XRAY - Model racing cars

ok, I made a set up sheet,

I thought maybe to close 1 or 2 holes in the front shocks or to put the yellow springs at the rear (actually Tony said this). But the springs are on an other car now so that's why I haven't tried.

I've no t1r. But I wonder if that car has downstops, i presume 'yes'. You didn't specify any value though.
I think trying the yellow springs to stabelize the car is the best option
But 2 other thoughts:

As I don't now your droop:

1) maybe reducing your droop at the back can help. Reducing weight transfer to the front.
2) or thinking totally the other way around. Increase droop because maybe the inner rear wheel looses traction in that specific corner.

Gr. Joep

you're right Joep, there is no value for downstops. This was what I remembered, I did not remember the droop but I'll measure that tomorrow.

I don't really get your second droop option, can you explain why this would lead to more grip in the rear?

My second option is assuming that:
1 weight is transfered to the front
2 chassis in the rear travels up
3 and rear arms go down
4 now the downstops kick in

normally this is the point weight transfer stops to the front.

But ...

if downstop value is to high / droop too low and springs in front are rather soft following can happen.

6 downstops kick in
7 you turn more in
8 chassis rolls to the outside of the corner and weight transfer to front goes on.
9 and because the rear inner wheel trafel is totally blocked it lifts.
10 side grip gone
11 spin or at least oversteer

Hope this helps.


btw: why not go 1 step stiffer in front instead of yellow in the back as a test?

Try checking the diff or asking someone to watch the car as you drive. Sounds like something is wrong as apposed to an unsuitable setup... Everyone else seems to be thinking its a setup issue. Sounds to me like the thrust bearing in a diff is gone and its locking everynow and then.

Col could be right: I ruined my final in the clubrace with the kit-supplied trust bearing

Also what body do you use on your T1R. At Mach some people drive not the usual shells

Have you tried a new set off tires yet. At the club I race I thought I was doing just fine until I changed to new tires and improved by 3/10 second.

I've had the same type of problem several times. Unfortunately I haven't learned to well, since each time I've chased setup options only to find out that the front tires were too soft a compound or I had added too much additive to them and they had too much grip mid corner.

I had the same problem just last week where I barely qualified for the A main with 25 laps while fighting the rear end every lap in the tight corners. After putting on a brand new set of fronts with a minimal dose of additive to the inside qtr, I came through the pack from seventh and won the main at 27 laps.

After looking at your setup sheet, I also noticed you are running .5mm higher rear ride height. One time I had this problem, and after putting on new fronts, I ended up changing the rear ride height to match the front and added 1mm of rear droop to make sure the inside rear wheel didn't lift off the ground at mid corner. Problem solved. Equalizing front & rear ride height and adding rear droop will allow the cars weight to shift forward on corner entry only to prevent off power push, but will allow the weight to shift rearward quickly at mid corner for better traction at neutral and on power.

I would suspect that once you find the problem, you may be able to stand your rear shocks upright a bit more and get better on power steering as well.

All this advice is good. But just for kicks, try a different set of tires like teamgp suggests first. Every once in a while you will be changing setups quite dramatically without any noticeable improvement only to find out that the tires were the real problem to begin with. This includes tweaks. If out of a set of tires one tire, especially on the rear, is slightly off the car will be difficult to race and have a tweak that no amount of setup can correct...

Experience Tony

Nah, lucky guess

I already changed the front and rear tires because I thought there could be 1 bad tire causing the whole problem. But I did not feel a difference.
I checked the diff and it feels ok.

BUT I think I solved the problem. I checked all the shocks and rebuild 2 of them because there was very little air in them. But I checked the downstops and they were way off. The front and rear were left to right not the same.
So I´ve set them on 3 on the front and 4 on the rear.
I think this was the problem but I'll also try a different set of tires tomorrow night.

is the setup I'm going to use tomorrow.

BTW: Frans, I use a Protoform Mazda 6, as you can see in the setup sheet.

If you still have problems, I'd still highly suggest lowering your rear ride height to match the front and increasing the amount of rear droop by 1mm.

ah tony know how you felt , tires on shelve we old inventory and were dry aparently in my case and handled like junk(felt like ski's on the back) bought new ones in the same compund didn't even need traction compund!

it handled really well last night. I tried the setup from the setup sheet and had enough grip both on the front as on the rear. after making a very small change to the downstops it was a little bit better.

I also tried to mount the top of the rear shocks 1 hole more to the outside but it did not improve the handling so I put them back the way they were.

thanks for the advice everybody. I'll see if I can try some more things tomorrow night.