740 shuddering at 50 mph

hi can anyone help i`ve a 1994 740i have aftermarket wheels on it of which have been checked but still can`t get rid of car shuddering between 50/65 mph...........................

hi can anyone help i`ve a 1994 740i have aftermarket wheels on it of which have been checked but still can`t get rid of car shuddering between 50/65 mph...........................

Check the rubbers on the traction strut. Wear-and-tear of the rubbers (cracks, space, age) are a likely cause of the shuddering. See the next link. If the strut-rubbers are bad, you'll need to replace either the rubbers, the struts, or both, depending on the damage done and which rubbers need replacing (parts # 5 and 6. Replace both sides at the same time):

http://www.realoem.com/bmw/showparts.do?model=GF63&mospid=47526&btnr=31_0248&hg=31&fg=05

Almost all the bushes, loose strut mounts...basically anything on the front end can be at fault. In my case, I was fortunate enough to get away with low tire pressure as the cause. Check the tires MAX PSI Rating and run your tire at about 3-4 PSI lower than the MAX PSI rating. For instance, my tires run a maximum pressure of 44PSI (NANKANG NS-1 if I remember rightly, 235/45R-17's all around), so I filled the tires to a pressure of 40 PSI. Eliminated the shudder... I'd check this first as it can possibly be your cheapest fix ever on your car!

Low tire pressure can also cause your tire bands to warp as a result of heat due to uneven wear. So if you do fill em up to 4PSI short of max rating, there still might exist a tiny bit of shudder due to the warped tire bands. But as DutchDaniel mentioned as well, the bushes can wear out over time and become old and brittle and need to be replaced.

No if only I can get that grinding noise figured out!:grinyes:

Your car is a bit older than mine but there is a post very detailed at e38.org telling about some front strut bushings.
I did this to my car and it fixed the problem for about 50k miles. Now the problem is reappearing and the repair place I just had my car worked on told me I needed rear ball joints!

Check out E38.org.

I've been recently experiencing this problem, so I will impart some of my knowledge to you.

I don't get shudder when accelerating or decelerating, just when braking. This means, that the Upper Control Arm bushings need replacing and indeed, mine do and as a result, the car tends to wander a bit all over the road. Polyurethane bushings are the better way to go as they are more stiff and apparently last longer than OEM replacements.

http://bmwe32.masscom.net/ - Under "Fixes --> Suspension and Steering --> Upper control arm bushes" Upper Control Arm Bushing (http://bmwe32.masscom.net/sean750/uca_bushing/Upper%20control%20arm%20bushing.htm)

If I did get shudder when ac/decelerating, then I'd be looking at a sticking caliper as the most likely cause, which I think I might have anyway due to a sort of "grinding" noise that's more noticeable at city to highway speeds.

http://bmwe32.masscom.net/ - Under "Fixes --> Brakes --> Brake Caliper Rebuild" Brake Caliper Rebuild (http://bmwe32.masscom.net/sean750/caliper/RebuildBrakeCaliper.htm)

Then there are the cars that you'll never be able to get rid of the problem despite having to replace the entire front and rear suspension and driveline vibrations...

Had the very same problem with my 01 735I with aftermarket 18" rims on. The answer for mine (Kindly given by A20 RYM on another forum) was 74mm to 72mm Spigot rings cost 26UKP delivered and solved the problem straight away. They act like a washer on teh inside of your wheel to make it fit properly. A quick test for whether you need them or not is to take the bolts out of your wheel and if you need to lift it slightly to see the hole clearly then you need the spigot rings.
Hope this helps.

Common symptom of shot upper control arm bushings (thrust bushings), if they are shot, I would buy some control arms with bushings and ball joints already installed (you can buy them with the urethane bushings form after market suppliers like BAVAUTO or BMA).

The polyurithane bushings will last a bit longer especially if you have 18" rims. They are stronger than OEM.