Judder through brake pedal...wide steel wheels

[RichardinNZ]

This may be one for Fastbrit or others who were driving Beetles in the UK with widened steel wheels in the 1970s...

I've been getting judder through my brake pedal when I brake at around 50mph and then again at around 20mph. Nothing through the steering so I'd assumed it was the rear brakes and that one or both of the Type 3 rear drums had been damaged when I had studs pressed into them.  I pulled the drums other day and had them machined/turned to ensure they were round.  I refitted and went for a drive... No better. 

I am running 5.5inch wheels based on stock smoothie centres (wide 5) which have had a 5.5inch rim fitted on them.  Modifications are quite strict here so I had the wheels modified by a local specialist who is the go to person for this work. The wheels have 205/70x15 tyres fitted but have not been balanced.

I've just swapped a pair of standard wheels with 165/80x15 tyres on to the car and the issues have gone.

My next step is to find somewhere that can balance the wheels and tyres.  However before I spend more money does anyone have experience of anything similar?  Will the setup ever be any good or are widened wheels always unreliable?

Thanks
Richard


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[RichardinNZ]

The offending wheels...

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[dragvw2180]

I would check for any run out on the wheels first , if they run true then I would have the tires "Road Force"   balanced . Even though tires are balanced that does not mean they are round or that the belts are equal to rolling resistance , that is what having Road Force checked will reveal . Hope this helps, Mike McCarthy

[RichardinNZ]

I would check for any run out on the wheels first , if they run true then I would have the tires "Road Force"   balanced . Even though tires are balanced that does not mean they are round or that the belts are equal to rolling resistance , that is what having Road Force checked will reveal . Hope this helps, Mike McCarthy

Hi Mike
I've now had the wheels and tyres dynamically balanced (but before I saw your reply, so not sure if it was road force balancing).  They commented that they had to. Add very little weight to each wheel.

I'll refit the wheels soon and see whether it has helped.... If not I will need to check what balance machine they used and potentially find another shop that can road force balance them.
Thanks
Richard

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[dragvw2180]

  If you hadn't changed the wheels and made the vibration go away I would have been looking at runout on the brakes.

[RichardinNZ]

It's really odd...

The car still has stock height rear suspension and some positive camber.  I'm wondering whether the fatter tyres don't like this?  When I had the centres mounted in the wider rims I had them made with the maximum backspace that would fit on my car (type 3 drums on short axles) so they look almost stock from the outside.

Would any of this cause issues...I'm wondering whether I should decamber the rear a little so the wheels sit more parallel when resting/empty.

The front is lowered with avis adjusters.

Thanks.

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[Eddie DVK]

When I had Judder in my brake pedal during braking..
I found out the drums where not round anymore. I replaced them en the problem was over..

Oh first thought it was a wheel bearing but the problem stayed after replacing them...

So maybe you can check if your drums are round and not oval...

Regards Edgar

[Eddie DVK]

  I pulled the drums other day and had them machined/turned to ensure they were round.  I refitted and went for a drive... No better. 

Thanks
Richard


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Oooooh did not read this... you already looked if they where round..

[RichardinNZ]

Yes... Had them machined yesterday.   The odd thing is that there is no problem when the stock original wheels are mounted.

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[Neil Davies]

Do you put the wheel on the drum in the same place each time? If so you could try moving it round by a hole. You could also try re-clocking the tyre on the rim by 90 degrees.

[RichardinNZ]

Good idea Neil.. I'll move the wheels round a hole and see whether that improves things...and work through various positions.

The easy option would probably be to get a new set of wheels...

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[Neil Davies]

You could also have the wheels balanced without the tyres on, that eliminates another issue.

[RichardinNZ]

The VW specialist who balanced the wheels commented on the small weights he needed so I guess the wheels and tyres are working well together....

I'm still wondering whether my large backspace doesn't help when compared to 356 wheels?  I'm not sure how it compares to say aftermarket BRMs?

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[RichardinNZ]

The VW specialist who balanced the wheels commented on the small weights he needed so I guess the wheels and tyres are working well together....

I'm still wondering whether my large backspace doesn't help when compared to 356 wheels?  I'm not sure how it compares to say aftermarket BRMs?

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Thinking further... Would have been a lot easier just to buy a set of aftermarket BRMs...

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