Freddymac Posted December 4, 2005 Share Posted December 4, 2005 Got yer attention? (How cheap and tawdry) I have a really weird whistling noise kick in @ 58 kph (36 mph). It leaves at 60kph. The truck is a 95 WD21 TrailBoss Package with 31 Inch Avon Rangers A-Ts at 32 psi without lift. Everything works as is should. Vehicle has 200K Klicks. Truck is stock other than an 18k load auto tranny cooler and Tranny flush (recently installed) and a K&N air filter. The truck has had diff fluids changed and checked to the nuts by 2 service centers, engine checked, oil flushed and changed and bearings deemed as OK. The shocks are 'Electro' originals yet need a Rancho 5000 upgrade. Coils could need replacement (oversensitive on bumps and bottoms out too quickly). 4 wheel drive has a slight whine but nothing to fret over. The Avons are made by Cooper and tougher than nails. They supply the stock 'tyres' for Landrovers. They give a sweet ride at 32psi onroad and average bite on rock and mud. However, these 'tyres' are noisy on road above 100kph, yet (might be wrong here), I doubt that the whistle is from the wheels. These tires, however, do not have the offset height lugs that is supposed to noise inhibit. Anybody else whistling Dixie while cruising over the rainbow?? Fred Link to comment Share on other sites More sharing options...
derogate Posted December 4, 2005 Share Posted December 4, 2005 I'd say tires. I can't think of anything else that would do that at that specific speed. Keep in mind the tires might not do that when new.. or even when they are older, but they due to tread wear over time, their characteristics change. I'd put my money on the tires. Link to comment Share on other sites More sharing options...
denisb Posted December 4, 2005 Share Posted December 4, 2005 (edited) I agree with derogate. Tires wear different on different vehicles due to alignment , weight etc. and can make tires noisy. Often a vibration or noise(hum) that apears at a certain speed and leaves at higher speed is alignment/tire oriented. My cousin has an alignment shop and said Coopers (specialy the snow tires) are known to give a bad bearing type hum. Denis Edited December 5, 2005 by denisb Link to comment Share on other sites More sharing options...
Precise1 Posted December 4, 2005 Share Posted December 4, 2005 I've never heard tires 'whistle' before. I know I can hear whistling from the intake at roughly 2500 rpm, generally second and 3rd gear. It could be something like a light bar, roof rack, etc that whistles at a certain wind speed. The fact that you are so precise about the speed range and that the effect only spans 2 kmh, I'm guessing it is something with the drive train. This would make particular sense with an automagic tranny. You can't get a general location of the sound source ? Try driving parallel to a wall with the window down, the reflecting sound helps isolate things a lot... B Link to comment Share on other sites More sharing options...
Terrano Posted December 5, 2005 Share Posted December 5, 2005 Hi, Fred Never heard tires make that "whistle"... Besides, I doubt that tires would whistle only for 2 km\h. P1's got a point recommending driving parallel a wall, it might really help you hear this noise better and find the source. Is your truck in 4H or 2H when this noise appears? Keep us informed about any developments in this matter! Link to comment Share on other sites More sharing options...
SC88Pathy Posted December 5, 2005 Share Posted December 5, 2005 Sounds like you are describing the whistle some people get from the K&N air filter. Although I think that is usually a constant noise? My guess is that's it's the K&N, if you still have a stock filter try replacing it and see if the noise goes away. Link to comment Share on other sites More sharing options...
Freddymac Posted December 5, 2005 Author Share Posted December 5, 2005 I'm guessing it is something with the drive train. This would make particular sense with an automagic tranny. Me thinks your right. I ran the tires at 40 psi as my wife was bouncing off the roof (oops, sorry sweetie, wardrobe malfunction...), same whistle, same channel. I carry nothing on top, side or front other than deflectors as I drive my truck to work and back 5 to 6 days a week 60 klicks a day. (deflectors were an afterthought after the fact.) Btw: tire pressure means nothing, same whistle back to 32psi. The sound goes down a half octive if I brake hard...must be the drive train, me thinks (...I wish I would have skipped French 102, Physics 1505.6, Seduction 304 and had the chance to get greasy and funky with Automech 101 and not bother you dudes with this trivial sheit.) Hmm, now what part? Noise seems to be central. No noise bounce back off the Freeway Meridian, only a slight knocking noise under load... To be honest, folks, can we just chalk it up to Truck 'individuality'... Ya, dat's it! The truck works great, The Leather seats heat up when I ass is froze, and my wife's headaches have stopped since I lowered the tire pressure. "What do I want for Christmas, sweetie? Awww, you too nice. Me want Rancho 9000 adjustables (and remember we get the DElux gauges and air compressor package from some speed shop for FREE in the middle of nowhere." "Honey, what about the whistle in the drive-train????" Merry Christmas, and to all a good night Link to comment Share on other sites More sharing options...
kmgar99 Posted December 5, 2005 Share Posted December 5, 2005 is it a whistle or could it be a high pitch whine? If it's a whine, it could be a bearing or like precise said some drivetrain issue. I did have a high pitch squeal/whine from under the hood at a specific RPM, it turned out to be the alternator. Link to comment Share on other sites More sharing options...
Precise1 Posted December 5, 2005 Share Posted December 5, 2005 Well Fred, if you have a aftermarket tranny cooler (if not, get one for x-mas !!), and the fluid in the tranny has been changed per maintanence schedule (along with the fluid in transfer case and differentials) and the drive shafts have been greased, just drive it... B Link to comment Share on other sites More sharing options...
derogate Posted December 5, 2005 Share Posted December 5, 2005 are you guys serious? I've heard that whistling from tires several times, Its especially bad with snow tires in the rain. Hell My parents vehicle sounds like the old school bombs from world war 2 are dropping down. The whistling changes tone depeding on the speed. When they where new they never did it either. Link to comment Share on other sites More sharing options...
