Search results for query: *

All run out had been checked out to be less than a millimeter with the wheels mounted on the car. I move on to the drive train.

I think I got the message. Although I don't think he said they all turn at the same speed (if that would be the case, your ABS and all those stability control gadgets were pretty much wasted money). He only said, at a constant speed (a 10-15 mph range) a vibration is either there or not and as...

Oh OK, that column! I'm sorry for being such a bonehead. I have this longer run recorded.http://files.engineering.com/getfile.aspx?folder=95f170ec-b7dc-457f-9251-f61d99dbbadc&file=ACCDATA.csv

Well, columns are good, so here it comes: Vehicle speed: 140 km/h, 39 m/s, 87 mph Wheel speed: 20 rps, 1200 rpm (120/6s) Vibration base wave lenght: T=6 seconds Vibration frequency: 15 Hz (90/6 seconds) Drive shaft speed: 3600 rpm (60/s and 360/6s) Engine speed (no effect) Transmossion speed...

@GregLocock I worked from these pictures and found all the data I posted. I am happy to provide more data if you need and if I know (but I really dont know how old is the captain, so don't ask that question please :) but seriously, what is the data you are missing?

Using TMOOSE's analogy (thanks for that post): 10cpm (6 sec wavelenght) and by a tire rotation speed of 1200 rpm the wheel diameter mismatch is 0.833 percent. At this tire size this makes about 5mm, 3/16th of an inch difference in diameter. This is very possible, although I do not have...

Hello again. I already published the diagrams. They are in the attached pictures. My conclusions after some math, measurements, counting and tire size consideration are as follows. At 140 km/h (39 m/s) the vibration base band is 6 seconds! This is the periodicity. The vibration frequency is...

To bad there is no post editing. The last pic is for the RIGHT FRONT wheel.

One more thing! Someone asked about the real time of the periods. As the pictures I already posted are smaller scale summaries, here I post a full size one where the periods are very clear. This is the side to side motion of the left front wheel for an exact 30 second period at 140 km/h (87...

First pic... Sorry, i can add only one at the time...http://files.engineering.com/getfile.aspx?folder=3c044271-12f4-4480-9eab-e9803e396845&file=image.jpg

I had a long conversation with a tire shop. They said again and again, periodic vibrations can't be the result of wheel balancing. The vibrations are either present or not (at a constant speed). More than that, they also said that a badly balanced wheels has symptomes at a constant speed only. A...

Really good clue! Right now I am measuring vibrations on all the 4 corners of the car. I will post results soon. Shocks are new though and so are shock mounts.

Oh boy. Forst of all, thank you all very much for your inputs. Consensus, it seams, is about a wheel related problem. So here comes my doubts: Wheel runout problems come out about 40 mph. The car is very smooth up to 70. Balancing have been done at least 10 times in the past 4 years in 10...

I have not swapped out wheels (rims). I have mounted multiple sets of tires and the wheels were rotated from rear to front or spare randomly. It also means that the wheels had been checked visually by multiple mechanics. The rims are made of steel. I understand your point, but how would you...

Thank you very much for this input. This car has a multiple link independent rear suspension. That means the differential is fixed with bolts to a subframe in the rear. That subframe is mounted to the car with huge rubber beds but also connected with multiple (10) links to the wheel assembly. So...

Hi everybody! First post, so please bear with me. I have a problem with my car for years. Out of experience I can say that almost all problems with card can be solved by sitting on the sofa and keep thinking hard enough, but this one got the best of me. I need ideas... so here it goes: Periodic...