| Author | Message | ||
     Rolf Versen Yet to post message Username: rolfversen Post Number: 1 Registered: 3-2013 |
Hi, I am new to the forum so hello to everybody. My Azure has a vibration I feel on my back and which shows in the mirrors vibrating. It comes on at 100 mph and goes at 120 mph. It is felt as well under hard acceleration starting at 80 mph. I am living in Germany, therefore the speeds. Has anybody experience with this phenomenon?: Thanks and kind regards Rolf | ||
| David Michael Leedy Experienced User Username: dleedy Post Number: 20 Registered: 11-2011 |
Hi I have heard from a rr parts supplier that a common complaint he hears from customers is a vibration at different speeds the results of vehicles that tend to sit for periods of time. Due to the heavy weight of the car, causes flat spots on the tires and warps them. Visually not detectable but once removed and put on a spinning machine revealed. Solution is to replace tires. Regards. Dave. } | ||
| A.R. Greenberg Experienced User Username: bergxu Post Number: 35 Registered: 2-2012 |
Does the Azure have the rear subframe dampers like the saloons? If so, those are typically also a contributor to vibrations. | ||
| Jan Forrest Grand Master Username: got_one Post Number: 465 Registered: 1-2008 |
As DML says: Vibrations that only come on between certain speeds tend to be tyre imbalance. As a one time tyre fitter I came across this many times and, depending on the degree of imbalance, can soon be eliminated by a rebalance of the (usually front only ) tyres. Be advised that if it is due to a 'flat spot' on the tread area it may work itself out eventually and the wheels may need balancing again at some time. In the meantime the vibrations could be causing untold damage to the steering and suspension gear so it should be attended to ASAP. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 313 Registered: 6-2009 |
Here is an article that was written about this issue in many of the SZ cars and published in the Modern Lady, Issue 03-1, pg. 361: SZ VIBRATIONS: DOES YOUR SILVER SPUR OR BENTLEY DERIVATIVE HAVE A TIRE VIBRATION THAT CAN’T BE FIXED? By Richard Vaughan One of the great things about attending the club’s national meets is that you get to talk to dozens of people who have the same cars and the same experiences that you have. This can be invaluable in diagnosing a problem or, as in this case, discovering that there is a problem that many owners are having. Through talking to SZ owners, I have discovered that a problem that I was experiencing is extremely common. The symptom is an annoying vibration that begins at around an indicated 70 miles per hour and continues through about an indicated 90 miles per hour. Outside of that range, the problem seems is less noticeable. Personally, I found this situation to be absolutely unacceptable. For some reason, I am particularly sensitive to vibrations and this situation made my driving experience less than enjoyable. I was determined to correct the problem at any cost. This article chronicles the long and very expensive process that I went through to fix a very inexpensive problem. Along the way, I fixed a few things that I didn’t know were broken. Ultimately, I have a much better car because of it. Upon buying the car (NAJ-22307), over 15 years ago, I realized that I had what seemed to be a tire vibration coming from the left rear of the car. At high way speeds, it was very obvious. Besides feeling it in the seat bottom, if the seat was empty, I could watch the passenger armrest oscillate to the motion. From the rear seat, the map pockets could be seen vibrating in the same manor. The first thing that I did was to have the original equipment Goodyear tires balanced at a tire shop that was familiar with Rolls-Royce jacking points, wheel removal, and torque specifications. Many tire shops do not realize that Rolls-Royce motor cars are reverse threaded. They also do not know the correct places to place a floor jack. Just as important, they over torque the wheel lugs and sometimes break them off. The Rolls-Royce specification for torquing the wheels is very low compared to other cars. My local technical expert has had countless customers with broken wheel lugs and bent bodies. In fact, He has had a few cases of poor jack location that were so bad that the rear door wouldn’t open on that side of the car. After I had the tires balanced, I realized that there was very little change in the vibration. I assumed that the shop had incorrectly balanced the wheels or that a wheel weight had fallen off as I was driving away. I took the car back to the shop and had them repeat the procedure. There was still no change. I spoke to my Rolls-Royce technician who informed me that I would have to have the front tires balanced on the car. On-car balancing brings the hub and rotor into the equation. It’s difficult to find a shop that has the equipment to do