Ask an expert
![wendywoo53](themes/aaAle/images/interface/profile-pic-placeholder.47cf740a.png)
We tow a boat on an unbraked single axle trailer. It has with the trailer a total weight of around 750kg. When going on holiday with the car loaded the rear suspension is sagging a little but tows fine. Inflatable air bags inside the rear springs have been suggested to raise the rear of the car a little in these situations. I am keen to do this but hear that fitting these requires certification. Would suspension air bags be the best option? Is certification needed? If so likely certification cost?
![Anon](/assets/aa/aa-avatar.png?m=1466990309)
Hi there,
It might be best to speak with an off-road specialist who could let you know what is available and the pro's and cons of such systems. Information of this kind would be more likely available from an enthusiast.
![wendywoo53](themes/aaAle/images/interface/profile-pic-placeholder.47cf740a.png)
Thank you. The Vanguard is not really an off roader. Its a slightly stretched Rav4 with a bigger engine. Are you able to advise re the certification, particularly whether or not it would be required?
![Anon](/assets/aa/aa-avatar.png?m=1466990309)
The type of modifications you are speaking of would be quite popular with off-road shops which is why they would be good to talk to. The WoF rules are outlined in this link-https://vehicleinspection.nzta.govt.nz/virms/in-service-wof-and-cof/general/steering-and-suspension/steering-and-suspension-systems
Any modifications will have to fall inside the modification threshold or certification is required.