XRAY - Model racing cars

Hey Everyone!

I have a small bit of tweak in my T4 '13. Once I run it through the setup station and set my ride height, then throw in on the tweak board it clearly shows the front left of the car lifting around 1/4" (maybe a bit less). I can take this tweak out with the springs, but it seems to extreme to do that.

I have removed the shocks and sway bars and laid the chassis down on my hudy board w/ droop blocks and their is no movement at all, it sits flat.

So at this point does that eliminate certain things like main chassis plate and top deck tweak, or are those still a possibility? If it does eliminate them, how do I go about determining where my issue is?

Thanks!

Luke

Have you got a bar or something you can use to push down on both shock towers at the same time?

We tend to do this when tightening the top deck screws to ensure that the chassis and top deck are both dead flat.

Check for bent screws in everything and make sure the droop at each corner is identical.

Skiddins

I tend to do the top deck with wheels off on a flat surface, but as long as you can push the chassis down onto a flat surface it should be ok.

Tighten the top deck screws diagonally, do them pinch tight, then go round and tighten them properly.

Skiddins

Thanks so much. I'll give it a go. If this doesn't solve it, where do I look next?

Check your droop is the same on both sides and that your shocks are the same length.

I either put the car on droop gauges or on a flat surface and tighten my top deck. When putting on a flat surface be aware of the front bumper, it's lower than the rest of the car.

Check Damper length and all other settings as mentioned above. Also roll bars flatness and adjustment.

Alright, great, thanks. This is basically the process I went through a couple weekends ago. Set the car on the droop blocks and re-set the top plate. Double and triple checked the droop. Measured all the shocks with my caliper (one was slightly longer, so I fixed it). Then checked the balance of the car with the balance pins - it was slightly off so I added a few grams to one side and that fixed it up. Still had the tweak after all that.

I will run through all of this again tonight and will remove all my electronics and check the flatness of the chassis without them.

Thanks everyone... I may be back to get some more help.

I had the same thing when I bought my T4.After taking the chassis off and putting it on the Hudy I saw it was twisted and therefore the tweak would never go regardless. Sent it back to Xray who replaced and agreed that it was a twisted chassis.

Thanks for all the help everyone. Did a half rebuild on the car last night and used my 3mm reamer to open up the holes in the top deck, put it all back together using the bar technique to hold it down firm and sure enough - no more tweak!

Ackkk, well, I spoke too soon.

I was checking my tweak at various points of reassembly, and I thought it was fine... then today I just went down to finish it all up. Soldered in my electronics, check all my shocks, reset them all to exactly the same preload (well, same # of turns anyway) and set my downstops before I put the shocks and tires back on so I could continue setup. Set my front to 6mm and rear to 5mm as per the standard setup sheet. Threw the shocks on, threw the tires on and checked the balance of the car. It was slightly heavy on my battery side (7000 mah ready = heavy) so I put weights on the other side one at a time until the balance seemed good. Then went to set my ride height and noticed I had to crank the same two (opposite) shocks to get the ride height correct and new right away the tweak was back. Sure enough I checked it and it is out, in the same orientation as before.

So, I guess it comes down to weight balance on the car. It might be extreme, but I'm going to go pickup 4 kitchen scales and set the car on it and see how each corner looks for weight and move stuff around until they are as even as I can get em.

Does this sound reasonable, or am I missing something crucial?

Thanks again for all the help so far! Even though I'm having some bad luck here, I'm really enjoying the problem solving.

Luke

Don't tell me, the heaviest corners were the near the servo and diagonally opposite?