View Full Version : Checking Tweak

2008.08.28, 04:32 PM
I'm getting ready to replace the main chassis on my F1 and was wondering what the best way to check for chassis tweak is? I did a search yesterday and only could find how to fix it which I already know how to do. I have a feeling that theres no real way to measure it, I just need to drive it and see what works and what doesnt.

Thanks for any info you can share.

2008.08.28, 04:56 PM
You can "penny drop" and see which wheel lifts off first, but I just drive it.

2008.08.28, 05:08 PM
Thanks Ruf, I had a feeling that would be the answer, I used a DPS to fix it before but would like to save the weight. Just for me to double check, you add shims to the side that the car spins out on, right?

2008.08.29, 07:42 AM
I always shim towards the spin out. I found it explained something like this:
If you are spinning right, it means the right rear tires is lifting during cornering, therefore, you shim the right side to get that tire down.

It has worked for me, but I must say I am an F1 novice :D Im still running all stock suspension on the rear.

2008.08.29, 07:59 AM
Very carefully check the front uprights for cracks. On turn in the corner collapses and the car spins. One of our group just had that problem. A number of us looked at it but didn't catch the problem until the whole front corner came adrift as they say.

2008.08.29, 10:23 AM
Sorry, I missed the part about new chassis. Thought it was an existing condition.

2008.08.29, 11:56 AM
Thanks for everyones advice, I'm getting ready to swap chassis now. I will drive the car tomorrow to get everything worked out before the race. Thanks again.

2008.08.29, 01:19 PM
With F1 you shim away from the corner. F1's always spin out toward the left, so add shims between the right side plate and the motor mount. You are trying to reduce the preload on the outside rear tire.

2008.08.29, 01:47 PM
Here is the post I was talking about. It was refering to loosening the screws instead of adding shims, but same concept. Its explained as the inside tire lifts, just as I remembered.


Its from this thread.

Since loosening the inside screws worked, but I saw ruf's post at the end, I ended up shimming the inside. Ive been doing it ever since and dont have any un-even turning/spin out problems.

I just rebuilt my chassis after sending it off to relfex for a 2.4 conversion. When it came back I put it together, saw which direction it spun out, and shimmed that side until it stopped.

I guess there is more than one way to skin a cat. :D

I would take Joes advice first, then if you cant get it worked out, refer to the thread I posted and see what you can do with those recomendations.

2008.09.01, 07:50 PM
I didnt have time to post after I rebuilt the chassis but I found the culprit, the carbon side plate on the left side of the car was in a "U" shape with the middle raised from the ground. I found this while I was inspecting the old chassis before it was taken apart.

Once I replaced the chassis with the new one the problem was resolved and the new chassis did not need any shims. I turned out there was nothing wrong with the carbon plate and it still works great.

I wanted to say thanks again for all the advice I was given, I will keep it in mind for future problems I encounter.