this; fortunately for me, the same shop that I had been using also did on-car balancing. Of course, after doing this, there was no change in the situation. In the meantime, Cal West had been having a discussion on the club’s technical email discussion forum about the correct tires for a Spur. He stated that the original Goodyear tires were not the best tires for the car and that blowouts, and splitting were a regular occurrence because of the weight of the car. He recommended Michelin tires and so did other members of the discussion group. Oddly, about a week after that discussion, one of my nearly new Goodyear tires split right down the middle. Fortunately, I was traveling at a very low speed. This was a perfect excuse to buy four new tires and rid myself of the annoying vibration. I ordered the correct Michelin whitewall tires and assumed that this was the end of my problems. I was in for a big surprise. The Michelin tires transformed the car into the true luxury car that it was designed to be. The Goodyear tires gave a hard and sporty ride, by Rolls-Royce standards. The Michelin tires were much softer and quieter. While the handling wasn’t as sharp, the difference in ride was dramatic. However, I still had that vibration. I took the tire shop manager for a ride. Both of us assumed that the new tires would have fixed the problem and that I must have bought a defective tire. He found a tire that had a very slight high spot and sent it back to Michelin. Even with a new one in its place, there was no change. I now knew that I had a problem of a different sort. The next step was to look at the wheels as the culprit. With the help of a qualified friend and a service manual, I put the car on a hoist and measure the run-out and out of round of each wheel. We did not find one that out of the factory specification. After that, I ran the car without the wheel trims to be sure that they were not the problem. Motor Region member, Marty Leavitt, graciously offered to let me borrow a set of wheels and tires from his Turbo R for a test drive on my car. Even with those tires and wheels, there was no change. I was beginning to become frustrated. Out of sheer ignorance, I assumed that Spurs were like Shadow and that the half shafts might have been the problem. They were removed and switched to their opposite sides. In Shadows, this usually is the problem, but there was no change. I later discovered that the design of the SZ half shafts was different and that even if they had been problematic, this would not have been the solution. Later, I took the car to my technician and gave him the full story on what I done up to that point. He checked all of the usual suspects such as the engine and transmission mounts, and the drive shaft coupling. No problems were found. He then removed the drive shaft and sent it to a shop that could check it for balance. It turns out that the drive shaft had a very minor imbalance, but that it would not have been enough to create a problem. It was rebalanced and reinstalled. Of great importance, he discovered that the rear subframe shocks were completely rigid. They were both replaced. The car was driven and the vibration was still there. Despite the fact that I still had a vibration, I was happy because the new rear sub-frame shocks had made the car ride like a different automobile. I wonder how many owners have replaced these items? The difference in ride was night and day. In addition, there was a reduction interior noise. The ‘booming’ that I didn’t realize was something wrong had been the rigid shocks transmitting the vibrations through the body of the car. The improvement in ride is most noticeable in situations where there are passengers and luggage. The cost of the parts was in the neighborhood of $500. He next removed the half shafts and very carefully inspected them for unusual ‘notches’ or flat spots. He found that the left rear half shaft was not perfect. These items are quite expensive at around $950 for a new one. In addition, there were none available in the US. Albers Said that they couldn’t remember even selling one in the last few years. Apparently they are not usually problematic on the SZ cars. I ordered a good used one from Tony Handler for about $500 which went onto the left rear side. There was definitely an improvement, but the car was not completely vibration free. BY now, most people would have given up, but I had made up my mind that I was going to fix this problem and enjoy my car.At least I had made enough of an improvement to be able to almost ignore it until the national meet at the Homestead. I knew that I would be able to find Cal West and John Palma, who might be able to discover something that I hadn’t. Before the meet, I printed out a list of everything that I had done and I put it in my wallet. One day, while shopping in the swap meet, I ran into the two of them. I showed them the list and John Palma said