Wheel Balancing
Discussion
My Cobra is currently plagued with vibration over 60mph or so.
A year or two back it would happily go up to 140 with little or no vibration, but recently i have to job to hang on to the wheel at normal dual carriageway speeds.
It's never been curbed, and the alloys have no dinks of dent from potholes.
It's on the same set of tyres that used to run fine.
They've not been flat spotted.
It's not been left standing on one side of the rubber for long periods.
It's not the bearings as they're new and well adjusted, as are the wishbone bearings / balljoints.
It's not thrown a weight since the last balance, i know this as i drew around them in permanent pen when they were fitted and they're still all there. (they're all the flat type stuck to the inner surface of the rear of the alloy.)
I'm not totally convinced the last balance job was done properly. (I've had it balanced lots of times and every time they put different weights in different places. - I even make sure they spin it up on the machine before they take any weights off to verify that it is 'out' before they balance it.)
So the point is, anyone know of anyone in Bristol who can balance a set of 245/45/ZR/17s and get it right, rather than just calibrate the wheel so it shows 'true' on their machine?
I've heard to do this properly it should be one on a 5 stud plate, rather that using a tapered central fixing? Thoughts?
A year or two back it would happily go up to 140 with little or no vibration, but recently i have to job to hang on to the wheel at normal dual carriageway speeds.
It's never been curbed, and the alloys have no dinks of dent from potholes.
It's on the same set of tyres that used to run fine.
They've not been flat spotted.
It's not been left standing on one side of the rubber for long periods.
It's not the bearings as they're new and well adjusted, as are the wishbone bearings / balljoints.
It's not thrown a weight since the last balance, i know this as i drew around them in permanent pen when they were fitted and they're still all there. (they're all the flat type stuck to the inner surface of the rear of the alloy.)
I'm not totally convinced the last balance job was done properly. (I've had it balanced lots of times and every time they put different weights in different places. - I even make sure they spin it up on the machine before they take any weights off to verify that it is 'out' before they balance it.)
So the point is, anyone know of anyone in Bristol who can balance a set of 245/45/ZR/17s and get it right, rather than just calibrate the wheel so it shows 'true' on their machine?
I've heard to do this properly it should be one on a 5 stud plate, rather that using a tapered central fixing? Thoughts?
Grease Monky said:
My Cobra is currently plagued with vibration over 60mph or so.
A year or two back it would happily go up to 140 with little or no vibration, but recently i have to job to hang on to the wheel at normal dual carriageway speeds.
It's never been curbed, and the alloys have no dinks of dent from potholes.
It's on the same set of tyres that used to run fine.
They've not been flat spotted.
It's not been left standing on one side of the rubber for long periods.
It's not the bearings as they're new and well adjusted, as are the wishbone bearings / balljoints.
It's not thrown a weight since the last balance, i know this as i drew around them in permanent pen when they were fitted and they're still all there. (they're all the flat type stuck to the inner surface of the rear of the alloy.)
I'm not totally convinced the last balance job was done properly. (I've had it balanced lots of times and every time they put different weights in different places. - I even make sure they spin it up on the machine before they take any weights off to verify that it is 'out' before they balance it.)
So the point is, anyone know of anyone in Bristol who can balance a set of 245/45/ZR/17s and get it right, rather than just calibrate the wheel so it shows 'true' on their machine?
I've heard to do this properly it should be one on a 5 stud plate, rather that using a tapered central fixing? Thoughts?
I've had similar concerns about the quality/workmanship of fitting/balancing. I would like to be able to do it myself so that I could get it absolutely spot on rather than just "good enough". Until you find someone you can trust to do it properly it is very difficult to prove how good the job is. Ideally you want to get them balanced on the car as this uses the same location points but I don't know anyone who can do that.A year or two back it would happily go up to 140 with little or no vibration, but recently i have to job to hang on to the wheel at normal dual carriageway speeds.
It's never been curbed, and the alloys have no dinks of dent from potholes.
It's on the same set of tyres that used to run fine.
They've not been flat spotted.
It's not been left standing on one side of the rubber for long periods.
It's not the bearings as they're new and well adjusted, as are the wishbone bearings / balljoints.
It's not thrown a weight since the last balance, i know this as i drew around them in permanent pen when they were fitted and they're still all there. (they're all the flat type stuck to the inner surface of the rear of the alloy.)
I'm not totally convinced the last balance job was done properly. (I've had it balanced lots of times and every time they put different weights in different places. - I even make sure they spin it up on the machine before they take any weights off to verify that it is 'out' before they balance it.)
