XRAY - Model racing cars

Gp, or Tony, i have a question about the rear wheelbase adjustment on the T2. From my experiances with wheelbase, usually you can adjust both the front and rear wheelbases. On the T2 you can not. Now, most of the time i like to run my cars very short, for the agressive steering feel, so i shorten the front and rears equally. On the T2 this isnt possible, so i just shortened the rear ( only a 1mm spacer ). I have been fighting problems with too much rear bite, and not enough rear rotation, and i think this is caused mostly by the fact that my rear wheelbase is too short. Moving the rear wheels forward should give the car more rear traction, atleast from my understanding of chassis dynamics. Im just looking for opinions to confirm my theory.

Basically atm, my car steers VERY well, especially on power. Im trying to gain a bit more turn in with a spool yet keep my on power steering in 19T. In stock the car steers too muchm and you can actually feel the car pivoting on the front wheels, especially off power ( alot of rear droop ). My delima is i have .5mm of front droop, and 5mm of rear droop to get the steering i want. Im also using the same spring front and rear and i have my rear shocks mounted all the way out on the tower, and the fronts 1 hole in from the outside. Basically im running out of options to get more steering especially when trying to get the nose heavy feeling off power in stock. Im hoping moving the rear wheels out, widening out the rear end and narrowing the front ( i have 1.5 mm shims for inboard toe out in the front which i think is causing part of the problem since it widens out the front ) will loosen the car up so i can us less rear droop and more front droop. I like the shocks mounted out, as i stated earlier i like an aggressive feel. Im just looking for your opinions on the matter to make sure im headed in the right direction. I feel like with the front droop so low it only allows the front to roll so much before the inside arm hits the droop screw, so the car doesnt roll much, hence my cry for rotation.

Am i making any sense ?? hehe

You are correct, if you only shorten the wheelbase at the rear (the only point you can do this on XRay cars) it will increase rear end grip and in general will lead to a less aggressive and potentially even understeering car. Having said that the shorter wheelbase will still result in a tighter overall arc, so in slower corners the car will possibly gain steering when you reduce the wheelbase from the rear.

Onto your problem. I assume you are running the steering arms in the forward position on the steering blocks as this will give the most steering. Since I gather that you don't really want to change the downstop settings the best option is probably exactly what you suggest yourself. Reduce the front track width compared to the rear. This will give you more steering. You should also consider running less caster to get more initial turn in into the corner. This will lose you a bit of on power steering though.

You can also consider running a bit of front anti-dive (i.e. front arms angled down towards the front). This will reduce your caster angle without the need to change the caster blocks and will give more initial turn in. It will also reduce the front chassis roll so to compensate you can then run a bit more droop at the front, again helping the initial turn in. You will however lose a bit of on power steering with this change as well.

by steering arms you mean the turnbuckles? I currently have them in the rear for less ackerman, as with a spool the ackerman caused a chatter ( im running on asphault ). I appreciate the input, so apparently im headed inthe right direction. Ill lengthen the rear by 2mm, take the washers out of the front to narrow it and try to widen the rear ( i was at 188 wheelbase both front and rear, id like 186 front and 189 rear ) and go from there. It will be a week before i get to test it, but ill let ya know how it goes.

Yeah, meant the turnbuckles. Sounds like you're trying the right things. Note that all of these are generally big changes so let's see where you end up with those. Once you get close to the right feel you can start fine tuning the setup.

the setup i have currently was a quickie so to speak, i have tried minor things with it, but just couldnt get the balance i wanted it either pushed into a corner or had horrible on power push. I think the wheelbase was the culprit. I have a friend who has my current setup on his T2 , ill get him to make the changes this weekend and see if he likes them.