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Old 09-21-2005, 04:36 AM   #6376
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Originally Posted by andrewdoherty
Has anyone had any problems with thier tires coning under unexpected circumstances? I have tried 2, 2.5 and 3 degrees of camber all around and I get smaller diameters on the outsides than on the insides on the front tires no matter what after one run. The rears have no such problem. I have set the camber using the older integy guages and an old fashioned RPM guage with freshly cut tires. I have been truing down to 59 mm and the outsides end up around 56.5 after 1 or 2 qualifiers. I have changed three different brands of tires with different compounds and have been rotating side to side after every run. I am using this set up exactly aside from the camber changes. Any ideas? This is getting expensive!!


http://www.mikeshobbyshop.com/
click set up sheets. Then choose TC4. Its the only one there.

i would try running lighter spring and oil.everything else i see doesnt look to be what would cause the coning.i would try 50 wt front and 40 wt rear and maybe lighten up on the spring tension some.let me know if this helps.
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Old 09-21-2005, 05:28 AM   #6377
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Question, what length are you guys running your shocks at???
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Old 09-21-2005, 06:09 AM   #6378
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LOL
Jason, you told him to do the exact opposite of what i said earlier. Raising the inner ballstud will increase his coning. For the purpose of this discussion, i will be referring to the car making a left turn, and the effect on the right side suspension. As the chassis rolls to the right when turning left, the inner right ballstud forces the turnbuckle towards the outer right ballstud away from the centerline of the car, as the arm moves in the opposing direction, towards the centerline of the car, forcing the hub to roll the tire on its edge. To counter this, the inner ballstud needs to be lowered when compared to the outer ballstud. Lengthening the rod is a greater effect than the height of the ballstud, but in theory shouldnt be longer than the lower pivot points, from hingepin to hingepin, and too short will tighten (bind) the car through corners. Generally, small tracks or tight radiused turns will use long links to rotate well, and larger tracks with large radiused turns can use (but not always) shorter links. A shorter turnbuckle WILL increase the change through suspension compression, but plenty of adjustment is available in ballstud height (up/down-inner/outer), that you should rarely need to shorten the camber link on carpet. There just isnt enough (shouldnt be) suspension travel. If the car IS rolling THAT much, then it is time to change the shocks, the hingepin mount height, tire size, and/or add swaybars. Incidentally, an easy way to get a bit more sidebite in any car is to raise the inner ballstud/lower the outer ballstud. Now, if the inner ballstud was mounted upside down, as in, pointing down, the ballstud would force the turnbuckle in the other direction in a similar scenario, pulling it towards the centerline of the car, for a totally different effect... the BJ4 is an example of this (at least the last set pictures of it i have seen). This would be good in offroad, as suspension compression would add negative camber, and stability through rough sections. Not necessarily more grip, as maximum grip is achieved with the crown of the tire flat with the racing surface... but more stability.

Im not stating this to start a spitting match, but it is easy to get these settings and the effects mixed. Roll center confuses alot of people, and quite frankly, there is a different explanation from just about every company, on how it works and how it "feels" to the driver. But geometry doesnt fail, and if the time was taken to actually draw and compare this on a piece of paper (one setting to another), or in a CAD program, you could see the difference in the geometrical change.

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Old 09-21-2005, 06:42 AM   #6379
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Tire Wear

How much play is in your suspension, wheel axles may need shimming ball cups could have to much play ther seems to be alot of variables.

try putting your car on a flat surface with the wheels slightly turned. Now push the opposite corner (say front left ) how much does the camber change with simulated load as oppossed to no load.

I used to race alot of nitro on road we used to set the camber at 3 deg but after running 10 mins wear would be at .5 deg.

if you dont have trouble with grip just adjust till tires wear to your satisfaction
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Old 09-21-2005, 07:00 AM   #6380
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Dave, matched up the chassis last night and yes the cells are further in and further forward. not sure how much but maybe 1/8th inch? Jason care to expand on this? We are comparing the cell placement from the tub car to the BMI chassis.

Bob
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Old 09-21-2005, 05:12 PM   #6381
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TEACH: Um... full length...? Its going to be hard to give you exacts, the plastic shock cap pops off of the tree at the very tip. Mine F/R are 2.475" at full extension, end of cap to end of cup.

BOB: It did look like it was forward some on the BMI tub. I just wanted to be sure of that, it will change the handling of the car when compared to an FTC4, as the FTC4/TC4 tub have the slots in the same place F/R. The BMI chassis should have slightly more initial steering/steering throughout the corner, than a tub or an FT chassis.

