Do I need shocks or springs (or both)?

Joined
May 7, 2018
Messages
1,660
Location
Northern KY
2009 Scion xB, purchased with 145k miles a few months ago. I have no idea what normal is supposed to feel like with this car but my impression is that the ride is rougher than I would expect. It doesn’t take a terribly rough road surface for it to go “thump” and jar you around pretty well. Is this an indication my springs are weak? Or maybe my shocks are worn? Or both? How do I know which part I should replace first?
 
I've gotten the impression that springs, at least the OEM ones, almost don't wear out. When people talk about replacing struts, there's a division between those that like "quick struts" (strut + spring in a pre-built assembly) vs replacing only the strut and re-using the OEM spring.
 
You need to assess all of the suspension components for symptoms of thumps, etc..
 
Unless you have a sagging or broken spring, you likely have a bad shock. But, its worth poking around for other broken or worn components like sway bar end links.

In simplistic terms, springs support the load and the shock absorbs the rebound and compression of the springs.

My indication of bad shocks is when I'm driving down a highway and I notice that it becomes harder to keep my foot from diving into the gas pedal.
 
What about tire balance? A thump isn’t likely a tire, but rough riding can be, especially if it comes and goes.
 
springs support the vehicle + shocks-dampers control spring occilations
 
Even after new shocks my 96’ Jeep would bottom out the suspension really bad on rough dirt roads. I had to replace the coil springs to fix that issue, I guess they were fatigued after so much abuse over the years?

But quick-struts are usually crap. Probably best to piece them together yourself.

You will probably have a pretty firm ride with an xB regardless though. Economy car.
 
Springs have a bigger impact on ride quality than shocks. If your vehicle is not bouncy on a rough road, the shocks are doing their job. Measure and see if your ride height is at specs to see if your springs are sagging.
 
Last edited:
What about installing a set of air bags in the rear springs? That seems cheap and easy. Or shocks first?

It looks like it would be super easy to just jam a set of air bags up into the coils, and no bolts locked together with 13 years of rust to remove.
 
I have an XB from the OP's gen, a 2014. At 65k miles I would say that the rear shocks are getting tired but not gone. I would surely expect both the rear shocks and the front struts/mount bearings to be mostly gone at 145k miles. The springs are likely OK, unless there was some severe impact.

The xB as well as the xD have crude as crude can be, straight beam rear axles. Shocks and separate coil springs. I'm not sure, but I think that can be referred to as "Chapman struts". Any axle tweaking and you're into eccentric washers for disc mounts, etc.

My xB rides particularly soft and compliant on 55 series tires. With the xD, you feel everything from the road.
 
Spring: do they sag or are they rusted? If not I'd leave it alone
Shocks or struts: if you feel like your car bounces around when driving, they are wron.
 
I wouldn’t rule out tires. I had a set of Mastercrafts on my Camry when I got it, thought the ride was off. New set of Monroes helped, but then a used set of RT43’s fixed. Small differences and quite subjective I know.
 
Back
Top