Steering control

[NoControl]

I finally got all my road tires for my tc5 for speed runs and just plain driving around, but I have 2 problems and I'm not sure how to fix them, I have ideas on how to fix and whats wrong but I'd like some more experienced advice.

Problem one my front left tire wobbles, I have the lock nut on tight and the wheel is up against the hex, the tire is mounted properly also.

The second problem is when going 50% throttle or more and I turn the wheel the car spins out of control till I let off the throttle, could this be due to the rear diff being locked or is there something else I need to adjust.

[maxair45]

Problem number one....Is it the tire itself or the tire and rim? If the tire it could be mounted wrong of so just get some CA releasant and try it again if the wheel and tire...make sure everything is tightened down and are you using the correct screws?(tie rod might be wobbeling in the thing that goes inside the rod end I forget the name right now) Some people get into the habbit of just grabbing a screw and going when it might now work properly there.

[NoControl]

Its the tire and wheel, its just an axel that goes threw 2 bearings and a crush ring at the steering block and castor block, and connects straight to the diff, the other wheel had the same problem, but was caused by some excess goop in the hex hub, cleared it out and the wheel is wobble free, but the left wheel still wobbles.

BTw thank you for mentioning theres a ca releasant, been needing to fix one of the rear wheels the foam slid and I have a flat spot in the tire lol.

[BL_RV0]

Your name is NoControl and you want control?!

Sorry I had to...

[NoControl]

Lol I didn't even think about that.

[Bondonutz]

Are they or did you, balance the wheels and tires prior to install ?

[NoControl]

No.....

[Bondonutz]

It's time consuming but easy and cheap to do, and makes a hell of a difference especially doing "speed runs"
Not saying thats the problem but somthing to consider doing to help .

[BrianG]

Originally Posted by BL_RV0

Your name is NoControl and you want control?!...

I was thinking the same thing...

Anyway, on my brushless 4-tec conversion, I noticed the spin-out issue as well. I found that heating the tires up does wonders for traction. No tire-warmer for me though; a couple minutes of drifting works well. (at the expense of tire wear). A looser diff can help too. Also, if the suspension is too tight, a little bump can lift a tire enough so that the tire with traction sends it in circles (a tight diff doesn't help this scenario at all).

As far as the wobble goes; can you shim the axles a bit? Again, in my 4-tec, I had wobble too and had to add a few shims between the carrier bearing and heax/pin. Not too much though or the bearing will bind up; just enough to reduce the wobble. Also, make sure the shim just covers the inner bearing race; if it touches both outer and inner races, it will cause drag, friction, and wear.

[NoControl]

So Brian you think it might be an issue with tire traction,and just warming them up will let them grip more?

Got one more question no offense Brian but if the speed calc is given most if not all values, how accurate is it, I puch in all my info and it says even with my nimhs crappy power I could reach 35mph+, but when I check this against a crude real world test, driving the car from a line on my street to a where I'm standing (208 feet away) The car clocks 5.8secs-7.3secs (on a very low pack) which gives me speeds of ~36.5ft/s - ~28.5ft/s then converted I only get 20-25mph, could this just be the tires spinning or am I basing it too much on the calc?

[PBO]

A quick thought...is the stub axle itself bent?

[BrianG]

Traction is just another possibility, not sure if it applies to you, but something to look at.

On the calc, you are probably using the ideal 1.2v/cell for NiMHs, but don't forget that voltage will dip under load, especially with NiMHs. Also, calculating the distance/time is not that accurate because for a good portion of that time, you are accelerating. That 20-25mph is you overall average, not top speed. The calc simply gets total motor rpm based on volts and kv, divides that by total gear ratio, and then multiplies that by tire roll out. It's up to the user to account for certain variables, and there are a number of help screens (the little ? marks) that explain each setting.

[NoControl]

Yea I realized the voltage drop and I did factor that in, to be as close to what my elogger showed the 1st time i ran it, the logger said the motor was running at 30130rpms and if I give it the FDR weight and tire size it says I'm going close to what the calc says, but still It made me wonder.