Tyre roar

Demetris

Demetris

Well-Known Member
... or what ever you call it, seems to be one of the most annoying parts of the P6 experience.
Noticeable from the lower speeds, it does become a little tiresome on fast motorway trips, beating even the wind noise on rough surfaces.
On the tyre front, i have already done my best, using fresh and modern Michelins all round. They do make a difference in comparison with the other brands that i have tried in the past, but i wonder if there is still room for improvement.
I understand that the design of the front suspension and bulkhead is responsible for the transmission of road noise. The suspension is based on the bulkhead, a bulkhead that has inbuilt galleries as air ducts, that also work as transmision line loudspeakers. :(
The only possible solution that i can think of is sticking heavy damping pads on the front and rear bulkheads. Does anyone have any other wild or tame ideas on the subject?
 
Mine got worse when I fitted the Vitesse wheels as they are wider (205/15), and also it got worse when I removed the thick layers of underseal from the front of the bulkhead (around the front spring mounts) and splash panels to replace it with the epoxy. Bear in mind that we have a lot of concrete motorways around here, and they are very loud.

You can get quieter tyres, but be aware they don't often last as long and the noise is measured from outside of the car, and may not make it quieter on a P6 as the noise transmission is different from everything else on the road.

Hope this helps

Richard
 
worth putting something in the 'ducts' to prevent transmission? expandafoam would obviously work but retain moisture potentially?
 
Hi Demetris,

From my experience, the two quietest brands that I have used are Michelin and Maxxis. The former were Energy XM1 and the latter MAP1, both brands in 205/70 HR 14. Michelin no longer make that tyre in that size.

Both tyres grip extremely well in both wet and dry, with little if any tyre noise, and certainly none that I can distinguish at highway speeds. As Richard said though everything comes at a price, and mileage wise, 12,000 (20,000km) will see them being replaced.

Ron.
 
I went from Michelin to Kumho . 195 70 14
Cheaper and quieter
I also bought a bigger stereo for high speed motoring
Gerald
 
quattro said:
Mine got worse when I fitted the Vitesse wheels as they are wider (205/15), and also it got worse when I removed the thick layers of underseal from the front of the bulkhead (around the front spring mounts) and splash panels to replace it with the epoxy. Bear in mind that we have a lot of concrete motorways around here, and they are very loud.

You can get quieter tyres, but be aware they don't often last as long and the noise is measured from outside of the car, and may not make it quieter on a P6 as the noise transmission is different from everything else on the road.

Hope this helps

Richard
Click to expand...

My upgrade to SD1 Mags and 205 tyres lowered the tyre road noise.
I suspect that part of Rovers use of the very thick under-carpet underlay was to reduce this noise, sadly many people have had to replace or remove it with the onset of window seal or rusted heater problems.
NZ whilst it doesn't have much in the way of concrete highways it has very coarse chip seal which makes road noise endemic for most cars and certainly made travelling in most cars in the 70's a bit of a chore regards to highway speed noise... the P6 was actually a relief compared to most Brit cars of the time.
Short of using original soft rubber bushing any real 1st principle means of reducing noise would require re-engineering the mount point and either modifying the fire wall mount point and or the attached suspension member.

Finding quiet tyres seems the easier option

Graeme
 
Not that it's relevant here, but weren't Rover looking at re-engineering the front suspension on the P6 in the early '70's to counter this problem?

Or am I dreaming this?
 
After the tyres you've got to be looking at the rubber components of the suspension. What do you expect after 40 years?

Even with this typre of suspension an awful lot is refleted back off the road into the car throught the wheelarch and floorpan.

I proved this with my modern VW. I added a layer of 3mm neoprene foam and some techsound 50 and it made a HUGE difference, especially with my winter tyres. Remember also my VW is new and has plastic wheelarch liners to soak up some noise which the rover hasn't. Although many modern cars are oddly getting noisier with ridiculously wide and low profile tyres and with weight and fuel consumption targets many are actually losing soundproofing (i.e. my Jetta vs the model before is noticeably noisier).

I suspect the jute/hessian soundproofing is pretty much useless. It simply isn't dense enough to block sound. If it does anything at all to help it'll be by decoupling the heavy carpet from the metal floor.

What you need is a continuous banket of dense, heavy but also limp material to act as a soundbarrier. I bet there is HUGE scope to cut road noise with decent moderrn materials, escecially if you improve the door seals too. Ultimately the limit is going to be wind noise and the low gearing if you haven't got 5 speeds or a ZF but the P6 was pretty refined for its time and I reckon wind noise aside you won't be far off a modern car.

An excellent primer on the topc is here: http://www.sounddeadenershowdown.com/

Note that if you see a vehicle proudly lined in expensive dynamat they've done it wrong. You need only about 30% coverage of sound dampers and probably not even that on a P6 with thick guage steel. The big difference is adding a barrier.
 
Regarding tyres, as i wrote in the original post, i am pretty much done. I am using Michelin Energy Saver 185/70/14 for a few years now and i find them noticeably better in comparison with other makes. Also i am not prepared to go back to the 165 width for various reasons.

The suspension rubbers are also fit enough for purpose. When something deteriorates, i don't hesitate to replace it. So no problems there either. Moreover i have looked after the cabin sound insulation with a combination of modern and traditional materials. The engine noise in not intrusive and with the combination of the V8 diff fitted, you have to go beyond 80 mph to be able to hear the engine when cruising. The door and window seals are new, so i cannot do much more in the wind noise front. On the road noise front i believe that there are some improvements to be made.
Richard's (quattro) mention of the underseal in the outside of the bulkhead makes sense to me, so sticking something heavy on it that will work as vibration absorber will probably work. I am thinking something like a combination of tar pads and wax based underseal on the outside, with careful application of something suitable from the inside. The rear bulkhead and the area that the rear springs are based could also receive a similar treatment. From factory there is only the original felt in there, so i could make up something better.
Rich, i have tried to line the air ducts internally with some thin, dense, closed cell foam wherever i could reach. Perhaps it helped a little, but obviously i cannot block them completely.
 
I can concur with Ron in regards the Maxxis tyres...quietest I've ever come across by a good margin...some loss of grip over say the Michelins, but not too bad.
Here are some ideas when I was looking at my options...


viewtopic.php?f=7&t=11714&start=15

Truthfully, I found the best "anti noise device" was having the stereo on.
 
You must log in or register to reply here.
Back
Top