[Closed] Car suspension question

It should be okay - the only time you would need new ones is if you fit shorter springs, as they will put the shock in a different static positionand not enable it to use it's full stroke. If you are carrying heavy loads then a heavy duty shock will perform more consistently, for longer, as they're designed for that work cycle. The standard ones may get a little hot and suffer a perfromance drop off over a long distance.

Ultimately your spring and damper combo is designed to work together, so ideally you should swap both regardless of fact that the spring length is no different. Your new firmer spring is now capable of producing higher forces and more acceleration when combined with the stock shock so you may find it "chatters" more over bumps and braking distances are increased a little. However the difference may be minimal, it depends on just HOW much different the heavy duty springs are. If you're towing a particularly heavy load, anywhere nearing the max towball weight (75kg) you might benefit from uprated springs and shocks, but the rear is the only place you'd need them and most decent sized cars can cope with an average towing weight (not at its extreme) for occasional towing. Thing is that when you're not towing you'll notice the car is a lot firmer. Personally on a normal car I'd probably just put up with the sloppy towing setup, if possible/safe enough.

frinds fitted some elastometer inserts from a caravan shop into his rear springs for towing, hve litte effect in the first bit of travel (so the car rides the saem height) but stop it bottoming out over bumps.

Hmm, kind of what I was thinking. The inserts looked a bit crappy but if they work well that could be the way to go.

Thing is, I dunno how stiff the heavy duty ones are. Apparently if you ordered your Passat with a towbar originally it came with stiffer springs, but again how stiff I dunno. It's an estate tho so the back of the car hangs over the axle a long way.

I used the rubber inserts on a Vauxhall Combo van when I used to transport my roll cab full of tools around. When the van was empty you couldnt tell they were in but with the roll cab in the back of the van they certainly kept the ride height at a "legal looking" height... 🙂

My father used them on an old car years ago, seemed to do the job OK.

had some rubber rings in the back of an old mondeo estate, stopped severe bottoming out when loaded with a dozen dh bikes or 5 bikes and riders, the towbar was starting to wear away with the scraping over speed humps it used to do