oddwraith

iTrader: (1)

Okay so long story short is I had my car into the dealership the other day for a high-speed vibration in the steering wheel. I figured it must have been a wheel out of balance or maybe a warped rotor? Anyways, shop forman confirmed that it was likely a wheel/tire out of balance. He/they told me I'd need a "laser alignment" this, and a "load/road force balance" that. He also said I might want to try drilled/slotted rotors, and that they are the way to go on these cars, since the brakes were undersized. I always thought simple blanks with a decent pad like hawks was what I would do next from my reading on here. I asked him if there was more wear with this setup, since that is what I had heard. He said that is a sort of misonception, and that they actually don't wear pads quicker and that in fact lead to less brake fade. I understood this to be that they hold up better to repeated braking (drilled/slotted), and he confirmed this.

So tell me, can I not just start out with a simple old-fashioned wheel balance first, then work to the more expensive road-force one? Do I need this laser-guided four wheel alignment? I just had the alignment done last year I believe and haven't messed with anything (tie rods etc.) since.

Also, are blanks fine for replacement of rotors, and shouldn't I try the balance first, before going ahead and replacing rotors? I mean, they indicated they were not hussling but simply "doing it right". But wouldn't doing it right include working from the least expensive action to the most expensive? I guess maybe just from my point of view and not GM's lol .

gofastwclass

iTrader: (2)

"Doing it right" means different things to different people. Assuming they aren't trying to get in your pockets, checking the most likely sources is what they are doing. I your case, suspension and balancing the tires would be the first things I would try. The laser alignment will tell the mechanic if the car is off and tell them if something is out of speck and can't be adjusted. They could take the rotors off and check them on the brake lathe, but at dealer rates you could probably replace them and the pads for the money invested. It isn't profitable for them to replace everything, it takes too long. They want to hit it once and be done so you are both happy.

Now you said you have a "high speed vibration in the steering wheel." I would ask you to narrow that down to when and where. I've included some likely scenarios and hopefully it helps.
* If it's under braking, warped rotors.
* If it's all the time or around corners makes it better / worse, bad tie rods or loose suspension.
* If it's all the time at any speed but gets worse as speed increases, bent wheel / bad shocks / tires / balance.

These are simply the first things I would check but not necessarily all the causes.

Now to throw a wrench in all of this... I have a car where I replaced the entire front and rear suspension, brakes, tires, shocks and wheels and STILL had a vibration at 70+ (good thing I was going to anyway). I knew the driveline angles were good because I did the engine / trans swap and it vibrated pre-swap. Turns out the mounts that hold the coil overs in the front were shot causing the front wheels to oscillate with the road frequency.

As for drilled / slotted rotors - everyone seems to have a wildly differing opinion on them. I've never owned a set and really don't plan to. They look cool, but for the driving I do I will stick to the proven blanks. I am a fan of stuffing the largest brakes you can fit behind your wheels, just not drilled and slotted rotors.

Stippy17

iTrader: (5)

What kind of speeds are you getting a vibration? And is it when your driving or on the brake? A warped rotor will only shudder the steering wheel when your ON the brake..not driving a steady 60mph or so. An alignment being off will only cause the steering wheel to be off center or make the car pull left or right.

What I think you need based on what you have already said is a wheel balance. Or possibly tires, depending on what yours look like. They can be wearing uneven and/or getting choppy. If your tires look good just go ahead and get them balanced regularly on a wheel balance machine. A road-force balance shouldn't be needed. If it been a year you can have the alignment atleast checked…they recommend doing it every 6 months. You don't have to touch your suspension for your alignment to be out. Hitting one decent pothole can send it out of alignment, but again that wouldn't cause a shake. Also, when they balance your wheels have them check for any bends you have have incured. That will also give you a shake. Lastly, check the air pressure in all 4 of your tires. Having 1 a good bit lower than the others can cause the car to pull and shimmy.

As far as the rotors go if your brakes look good don't replace them unless your getting the shaking when your braking. If/when you replace them you can go with blanks and a good pad such as hawk. You were right with your thinking on that. In my opinion drilled/slotted rotors will last longer than blanks because the blanks will warp easier and rust away faster, BUT they eat pads faster than blanks.

Hope some of this helped. A little more specific info from you can help really narrow the problem down tho.

xBrian

I would get the balance and i would probably get the alignment too, unless you know those tie rods haven't budged.

As for cross/drilled rotors, they do not add to the performance of your braking system. In all reality they are weaker than blanks and blanks actually dissipate heat quicker. Cross/drilled rotors can start stress fractures in the drill holes. I would imagine they could warp easier.

When you have a chunk of metal and go to cutting on it and punch holes in it, it just stands to reason that it's not going to be a strong as it used to be. I do not believe that is 'doing it right'

That being said, i do have cross/drilled c5 directional rotors on my ls1. I like them. I like the look of them. I also know i am not that hard on my brakes. They aren't going to fail on me by any means. If you like that look, then let them do it. If not, just pass on them.

