How to scale wheel colliders?

[pellinor]

Here are two reference images for wheels and legs, shrunk and enlarged by writing the member localScale of the part's "model" transform:
http://imgur.com/a/cxMsU
http://imgur.com/a/PHmFS

It looks like something more needs to be done to get the wheel collider and the suspension limits right. When rolling, the rotation speed is also wrong (probably from using a wrong wheel radius). This behavior broke with the switch to unity 5 and the new wheel modules.

When using the config value "rescaleFactor" for scaling, KSP seems to do these things right. The fields mentioned in the part.cfg are all unchanged for such a wheel, and I couldn't get the physical behavior right by tweaking them.

Can anyone tell what needs to be done to bring those wheels to the right scale?

 

PS: poking around I found that ModuleWheelBase::Wheel seems to always be null (checked OnLoad and OnStart), isn't this meant to lead to the inner workings of the wheel system?