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Old 01-25-2005, 09:23 AM   #1
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Default Steering Centering Problem

I know that this subject has been beaten to death but I need some help here. I have an HPI RTR 4 /3 Evo and the wheels don't seem to straighten after turning. I though I had a bad servo so I have replaced it with a Hitec high torque servo (analog). Its a little better but not perfect. I adjust the ST trim even a little to center and the wheels seem to point slightly either to left or right after steering depending on which way I adjust the ST trim. Doesn't really look like a big steering problem until I drive this car on a flat surface and it just flys off to left or right and ST trim don't seem to center it perfectly. What can I do? I even loosened the bolt that holds the steering arms to make the wheel turn smoother thinking maybe its not returning to original position because its getting stuck. But still not perfect. Any suggestions would be appreciated.
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Old 01-25-2005, 10:49 AM   #2
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1st: check out your transmitter setting is not the culprit ie. no bad setup. Make sure your radio equipments are working properly, especially the servos.

2nd: make sure you don't over tighten the Knockle Arm Adjusting Nut. Its silver hexagonal nut that push pivot ball inside the arm.

The best way to check is by removing the steering linkage from servo and check for free steering movement left and right. Ditto with suspension arms moving freely up and down without suspension.

Make sure these :



Don't push / overtighten these :

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Old 01-25-2005, 02:34 PM   #3
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Quote:
Originally posted by asw7576
1st: check out your transmitter setting is not the culprit ie. no bad setup. Make sure your radio equipments are working properly, especially the servos.

2nd: make sure you don't over tighten the Knockle Arm Adjusting Nut. Its silver hexagonal nut that push pivot ball inside the arm.

The best way to check is by removing the steering linkage from servo and check for free steering movement left and right. Ditto with suspension arms moving freely up and down without suspension.

Make sure these :



Don't push / overtighten these :

The rs4-3 doesn't have pivot ball suspension so that wouldn't be the problem.

A3, you need to isolate the problem. Disconnect the linkages and rotate the steering bells to make sure they are rotating smoothly. Same with the steering knuckles. Somthing is binding. I am assuming that your servo is working properly although you can check that too. Turn your radio and receiver on and try to turn the servo horn. Does it move? turn the wheel on your radio and make sure the servo is operating smoothly.
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Old 01-25-2005, 10:46 PM   #4
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Low battery ?
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Old 01-25-2005, 11:27 PM   #5
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weak servo saver?
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Old 01-26-2005, 03:52 AM   #6
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No offence to Hitec but Many drivers here in Oz including myself have encounted the same problem. After going through the whole front end we were still having the same problem. In the end we changed the servo to something at the top end of the market and found it was fine. We could only put it down to the hitec servo. After talking to a friend of mine who works in a hobby store he said "your not the only one with the same problem" and suggested to spend a little more on this servo and you will have no probs.
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Old 01-26-2005, 07:22 AM   #7
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Thank you all for your input. I have tried to isolate the problem. The linkages and steering bells are smooth and it doesn't seem to be binding anywhere and all batteries were even replaced. The horn on the servo doesn't seem to move when pushed by hand while the power is on and I am assuming this is a good indication that the servo gears are not worn already. I tried to see if there was an inexpensive fix for this steering problem but I may try going with a little more expensive servo if all fails. What servo do u guys recommend? Do I go with a high torque or high speed servo for steering? And what are the benefits of digital servos other than just being very accurate? I do not plan on racing anytime soon and right now I am mostly a parking lot basher. =)
Oh and by the way, I have noticed something strange the last time I ran my car. When I try to do small donuts at WOT it doesn't seem to do it anymore. The donut (circle) is not tight and keeps getting larger and larger and no longer tight. Is this an indication that my clutch or my tranny needs replacing? I have checked the teeth on the spur gear and they seem to be intact. What are the visible signs of a worn out clutch? Any input is much appreciated.
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Old 01-26-2005, 07:28 AM   #8
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Which Hitec servo do you have?
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Old 01-26-2005, 07:50 AM   #9
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I have the Hitec HS-645MG Ultra torque servo. And it seems to function fine I think. Do you think that this might be the problem?
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Old 01-26-2005, 08:08 AM   #10
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The HS-645MG is an upgraded basic servo.


If you wish for the performce of the $$$$ servos without the big $$$ checkout:

The HS-5925/HS-5945 or the new Karbonite or Ti servos.
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Old 01-26-2005, 12:21 PM   #11
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I really don't think its the servo. I use that same steering servo on 2 r40's and they have worked fine. Before that I had them installed in an RS4-2 and a racer2.

drfritz brings up a good point. Reattach all of the steering linkages and put tires on. Turn on the radio and reciever. Then wiggle the front wheels gently and see how much play you have. Now try and turn the wheels left or right harder to see how much force is needed to make the servo saver kick in. You shouldn't have too much play and it should take a good amount of force to make the servo saver kick in.
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Old 01-26-2005, 06:02 PM   #12
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Are the front toe settings okay?
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Old 01-26-2005, 07:00 PM   #13
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You guys..the lower end hitech servos are junk..Roy if you have a 645 and dont have centering problems your one of the few,I would go with any mid to top line servo from JR, Futaba,Airtronics,KO,I'm just not sure on the high end hitec stuff,right now I'm trying one of their digtal servos(5925)so far so good,But i have allways had good luck with Airtronics(94357,94358,94359),JR's mid range 590's and 650's,Futaba 9404's and the 9550 digtal.If you have NO binding and the linkage is fine,That leaves two thing..THE servo saver and the servo,I would change the servo saver first(I dont run them my self)I would bet its the servo saver causing most of the centering problems..That and maybe the servo,the 645's are known for their centering issue's..
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Old 01-26-2005, 10:15 PM   #14
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Default Re: Steering Centering Problem

Quote:
Originally posted by A3
I know that this subject has been beaten to death but I need some help here. I have an HPI RTR 4 /3 Evo and the wheels don't seem to straighten after turning. I though I had a bad servo so I have replaced it with a Hitec high torque servo (analog). Its a little better but not perfect. I adjust the ST trim even a little to center and the wheels seem to point slightly either to left or right after steering depending on which way I adjust the ST trim. Doesn't really look like a big steering problem until I drive this car on a flat surface and it just flys off to left or right and ST trim don't seem to center it perfectly. What can I do? I even loosened the bolt that holds the steering arms to make the wheel turn smoother thinking maybe its not returning to original position because its getting stuck. But still not perfect. Any suggestions would be appreciated.
Had the same problem with top Hytec servos.
Good digitals will return you to the center position every time. My choices are the Futabas and /or KO Propos.

The other thing is, any sloppiness (play) in the steering linkage will cause an apparent failure to center on the set up gage by the amount of play in the system. Since the front suspension is self centering, this is not apparent when driving, as the wheels will self center to neutral, and the servo also returns to neutral.
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Old 01-26-2005, 10:22 PM   #15
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Used to suffer the same problem with Hitec servo's thought it was my car... ended up trying three different servo's cause there figures are great for the price... but thats where it stops and still the same problem.

I only run Ko digital servos now, and there is no comparison - you get what you pay for. Even the low budget servo's that come with radio's i found better.

Get yourself some Ko's and Ko the problem
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