which wheel is unbalanced

Do you have a spare wheel that is normal sized like all the others? You could swap it around sequentially and see if the vibration stops though you have to hope it is the wheel and tyre that is unbalanced and the vibration isn't caused by something else. Personally I would just take the vehicle to a reliable tyre dealer or garage and get them to check it though I am fortunate that one I get tyres from is still a family run independent, they work on the principle that if I buy my tyres from them they will squeeze little tasks like that in quiet periods for very little or no charge. Often a packet of chocolate digestives for their tea break covers it.

G.Harman

Ask someone with a wheel balancer to check?

Most places will check them all and only charge you for the one(s) that are off balance. You'll have to go there in the end anyway to get it fixed.

Andy

Usually, any vibration from the front wheels would also be felt on the steering wheel.

Might well be a propshaft if its rear wheel drive :-)

wheel is unbalanced. Reasoning that the vibes would be greatest directly over the wheel in question, I downloaded a recording accelerometer app onto two smartphones and put them (i) in the boot over the wheels and went for a spin down the local dual carriageway then (ii) put them in the footwells and did the same.

blem is that the levels are extremely similar above all four wheels and non e of them stand out as being worse than the others.

below the suspension springs. Or could it be that all 4 wheels are a bit u nbalanced.

Not hard to tell, as they rotate something like 4x as fast as tyres. Calcul ate from 16Hz to see which it is.

NT

When I had a similar problem I swapped the spare for the others one at a time.

Turned out to be one of the ones on the back. It was quite badly out - on the back, this presented as a vibration at 65ish. On the front, it got scary at anything over 20...

I have and 16Hz is what I would expect from a standard car, with 2m circumference and diameter of 65cm at 70mph.

I've had propshaft UJs fail and the vibration is at a much higher frequency.

However it would be useful to know if the OP has recently put roof bars or a roof box on his car!

I have to do my own motor scooter as the local bike shop can't do that sort of wheel on their machine. I made up a pair of cones on a hardened steel shaft and sitting in a pair of lightly oiled shielded bearings. You support the wheel up on said spindle (two car axle stands are good for that), allow the wheel to rotate freely and see if it settles at one point. If it does, stick (using tape initially) a small weight to the high side, turn the wheel 90 degrees let go and see which way it turns. If the weight moves up it's not enough etc.

I think they used to use that method for balancing racing bike wheels (and may still do) and I'm going to make up a carrier for doing trailer wheels (partly for the s&g's and partly because they rotate so fast so might appreciate balancing. Plus we have quite a few trailers!).

Cheers, T i m

It would have to be the wheel. 71 mph is 104 feet/sec. A 16Hz vibration occurs every 6.5 feet - which is one revolution of a 16" or 17" wheel with an appropriate tyre.

If you're driving alongside a car with a badly out of balance wheel, you can actually *see* the vibration. The OP may be able to set his door mirrors to enable him to see his own rear wheels. Front wheels would be a bit more tricky. Maybe a passenger leaning out with a hand-held mirror?

No I didn't

ch wheel is unbalanced. Reasoning that the vibes would be greatest directl y over the wheel in question, I downloaded a recording accelerometer app on to two smartphones and put them (i) in the boot over the wheels and went fo r a spin down the local dual carriageway then (ii) put them in the footwell s and did the same.

roblem is that the levels are extremely similar above all four wheels and n one of them stand out as being worse than the others.

g below the suspension springs. Or could it be that all 4 wheels are a bit unbalanced.

lculate from 16Hz to see which it is.

Yes, I figured 16 Hz was exactly right. It is FWD, so no prop shaft proble ms.

ch wheel is unbalanced. Reasoning that the vibes would be greatest directl y over the wheel in question, I downloaded a recording accelerometer app on to two smartphones and put them (i) in the boot over the wheels and went fo r a spin down the local dual carriageway then (ii) put them in the footwell s and did the same.

roblem is that the levels are extremely similar above all four wheels and n one of them stand out as being worse than the others.

g below the suspension springs. Or could it be that all 4 wheels are a bit unbalanced.

lculate from 16Hz to see which it is.

Yes, I can rotate the mirrors down and see a bit of the back wheels but can 't see any vibration, which doesn't mean there isn't any. And 70-ish is a bit fast for someone to poke their head out to see the front ones.

wheel is unbalanced. Reasoning that the vibes would be greatest directly o ver the wheel in question, I downloaded a recording accelerometer app onto two smartphones and put them (i) in the boot over the wheels and went for a spin down the local dual carriageway then (ii) put them in the footwells a nd did the same.

lem is that the levels are extremely similar above all four wheels and none of them stand out as being worse than the others.

elow the suspension springs. Or could it be that all 4 wheels are a bit un balanced.

Good idea, I've got an aftermarket skinny spare which is 2" smaller diam bu t shouldn't be run at 71 mph. One garage didn't seem at all interested in checking the balance, ie. they prefer to fit new tyres. The two fronts are nearly worn out, but there's no vibration at the steering wheel so its pro bably a rear one, as luck would have it, which both have >10k miles left.

That method doesn't work very well with wide rims/tyres.

No, I don't suppose it does but still might be better than nothing?

Cheers, T i m

heel is unbalanced. Reasoning that the vibes would be greatest directly ov er the wheel in question, I downloaded a recording accelerometer app onto t wo smartphones and put them (i) in the boot over the wheels and went for a spin down the local dual carriageway then (ii) put them in the footwells an d did the same.

em is that the levels are extremely similar above all four wheels and none of them stand out as being worse than the others.

low the suspension springs. Or could it be that all 4 wheels are a bit unb alanced.

If you're bent on saving money, try the spare wheel on each corner until th e vibration disappears. Then take the culprit in to be rebalanced.

Well, which is the one that gets clobbered most when parking. One of the front ones certainly, and if the vibration is through the steering its likely to be a front one. My now late father had this on an old Consul Classic and it was always a front one, usually the offside one.

Brian

Also of course dodgy shocks can make this sort of thing a lot worse. I was in a minibus the other day and it was very sickmaking when he hit a certain speed, and on a certain surface.

Brian

I had a vibration problem like that so I put the front tyres on the rear. Ok except that I did I did get a vibration at 70+ so I just tried not to go that fast to save fuel. Then at about 55-60 mph fortunately on a straight bit of not very busy duel carriageway I got what I thought was a puncture. When I took the wheel off I found there had been a bare patch in the middle of the tread.

A little while ago there was a bit of Top Gear where they put an old car through a German vehicle testing truck. One of the things they checked for was wheel eccentricity. I now see the point of that!