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View Full Version : MR-02 ASF Unequal Turning Radius Left/Right


Traveler
2009.11.15, 10:33 PM
One of my ASF MR-02 exhibits this unusual behaviour. Any help is appreciated.

First, this particular chassis will not run straight with the steering trim centered. I must set my EX-I UR to R-2 to get the car to track straight. But what is more frustrating :mad: is that the left and right turning radius is different.:confused: The left turning radius is smaller than the right. This makes the car a lot better at turning left than right. Unfortunately at our track we run clockwise with more right turns.:(

Is this something that can be adjusted on the ASF board? If so, what do I need to do?

Thanks!

B-main
2009.11.15, 10:55 PM
my car is the same way .i have my steering balance set to left 67 right 98 trim r 2

blt456
2009.11.15, 11:17 PM
I don't know if this is a fix for your problem, but my car had the same issue. The left to right turning radius was way off. My right steering was fine but when turning to the left it had about half the radius of the right wheel. I was told by a local expert that I should replace the pot... I soldered in a new Kyosho pot and my problem was immediately fixed... I hope this helps..

byebye
2009.11.15, 11:23 PM
Did you try different tie rods???

Kris

Traveler
2009.11.16, 06:27 AM
Thanks for the responses guys! I've tried different tie rods to no avail.

The reason I asked about the board is because on the Gen1 XMODS boards you can adjust the steering pot with a screwdriver. I believe this is true for the MR-02 AM boards as well, but I never had to adjust any. Wondering if there is a screw adjustment on the ASF board for this.

I have a new pot laying around, but was going to see if there were other solutions before swapping that part out.

JeremyC
2009.11.16, 01:26 PM
Thanks for the responses guys! I've tried different tie rods to no avail.

The reason I asked about the board is because on the Gen1 XMODS boards you can adjust the steering pot with a screwdriver. I believe this is true for the MR-02 AM boards as well, but I never had to adjust any. Wondering if there is a screw adjustment on the ASF board for this.

I have a new pot laying around, but was going to see if there were other solutions before swapping that part out.

The AM boards have a small pot on the board that you can use to center the wheels. I am 99% sure ASF cars don't have this adjustment. See the photos in this post (http://mini-zracer.com/forums/showpost.php?p=291486&postcount=2).

A bad or dirty POT could be causing your problem, but what are the end point adjustments set to? Did you try what B-main suggested?

Does your car make any funny noise when you turn the car all the way to the right?

-Jer

Traveler
2009.11.16, 01:34 PM
Guess I'll have to take the servo assembly out and see what's going on. I don't see any adjustment point in the pics of the ASF board either. I don't want to live with the steering balance set to different left and right points to compensate as I'm not sure what if anything this will throw off. My goal is to make the thing go straight and have an equal L/R turning radius without any radio inputs.

Will post if I learn anything after taking it apart.

Thanks!

mk2kompressor
2009.11.16, 01:51 PM
it may not be the pot,maybe an extreme case of tweak.
check this out,



H-plates can cause the car to have tweak (any pan or touring car drivers worst nightmare) here is how to get the plate as flat as possible to the chassis.

unscrew the two long screws holding the H-plate to the chassis and remove the small oblong spacer.

http://i119.photobucket.com/albums/o130/mk2kompressor/tuts020.jpg

take a look at the part of the chassis that spacer came from, you should see where the screws were tightened at the factory there will be small raised part around where the screw enters the hole.
this needs simply scraping off with a hobby knife so the mounting point is flat and the H-plate re fitting.

http://i119.photobucket.com/albums/o130/mk2kompressor/tuts021.jpg

as you tighten the H-plate screws try and get them in as even as possible and be carefull not to overtighten them.

or maybe one of the front knuckles is binding

Traveler
2009.11.16, 01:57 PM
Wish you were right. But when I turn the car over and turn the wheel on the TX from far right to far left, I can see that the front wheels don't turn as much to the right as to the left. And there is no servo motor noise at far right indicating that maybe the servo gears are jamming at that point.

cosmicsoul
2009.11.16, 02:32 PM
Sounds to me like your board, pot and chassis are totally tweeked. Just since I am a nice guy I will give $10.00 for your junk.

Don't wast any more of time or money on this thing. All your after market aluminum parts are probably ruined as well because of mini-z tweekmosis.

I hate this has happened to you Traveler. I can sell you a brand new board and parts at a discount if you give me all your old hop ups.

They will cost you a lot more than here at the shop or anywhere for that matter. But have all been handled by Rodney, James, Wade and Pedro so you know they have to be good.

Send me a PM so we can get this deal done!

