, tl;dr...you need to gear for the speed that you want to achieve in relation to the motor that you're running (taking factors such as voltage and KV sag into consideration). There's really no way to go about this in another fashion.

Hope this helps. If not, please return fire

Yes 1721 2400 kv

 

[SrC]

I can't see a 2400kv motor with more than 1:1 ( Pinion:Spur) An Over geared spur.
You should be somewhere in the Under geared range. Pinion always smaller than the spur.
Not enough torque with 2400kv to over drive the spur.
Generally speaking here. And there are other variable factors to consider.

 

[Diem Turner]

I can't see a 2400kv motor with more than 1:1 ( Pinion:Spur) An Over geared spur.
You should be somewhere in the Under geared range. Pinion always smaller than the spur.
Not enough torque with 2400kv to over drive the spur.
Generally speaking here. And there are other variable factors to consider.

A 2400KV motor on 6S with 1:1 gearing is a 170mph car (roughly, assuming your batteries can supply the needed power).

As for the 1721 lacking torque, I made my 122mph pass on 3S with a 39/30 gearing. It's a pretty beefy motor that will surprise you.

Yes 1721 2400 kv

You're not going to be running a larger pinion than spur with the 1721 on 6S for the above stated reasons.

 

[Jeppyjep]

A 2400KV motor on 6S with 1:1 gearing is a 170mph car (roughly, assuming your batteries can supply the needed power).

As for the 1721 lacking torque, I made my 122mph pass on 3S with a 39/30 gearing. It's a pretty beefy motor that will surprise you.

You're not going to be running a larger pinion than spur with the 1721 on 6S for the above stated reasons.

I need to post up my data tonight because on 6 s I’m fine when I try 8s It’s cutting off around 110 . Maybe when I post the data it will help . Currently I have a 32/39

 

[Diem Turner]

I need to post up my data tonight because on 6 s I’m fine when I try 8s It’s cutting off around 110 . Maybe when I post the data it will help . Currently I have a 32/39

What ESC are you using?

 

[Jeppyjep]

What ESC are you using?

Xlx2 with CNHL 3s that I purchased from @real_name_hidden and they’re awesome and then my 4s 8000mah are power hobby’s and those are the ones that cut but not sure if it’s me or the batteries . I have Onyx 4s that will be in on Saturday so will see what happens . But I will post up my data tonight when I get home . I have no clue how to read it

Not aware of any method to speed run at speed above 100 mph without needing a long road to avoid massive voltage drop.
Voltage drop is avoided by a slow throttle pull and appropriate gearing for the speed and abilities of the lipos.

I have good area but not like James McCoy or anything . I have like 2400 ft roughly

 

[LibertyMKiii]

You almost always have to reduce the pinon size when going from a 6s setup to an 8s setup.
You must take baby steps and work up the speed. Checking the data logs all the way along. Jumping in head first almost never works unless you are a highly experienced veteran speed runner.

 

[Jeppyjep]

You almost always have to reduce the pinon size when going from a 6s setup to an 8s setup.
You must take baby steps and work up the speed. Checking the data logs all the way along. Jumping in head first almost never works unless you are a highly experienced veteran speed runner.

Ok makes since , I’ll keep plugging on smaller batteries until I get my experience under my belt .

 

[LibertyMKiii]

Ok makes since , I’ll keep plugging on smaller batteries until I get my experience under my belt .

If you want to make a run with moderate gearing and post the logs I'd be happy to advise on next steps and how to dissect the info you see in the logs.

Some good pointers in the how to read castle logs page. https://www.arrmaforum.com/threads/speed-runners-reading-castle-data-logs-and-esc-settings.37182/

Post #13 about how to zoom in to the logs is critical

 

[Diem Turner]

Xlx2 with CNHL 3s that I purchased from @real_name_hidden and they’re awesome and then my 4s 8000mah are power hobby’s and those are the ones that cut but not sure if it’s me or the batteries . I have Onyx 4s that will be in on Saturday so will see what happens . But I will post up my data tonight when I get home . I have no clue how to read it


I have good area but not like James McCoy or anything . I have like 2400 ft roughly

You're gonna laugh...James Mccoy's stretch of road is about 2100ft. Crazy, no?

 

[LibertyMKiii]

You're gonna laugh...James Mccoy's stretch of road is about 2100ft. Crazy, no?

He seems to be the exception to most rules.

 

[Diem Turner]

He seems to be the exception to most rules.

This is true. But it does also help put into perspective what is possible. Not for everyone, obviously. But it shows that ultra long stretches aren't necessarily needed for really high speeds. Personally, after participating in the 3S challenge, I think you actually need much longer stretches running low voltages as slow trigger pulls are even more critical. In addition to that, the tall gearing required for high speed 3S passes makes slowing down take a lot longer too.

 

[Jeppyjep]

If you want to make a run with moderate gearing and post the logs I'd be happy to advise on next steps and how to dissect the info you see in the logs.

Some good pointers in the how to read castle logs page. https://www.arrmaforum.com/threads/speed-runners-reading-castle-data-logs-and-esc-settings.37182/

Post #13 about how to zoom in to the logs is critical

Thank you

 

[LibertyMKiii]

This is true. But it does also help put into perspective what is possible. Not for everyone, obviously. But it shows that ultra long stretches aren't necessarily needed for really high speeds. Personally, after participating in the 3S challenge, I think you actually need much longer stretches running low voltages as slow trigger pulls are even more critical. In addition to that, the tall gearing required for high speed 3S passes makes slowing down take a lot longer too.

That is very true, you are regulating average spikes with slow pulls.
In the end, that same thing helps in higher voltages too. I think it is just less sensitive because you have some much raw power available.