Bandwidth dictates how "tightly" the motor is driven. An analogy would be a car's suspension. More comfortable the softer it is set but with the likelihood of overshoot, more precise the harder it's set but less comfortable overall.

The default Bandwidth setting of 0.5 is chosen as a compromise between accuracy and comfort but with the IR-18, the theoretical added discomfort of running at 2.0 is offset by the reduced effect of the oscillatory behaviour inherent in the input signal.

For cars without as extreme a FFB response as the IR-18, you want the Max Speed value as high as your preference dictates. It is a secondary tuneable i.e. it modifies the behaviour of Weight by altering the threshold at which it starts to be applied.

If the car is sufficiently well-behaved (e.g. the Formula Vee), Max Speed @250 & Weight @0.25 is possible

There you go guys, thanks.
For iRacing I set the wheel value at 20Nm and the Force/Scale doodad I usually auto but most cars are usually within 10Nm. I added the 2% weight recently (prior to this request). I usually drive the L49 and that can take 20-22Nm of Force with my 7 caster setting and 10:1 steering ratio.
I’d be interested to know what the Hz setting does (I read iRating use 60Hz) and someone on the forum said reduce the speed and have a narrow range of weighted centre. I’ll wait to see what you think. It’s the only car I’ve experienced this in and I’ve driven lots!

Can you post a screenshot of your Settings & Advanced tabs in your desktop app as well as your iRacing FFB settings?
We'll configure accordingly at this end to see if we can replicate the behaviour and work out why IR-18 behaviour differs from other cars within the sim.