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Old 09-21-2005, 05:37 PM   #6382
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hey dave,

i agree with you on your explenation.i was under the assumption that his tires were coning smaller on the inside which led me to believe that his ballstud was too low .i have mixed feelings about some of the statements made in general about roll center changes.i find when i raise the inner link the car stays more level through the corner but at the same time does increase traction.each of my cars react a little differnetly to these changes.the tc4 seemed to stay more level when i raised the front link and had less camber gain(less camber gain is obvious).however there are so many things in the setup that can change the feel you get from this so it is really difficult to have a general explination for what will do what.all we can do is try it and see if it helps.i have had some odd things work out from doing this.
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Old 09-21-2005, 05:49 PM   #6383
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and to answer the question about my chassis kit,yes,i did move the batteries forward on the chassis.i also moved the motor and servo forward.i moved the batteries a little more inboard too.i based this off of the stock tub.i did this to achieve even weight distribution for a more linear feel in the corners.i messed with all of these positions for a while until i found these locations that seemed to make the car enter the corner really well and under acceleration,it smoothed the weight transfer to the rear and didnt start to square up until the car was just about at the exit.i found that i was not scrubbing as much speed with oversteer.i also changed the steering geometry for ackerman adjustments that better suited this chassis kit.
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Old 09-21-2005, 06:00 PM   #6384
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I have a set up that was e-mailed to me that ahs a little softer setings. It raises the inner ballstud .060 though. Like was mentioned earlier, there are a lot of variables to work with here, so I am going to try this new set up by the book and see where it gets me. I have play in my suspension, but its in places that I can't do anything about. Like in the arms. Not front to back play that can be shimmed, but a wobble like teh hole in the arm is too big for the hingepin. This is with new plastics installed just last night. It doesn't seem like there is enough play in the suspenion to cause this coning, but it could be. I know the littlest things make the difference in these small cars. Theres no play in my ball cups though. New rpm's. Thanks for the ideas and thoughts guys. Its all good reading. Ill let you know how it goes after this weekend.

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Old 09-21-2005, 06:48 PM   #6385
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Quote:
Originally Posted by andrewdoherty
. . . . . . . This is with new plastics installed just last night. It doesn't seem like there is enough play in the suspenion to cause this coning, but it could be. I know the littlest things make the difference in these small cars. Theres no play in my ball cups though. New rpm's. Thanks for the ideas and thoughts guys. Its all good reading. Ill let you know how it goes after this weekend.
Andrew
I noticed that my newly assembly FT-TC4 has play, between the rear hub and aluminum hex hub, do I need to add another shim to lessen the play, between the 2?

The instructions said to only place 1 shim.


And the rear hub has oly a small clearance about 2-3mm from the rim of the rear tire? is this the same with all standard rear hub? Might ned to change to a losi hub?
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Old 09-21-2005, 06:54 PM   #6386
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I used to break rear hubs a lot. I changed to the losis and haven't broken one since. Theres more clearance too. Does the FT TC4 come with an aluminum steering rack? I think I narrowed some of the play in my steering down to the rack. I shaved the posts down to eliminate teh up down movement, but there seems to be play, at least in the plastic part, between the rack and the posts that are attached to the chassis. I am not talking about the posts attached to the chassis, buth the bushings that fit into the steering rack. I think I read that the aluminum rack from a company I can't remember eliminated this play. Any comments from aluminum rack owners?

Andrew
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Old 09-21-2005, 07:28 PM   #6387
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has anyone noticed the front rims are like 1mm away from hub? (this is using the foam setup) if u get hit the rim will hit the hub and we'll have to buy a new set of foams. can anything be done to fix? can anyone show a pic of the steering assembly fix? some say to cut down the piece the steering arms mount onto, but there's still play.
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Old 09-21-2005, 08:03 PM   #6388
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does any one have an old tc4 chassis that i can have for free PLEASE its because some bully got jelous of my tc4 i guess and trew it strieght down to the flor and cracked i am still trying to get other pieces too but if you do or have an offer please PM me

THANK YOU
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Old 09-21-2005, 09:31 PM   #6389
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Quote:
Originally Posted by anthony390
does any one have an old tc4 chassis that i can have for free PLEASE its because some bully got jelous of my tc4 i guess and trew it strieght down to the flor and cracked i am still trying to get other pieces too but if you do or have an offer please PM me

THANK YOU
Dude you live in Killafornia, put a hit on him
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Old 09-21-2005, 10:45 PM   #6390
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Quote:
Originally Posted by gonzo416
has anyone noticed the front rims are like 1mm away from hub? (this is using the foam setup) if u get hit the rim will hit the hub and we'll have to buy a new set of foams. can anything be done to fix? can anyone show a pic of the steering assembly fix? some say to cut down the piece the steering arms mount onto, but there's still play.
This was a problem from the beginning. Some foams don't even fit on the front without rubbing. It just depends upon the brand and the mold they happened to be using that day. Frankly, I think AE just screwed up and designed the front steering knuckles for 26mm without thought of the 28mm front foams that are now sold.

As a fix, I use Tamiya's wheel spacers (they're washers that go on the axle between the hex and the wheel). It still peeves me that an American company can't figure out carpet racing. Maybe its too much California sun.
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