right away, “ Oh, there’s only one way to fix this. It’s the weight of the car and the tires.” He explained that he has had a number of customers go through this, some of whom have gone to greater lengths than I have. He also mentioned that the problem is even worse on Azures and the other big two door cars. The solution, according to John, was force variance balancing. What is force variance balancing, you ask. From the Discount Tire web Site: “On rare occasions, a tire may be manufactured with slightly inconsistent sidewall stiffness (creating what is called force variance) which leads to a ride problem. There is a new generation of balancers that can detect this condition and guide the technician to remount the tire in an optimum position that puts the assembly within specification and eliminates the problem. If specifications cannot be achieved, the defective tire is identified for replacement.” I watched the tire shop technician perform the force variance balancing. The way it works is somewhat different from a normal tire balancing job. The tire is inflated and mounted to a machine that has a drum which is pressed against the tire as it spins. The drum applies high pressures to the tire in order to simulate the weight of the car moving down the road. The computer makes calculations to determine the location of the inconsistencies in sidewall strength. The tire is then removed from the wheel and the wheel is put onto the machine and spun. The computer determines where the problem spots on the wheel are located and marks them. The technician then remounts the tire so that the worst spots on the tire are opposite from the worst spots on the wheel. After having this done, the vibrations were 95% eliminated! The total cost of the job was about $80 for all four tires. I was amazed that such a simple thing could fix such a troublesome problem. The car rode like a magic carpet. Of course, a few things along the way helped make the ride perfect. If I hadn’t been through this exercise, I would never have known about the sub frame shocks and the slightly out of balance drive shaft and half shaft. It’s important to point out that very few shops have the equipment to do the force variance balancing because the cost is about $15,000. I found that my local Discount Tire had the equipment and the right attitude about fixing my problem. You may have to call a number of shops to find one who can do the work and is willing to pay attention to the proper removal and installation your wheel trims, and wheels. | ||
| Rolf Versen New User Username: rolfversen Post Number: 2 Registered: 3-2013 |
Thanks, Brian and all, I am just having the propshaft balanced and then we will see. In the meantime I will try to find a tire-shop who does the procedure. I will report about this. | ||
| Rolf Versen New User Username: rolfversen Post Number: 3 Registered: 3-2013 |
now the propshaft is freshly balanced and the sliding piece which was not working properly was renewed and the vibrations are competely gone. The tyres do need some balancing and I will have on car balancing as Brian has described in his very interesting post. Thanx all and regards from the old world | ||
| Colin Silver Prolific User Username: colsilver Post Number: 147 Registered: 8-2008 |
Rolf said "now the propshaft is freshly balanced and the sliding piece which was not working properly was renewed and the vibrations are competely gone." What? A factory prop shaft being unbalanced? I can understand this with a race car that has a lot of torque pressuring the tailshaft. I take it you don't do this to your propshaft (tailshaft). Rolls and Royce would not be happy at your post :-) | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 998 Registered: 6-2006 |
If they were able to worry , I think they would be worrying about other matters, not Rolf's prop shaft! lol. | ||
| gordon le feuvre Experienced User Username: triumph Post Number: 15 Registered: 7-2012 |
The "Factory" was not perfect. Had brand new Shadow 1 in early 1970's with vibration, turned out problem was prop had never been tightened, just nipped-even though it had blue paint to signify it had been checked AND then yellow on top to signify it had been double checked! | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 173 Registered: 10-2010 |
Carroll Smith (who prepared the GT40s for their Le Mans wins) wrote a couple of excellent books on race car preparation. One advice was "there's no such thing as an un-torqued bolt on a race car. If you're not going to torque it correctly when you put it in, then don't put it in." I know we're not exactly maintaining race cars here, but there's still a wealth of great advice in his books. Jeff. | ||
| Graham Burn New User Username: graham Post Number: 10 Registered: 6-2013 |
Hi Jeff, I see where Carroll is coming from but try this on a cylinder head on an all alloy engine and see where you end up!!!! Graham |