So the point is, anyone know of anyone in Bristol who can balance a set of 245/45/ZR/17s and get it right, rather than just calibrate the wheel so it shows 'true' on their machine?
I've heard to do this properly it should be one on a 5 stud plate, rather that using a tapered central fixing? Thoughts?
I went to a new fitting place in the end that had modern balancing machines. (one less thing to worry about)
In the end, all 4 wheels showed as 'out' as they checked them before removing the weight.
A closer inspection showed the rim was slightly deformed on all 4 wheels. (about 1 or 2 mm movement in/out as they span)
Looks like at some point i must have encountered one of Bristol's many and varied potholes.
With the weather over the weekend being torrential i've not had a chance to check what it's like at speed, but on the drive home it appeared to be much better.
In the end, all 4 wheels showed as 'out' as they checked them before removing the weight.
A closer inspection showed the rim was slightly deformed on all 4 wheels. (about 1 or 2 mm movement in/out as they span)
Looks like at some point i must have encountered one of Bristol's many and varied potholes.
With the weather over the weekend being torrential i've not had a chance to check what it's like at speed, but on the drive home it appeared to be much better.
Hello,
I hope I can be of some help
Firstly balancing is all to do with correct centering of the wheel/tyre package onto the shaft of the balancer.
Any balancer can be made to give the OK-OK reading for a wheel thats being spun.
However, If the centering is untrue then you may aswell have not balanced the wheel at all.
Find a garage which uses a tapered cone or collet back coned on the wheel (this is important) then ensure they use a Flange plate kit to secure the wheel onto the cone through the stud holes in your wheel. (this is the only way to ensure correct centering as badge holes are not always in the true centre of the rim and using the stud holes in you wheel for centering will give you true centre).
This should as long as the balancer is in calibration give you good results from the balance.
Secondly even a square wheel can be balanced! And that would give you some vibration at any speed!
Tyres and rims are not in anyway perfect. Rims have high and low radial run out spots and tyres have high and low RFV (Radial force Variation) spots.
If you think of a tyre a being made up of a hundred springs
One, Two or even more of these springs could have a higher srping rate than the others due to rubber being relatively un-uniform.
As the tyre rotates the "Problem" spring causes a harmonic on each revolution which you pick up as vibration from the car.
Many tyres have the 1st harmonic (Biggest "problem" spring) RFV spot marked on them and buy matching this with the Low radial run out spot on the rim of the car can help with the vibration.
I would suggest find a good tyre shop that uses the right balancer mounting accessories. This should solve you problem.
If you still have vibration issue's you need to find a Hunter GSP9700 wheel balancer which can diagnose and solve any RFV issue's in most cases.
If you need the latter let me know and I'll find the nearest one in your area for you.(there are no that many in the UK as of yet!)
Chris
I hope I can be of some help
Firstly balancing is all to do with correct centering of the wheel/tyre package onto the shaft of the balancer.
Any balancer can be made to give the OK-OK reading for a wheel thats being spun.
However, If the centering is untrue then you may aswell have not balanced the wheel at all.
Find a garage which uses a tapered cone or collet back coned on the wheel (this is important) then ensure they use a Flange plate kit to secure the wheel onto the cone through the stud holes in your wheel. (this is the only way to ensure correct centering as badge holes are not always in the true centre of the rim and using the stud holes in you wheel for centering will give you true centre).
This should as long as the balancer is in calibration give you good results from the balance.
Secondly even a square wheel can be balanced! And that would give you some vibration at any speed!
Tyres and rims are not in anyway perfect. Rims have high and low radial run out spots and tyres have high and low RFV (Radial force Variation) spots.
If you think of a tyre a being made up of a hundred springs
One, Two or even more of these springs could have a higher srping rate than the others due to rubber being relatively un-uniform.
As the tyre rotates the "Problem" spring causes a harmonic on each revolution which you pick up as vibration from the car.
Many tyres have the 1st harmonic (Biggest "problem" spring) RFV spot marked on them and buy matching this with the Low radial run out spot on the rim of the car can help with the vibration.
I would suggest find a good tyre shop that uses the right balancer mounting accessories. This should solve you problem.
If you still have vibration issue's you need to find a Hunter GSP9700 wheel balancer which can diagnose and solve any RFV issue's in most cases.
If you need the latter let me know and I'll find the nearest one in your area for you.(there are no that many in the UK as of yet!)
Chris
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