Anestheticg

so I'm getting some wheel shudder when I hit over around 70-75 mph. I have a 2000 c2 18 in wheels 225/40 front 265/35 rear. It seems to be worse when I let off for accelerator and isn't as bad when under power. So i did some looking and seems there can be a combination of 3 causes (

1) all tires were at 36 psi after a warm up. Door panel says 36 front 44 rear.. I should follow the door panel right?
2) front tires are very worn. Almost at wear bars... need to replace asap
3) I didn't really notice till I really looked... and here's where it gets interesting but the tires are different. Front worn tires are both pirelli Rosso
back tire is pirelli p zero nero and another tire is pirelli all season plus. Both back tires have lots of tread...

i just bought the car last week (I know I missed some details) but fingers crossed there isn't a bent wheel or something. I obviously change two front tires but what would you do?
just swap all 4 tires to a uniform type? Change 3 to p zero Nero?
Its kind of a strange situation hence my reaching out to your Porscheofiles

docmirror

Bump steer(not tramlining) is usually caused by worn parts in the front end.

Mileage?
Front wheel offset?
Past road conditions driven on?
Wheel balance(shake) on smooth roads?

Gonzo911

Bad tires will do that.

Buy 4 new tires from a reputable shop. That way they'll be balanced correctly. If necessary get an alignment.

Its likely not a bent wheel. Good luck.

Anestheticg

just shy of 37k miles
no offset
not sure... car has been babied it seems from low miles. Lived in Texas for a while.
No shake on smooth roads. It's kinda intermittent and only noticeable as described...roads do seem to have a small factor

Anestheticg

thanks man!

docmirror

I don't think you understand what wheel offset is. But if they are stock wheels, that's ok.

Get it up in the air, and have a suspension savvy guy look it over for worn bits before you blow a few thou on new stuff. Unless you would just prefer throwing money without diagnosing.

Southern Man

So, now you can ask what tires we recommend!!! (Ducks for cover.)

Anestheticg

errr yeah wheels are stock "twisties" and I don't understand offset. I'm not exactly a gear head.
I imagine tires would cost me about 800-1k. The car is old but not many miles. I think it has been maintained but maybe not quite up to stuff. Would worn suspension components happen over time regardless if mileage?
Seems like front tires need replacement regardless. If the back two were the same tire I would just replace fronts with what the rears are but they aren't... I guess I'll have it looked over and will also need 4 new tires...
man these cars are money pits but not as bad as a boat 😂

Anestheticg

Already had a thread on this. Think I'll do Michelin AS3 or p zero all season. Something UHPAS as I will drive drive the car in cold temps as long as there is no snow

Southern Man

I think tires will likely solve your problem. Even without vibration, from what you describe about the state of the current tires, I would change them ASAP.

Not sure you would have that much wear on the fronts with the stated mileage, especially since they weren't the originals. What kind of records came with the car?

And yes, get the rear tire pressures up to 44psi!

Anestheticg

very little. I bought the car from a guy I know from work. Have some Porsche docs with some service intervals filled in from dealer but the last was 2004... my friends dad had the car for years in Texas and recently gave it to him. I'm confident it's been maintained but doubt it's quite up to exact recommendations. He's going to get me the records from his dad but I'm not counting on it. The car is pretty solid and I figured if it blew up I know where he lives and works... and that I could sell it as a roller for 5kish and I took the risk. I know he isn't/ wasn't trying to hid anything from me deliberately but of course as soon as I've got it the (aftermarket) Sony snap in radio doesn't work and the tire issue... besides that it's in great shape. 3717 miles when I bought her. Paid 14k which I thought was fair as it's a tippy (I know I know but I bought the car on a whim really). The worst part was having state of CT get me on sales tax when I registered the car. I'm hopIng to get this shudder taken care of and enjoy it for a bit before maybe biting the IMSB bullet along with water pump, belts, spark plugs, and whatever else has been neglected

docmirror

Let's review. You have a car with no driving or mx history. It's at 37k miles(presumably). You have very worn front tires. You have no problem with smooth road vibration, but you do have a problem with bump steer.

Does this sound kosher to you? What perchance would cause front tires in a rear engine car to wear down at 37k miles?

Are you possibly confusing cause with effect?

Anestheticg

forgive my ignorance. What would caUse front tires in a rear engine car to wear (prematurely)?
I inflated rear tires to proper PSI (they were at 36 all around before) and it seems to have helped. I will have to take it out on the higway tomorrow to really know for sure.
Mileage checks out via car fax. I trust the seller. I don't think a console was swapped out etc and condition of car reflects low mileage.
I just pushed the car to a highish speed and she feels really good. This vibration thing doesnt mean the sky is falling. In fact the car runs really well... as others have suggested likely swapping out all tires will help significantly but I'm not naive enough to think that the car probably needs a fair amount of preventative maintenance items performed.

I don't know if what I'm describing is bump steer per say as the movement of the wheel doesn't cause a change in steering direction if that makes any sense... in any case new tires are in order and even if that fixes it ill still have all maintenance items that need addressing done. Thanks for your input and sorry for any frustration I've caused. I'm quite new to Porsche and as you can tell I'm not a gear head or tinkerer at all

Gonzo911

Seriously Doc? I'm lucky to get 15k miles from my front tires. Replaced the OEM Michelin P's at 15k. No tracking or harsh driving.

I know everyone wants to always jump the gun around here, but the OP said the front tires were worn, and if the car sat for a long time, likely 4 flat spots as well. Sounds like they weren't inflated to the proper PSI as well.

He should start with replacing the tires/balanced because he has to do it anyway. If that doesn't solve the problem, then he should look elsewhere.

Not knowing much about these cars isn't a crime, but walking into a shop with little knowledge and having them assess your suspension could result in one...

Anestheticg

thanks man. Anyway I'm biting the bullet and bringing her into a "porche specialist" to get tires (going with pilot super sport A/S 3+) and going to get the IMSB done along with a thorough evaluation and subsequent replacement of any components that needs it (coils, oil/air serperator, water pump, etc etc etc) gonna hit the wallet a bit but then she'll be all set for a glorious spring