Wheel balancing - is it a black art?

[Steve928]

I had 4 new tyres fitted to the van last week and the balancing just wasn't correct. I gave it my best shot and swapped fronts to back etc. to try and find a fit that worked, but no. So back to the tyre depot today and all four wheels re-balanced (and not yet fully tested). I can see from the marks on the rims that there have been some fairly large changes to the weights, inside and out.

I've had similar experiences with the local garage who admittedly aren't a tyre depot but do have all the usual equipment. As often as not the first balance isn't right and needs re-doing.

Also in the past I've experienced new and perfectly balanced wheels going out of balance at some 500-1000 miles old.

 

I know that we have some people with tyre industry knowledge on here so can I ask just why does it seem so difficult to get the process right in the first instance?

Is a balance even repeatable, or if you were to balance a wheel, take it off the machine and walk it around the workshop before putting it back on the machine, would you get a different result?

 

Finally, what's it all about anyway and what happened to balancing on the vehicle where they used to spin the wheel up with a roller and shine strobes on it? :-)

[747]

Back when I was young and skint I always balanced my own tyres. While 'salvaging' spare parts in the breakers yard, I pocketed assorted weights. I did the tyres on the front wheels by first finding the 'heavy bit. To be more accurate, I moved it halfway up and let go. When the tyre stopped moving, I put a chalk mark on the bottom of the tyre. I repeated this in the opposite direction and put another chalk mark at the bottom. The weights needed to be fitted exactly opposite the midway point of the 2 chalk marks. I forget how I came up with this procedure but it worked very well. It was just a matter of trying different weights after that until it was balanced.

[Steve928]

Presumably your DIY method only involved putting weights on the outside rim edge? When a tyre depot does it though they put different weights in different positions on both outside and inside rim edges, unless of course it's an alloy wheel requiring stick-on weights in which case they just put one row of them somewhere near the centre line of the wheel.

[RogerThat]

I'd expect the same machine to show the same balance points for the wheel, no matter how far you walked it around :-D

 

But at the same time I'd also expect a different machine to give different results *-)

 

Are you adding anything to the wheel after it's been balanced? Hub caps? (You didn't say if it was a steel or ally rim) Or TPMS sensors? Or fancy / unusual dust caps?

 

[747]

Steve928 - 2016-08-22 7:17 PM

 

Presumably your DIY method only involved putting weights on the outside rim edge? When a tyre depot does it though they put different weights in different positions on both outside and inside rim edges, unless of course it's an alloy wheel requiring stick-on weights in which case they just put one row of them somewhere near the centre line of the wheel.

 

Yes that's correct but my method worked. Sounds like the professional boys method did not. :D

[Derek Uzzell]

Steve928 - 2016-08-22 3:29 PM

 

...Finally, what's it all about anyway and what happened to balancing on the vehicle where they used to spin the wheel up with a roller and shine strobes on it? :-)

 

Wheel balancing is normally only carried out when a tyre is changed. At this point the wheel has been removed from the vehicle, so it’s easier to take the wheel to the balancing equipment (that may be anywhere in the workshop) than put the unbalancing wheel back on the vehicle and balance it in situ.

 

I vividly recall having a new pair of tyres fitted to my first Golf GTi and these producing out-of-balance vibration at higher speeds. The tyre-fitters tried off-car balancing twice but this didn’t cure the problem. Eventually they suggested on-car balancing but, as the vibration was only appearing when the car was driven fast, they couldn’t use rollers.

 

The front of the car was jacked up on both sides so that the wheels were well clear of the ground: I sat in it, started the motor and engaged 5th gear. I then ‘drove’ the car with about 90mph on the speedometer while the tyre-fitter shone a strobe on each wildly vibrating wheel. The car was then stopped, weights attached to the wheels and the process repeated until the vibration stopped. The procedure worked but, with hindsight, it was a ridiculously reckless thing to have done.

 

I had a problem with my 1996 Transit-based Herald motorhome when four new tyres were fitted and all of the wheels needed to be rebalanced. The tyre-fiiter told me that it was due to the central ‘hole’ in the wheel not being truly in the centre and he used an adapter to attach the wheel to his balancing machine via the wheel’s wheel-stud holes instead of using the normal (much quicker) ‘cone’ method.

