On-Point Racing

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Old 11-14-2012, 06:44 PM
  #286  
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Originally Posted by LonnyJ1950 View Post
What happens if you reduce the reactive caster. I've been running 10' for a while, but several guys at our track are switching to 5'. We run at Competition Hobbies in Tucson, and share an indoor space with an off road track. The track is generally low to medium grip and a little dusty, especially off line. Many of them are also reducing the static caster which runs counter to my experience in low grip situations. Any thoughts?
This is what I think but its just my opinion and for an AE front end.

Less reactive given the same castor angle, (castor measured with a camber gauge so you know where you are) will have more steering and be better on lower grip. If some one is running 10 and goes to 5 they will need to change the castor setting because the king pin will be automatically leaned back when you move the reactive castor block. So when they are changing reactive they might just be putting the static castor back to where it was, thats if they even took the time to see where it was to begin with.

Less castor is always less steering everywhere but can be twitchy at the same time, twitchy does not mean it has more steering. More castor is always more steering center out, but can be a little easier on center. The trick is to get the reactive/camber/castor balanced so you can drive it and has good steering. The main idea of the reactive castor is you could run a lot of castor so it would be easy to drive on center and when you got into the turn the suspension compresses, standing the king pin up, giving less castor and not over steering with so much castor to begin with.

If your track is low grip, id start with 5 deg reactive and 5-6 degrees of static castor and go from there. Make sure the tires wear flat adjusting the camber as needed. If you need more steering then add more castor and to get the tires to wear flat you might need to take out more camber. The reason for this is as you turn the wheels more camber is induced because of the castor, so more castor will make more camber through the steering input.

Hope that helps!
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Old 11-14-2012, 07:04 PM
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Thanks!
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Old 11-14-2012, 11:41 PM
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Always appreciate little nuggets of info like this
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Old 12-05-2012, 06:33 PM
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Paul,
Skimmed through the thread and didn't see this so if you would explain it to me I would appreciate it. My rear pod is really heavy to the end bell side of the motor (away from the spur) how can I fix this? I am running a 13.5 Rev-tech.
Thanks
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Old 12-09-2012, 10:26 AM
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Is the on-point car's pod the same sizing as the S120LT? The reason I am asking is the Serpent seems tougher to get certain size pinions/spurs in there w/ the motor wanting to touch the axle. I am having a pitboard made and can have a gear chart engraved on it. Wondering what are the spurs/pinions range that will actually fit this car. I am running on a small track ozite carpet track in 17.5 blinky class (currently) I know one of the CRC guys are running 72/40. I will use gearchart to make the chart but it doesn't allow me to choose which spurs. Only a range. I know through that range some of those spurs are not made...
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Old 12-09-2012, 10:41 AM
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Originally Posted by mracer View Post
Paul,
Skimmed through the thread and didn't see this so if you would explain it to me I would appreciate it. My rear pod is really heavy to the end bell side of the motor (away from the spur) how can I fix this? I am running a 13.5 Rev-tech.
Thanks

I'd add some lead golfers tape to the right wing of the pod until its balanced. Make sure you have everything shimmed correctly with the rear axle otherwise it will throw everything off.
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Old 12-09-2012, 10:46 AM
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Originally Posted by SNIPR View Post
Is the on-point car's pod the same sizing as the S120LT? The reason I am asking is the Serpent seems tougher to get certain size pinions/spurs in there w/ the motor wanting to touch the axle. I am having a pitboard made and can have a gear chart engraved on it. Wondering what are the spurs/pinions range that will actually fit this car. I am running on a small track ozite carpet track in 17.5 blinky class (currently) I know one of the CRC guys are running 72/40. I will use gearchart to make the chart but it doesn't allow me to choose which spurs. Only a range. I know through that range some of those spurs are not made...
No matter what pod you have as long as the slots are back enough you can get any motor to touch the axle, usually its the other way around you'll have a problem with, going forward. You dont want to have your motor too far back as the car will handle bad. 40/72 seems really low for a 17.5 blinky car, usually they are in the 55-60 tooth range. If I was going to run a 40/72 I'd bump up the spur to a 80-84 and run a bigger pinion to get the motor moved a bit more forward. A general rule is the motor should be around 4mm from the axle. My serpent pods and OP12C pods have slot moved forward so you can get really big gear ratios.
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Old 12-09-2012, 12:10 PM
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I am currently running a 40/80 but have ordered a 44p our track is rather small I think it is like 36'x40'

Originally Posted by chicky03 View Post
No matter what pod you have as long as the slots are back enough you can get any motor to touch the axle, usually its the other way around you'll have a problem with, going forward. You dont want to have your motor too far back as the car will handle bad. 40/72 seems really low for a 17.5 blinky car, usually they are in the 55-60 tooth range. If I was going to run a 40/72 I'd bump up the spur to a 80-84 and run a bigger pinion to get the motor moved a bit more forward. A general rule is the motor should be around 4mm from the axle. My serpent pods and OP12C pods have slot moved forward so you can get really big gear ratios.
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Old 12-09-2012, 04:05 PM
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Originally Posted by SNIPR View Post
I am currently running a 40/80 but have ordered a 44p our track is rather small I think it is like 36'x40'
Ok that is pretty small. I'd try and get the motor where is said though with the same roll out you have now. You might even be able to use an 84 or 88.
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Old 12-09-2012, 10:19 PM
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OK so I am not misunderstanding gearing. A smaller pinion w/ a larger spur would give me slower speed off line but a lot of top end. A larger pinion w/ smaller spur would give me faster off line speeds but lose of top end?

