View Full Version : Right turn understeer
2002.06.27, 07:50 PM
My car pushes real bad only during right turns. I've tried many things to try and fix this but nothing seems to work. I have
Top Cad's alloy motor mount and front bulkhead and a ball diff.
I also have alloy steering arms, steering rack and front stabilizer
as well as complete rear suspension. I've tried different wheel/tire combinations and also tried jacking the weight with
different spring set-ups in the rear. I have the red (softest) springs in the front-this should give me the most steering.
I am running only rubber tires on smooth concrete. I have tried
both wide aluminium wheels and stock. During left turns, the car
handles great but when I turn right-it pushes so bad that I can hear the bearings vibrate. This problem is taking the fun out of it
for me. I've spent about $500 on this car so far- I must be crazy.
Anybody out there please help!!!!!!!!!! =(
2002.06.27, 09:44 PM
could this be torque steer? if so, this is normal....
Sounds just like my trick that I tell to everyone but noone wants to try. Sounds to me like the tweak in your H bar is out of whack a little bit. Set the steering as straight as you can w/ the trim, then from a stop, give your car full throttle. Does it spin one way and start doing donuts soon after you accelerate?
You said your car understeers to the right really bad. H bars aren't always perfectly flat, especially the stock ones. If you want your car to turn right better, you need to get more grip to the left rear wheel. Lets say the spur gear side of the car is right, and non-spur gear side is left. Unscrew the front left H bar screw 1/4 turn. Now put your car down & give it full throttle again. It should be better, if not corrected. If you need to do more, unscrew it another 1/4 turn. It is easier to correct this with the stock motor mount because you can also unscrew the right rear screw 1/4 turn. You can still try unscrewing the right rear screw, or screws, but if they are like the GPM motor mount (metal screws & metal motormount) you don't want to do this because you'll lose your screws.
If you want to know what you just did, here goes. The right rear tire had more grip than the left rear. So, when you set the car down on flat ground, it would have more weight on the right rear. By unscrewing the front screw oposite the side with more grip, you let the H bar flex more until it is flat and distributes the weight evenly to both rear wheels. This is a big part of 1/12 pan car racing, most those guys check their H bar tweak after every battery pack.
Hope this helps!!!
2002.06.27, 10:40 PM
I do a similar thing but I wanted to keep the screws tight, so I tried paper of different weights (thickness) as a shim until it was just right.
2002.06.28, 10:54 AM
This happens if you spend to much money on mods, send me some expensive alloys parts and I will replace them with standard items. That should fix. :p
BTW, torque steer only happens when you accelerate hard. So its not that.
2002.06.28, 06:34 PM
Last night I was up until about 12:30am expiereminting
w/some extreme weight jacking trying to fix my push problem. I went thru 3 sets of NiMh batts but I was able to stabilize the
Handling. I used a soft RED spring on the right rear and a hard
YELLOW one on the left w/a couple of small rubber rubber O-rings
under the spring. I'm using a soft RED fiberglass H-plate. (You're
right Russ the Fiberglass ones really do suck) I ordered a Carbon
set from Mini-Z today. As I said I was able to stabilize the handling but, with the hardest spring on one side and the softest on the other, it does'nt leave a whole lotta room for tuning on different track surfaces. After reading the replys today, I tried the
paper shim trick from Ken Mifune. I put the RED soft spring back
on the left side and shimmed the H-plate with peices cut from one
of my business cards- I had to use 5 pieces of thickness- still
pretty extreme, but it worked. Now the car still under steers, but it's about the same both ways. I should be able to tighten it up
W/ harder springs or a stiffer H-plate. I used to run 1/12th scale
back in the '80s and yes, I did ck my tweak after every run, but
these little cars are a whole new world. THX Guys ZYAL8R
2002.07.03, 04:23 AM
thank you for your tips on correcting the car's tendency to hook to one side. if i played on my slippery kitchen floor, it would spin out to the left. so i took you advice and cut out a small peice of cardboard(GPM turbo package) and stuck it under the front left side of the h plate. just one did wonders. when the car is off the ground it looks a little twisted, and a little when on the ground, but it drives awesome.
if there is another way to do it, let me know. thanks b
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