High Speed Driving 300E
 

I have had the opportunity to take my '91 300E 3.0 up to the 130mph range a couple of times on a safe track area but get some vibration that I can't tell if it is wheel balance or suspension components. At 75-85 it's very smooth. I have about 40K on new tires now so wondering if I should rotate and balance. What other components do I need to check and how? I have new struts and shocks all around. Seems like it could be rock solid!!!

Thanks,

sptt

What are your tires speed rated for? :)

What tire pressure were you running?

Oh...good question John! I don't know but will find out! Seems like it runs super smooth anywhere from 75mph tp 85mph. I didn't even think about that but I do have the pressure at about 5psi below max (I think they're 45psi rated).

Trying to Interpolate
 

the Tire pressure you're running...

Are you saying the tires are a Max PSI rated @ 45...
AND you're running them @ 40 PSI?

If so MUCH, MUCH TOO MUCH PSI !

See the Tire Inflation Placard on the Inside of the Fuel Fill Door.
It has a Proper Inflation Pressure for High Speed Operation.

You'd better be running At Least H rated skins at that speed.

(Also,take into account the increased heat/pressure from High Speed operation.)

If he is running performance low profile tires, 40psi is normal.

Stock size tires shouldn't be running at 40psi.

Also, how often are you doing the R&B with those things?

I wouldn't attempt any land-speed records (personal!) if I hadn't just had the tires rotated, balanced and checked over for ANY SIDEWAY/TREAD issues at all. And, how'd the last alignment go for you? Everything in spec.?

130MPH? GPS co-ordinated and confirmed?

And...when did you check those inflation numbers? When the tires were cold, not driven on yet for the day?

Your tires should be R&B at least every 7,500 miles...minimum. And there IS a difference when it's done correctly...you can feel it.

Do the R&B before you spend money on anything else...unless you like having less weight in your wallet. :rolleyes:

... I would not be going on any top end sprees with a driveline vibration present at lower speeds. It is only going to become worse the faster you go...

Inspect the flex discs too.

How are your tyres new when they have 40000 miles on them? :confused:

Unless you have fairly new H, V or Z rated tires, balanced and rotated, let us know what day and what freeway you will be on here in SO CAL so I may stay safely in my garage.:eek:
Anziani
'93 300CE 196K
'95 E420 122K

is the vibration comming from the front of the car or rear? does it vibrate wen you accelerate? does it vibrate when you coast?

Just an FYI - If your going to be doing high speeds for an extended period of time, raise your tire pressures 6-8 psi.

Thanks guys. I'm going to have the tires rotatated and balanced again. I think it has been over 7500 miles since the last time I had this done. I don't plan on driving that fast again but was wondering if something in the suspension that looks and feels ok could cause the vibration. Both flex discs are newer and in good shape, and front is the correct flex disc as well as the back. I will deflate the tires to the recommended 27/27 psi that the fuel door shows. Wow! I never knew that label was there. I'm glad I asked! I filled the tires with air after driving and in hot weather conditions but could not find the inflation recommendation anywhere before. These babies are probably way too tight!!! Duhhh! The suspension is nice and stiff and turns are very tight with little to no play in the steering wheel.

Please do yourself (and everybody else you put at risk) a huge favor and learn about tires.

You don't know when your last rotation/balance was, you don't know how to check your tire pressure, you don't know what your tire pressure should be, you don't know the speed rating of your tires, you consider them "new" at 40k miles, and you're taking the car to a claimed 130 mph.

Way too many damned important "details" being ignored in this scenario.

Ramonajim...Wow! That was pretty harsh. I hope you feel good about that lashing you just gave me. If you knew me you wouldn't have done that. Most of these guys are very helpful in this forum. Maybe I'm an idiot here on this one but at least I'm trying to find out and do the right thing. If you read my first thread correctly, I said I was on a safe track and that the tires were new and now have 40K on them. Have a great day. You seem like a sharp, wonderful individual yourself ;)

Meh. This went 130mph back in 1909. (On wooden spoke wheels). Leave the poor guy alone. ;)

http://4to40.com/images/earth/scienc...ey_steamer.gif

Thanks John! Lol!