I have to Write the story as it was on a german only youtube. There Was this guy at his wits end with his fast car in germany having vibration on autobahn worst at 150kph and yes Germans have some unlimited speed districts. Anyohow many garages fixed the problem one place fitted ceramic disks worth 4000 euro to that car and it still vibrated Hence customer was at its wits end when he came to this German garage who did fix the problem.
gph1961,
Jan 16, 6:29am
fitted a hose clamp to rear of drive shaft (prop shaft)
intrade,
Jan 16, 6:32am
So He hooks up the pico oscilloscope with nvh sensor to driver seat because you got to mesure from where the complaints vibration comes from. The software is written by dr john kelly from weber state university usa and licensed to picoscope. Anyhow so he went on the autobahn 150kph and sure enough fibration was recorded some on front and some on rear axle. The picoscope calculates with rpm and speed of tyre rotation if and where the vibration is. So He drained the diff oil nothing there . measured the drive shaft all within tolerance . mesured the ceramic disc 1 tousends of a mill untrue not that so it got to be the brand new tyre or rims . He fits his set of tyre and rims goes for a blast on autobahn 150kph no visible vibration. He checks the tyres balance all OK Then it dawned on him what the problem was. I doubt you know this as i sure did not but its definitely it. What is the problem?
intrade,
Jan 16, 6:42am
i wonder if that ronaldo guy knows this , na wait he will claim he cant understand what i wrote. And i tell you if you know this then you are extreme good. i know he was correct after he said his penny dropped what the issue was to me it probably would have stayed a mystery but its something else to put in the memory bank now.
intrade,
Jan 16, 6:43am
no was 1 front and 1 rear vibration
ml6989,
Jan 16, 8:45am
C'Mon Intrade, it's been a hot day and after 2 hours the suspense is almost too much for me to bear any longer!
s_nz,
Jan 16, 9:07am
I would guess out of round tires or a bent rim.
evotime,
Jan 16, 4:13pm
Centring the wheels on the wheel studs/ wheel bolts rather than centring/locating on the hub spigot? Used to get that a lot with aftermarket wheels.
gph1961,
Jan 16, 5:30pm
directionals reversed
tamarillo,
Jan 16, 5:51pm
brilliant,
intrade,
Jan 16, 7:33pm
So no one else one post is close to it . but remember all is well the tyre are not out of round no nothing is wrong and its perfectly balanced. but there is something wrong. Strange that all the people who come here and say bull$t when i write something now are gone to thin air silent?
philltauranga,
Jan 16, 7:37pm
Mag lock nut different weight to other wheel nuts?
3tomany,
Jan 16, 7:38pm
crack in the rim?
intrade,
Jan 16, 7:44pm
i am getting my cofee and read my emails a nd then i tell you what it really was keep posting remember its something you would never think off. a clue is the 150kph speed and no one has done nothing wrong from all the shops who did not fix it apart from not finding the fault and selling stuff he probably did not need.
poppy62,
Jan 16, 7:46pm
Tyre pressure sensors, unbalancing the wheels at high speed.
philltauranga,
Jan 16, 7:56pm
150kph. Aerodynamic vibration? Clue please. Is it in the chassis or is it in the rotating parts of the driveline, bearings, cv joints worn?
intrade,
Jan 16, 8:00pm
What it was here is what he said when his penny dropped. its a bit like my penny dropped with 91 to 95 Ron fuel problem that's almost as difficult to understand why no cars can run only struggle along on 91 cat pi$$ but thats another subject lol The Clues are the "150kph speed " the vibration is at on the german autobahn He said a Tyre balancer balances a Tyre for about 40kph and it balances the rim and the tyre for that speed.
But the "imbalance is in the Tyre it self. ! and at 150kph tyres expand like on a drag car when they warm up tyres you can see how they expand= that imbalance in the tyre now shifts its imbalance to a new location at that speed and thus the tyre no longer is balanced correct at that speed. The problem is a "tyre that was not balanced during manufacturing-correctly" to have that speed rating on it. For the merc who can easy and quickly go to 250kph plus with 4000 euro ceramic disk brakes.
intrade,
Jan 16, 8:03pm
#16 is almost on the money. The tyre has a heavy spot on the thread and should have only be rated for speed below 150kph . But corner cutting manufacturing and poor quality is now all and everywhere. He did not name the tyre brand but i think he did say it was not a cheap name-brand if i recall correctly. He also said he seen numerous times that problem reported of vibration at 150kph from other people say the same thing, So 150+ seems to be the speed a Tyre noticeably expands and the centrifugal forces get so large to counteract the balancing lead on the rim. Now i doubt anyone did think of that to be the problem but its plausible and straight forward physics .
philltauranga,
Jan 16, 8:11pm
Interesting, makes sense. I've had a few tire guys put balancing beads into the steer tires on the heavy trucks I've driven, hard to say if the difference was noticeable because the tires were replaced.
philltauranga,
Jan 16, 8:30pm
I would say #7 was "almost on the money". "out of round tires" BUT then read #11? Is a heavy spot on the tread. "almost" like out of round? To quote #11: "but remember all is well the tyre are not out of round no nothing is wrong and its perfectly balanced"
either than or a very obese guy causing the car to lean on one side causing 'imbalance'.
intrade,
Jan 17, 3:52am
https://www.picoauto.com/downloads demo works need hardware to enable it to work but if you want to learn how scope works demo shows signals to mess with. i dont think nvh however that needs registration as it is a license cost to dr john kelly from weber auto youtube who has videos on nvh
jesus2000,
Jan 17, 4:42am
I would have assumed they would have tried a new set of tyres before changing the disc rotors! Muppets!
I used to use a PJ1 sealant/balancer on my motorbikes. It supposedly gave the perfect balance if either you were doing 100kph or 200kph
its not that garage who changed the rotors and the tyres are brand new and fully accurate balanced. #24 They have a heavy spot that comes to show at 150 kph only. As seen on picoscope diagram.
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