Do I need new shocks?

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

Rotated my tires today and noticed that the rear (before rotation) tires are both cupped on the inside edge. By cupped, I mean as you move your hand along the inside edge of the tire, it feels "bumpy". The driver side is definitely worse than the passenger side. I've got 110k miles on the OEM shocks, I figure its probably time to replace them anyways, is this the likely cuprit?

Just asking b/c $ is kinda tight right now. I need new tires soon, but I don't want to just throw new tires on if they are going to cup the same way. Wear seems pretty irregular from side to side also. My front right (before rotation) tire is BEAT (~1.5-2/32") and front left still has ~4/32" tread on it.

I should clarify, I do NOT believe tire balance is the culprit. After rotating to the front, I feel almost NO shake out of these tires, and I'm pretty anal about my tire balalnce. Tires are Dunlop Direzza Z1*s.

Are there any better tests than the "bounce" test to diagnose that the shocks are actually bad? What should I look for? I know to look for fluid leaks, anything else? I want to be SURE that its the shocks before I take the $600 hit (cuz I'm not gonna replace with OEM if I have to replace the shocks).

MarcusMcRae · **Posted:** Thu Jul 16, 2009 2:14 pm

It is unlikely that worn shocks would cause the tire wear you are experiencing. When was your last alignment?

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

its definitely been a while, but I was under the impression that alignment issues would lead to even (around the circumference of the tire) wear either on the outside (excessive toe in) or inside (excessive toe out) edge of the tire. Look at this picture:

The "failed shock" picture is sort of what my tires are like, except only on the inside edge. Since the 3 has a good amount of negative camber in the rear with a stock alignment, I figure this is why the cupping is on the inside edge. I suppose I also could have some combination of alignment issues+shocks or alignment+wheel balance issue (although now that the tires are on the front, they actually hardly shake at all).

I KNOW I need an alignment, I'll definitely get that done. I know I need new tires, I'm going to get them soon too (probably after Laurinburg). Just wondering if I need to do shocks as well. I'm gonna get Konis when I do get shocks, and from what I understand, they can change ride height somewhat. I'd hate to get tires, get an alignment, and then realize I need new shocks, and have to get another alignment.

Part of me thinks its time to do shocks anyways, and now is the time, its just not the best time as far as $ goes.

Jason Mauldin · **Posted:** Thu Jul 16, 2009 4:03 pm

BriceJohnson wrote:

Part of me thinks its time to do shocks anyways, and now is the time, its just not the best time as far as $ goes.

At 110K miles, that's probably a fair assumption to make.

MarcusMcRae · **Posted:** Thu Jul 16, 2009 4:30 pm

I've never seen a tire look like the "worn shock" tire in your picture.

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

it literally is sort of bumpy, there are definitely high spots and low spots around the inside of the tire. I was wondering if it maybe had to do with lifting the inside rear tire maybe as opposed to (or in combination with) being a worn shock?

The ride doesn't seem excessively bouncy or anything in the back, but then again its possible that the slow degradation of the shock has made it harder to notice.

steve remchak · **Posted:** Thu Jul 16, 2009 6:46 pm

Jason Mauldin wrote:

BriceJohnson wrote:

Part of me thinks its time to do shocks anyways, and now is the time, its just not the best time as far as $ goes.

At 110K miles, that's probably a fair assumption to make.

i thought Mazda shocks lasted forever. like Honda's and Toyota's do. i didn't think Japanese cars required maintennance. everything i read from Consumer Reports tends to back this theory of mine.

wow, learn somethin' new ever'day. :twisted:

Hey Marcus, you don't suppose there might be some worn suspension parts also do you? :roll:

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

I expected to replace them within the next 10k miles or so, I'm just hoping that they can last another 3 or 4 months. They honestly don't FEEL worn out. Going over speed bumps, the rear compresses and comes back up, no bounce. The handling seems excellent still (good enough to win ST at the triad event last week).

Thats what seems so weird to me about it. I'm not like the typical Camry driver who's shocks totally blow out and they don't even know. I normally notice the tiniest thing out of whack with my car.

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

I'll bet it's your alignment.. some toe-out in the rear. (That will help rotate a FWD car in corners

) Is the cupping starting to happen on the tires that are now on the rear? How many miles do you go between rotations?

steve remchak · **Posted:** Thu Jul 16, 2009 9:04 pm

BriceJohnson wrote:

I expected to replace them within the next 10k miles or so, I'm just hoping that they can last another 3 or 4 months. They honestly don't FEEL worn out. Going over speed bumps, the rear compresses and comes back up, no bounce. The handling seems excellent still (good enough to win ST at the triad event last week).

Thats what seems so weird to me about it. I'm not like the typical Camry driver who's shocks totally blow out and they don't even know. I normally notice the tiniest thing out of whack with my car.

let's see if i can explain this to you Brice. when you bought this car you were a total noob. car handled great, better than you had skillz to utilize all the goodness.

today the car does what you expect it to do and handles suprisingly well given the mileage you have put on it. and apparently your competition in ST is lacking :twisted:

your learned skillz.

110k on an OEM set of shocks and struts is enough already. were it me i would have swapped them at about 60k, but then again i have never competed in a vehicle that has that Mazda goodness. :roll:

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

I guess what I'm asking is how would the worn shock would manifest itself. The low frequency damping is clearly still there based on the speed bump test (no bounciness whatsoever). Does the high frequency damping degrade first?

Af ar as my competition in ST being lacking, that was definitely true due to the lack of clean runs at that event. Lee Williams also wasn't there to whip my ass like he normally does. . .

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

Pick a bumpy street, one with lots of half-filled pothole patches and frost heaves. (Durham is full of those) If the back end of the car skitters around a bit on that (as opposed to just crashing through the bumps and holes), your shocks are worn.

Drive down a bumpy street near the Mazda dealer Durham, then go test drive a new Mazda 3 on the same street.

In any event, you will be amazed by the difference a set of adjustable performance shocks/struts will make.

Sean O'Connell · **Posted:** Fri Jul 17, 2009 7:09 pm

Brice, i dont think this is a new issue your car is having. i got your old set of azenis from a year or more ago and they have a strange ware pattern similar to what you described your current tires looking like. i believe it is referred to as scalloped tread wear on the inside tread blocks and is probably due to worn suspension parts. possibly the shocks, possibly bushing or ball joints. or a bad alignment if you have gone that long without one.

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

Interesting, thanks for the heads up Sean.

Stephen Westerfield · **Posted:** Sat Jul 18, 2009 9:54 pm

Sean O'Connell wrote:

Brice, i dont think this is a new issue your car is having. i got your old set of azenis from a year or more ago and they have a strange ware pattern similar to what you described your current tires looking like. i believe it is referred to as scalloped tread wear on the inside tread blocks and is probably due to worn suspension parts. possibly the shocks, possibly bushing or ball joints. or a bad alignment if you have gone that long without one.

Funny you should mention that. I've got Brice's last pair of Dunlops in my garage right now (courtesy of Kendt) and two of the tires (I assume the ones you were running on the rear) have the same scalloped tread wear as well. The other two the wear is very consistant across the tire.

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