1/12 forum
Tech Champion

Joined: Nov 2001
Posts: 7,191
From: Hawaii, USA
Hi guys,
I haven't a huge experience with these cars so I ask for a simple problem.
My crc xl has more steering on left corner than on the right ones.
I reverse the battery position but nothing happened. The Car on right turn had lots of understeer even on power, instead in left turns the car simply get istantly lose at the rear.
What can I check suspension balancing? Weight balancing?
Thanks for help
I haven't a huge experience with these cars so I ask for a simple problem.
My crc xl has more steering on left corner than on the right ones.
I reverse the battery position but nothing happened. The Car on right turn had lots of understeer even on power, instead in left turns the car simply get istantly lose at the rear.
What can I check suspension balancing? Weight balancing?
Thanks for help
Another thing to check is to make sure you have the same caster block on both sides of the front suspension. The stock plastic ones can sometimes be difficult to tell the difference between the 5* and 10* blocks.
Tech Initiate
Joined: Sep 2013
Posts: 31
Hello!
I need som gearing advice, just bought a Xray X12 2014, and have no idea where to start in my pinion choise.
My set-up:
Xray X12 2014
Trackstar 4.5T
Jaco prism tires (both front and rear), don't have the diameter in my head.
96T spur
Going to run on a pretty large outdoor asphalt track.
Also have 10.5T and 13.5T motors.
Also: Any suggestions where to buy pinions, good quality and a good price?
Thanks!
I need som gearing advice, just bought a Xray X12 2014, and have no idea where to start in my pinion choise.
My set-up:
Xray X12 2014
Trackstar 4.5T
Jaco prism tires (both front and rear), don't have the diameter in my head.
96T spur
Going to run on a pretty large outdoor asphalt track.
Also have 10.5T and 13.5T motors.
Also: Any suggestions where to buy pinions, good quality and a good price?
Thanks!
Tech Regular
Joined: Nov 2008
Posts: 429
From: Springfield, VA
Hello!
I need som gearing advice, just bought a Xray X12 2014, and have no idea where to start in my pinion choise.
My set-up:
Xray X12 2014
Trackstar 4.5T
Jaco prism tires (both front and rear), don't have the diameter in my head.
96T spur
Going to run on a pretty large outdoor asphalt track.
Also have 10.5T and 13.5T motors.
Also: Any suggestions where to buy pinions, good quality and a good price?
Thanks!
I need som gearing advice, just bought a Xray X12 2014, and have no idea where to start in my pinion choise.
My set-up:
Xray X12 2014
Trackstar 4.5T
Jaco prism tires (both front and rear), don't have the diameter in my head.
96T spur
Going to run on a pretty large outdoor asphalt track.
Also have 10.5T and 13.5T motors.
Also: Any suggestions where to buy pinions, good quality and a good price?
Thanks!
This is the wrong thread for Xray sedan stuff but this http://www.petitrc.com/reglages/xray...immee20140406/ would be a good start for setup and gearing for a large asphalt track with your 4.5 motor. I really like Xenon gears, both pinion and spur http://xenon.ocnk.net

