New tyres, lots of rumbling at motorway speeds! Whats going on?

OK, I've literally just fitted a set of 235/70/16 Insa Turbo Traction Track tyres to replace the standard 205/80/16 tyres it came with.

The car rides fine but I came onto some dual carriageway earlier and whilst I don't mind the 'aircraft' noise that chunky tyres tend to make, there was a significant rumble throughout the whole car, mostly from the rear I think. This was not apparent with the original tyres.

It didn't feel like the wheels were out of balance (it wasn't a 'wobble' as such), but there was a definite, distinctive rumble - one that you could hear and feel. It was very 'bassy' too. It started at 60mph and got louder/fiercer the faster I went, up to about 75mph when I stopped trying!

The weird thing is, when I let go of the accelerator completely, everything went quite. Barely any tyre noise, no rumbling/shaking, nothing. :doh:

So, are the new, bigger, grippier tyres at fault or are they highlighting a mechanical weakness somewhere in the drivetrain, rear diff maybe? Help!

Thanks guys (and gals).

It wasn't a concrete road surface by any chance?

Nope, although the effect was similar, but much worse!

This was one of the sites I used when choosing the tyres: http://www.4x4tyres.co.uk/2357016-insa-turbo-traction-track-terrain-p-528.html

Designed to give you confidence to tackle the toughest off road conditions on rough and slippery ground. The traction track is also extremely supple, offering a comfortable ride over uneven surfaces, potholes and rocky tracks, while its dual purpose tread is remarkably quiet and responsive on tarmac.

· Small blocks situated at the central

· Side of the tread

· Heavy alternating shoulder lugs

· Sophisticated tread pattern

· No directional traction design

· Enhanced road performance

· Optimum traction on mud and snow

· Reduced noise level and increased off road motoric

· Excellent self-cleaning (mud, snow, sand)

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It's the bold bits I currently dont agree with! Could the chunky new tyres be exposing weaknesses in the rest of the car?

My money would be on the tyres.

Refit the old tyres>same road>same speed, see if the noise has gone???

my money would be on the tyres, not sure how that would effect when you ease of the throttle though,

all insas are the niosey on the road though

Well the old tyres are in the bin at the tyre place! But I know that on those there was no road noise, they were fine.

So, the only thing to have changed was the tyres - but all the reports suggested they would be fine on the road, which is why I went for these over a more aggresive mud terrain tyre!

Also, surely the tyres would still make as much noise when off the throttle as they do when on it?

If ya fits tratter tyres ya gotta accept the noise.

MikeV8SE said:

Well the old tyres are in the bin at the tyre place! But I know that on those there was no road noise, they were fine.

So, the only thing to have changed was the tyres - but all the reports suggested they would be fine on the road, which is why I went for these over a more aggresive mud terrain tyre!

Also, surely the tyres would still make as much noise when off the throttle as they do when on it?

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Yeah but the test driver for the tyre company, that did the write up on them, was deaf.

MikeV8SE said:

Well the old tyres are in the bin at the tyre place! But I know that on those there was no road noise, they were fine.

So, the only thing to have changed was the tyres - but all the reports suggested they would be fine on the road, which is why I went for these over a more aggresive mud terrain tyre!

Also, surely the tyres would still make as much noise when off the throttle as they do when on it?

Click to expand...

Yeah but the test driver for the tyre company, that did the write up on them, was deaf.

MikeV8SE said:

So, the only thing to have changed was the tyres - but all the reports suggested they would be fine on the road, which is why I went for these over a more aggresive mud terrain tyre!

Click to expand...

Ear Plugs or IPod....sorted..........:behindsofa:

If you're certain that it's the tyres, and it sounds like it, then all you're left to play with is the pressures. Get the chalk out.

Chalk? The tyre guys put 30 PSi in all round, might let a bit out the fronts...?

Is it likely that because they are remoulds they will "flatten off" after a bit of use?

I really don't understand - they are a lot noisier than the Insa Turbo Dakar's (a Mud Terrain tyre!) on my mates Disco. I was expecting these to be quieter.

As I say, the high pitched aircraft-type noise I was expecting and it is there, but quieter than the Dakars. This deep, bassy droning I was not expecting, something isn't right!

One of the reasons the noise is louder with throttle is the fact that the engine is trying to drive the wheels faster than they are going presently, this has the effect of moving the tyre tread blocks, and the 'humming' noise is the blocks moving back into place once they have left the road surface and the noise is echoed around the empty airspace within the tyre hence the low bass sound (as the tyre is acting like the skin of a drum)

When off the throttle, the tyre isn't trying to impart traction into the road surface anymore but merely 'going with the flow' so the tyre treads don't move about as much....

This is why new tyres are noiser than worn and also why Mud tyres are noiser than Road tyres as the blocks are bigger and impart a greater movement and vibration.

Just my twopeneth worth...

Saint.V8 said:

One of the reasons the noise is louder with throttle is the fact that the engine is trying to drive the wheels faster than they are going presently, this has the effect of moving the tyre tread blocks, and the 'humming' noise is the blocks moving back into place once they have left the road surface and the noise is echoed around the empty airspace within the tyre hence the low bass sound (as the tyre is acting like the skin of a drum)

When off the throttle, the tyre isn't trying to impart traction into the road surface anymore but merely 'going with the flow' so the tyre treads don't move about as much....

This is why new tyres are noiser than worn and also why Mud tyres are noiser than Road tyres as the blocks are bigger and impart a greater movement and vibration.

Just my twopeneth worth...

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Thanks for the explanation Saint! So this could be why my mates worn Dakar's are quieter than my brand new Traction Tracks, even though mine are less aggresive?

Hopefully mine will quieten down a bit with use then - but I still think the amount of noise generated is too much, much more than I expected!

re-moulds? really?

I'd expect the noise to quieten with the throttle off, when under-load pushing the brick-like car through the air there will be significant tread-block deflection at speed, this will increase noise. Lifting off the tread blocks will return to the more "upright" position, try inflating the tyres to higher pressures. It may help.

Hi have you tried jacking the rangie up and slackening the wheel nuts and making sure the wheel is flat against the hub and re tightening, as I have in the past had a wobble effect after fitting new tyres due to tyre fitter tightening up with a air gun and wheel not being truly flat on hub.

MikeV8SE said:

Chalk? The tyre guys put 30 PSi in all round, might let a bit out the fronts...?

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That seems rather low for the rears, shouldn't they be nearer 40psi?

I'm pretty sure in my Classics I used 28-30psi in the front and 36-38 in the rears....

I do know the rear tyres need to be higher pressure than the fronts according to Land Rover....