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Thread: I need to help with a chatter or shudder when accelerating.

  1. #1
    Join Date
    May 2015
    Posts
    32

    Question I need some help with a chatter or shudder when accelerating.

    I have two FCR's that both chatter or shudder on accelerating out of a turn or in a straight a way. So bad that they de-slot. I have installed new oilites in both front and rear of cars. Also axles and tires. Checked chassis on block and its straight. Round off tire edges. And they still have issues. One has a deathstar motor and the other has a Pro Slot 2003 motor. Gearing is 9/27 on the deathstar and a 10/27 on the Pro Slot. Track is a 145 kingleman. Thanks for any help.
    Last edited by Tech-7; 08-27-2015 at 11:41 AM.

  2. #2
    Join Date
    Apr 2012
    Location
    California
    Posts
    35

  3. #3
    Join Date
    May 2003
    Location
    Great Valley,NY
    Posts
    1,227
    Do you have a good pinion on your motors?
    It might be the gears making the things chatter.
    Try an angled ARP pinion if you aren`t already using them.

    But do yourself a favor and start running a better class of cars.

    Parma stuff is junk.

    JK makes some real nice stuff and Mosetti is introducing a new stamped steel chassis.

    If you are obsessed with running hardbody cars, B&E Slotsport has some pretty neat new chassis.

    They have a Facebook page if you can`t find them here.


    I just looked at a new Parma RTR that was missing a rear axle oilite on one side.
    It was shipped to the raceway that way.

    It`s sad but true.
    Parma makes some nice bodies and a few other items but they are in pretty bad shape these days.
    Last edited by La Cucaracha; 08-27-2015 at 09:18 PM.

  4. #4
    Join Date
    Feb 2005
    Posts
    3,399
    You might try narrower/ harder tires.

    These FCR chassis are a mystery to me.

    A lot of my local guys have ones that hop/chatter.

    They do seem to get better the more you run them.

    The one I use for hardbody racing works great.

    Maybe it's my imagination, but it seemed to get better after I was goofing around, launching it off a crude ramp I made.

    It made at least one trip, over the wall, on the end of the straightaway, on to my cement floor.

    Stress relieved?
    "Get Yourself Retrofied"
    Chicagoland Raceway
    17B West Ogden Ave.
    Westmont,Il. 60559
    Phone-708-203-8003
    mikeswiss86@hotmail.com

    Check out Chicagoland Raceway on facebook.

  5. #5
    Join Date
    May 2015
    Posts
    32
    Thanks guys, the Hardbody is 1968 Mustang fastback and 1968 firebird,the other body is Dodge Nastruck body 10 thousand. I thought it might be to much power for the track. With the Pro Slot motor 2003. It replaced the Parma Green end bell. But both cars do it. The other car is a deathstar. I have tried several different pinions. From 7 to 10. With spur gears from 26 to 33 all seem to do it. I do think it might be my tires. Running .840 rear tires. What about different compound tires? What brand? I'm running Tuna's.Thanks for all the help. PS. This is just a class that our track runs. I do run JK and Champion chassis in the other classes
    Last edited by Tech-7; 08-28-2015 at 10:58 AM.

  6. #6
    Join Date
    Jun 2002
    Location
    Paonia, Colorado
    Posts
    1,452
    We need to get Brian Meharry to look at this thread. He's the best with these cars that I know.

    All of the other scale cars we use, from flexis to 1/24 ESs have a ton of play essentially everywhere. FCRs don't. I suggest adding some play where you can. Try unsoldering the rear oilites, a little more gear lash than usual, a little more side to side play in the rear axle, loose pin tubes instead of velcro for body mounting, and as Mike said, thinner or harder rubber in the rear. I suspect that Mike's crash, described above, simply auto-loosened his car up a little.

    Greg

  7. #7
    Join Date
    Oct 2014
    Location
    ANDERSON INDIANA
    Posts
    4
    hey TECH-7,I HAD THE SAME PROBLEM,I TRUED MY TIRES,CLEANED THEM AFTER EVERY HEAT WITH LIQUID RUBBER CLEANER,ONLY TO FIND THAT USING A LITTLE BIT OF KOFORDS MEDIUM TIRE GLUE CURED MY PROBLEM,NOW IT DOESNT CHATTER OR DE-SLOT,MY LAP TIMES ARE FASTER AND NOW COMING OUT OF THE TURNS IM NOT SLIDING TRYING TO GAIN TRACTION.NORMALLY I DONT BELIEVE IN TIRE GLUE BECAUSE OF THE MESS,BUT IF YOU WANT TO GET TRACTION,IT TRUELY HELPS!!!!!

  8. #8
    Join Date
    May 2015
    Posts
    32
    Thanks, Brian. I have tried cleaning the tires several times and installing some glue. To me it acts like its getting to much traction. This happens coming out of the deadman and the straight a way only. I do have a tire truer coming. Hopefully this helps. I'm thinking it might be tire compound? But thanks for the help and I will try what you said. Thanks again.

  9. #9
    Join Date
    Jun 2002
    Location
    NorthWesterner now in Philippines
    Posts
    9,648
    Be sure you also true the FRONT tires.

    As Adrian Monk would say "You'll thank me later".

    PK
    - - - - - - - - - - - - - - - - - - -
    Paul Kassens
    OWH Slot Car Talk "Mom"
    The Old Weird Herald
    email: paulk@oldweirdherald.com

    - - - - - - - - - - - - - - - - - - -

  10. #10
    Join Date
    Apr 2005
    Location
    North East. PA
    Posts
    490
    Could be a number of things with the FCR. Bent hubs on the front tires, too soft of fronts, not freewheeling if riding on the fronts, body rubbing, too hard of a rear tire, guide flag bent down or bent front axle. Nothing wrong with racing FCR cars they are a staple class at our track. Since you changed axles and front tires that would eliminate those. Try coating your front tires with either super glue or finger nail polish. I had this same issue with one of my cars and that cured the problem.
    Member of the original Fast Eddy Race Team

  11. #11
    Join Date
    May 2015
    Posts
    32
    Sorry, But I painted both chassis front tires with nail polish. And that did not help. I have a tire truer coming.

  12. #12
    Join Date
    Apr 2005
    Location
    North East. PA
    Posts
    490
    Front ride height, have you tried different ride heights ?
    Member of the original Fast Eddy Race Team

  13. #13
    Join Date
    May 2015
    Posts
    32
    Yes sir, tried different tires. And different sizes. Also no tires on front. And it still does it. It does it coming out of the deadman curve and down the straightway. Getting on the gas. Thanks for help everyone

  14. #14
    Join Date
    Dec 2011
    Location
    FLORIDA U.S.A.
    Posts
    298
    Check these things.

    Basics

    Jig and align the chassis.
    Add a horseshoe brace from the motor mount to the rear up-rights if rules allow.
    Rear bushings are oversize - wear.

    Other tuning:

    Tires too soft of a compound.
    Try bigger hub size.
    Radius the edges.
    Make sure the front motor mount is installed and shimmed properly as not to bind the endbell.
    Too much rear axle endplay.

    Note: If the front mount is not installed and there is no brace between the motor mount and the rear up-rights the motor will 'chatter' in a vertical motion.

    Hope that helps...
    - Gator Bob-

  15. #15
    Join Date
    May 2015
    Posts
    32
    Motor is soldered in. No brace can be installed. Thanks for the help. Still working thru it. Have not found a fix.

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