[stahl]

Hi!

I'm new to this forum, even if I have been a regular visitor since I bought my Touareg a couple of years ago.
(And I'm sorry if I can't find the right words all the time, since English is not my native language...)

Now to my problem, witch I haven't found an answer for.
I have some problems with twitching in highway pace, starting around 90-100 kph. (Like 55-60 mph).
I took it to the workshop, and they thought that there were some trouble with the gearbox. They fixed the converter, oil pump and the valve package.
This toook some time, and the snow came. The workshop changed to winter tyres, before I received the car.
Everything was great, exept for the bill!
Now the spring is here, and I changed back to the summer tyres. And pop, the twitching is back...

I have read some forum threads, saying that different rolling diameter can cause damage to the transmission. But I havn't found out what really happens if that's the case?
I had a flat tyre, and didn't understand the consequence with just change two of them, on the same axle. So now it differes around 3 mm between front/back tyres.

Can this cause the twitching when I drive over 80 kph? (According to Nooby who says that over 80 kph there is no electric compensation?)

I'm not so keen on buying a set of four new tyres before I know that it can solve the problem.
So I would be pleased to hear your expert comments.

 

[Marbles]

Have you have the tires and wheels inspected for balance and damage? Could have a bent wheel. Where the summer wheels put back on the same locations as they were last year, or were they rotated. But if it was smooth and steady with the winters and now there is a problem you might need four matching tires.

 

[Ragman]

On this forum there is plenty of history regarding different tyres causing issues.
even the same brand and age with slightly different tread pattern can cause odd noises.

I think you have realized its the tyres, as the issue recurred when the odd tyres were refitted. ie the "twitching" came back.

Probably should have tried new tyres before you spent the money on the transmission?

looks like you are up for a set of tyres!

 

[stahl]

Thank you for your quick reply!
The problem is not constant. I have to drive like 5-6 km before it occures. Then it twitches a few times. After that I can drive for a while again, before it happens. So I don't think it has to do with balance or location?
My thougt was that the ABS/ESP or whatever, is trying to compensate for the lack of sync by braking two of the tyres? Could that make any sence?

 

[Ragman]

I would only be guessing what could be going on, maybe the transmission takes a while to wind up and the twitching is the release?

In any case several mm difference in tyre diameter will not be doing any good.

 

[Rudster]

Why not put the other set of tires back on (if you know they're within diameter specs) and see if the issue goes away again? Then you can eliminate or confirm tires as the issue.

 

[stahl]

I'm lazy by nature, and was hoping not to have to change the tyres again...
But I will change back to the winter tyres, and see if the problem disepares. If it does, then I go for new tyres.
But I was also interested of what is happening in theory, when these kind of things appears...
Thank you all for your quick responds!

 

[ShadowImg]

Yes, the problem you describe could be caused by mismatched circumference tires. There is a tolerance for it, and if you go beyond that, some level of weirdness will start to happen with the AWD system.

 

[FSJ Guy]

Yes, all wheel drive systems require that the tires be the same actual size. Otherwise you will get "windup" in the drivetrain. The "twitching" is the tension releasing in the drivetrain.

It will not harm your actual transmission, but rather the axles, drivelines and the transfer case. But regardless, you want to fix the problem, which is mismatched tires.

 

[stahl]

I think we can consider this case closed!
I will by a new set of tyres, and avoid driving on the highway until I get them.

I have ordered the new Tiguan, and was hoping not to pay anymmore repairs on the Touareg. Even if I love this car!

 

[noobytoogy]

It does sound like a mismatch between front and rear tyres.

As others have said, it sounds like you are getting transmission wind up due to the differences in tread depth [assuming all four tyres are of EXACTLY the same same make, size, model and tread pattern] and it releases before winding up all over again.

If you are driving on loose, wet or slippery surfaces, you won't notice this as the wheels can slip. Driving on hard dry surfaces where the wheels cannot slip will highlight the issue.

It might also be a duff stepper motor. A lot of the early cars had theirs' changed as they were an issue. It is easy to get under the car and check the part number and the date of manufacture. If it the number ends with an A you have an original - and potentially duff - motor.

http://ww2.justanswer.com/uploads/vwtech0405/2010-02-12_003812_12.jpg

 

[ShadowImg]

I think we can consider this case closed!
I will by a new set of tyres, and avoid driving on the highway until I get them.

I have ordered the new Tiguan, and was hoping not to pay anymmore repairs on the Touareg. Even if I love this car!

You can measure your existing tires and have them shaved down to tolerance of each other. That is if they aren't worn out to the point where it just makes sense to trash them. If you just have 2 worn unevenly from not rotating, but still with tread life, this is a good option.

 

[noobytoogy]

Good idea but, whilst tire shaving seems well known in the US, it isn't in Europe. Worth a try though.

 

[stahl]

Report: Problem solved!
Got hold of a used set of Cayenne wheels, with more or less new tyres. (Three months old).
Been driving approx. 45 km highway, with nooooo "twitching", or hick ups, or studdering! I could never imagine that 3 mm could have such an impact, on such a robust car...
I will never trust a mechanic again. Only ClubTouareg members!

 

[lml999]

I have a similar problem, just got the Touareg back from the dealer in Wellesley...no trouble found. My summer tires were all new in December, matching tread, size, etc. I don't remember this happening with the winter tires...thinking about putting them back on to see if the problem follows...

 

[noobytoogy]

Report: Problem solved!
Got hold of a used set of Cayenne wheels, with more or less new tyres. (Three months old).
Been driving approx. 45 km highway, with nooooo "twitching", or hick ups, or studdering! I could never imagine that 3 mm could have such an impact, on such a robust car...
I will never trust a mechanic again. Only ClubTouareg members!

Glad you're sorted.