One of the faster guys is about 1.8 gear ratio (72/40) w/ a rollout of close to I think it was around 74.35

Now for our track should we try and be close to an 80 rollout still? I was around 70.21 as to why I was going to go 44p/80s which should get me to a 77.24 or 1.82

Thank you by the way for taking the time to help as much as you do!

Originally Posted by chicky03 View Post
Ok that is pretty small. I'd try and get the motor where is said though with the same roll out you have now. You might even be able to use an 84 or 88.
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Old 12-10-2012, 07:24 AM
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Originally Posted by SNIPR View Post
OK so I am not misunderstanding gearing. A smaller pinion w/ a larger spur would give me slower speed off line but a lot of top end. A larger pinion w/ smaller spur would give me faster off line speeds but lose of top end?

One of the faster guys is about 1.8 gear ratio (72/40) w/ a rollout of close to I think it was around 74.35

Now for our track should we try and be close to an 80 rollout still? I was around 70.21 as to why I was going to go 44p/80s which should get me to a 77.24 or 1.82

Thank you by the way for taking the time to help as much as you do!
Smaller pinion and bigger spur will give you more punch, bigger pinion and smaller spur will give you more straight speed. Roll out and not having your motor hitting the axle is all you should be worried about. You can have a huge spur gear and pinion and have the same roll out as a small pinion and small spur, just make sure the roll out is the same.

If the fast guy at the track is running a 74.35 roll out why do you want to run 80?
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Old 12-10-2012, 12:30 PM
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Good question. Rollout would be different for each different track. I will check with others and see what their rollout is and stick to that. Ultimately the rollout will remain the same along w/ speeds no matter the gearing. Should rollout change from 17.5 blinky to say another class?

Originally Posted by chicky03 View Post
If the fast guy at the track is running a 74.35 roll out why do you want to run 80?
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Old 12-10-2012, 04:33 PM
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Originally Posted by SNIPR View Post
Good question. Rollout would be different for each different track. I will check with others and see what their rollout is and stick to that. Ultimately the rollout will remain the same along w/ speeds no matter the gearing. Should rollout change from 17.5 blinky to say another class?
The 'best' choice for rollout will change with class, motor timing, tracksize and driver skill. a 1/12 car with 17.5 blinky will want a higher rollout than 13.5 on the same track. a big open track will want a higher rollout than a small tight track. further, for me the faster drivers will tend to be faster with a slightly higher rollout than less fast drivers. (the faster drivers dont lose as much speed in the corners so they can gear more for straightline speed while us mortals need a little help out of the corners) notice these statements are all relative.

find attached a spreadsheet (in a zip file) it is designed to print out a sheet for a spur gear. you need to adjust the spur size for your situation. also notice at the top there is a maximum and minimum number of teeth. for a given pod and motor(some motors have beveled edges which make a difference) there will be a maximum forward and rearward position for the motor. these positions correspond to the max and min number of teeth that will fit (total number of teeth is pinion + spur) the purpose of this to keep track of what the max and min size pinion possible is. if you compare to other cars, you will notice that the op12 has a pretty wide range possible, but as pointed out pinion/spur combination towards the larger end is preferred.

i prefer to print out 1 sheet for each spur gear size i have and keep them handy. this spreadsheet is a modified version of one that CarbonJoe posted some time ago.
Attached Files
File Type: zip
1_12_rollout_op12.zip (13.3 KB, 33 views)
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Old 12-10-2012, 04:35 PM
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Originally Posted by SNIPR View Post
Good question. Rollout would be different for each different track. I will check with others and see what their rollout is and stick to that. Ultimately the rollout will remain the same along w/ speeds no matter the gearing. Should rollout change from 17.5 blinky to say another class?
Rollout can change from motor to motor, car to car, layout to layout, person to person with the same motor, different timing, different rotors. It's normally not that complicated but does happen. Find out the most you can from the fast guy and use it as a guide to help your program. You are most likely not going to end up in the same place but you need a place to start. Hope that helps!
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Old 12-10-2012, 04:37 PM
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Originally Posted by avs View Post
The 'best' choice for rollout will change with class, motor timing, tracksize and driver skill. a 1/12 car with 17.5 blinky will want a higher rollout than 13.5 on the same track. a big open track will want a higher rollout than a small tight track. further, for me the faster drivers will tend to be faster with a slightly higher rollout than less fast drivers. (the faster drivers dont lose as much speed in the corners so they can gear more for straightline speed while us mortals need a little help out of the corners) notice these statements are all relative.

find attached a spreadsheet (in a zip file) it is designed to print out a sheet for a spur gear. you need to adjust the spur size for your situation. also notice at the top there is a maximum and minimum number of teeth. for a given pod and motor(some motors have beveled edges which make a difference) there will be a maximum forward and rearward position for the motor. these positions correspond to the max and min number of teeth that will fit (total number of teeth is pinion + spur) the purpose of this to keep track of what the max and min size pinion possible is. if you compare to other cars, you will notice that the op12 has a pretty wide range possible, but as pointed out pinion/spur combination towards the larger end is preferred.

i prefer to print out 1 sheet for each spur gear size i have and keep them handy. this spreadsheet is a modified version of one that CarbonJoe posted some time ago.
Thanks, we were typing at the same time
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