Traveler
2009.11.16, 02:37 PM
But are you willing to make me a member of your racing franchise and change the name to MAWG??? :D:D:D

LED
2009.11.16, 03:31 PM
This probably won tbe it but eliminate the radio first. Maybe there is something wrong with it. Try reversing left and right and see if its still the same side that has less steering. If thats not the case its the radio.

GL

Traveler
2009.11.17, 08:31 AM
Got up early this morning and opened up the chassis hoping to find a chunk of RCP restricting the movement of the servo saver on one side. No such luck!

I removed the servo assembly and sprayed everything with some canned air to get any small particals out. Reassembled the chassis but problem remained. :(

I took it apart again and replaced the pot. Reassebled the chassis but problem remained. :mad:

I wanted to chunk the chassis at this point, but now I am on a mission. Next I will replace the servo gears. Didn't want to do that when I replaced the pot, because if it worked properly afterwards I wouldn't know which fix corrected the problem.

PadrinoNY
2009.11.17, 08:37 AM
Got up early this morning and opened up the chassis hoping to find a chunk of RCP restricting the movement of the servo saver on one side. No such luck!

I removed the servo assembly and sprayed everything with some canned air to get any small particals out. Reassembled the chassis but problem remained. :(

I took it apart again and replaced the pot. Reassebled the chassis but problem remained. :mad:

I wanted to chunk the chassis at this point, but now I am on a mission. Next I will replace the servo gears. Didn't want to do that when I replaced the pot, because if it worked properly afterwards I wouldn't know which fix corrected the problem.

Traveler did you make sure that the pot was centered if it is then it can be that you tweaked the front end try another chassis and make sure that you cables are all solder on the board. Also, check the plates and make sure that they are all holding on and that there is no play where the pot is on.

cosmicsoul
2009.11.17, 10:46 AM
Come on man, when are you ever going to start listening to me? Have I ever steered you wrong? No pun intended.

Just because you have more posts than me and have spent several thousand more dollars at this stuff doesn't mean you know more than me.

For the sake of all that as good give me your junk and be done with it! Even if you only made $10.00 an hour will all the time you have invested in this thing you could have already bought one of my overpriced, record setting, not to mention race winning setups.

Heck I might have even let you carry my gear into the shop this week.

Traveler if your ever going to be considered for MWGR your going to have to do a little better than this. Hopefully James hasn't stumbled upon any of this.

CristianTabush
2009.11.17, 11:17 AM
Thanks for the responses guys! I've tried different tie rods to no avail.

The reason I asked about the board is because on the Gen1 XMODS boards you can adjust the steering pot with a screwdriver. I believe this is true for the MR-02 AM boards as well, but I never had to adjust any. Wondering if there is a screw adjustment on the ASF board for this.

I have a new pot laying around, but was going to see if there were other solutions before swapping that part out.

There is nothing wrong with having to set your endpoinsts slightly different L to R. This is the reason why you got a high-end digital transmitter. :) No 2 boards are exact, as well as the parts that are made. If your steerig is off 3-8 clicks to the right or left, this is perfectly normal. Same with steering throw.

One other thing you can try is to replace your servo saver. They have been known to cause erratic behavior on the steering. As somebody mentioned, make sure the wires from the pot are routed properly and that they are not binding the steering mechanism in no way. I sometimes have to recess the servo plates so that the wires can make it around from the pot to the board without jamming anything up.

Traveler
2009.11.17, 12:21 PM
Thanks for the responses guys. That's what makes this forum a great place. Will keep working on it. :)

ruf
2009.11.18, 08:43 PM
Check the subtrim on the radio. Set the electrim to 0, and center the servo using the subtrim. Mine is usually in the 10-20 range to one side. The electrim should only be used for last-minute fine-tuning adjustments, since it doesn't affect EPA.

Set the L/R EPA equal and see if you get the same steering throw left to right with the car off the ground. The steering should barely reach full lock on both sides. Mine are usually within 5 of each other left to right.

Then try slow turning circles on the track. If the turning circle increases to one side and not the other with speed, then it's not your steering, your setup is tweaked. Set your tweak on the H-plate.

Traveler
2009.11.19, 06:15 AM
Thanks Joe! I'll try that too!

Traveler
2009.11.21, 06:24 AM
Joe,

To get the car to track straight and to have equal turning radius L/R I had the following settings on my radio (before). By adjusting the subtrim (after), the balance is now even. Car tracks straight and has equal turning radius L/R. :)

S: Trim R4 (before) 0 (after)
S: Subtrim 0 (before) R9 (after)
S: Balance L70 R80 (before) L70 R70 (after)

So why did the subtrim adjustment take care of the balance when the trim adjustment did not?

