XRAY - Model racing cars

Hi Guys,

My T4 is becoming for lack of a better description feels like the rear is over driving in the front.

Running rubber tyres but has a very similar feeling as if I was running foams with a larger diameter rear tyre than the front.

I have checked belt tension which seemed ok what else should I look at.

Thanks.

What do you mean by belt tension is ok?
Rear should be almost slack and front should be almost tight to give slight pull from front not push from rear,
When does it happen on straight, corner entry, mid,exit?
Easier to post a setup sheet in most cases so people can help

The problem has slowly been developing over time and was first seen on high speed sweepers but is now also seen on the straight, and corner exit when on power.

The rear diff cams are set so the rear belt tension is as loose as it can be and the front belt tension is a bit tighter but certainly not overly tight.

As a test I tighten the front belt which had no effect.

Does the chassis roll easily (pinion removed)
What rear toe are you running?
What diffs front and rear oil etc do the run smooth
What are drive shaft and out drive conditions
Again fill out a setup sheet it's much easier than asking questions about your setup

Thanks,

Setup Sheet below

xform/index.php?act=view&ID=243&setup=t4_2015

Driveline is free.

from that i would say put the diffs back up and reduce rear toe in to 2.5,sheet says high grip so shouldnt need so much toe in
what tyres/additive are you using and when you say overdrive from the rear would that also mean its over rotating in the tight corners?
usually people would recommend thicker rear diff oil for that issue

Thank you for your input.

Yes my home track is high grip.

At my home track I can easily drive around the over drive but I will be attending an event this weekend that is on a low grip track and eats rear tyres.
I would like to have the rear end as locked in as possible as a starting point to conserve rear tyres and dial up more steering as the grip changes.

For tyres typically run spec tyres which are used as control tyre for local events.

Additive depends on the tyre, LRP carpet works well in muchmore rush, volante, others I typically use buggy grip or MG V3 LGC2 ect.


The car does over rotate slightly in tight corners, but also feels over driven on the straight and is evident on fast sweepers.

Going to a thicker diff seems to make this worse.

I haven't tried the diffs in the up position but I will give it a shot.
I must admit the front diff height description in the manual I don't exactly understand.

The rear diff makes sense though.


Front diff upper position provides more steering but
provides less front traction. Recommended for medium
- high grip tracks and technical tracks.


Less traction but more steering I am not sure how this works?

Front diff lower position provides more front
traction but makes the car push more on power.
Recommended for low traction tracks

More traction but push on power I assume this means more initial steering?

Rear diff upper position provides more on-power steering but
makes the rear slightly more loose. Recommended for medium
- high traction tracks.

Makes sense

Rear diff lower position provides more rear traction, mainly on
power traction and makes the car more stable in the chicanes,
but makes the car push more on power. Recommended for low
- medium traction tracks.

Again makes sense

try adding shims to the rear inner camber links,on low grip ive used up to 3mm

Thanks