http://www.teamxray.com/x12/
Tech Regular
Joined: Nov 2008
Posts: 429
From: Springfield, VA
Tech Apprentice
Joined: Jul 2013
Posts: 95
From: Melbourne Australia
What's a good ratio for 13.5 blinky on asphalt? I'm new to the whole pan car thing so could you reply with teeth numbers rather than roll out etc as I don't really understand all of that yet. Thank you.
-Jeremy
-Jeremy
Roll out is the distance the car will move with one revolution of the motor, to calculate roll out=3.14*tire diam/(spur/pinion). Or go to GEARCHART.com to figure out gearing.
With foam tires and their always changing diameter, unfortunately fixed ratios don't make much sense. That's why people use roll-out on pan cars instead. But it's actually not that difficult:
Just calculate gear ratio: pinion/spur (=how often the tire will rotate per motor rotation*)
[* in TCs usually the inverse number is used: how often the motor needs to rotate to give the tire one full rotation (although a TC's internal gear ratio will modify that number again)].
Take that gear ratio times the circumference of your rear tires (which is simply: diameter*Pi) and you're done.
Example (random numbers): 100t Spur, 30t pinion, tire diameter 50mm:
gear ratio: 30/100 = 0.3
circumference: 50*Pi[3.1415] = 157.075
rollout: 0.3*157.075=47,1225mm or just 47mm
With foam tires (as opposed to rubber tires with their more or less constant diameter) this is the only proper way.
Just calculate gear ratio: pinion/spur (=how often the tire will rotate per motor rotation*)
[* in TCs usually the inverse number is used: how often the motor needs to rotate to give the tire one full rotation (although a TC's internal gear ratio will modify that number again)].
Take that gear ratio times the circumference of your rear tires (which is simply: diameter*Pi) and you're done.
Example (random numbers): 100t Spur, 30t pinion, tire diameter 50mm:
gear ratio: 30/100 = 0.3
circumference: 50*Pi[3.1415] = 157.075
rollout: 0.3*157.075=47,1225mm or just 47mm
With foam tires (as opposed to rubber tires with their more or less constant diameter) this is the only proper way.
No, that tape that looks like it's over the side link is just a little tab so I can peel the tape up easier. It goes in-between the link and the chassis.
I drove it a bunch yesterday, and got a great idea when I was out.
I want to get some 1/12 wheels, and then try and make rubber tires by super-gluing the crap out of some tread from an old BMX bike tire onto them... I even have blue and red BMX tires, so that'd be interesting.
I have a tire balancer, so I could make it at least SOMEWHAT balanced.
If that doesn't work, I want to get some really thick tires, I am getting tired of scraping all over pebbles, but I just love the attitude of this car!
I was catching "air" with it yesterday, there was a super-smooth transition in a concrete courtyard, and I was running a circuit, and around the inside of the far corner, I was getting maybe an inch or two of air, and coming down smooth, it was awesome
There was also a slight high-bank turn on the other end of the circuit due to a rather steep angle of the concrete to help with drainage into a grate.
I was also thinking about possibly just going full bolink and putting some old buggy tires on it.
I drove it a bunch yesterday, and got a great idea when I was out.
I want to get some 1/12 wheels, and then try and make rubber tires by super-gluing the crap out of some tread from an old BMX bike tire onto them... I even have blue and red BMX tires, so that'd be interesting.
I have a tire balancer, so I could make it at least SOMEWHAT balanced.
If that doesn't work, I want to get some really thick tires, I am getting tired of scraping all over pebbles, but I just love the attitude of this car!
I was catching "air" with it yesterday, there was a super-smooth transition in a concrete courtyard, and I was running a circuit, and around the inside of the far corner, I was getting maybe an inch or two of air, and coming down smooth, it was awesome

There was also a slight high-bank turn on the other end of the circuit due to a rather steep angle of the concrete to help with drainage into a grate.
I was also thinking about possibly just going full bolink and putting some old buggy tires on it.
I just finished building the Yokomo R12 C3, everything came together perfectly. However, the one piece sway-bar is causing a minor tweak in the front suspension arm. I've done all I could to remedy the problem but it's still causing a slight tweak on the left suspension arm. The tweak is probably 0.2-0.5 mm.
Everything else in the suspension is spot on, all I need to do now is to figure out how to un-tweak the sway-bar.
I checked on the Yokomo Thread and there have been a few issues with the three piece causing suspension tweak, but mine is a one piece.
I was thinking of lightly sanding the ends of the sway bar which insert into the suspension arm. This would remove some material from the bar and maybe help correct the sway-bars imperfection.
Looky what I found !
http://m.youtube.com/watch?feature=y...&v=kzoqI-kQqQw
Everything else in the suspension is spot on, all I need to do now is to figure out how to un-tweak the sway-bar.
I checked on the Yokomo Thread and there have been a few issues with the three piece causing suspension tweak, but mine is a one piece.
I was thinking of lightly sanding the ends of the sway bar which insert into the suspension arm. This would remove some material from the bar and maybe help correct the sway-bars imperfection.
Looky what I found !
http://m.youtube.com/watch?feature=y...&v=kzoqI-kQqQw
Last edited by EDWARD2003; 04-21-2014 at 03:44 AM.
Tech Apprentice
Joined: Jul 2013
Posts: 95
From: Melbourne Australia
Thanks guys for answering my gearing question. Guess I'll get a 76 spur and stock up on pinions.
I just finished building my RC12R5.2

More photos at: http://www.apexattitude.blogspot.com...ll-almost.html
-Jeremy
I just finished building my RC12R5.2

More photos at: http://www.apexattitude.blogspot.com...ll-almost.html
-Jeremy
Figured this is a worthwhile bump. Some of you 12th scale-ers may appreciate this, and I've haven't seen any discussion of this chassis in this thread...
Just starting the build of my new Kawada M300 FX3. Anyone else out there running one of these? I've converted to 1/8 front axles and have different hubs and axle for the rear, as the stock wheels are proprietary.


I'm kicking myself for breaking one of the damper tubes while assembling. It probably won't see any track time until the fall!
Just starting the build of my new Kawada M300 FX3. Anyone else out there running one of these? I've converted to 1/8 front axles and have different hubs and axle for the rear, as the stock wheels are proprietary.


I'm kicking myself for breaking one of the damper tubes while assembling. It probably won't see any track time until the fall!
Last edited by S.Stew; 04-25-2014 at 05:35 PM.
If you're waiting on a dampener tube, just get a Speedmerchant or CRC or any other dampener tube and sand the anodizing off it, and go racing.
That is a really cool front dampener design, i like it a lot.
That is a really cool front dampener design, i like it a lot.



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