 

However, assuming that there’s nothing physically wrong with the wheel and/or tyre, a competent tyre-fitter with modern equipment should be able to balance a wheel accurately ‘first time’.

[Steve928]

RogerThat - 2016-08-22 8:11 PM

Are you adding anything to the wheel after it's been balanced? Hub caps? (You didn't say if it was a steel or ally rim) Or TPMS sensors? Or fancy / unusual dust caps?

 

Only the standard Peugeot wheel trims on steel rims. The tyres do pick up a fair few stones on the way up the lane though so perhaps that needs considering. The TPMS sensors are in the wheel as part of the valve.

By the way, although not relevant, a Schrader TPMS valve/sensor weighs the same 30gr. as a standard bolt-in metal valve.

 

 

747 - 2016-08-22 11:26 PM

Yes that's correct but my method worked. Sounds like the professional boys method did not. :D

 

Indeed! I wasn't criticising your method rather just pontificating as to why steel wheels get outside and inside balance weights while alloys only get central balance weights.

 

 

Derek Uzzell - 2016-08-23 9:21 AM

I had a problem with my 1996 Transit-based Herald motorhome when four new tyres were fitted and all of the wheels needed to be rebalanced. The tyre-fiiter told me that it was due to the central ‘hole’ in the wheel not being truly in the centre and he used an adapter to attach the wheel to his balancing machine via the wheel’s wheel-stud holes instead of using the normal (much quicker) ‘cone’ method.

 

The 73mm central hole of the Boxer/Ducato wheels seem to be a very snug fit on the hub with no wiggle room for the bolts to relocate the wheel so I doubt that this imbalance could arise from that scenario.

 

 

Hopefully all is good now on the second attempt - I'll pop out later to give it a try.

[KeithM]

Whilst there, you will of course check all steering, suspension, wheel bearings etc. for any problems. ;-)

[Derek Uzzell]

Steve928 - 2016-08-23 10:09 AM

 

747 - 2016-08-22 11:26 PM

Yes that's correct but my method worked. Sounds like the professional boys method did not. :D

 

Indeed! I wasn't criticising your method rather just pontificating as to why steel wheels get outside and inside balance weights while alloys only get central balance weights.

 

 

In the 1980s - when my Golf GTi Mk 1’s alloy wheels needed balancing - adhesive balance weights were generally unavailable and clip-on weights were fitted to an alloy wheel’s inner/outer rim as continues to be the norm nowadays with steel wheels.

 

In fact, clip-on weights are still advertised for those alloy wheel types that are designed to accept them

 

http://www.traxjh.com/sites/default/files/Trax_bro_may2014_WEB_0.pdf

 

These links may be of interest

 

http://tires.about.com/od/Tire_Safety_Maintenance/a/The-What-Why-And-How-Of-Wheel-Balancing.htm

 

http://www.gregsmithequipment.com/Hub-Centric-Vs-Lug-Centric

 

http://www.gregsmithequipment.com/Atlas-Universal-Adapter-40mm-Shafts

[audiseller]

747 - 2016-08-22 4:40 PM

 

Back when I was young and skint I always balanced my own tyres. While 'salvaging' spare parts in the breakers yard, I pocketed assorted weights. I did the tyres on the front wheels by first finding the 'heavy bit. To be more accurate, I moved it halfway up and let go. When the tyre stopped moving, I put a chalk mark on the bottom of the tyre. I repeated this in the opposite direction and put another chalk mark at the bottom. The weights needed to be fitted exactly opposite the midway point of the 2 chalk marks. I forget how I came up with this procedure but it worked very well. It was just a matter of trying different weights after that until it was balanced.

 

 

This system can work reasonably well if no access to proper equipment but only deals with static balance, not dynamic.

[audiseller]

Steve928 - 2016-08-22 7:17 PM

 

Presumably your DIY method only involved putting weights on the outside rim edge? When a tyre depot does it though they put different weights in different positions on both outside and inside rim edges, unless of course it's an alloy wheel requiring stick-on weights in which case they just put one row of them somewhere near the centre line of the wheel.

 

If that's what your depot does on alloy wheels then they are only correcting static balance not dynamic. A lot can also depend what tolerance they set their balancer to as some operators set to a wide tolerance to get a quicker apparent balance reading.