XRAY - Model racing cars

I tend to agree, harder springs are needed.

Yes harder springs will stop body roll but won't produce as much grip. If the body roll is causing the side of the chassis to scrap then you need to siffen your springs but if it isn't that bad you may be better with the springs you have. The suspension can also be stiffened by standing up the the shocks.

It depends on why the car grip rolls. If it grip rolls over dots or kerbs then harder springs will only make it worse. If it is truly purely the grip then obviously you need to take grip away.

Some tips to get you started in order of priority:

1. Put super glue on the sides of all four tyres up to about 1mm below the running surface. This will make the side walls harder reducing tyre deformation during cornering. Think about a box and how it topples over. You first need to get the CG high enough compared to the outer edge before you can topple it over. Same goes for a car with the outer edge of the tyre. If the tyre can deform too much it will be relatively easy to get past the outer edge and roll the car.

2. Increase the camber (starting with the front) to 2 or even 2.5 degrees. Same reasoning, the increased camber will make it harder to get the car to topple over the outer edge of the tyres. Moreover this will also decrease the grip a bit.

3. Give the front shocks more angle combined with harder springs. This will give a smoother damping action will preserving the limited chassis roll you have now. However if you roll over dots or kerbs this might not work so well.

These three suggestions should get you going in the right direction.

You could also try making the roll centres higher if you haven't already. This will reduce body roll and will make the car more responsive.

The only thing I'd add is widening the front and rear track width by say 2mm. Try another 1mm shim in between all of the suspension holders and the bulkheads they're mounted to.

TonyV and Team GP make excellent suggestions. After looking at the setup, i would go with widening the front and rear ends, and i would also stiffen the chassis completely, if you havnt already. You could also try harder tires, 24's are kinda soft, and with grip roll, it sounds liek there is plenty of traction try a 28 maybe.

Strange at the one club I don't have grip roll problems but at the other it is really bad, which unfortunatley is the one I need it to work at. I ran the car last session with stock setup and it worked, but now the weather warmer in the UK I am really am suffer grip roll mid corner.

I have tried 25ib springs now and althought better I think this is to much compare to the 22ib. Total lost now I must admit it , I have now reduce the front downstop to 6 now to see if that helps as I know a couple of guys run 6 with standard springs and same tyres and they don't seem to suffer.

Ok, Sheet now updated with missing items. I'll take as many of these ideas I can and try them with the limited time I have. if anything else is missing off sheet it should be as standard.

http://www.teamxray.com/xforum/xform/in ... 5&setup=t2

Not trying to sound repetitive, but I'd start off by increasing the front and rear track width to 190mm. And with that change, I'd also stand both the front and rear shocks up to either holes #4 or #5 uniformly. The wider track width will get rid of the traction rolling. Then its all up to balancing out the front rear grip as you would regularly.

I say this from an experience I had last year with my FK05 where I attended an indoor asphalt track that had unbelievable grip, even when running CS32's. I was told that no one had been successful with running a stiff suspension setup, because the initial steering response would cause the cars to traction roll instantaneously at turn in. Therefore all the drivers were running very soft setups and smoothing out their driving styles.

I decided to widen the car to the limit (190mm) and run an adaptation of the stiff carpet/foam setup I was running and I never had a problem with traction rolling.

Now at the race, I had a problem with oversteer. But that was due to a faulty rear diff and a bent rear hinge pin that I didn't find until the week after.

A few months later, I returned to the track and tested my latest, even stiffer, carpet/foam setup and it worked perfectly with foams on the grippy asphalt. Then with a few minor changes, it worked perfect with CS32's in the front and CS27's in the rear (needed for the one-way) and a 19t motor. No traction rolling, oversteer or even understeer. Zero traction rolling sounds impossible when you see that I was using red springs front and rear WITH the one-way.

Here is the setup, just to give you an idea:

http://www.teamxray.com/xforum/xform/in ... tup=t1fk05

Just a thought on top of this, would an anti-roll bar on the front be worth investing in for the front ?

It's always a good thing to have if you need to quickly reduce grip at the front and don't have any time to dial in the cars balance through the basic suspension options.