Precise1 Posted December 5, 2005 Share Posted December 5, 2005 You had tires that made whistling noises in a 2kmh range and at no other time ? B Link to comment Share on other sites More sharing options...
denisb Posted December 5, 2005 Share Posted December 5, 2005 I agree with Precise. Tires shouldn't give a difference in road noise within a 2kph range. Link to comment Share on other sites More sharing options...
Freddymac Posted December 6, 2005 Author Share Posted December 6, 2005 are you guys serious? I've heard that whistling from tires several times, Its especially bad with snow tires in the rain. Hell My parents vehicle sounds like the old school bombs from world war 2 are dropping down. The whistling changes tone depeding on the speed. When they where new they never did it either. Hey derogate I've done a bit of 'closer' listening (and deep thinking) today while driving home from work. The noise is more pronounced when slowing down that speeding up. Here are a couple of theories of mine: 1) When speeding up the noise level will increase even though the sound dampening in this truck is working as it should. The tight band audio spectrum that I'm hearing inside the vehicle may be masked out by the working noises of the vehicle and enviro sounds such as the air being pulled over the body as the vehicle gathers speed. 2) When slowing down, especially in hard braking situations, the engine noise, drive train and wind noise is diminished at a far higher level, thus allowing me to physically hear an actual drop down to what my ear would consider half an octave. Beyond that the noise disappears. Based on these two observations, plus the fact that these tires are very noisy beyond a crawl, I would venture that the design of this tire may have been an early candidate for current noise cancelling tech. If I may be so bold, in case this is not familiar to this forum, Noice cancelling in audio electronics is achieved by recording the background noise as a variable wave via a highly sensitive mike and reversing that same wave back to the origin into the 'speakers. When the positive wave is introduced to the opposite negative audio wave at the right balance and volume, the two waves should cancel each other out. In other words: DEAD SILENCE. For example: Wanna sleep on a very noisy plane when you get the 'back of the bus seating' on a plane with wing mounted jets? Buy a pair of Noice cancelling headphones if the device has senitive enough mikes, top quality tuned speakers, highly processed Analog to Digital Converters, and of course enough battery juice to also cancel out the ambient cabin noise of Junior trying to play 'Doom4' on his PSP at full volume right next to you. (Btw: You should consider listening to a piece of music that you love with this technology with the least amount of ambient background noise possible. I swear you will never listen again to the same piece without wiping a tear out of your eyes for sheer intensity..) I believe that tire technology, at this time, tries to meet the same requirements by a clever use of offset lug heights to mimic the same concept. We all know that lugged tires will introduce noise. The faster the tire turns, the louder the tires will howl. I believe that the outer lugs causes the most noise as the tire squirms to keep your baby in line with the road. The offset lug concept works along the same as tsome noise cancelling headphones: A large standard lug will cause the noise at a given level as a musical note ; a smaller lug will produce the same musical note except one octive higher, or possibly in 'tune' as part of a chord, making the tire hum in a pleasing fashion (2, 3, 4 part harmony) Consider this, mon compadres, if you knew EXACTLY what each lug height will resonate at certain speed spectrums, you could use the same computer data that you've gathered as a tire manufacturer to to find out exactly where the different lug heights will actually cancel each other out. There is only one flaw to this technology: As the lugs wear down, the carefull balance of the sum parts break down to sheit. My tires have 50% life left. I think what caused the very tight audio spectrum to be heard as a whistle is this: The tires produce noise at all times. At low speed, the tires are sub sonic (inaudible). At high speed (beyond 36 mph) the tire's noise is masked by background noise (again inaudible, possibly beyond hearing levels as ultrasonic). At 36 mph, the worn down lugs have produced a whistle that probably would never have been noticed by the original buyers of the tires when they were new. Needless to say, personal noise dampening tech must never be used in urban driving situations due to extreme safety concerns. In an off-road situation, my friends, I won't even go there... Be well Fred Link to comment Share on other sites More sharing options...
Slick Posted December 6, 2005 Share Posted December 6, 2005 Link to comment Share on other sites More sharing options...
Freddymac Posted December 6, 2005 Author Share Posted December 6, 2005 Link to comment Share on other sites More sharing options...
kmgar99 Posted December 6, 2005 Share Posted December 6, 2005 Link to comment Share on other sites More sharing options...
Precise1 Posted December 6, 2005 Share Posted December 6, 2005 I think you are going to drop a driveshaft, reversing the variable wave of you actually getting home with any resonating frequency... Nice theory, but lay off the booze for a bit, eh ? B Link to comment Share on other sites More sharing options...
denisb Posted December 6, 2005 Share Posted December 6, 2005 I think you are going to drop a driveshaft, reversing the variable wave of you actually getting home with any resonating frequency... Nice theory, but lay off the booze for a bit, eh ? B Link to comment Share on other sites More sharing options...
Freddymac Posted December 7, 2005 Author Share Posted December 7, 2005 I think you are going to drop a driveshaft, reversing the variable wave of you actually getting home with any resonating frequency... Nice theory, but lay off the booze for a bit, eh ? B "If a writer knows enough about what he is writing about, he may omit things that he knows. The dignity of movement of an iceberg is due to only one ninth of it being above water." Ernest Hemingway Link to comment Share on other sites More sharing options...
kmgar99 Posted December 7, 2005 Share Posted December 7, 2005 Tough Crowd! Tough Crowd! Link to comment Share on other sites More sharing options...
packie88 Posted December 7, 2005 Share Posted December 7, 2005 to long to read and lost me about two paragraphs into it. Link to comment Share on other sites More sharing options...
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