EchoMirage

iTrader: (3)

do a search and youll see drilled/slotted rotors are completely worthless. they do absolutely NOTHING for braking, and may hurt more then they help.

as for the vibration, go through a checklist like gofast said. check suspension pieces, an alignment wouldnt hurt but i dont think that would cause a vibration, but moreso affect steering wheel position, handling, pulling to a side, etc.

oddwraith

iTrader: (1)

Okay thanks guys, I'll give a little more info. Usually at about 55mph I get a slight vibration in the steering wheel, that sometimes doesn't even seem noticeable. It is not when I am braking and I am getting no pulsing in my brakes when I apply them. The car does not pull one way or the other however, I do notice that the front driver's side tire seems to be feathered as compared to the other (p27540r17-Nexxen directional) side? Could low air in one cause this? Also I had all the tie rods checked and suspension components as well, and all is tight and good. I noticed a small amount of play in the steering shaft (upper knuckle below the rag joint) but can't see how this could cause a fairly consistent vibration at highway speed. It does not clunk when turning it from lock to lock or anything. Perhaps I can proceed to check the air again as well as have a basic balance done on the fronts. I am not getting any pulsing in the brakes but they have really started to squeal a lot recently, nearly every stop. Thanks again guys, I just wanted to make sure that these things the dealership recommends is not just a money grab.

xBrian

Maybe wheel bearing? If the car is jacked up, push on the top and bottom of the wheel, if there is much movement, wheel bearings.
If you push on the left and right sides and there is movement, then tie rod ends.

I have the same tires, and i experience some "walking" but that's basically attributed to the wideness of the tires and the conditions of the roads around here. I swear there's not one flat road here anywhere.

If these tires are not aired enough they easily bulge and wear the edges more than the center part and yea i feel that can cause some vibration, but you said there's no pulling so i doubt it's the tires.

oddwraith

iTrader: (1)

Well definitely not tie rods but perhaps bearing. I hear no humming or howling noise coming from it though, but you never know.

01ssreda4

iTrader: (96)

In my opinion you need an alignment and two new front tires. Simply wearing one uneven will cause it to vibrate. Sometimes they can look fine and really cause some havoc (vibration, pulling, noise)

Stippy17

iTrader: (5)

IF its just at 55mph and not when applying the brake have a basic balance done on all 4 of your wheels/tires. That is most likely the culprit.

Stippy17

iTrader: (5)

Also, post up a pic of the feathering you are talking about. If its starting to "chop" the tread that could give you a vibration. If its just wearing an outside/inside smooth that wouldn't or atleast shouldn't give you a vibration.

1 FMF

iTrader: (1)

i picked up drilled & slotted rotors off a store on ebay about 4 maybe 5 years ago, also zinc coated. They have held up great and I have had no brake problems, have about 20k-30k miles on them I think, and I am not hard on the brakes at all which is probably the most important thing. What I will say is i think the slots in the rotors cause some brake noise, after the first 1000 miles or so when doing medium effort stops i have a decent groaning noise, but no pulsation and everything feels smooth and car stops well. I can't say if the rotors being slotted and/or drilled has any real performance effect, I honestly don't drive at that level for it to be relevant, I chose the rotors for the look, price, and zinc coating since i had polished the calipers and have chrome wheels. I believe brake pad choice will have the greatest affect on braking performance, the only time the rotors really matter is if you get larger diameter rotors.

not a fan of the road force tire balance. had it done, thought it made things worse. I high speed vibration on the highway, when not using the brakes, is going to be in order of cheap to expensive wheel/tire balance, wheel alignment, the tires themselves and don't forget tire pressure, or wheel bearings or the wheel hub or ball joints and front end bushings.

HAZ-Matt

iTrader: (8)

But the dude on Motorweek said people should get tires road force balanced?

Does it just vibrate, it doesn't veer off in any one direction? Depending on the alignment it might seem to vibrate if the road isn't smooth and you have odd caster specs I suppose. But I would consider an out of balance tire, wheel or tire out of round, or slop in suspension components like tie-rods or worn out bushings.

As far as the brakes, it is so controversial it isn't even funny. Regardless of performance benefits or not you won't fix a problem with C/D or slotted rotors because you probably aren't having a rotor problem. Even if you were it isn't guaranteed that swapping rotors would solve the problem since rotor "warping" comes from uneven pad deposition and has to do with bad braking habits and pad choice almost more than the rotor.

slowside

I feel like I'm really beating a dead horse saying this. Balance your tires, get a lifetime alignment at firestone so you can take it back after you hit a nice pothole, because it does happen every now and then. Before I would get drilled or slotted rotors I would spend $20 bucks on round aluminum ducts and ram air through the rotors. If your suspension is old, and you feel it might needs replacing, just do everything from ball joints to bushings, all the way up through mounts, seats, insulators and isolators. I did this and my car drives great. Good Luck.