Thanks again guys! :D

ruf
2009.11.23, 02:50 AM
Subtrim moves the L/R EPA's with the center adjustment. So if you move the Subtrim right 9, the leftt EPA also moves right 9 and the right EPA also moves right 9. The electrim does NOT affect the EPA's, so if you make the center adjustment there, you have to shift the EPA via the balance as you noticed in your old settings.

L=====C=====R

Subtrim adjust:
....L=====C=====R

Electrim adjust:
L=======C===R

Traveler
2009.11.23, 05:30 AM
Got it. Thanks again! My LM car is now ready to race.

SkullCrusher
2010.02.14, 06:40 AM
i thought the unequal turnings would be the geared diff.

machgo5go
2010.05.05, 11:02 PM
Subtrim moves the L/R EPA's with the center adjustment. So if you move the Subtrim right 9, the leftt EPA also moves right 9 and the right EPA also moves right 9. The electrim does NOT affect the EPA's, so if you make the center adjustment there, you have to shift the EPA via the balance as you noticed in your old settings.

L=====C=====R

Subtrim adjust:
....L=====C=====R

Electrim adjust:
L=======C===R
Thanks you all for the TX advice! It solve the exact same issue on mine which one of the great racer notice it at our track.

DJ Rattray
2011.02.13, 02:31 PM
Im new to mini z but Ive been racing rc for 10 years and ive been a machanic at a few hobby stores. Im also experiencing unequal steering radious on my 02 stock. It was perfect before but I changed my board out to one with stacked fets. And the wheels were so far left I couldnt even trim it straight. (Im assuming the pot is the round black thing that positions the servo motor) Well I thought I had installed it wrong but everytime I set it in I had the same result. I put the old board back in and It worked perfectly as it did before. I then changed the (pot?) from board 1. to board 2. still the left pointed wheels. It was night before practice day and 5 hours till work started so i removed the pins that hold the (pot?) in place positioned it so that my wheels straightend and carfully glued it in place. Its held up strong so far tracks straight with trim knob close to center. Id prefer it To have the pins and work like my old board but I like the punch from the fets. Any way I can properly fix the problem from this board I purchased?

EMU
2011.02.13, 03:12 PM
Is this an AM board or ASF?

AM has a small pot on the board itself that you can adjust to center the steering. ASF does not...

DJ Rattray
2011.02.13, 03:43 PM
yes its an AM board and is it the part of the board that looks like a phillops screw head? and what is the little round black device in the servo that positions the motor called? thank you.

EMU
2011.02.13, 06:14 PM
There are two pots on the AM board. One that tells the board what position the servo is in (attached to gears), and one that can be adjusted (on the board) to center the board. Very small adjustments can make a big difference. I usually center my radio first, then adjust this pot with the car on (with a plastic tool, so I dont short it out), to get the steering as close to center as I can...

The names would be Servo pot, and servo centering adjustment pot. :) Hope this helps.

DJ Rattray
2011.02.14, 03:40 PM
oh yeah helped alot thanks.

herman
2011.02.14, 11:16 PM
there is a third pot that i believe very little people know about... however it's on the kt2 tx controller... there might be one on the kt5 but i really haven't looked...

if you take out the center screw of the steering wheel on the tx, then proceed to take off the steering wheel... in the hole where the center screw attaches there will be a pot that you can also adjust with a screwdriver... just make sure it's long enough, and it's plastic so as not to short anything out...

i've tried this out myself and it works... :D

DJ Rattray
2011.02.16, 04:30 PM
ok cool good to know. I now have another problem my carbon t-plate wont stay in the center position. I cant seem to get the screws tight enough I dont want to strip out the holes in the chassis. so now when I take a good hit to the rear end I dog track bad. Im starting to get aggrivated with this little car. every time I fix a problem something that worked fine starts messing up. Do they ever stop robbing your wallet?

Traveler
2011.02.16, 04:58 PM
DJ, there is a solution for this problem. Check with me tomorrow.

And no, they never stop lightening your wallet :o

Marwan

DJ Rattray
2011.02.19, 10:18 AM
that worked great Marwan thanks. cars flyin. just broke my new chassis.:D

Traveler
2011.02.20, 02:43 AM
Glad I could help! What do you mean you "broke" your chassis? How? Where?

DJ Rattray
2011.02.20, 11:59 AM
I got that clear chassis wade had for sell at the store and I threw my rear end on it with my body put the other one together for the girlfriend I was flyin with that double a-arm and smacked the girl friends car with my right side and broke them both had to get new servo gears for hers and mike was nice enough to give me a couple of used grey chassis for mine. I think well be able to race thursday.