Citroen C5X tyres

[Sloppysod]

My C5X (PHEV),@20,100 miles. It has 3 of the original Michelin eprimacy tyres as one was replaced a month before I bought the car.
The car is very quiet, yes it bangs going over UK and potholes, but in general it rides well, admittedly not as good as previous C5`s.
The adaptive suspension is noticeable but I don't think it's as good as they advertised it to be.
As the sidewalls are stronger to take the weight you have to accept more banging over potholes, but apparently, even with the 17" wheels and larger sidewalls, there isn't that much difference.

[DS9]

Thanks folks for your reply. I'm cynical about the whole DB thing myself. Like I said it's passer by noise and the EU are apparently quite aggressive at asking tyre manufacturers to reduce it over time. But to me it stands to sense a manufacturer has a compound which they test for wet/ dry. etc and then it throws up a level of noise overall, and they must then try and tweak this total noise to go up/down in the wheelwell (increasing cabin noise) and try and dissipate as little as possible sideways.

One thing I notice is it seems nobody anywhere seems to do a "lets test a standard car with 6-10 different types of tyres on the car and compare DB cabin noise compare to the passer by DB rating". The EU commissars would hate this.

All we are left with is anecdote like this which I can see as being realistic https://www.volvoforums.org.uk/forum/te ... less/page3

"Ok, back to noise ratings being pointless. I can now confirm this based on various sets of tyres.

The car came with budget 225/45/17 Tyres, loads of tread depth rated at 73dB, these seemed noisy.
Gave me a cabin reading of about 75dB.

I then fitted new 225/45/17 Goodyear EfficientGrip Performance rated at 69dB, still seemed noisy.
Gave me a cabin reading of 73-74dB. (I forget exactly)

This was disappointing as I was hoping for much less road noise considering they were rated 4dB less than the budget ones.

I have now fitted 205/55/16 Nokian WR D3 tyres, an aggressive tread and rated at 72dB.
These give me a cabin noise of 71dB. Thats 2 – 3dB quieter than the ones that should be quiet.

So why does a noisy tyre Rated at 72dB give a quieter ride than one rated at 69dB?

I wish the tyre ratings were based on an internal cabin noise measurement."


I think from the 3 examples exclude the budget tyres and just look at the other 2. This guy is essentially saying a tyre that a tyre rated 3db higher is actually 2-3 db quieter in the cabin which kinda supports my hypothesis, the amount of the sound coming from the tyres is about the same in both cases but in one case this is pushed outwards, and in the other it's pushed into the wheel well and ultimately into the cabin. Shame he didn't go further and test a premium tyre with say a 75db rating, with this he may have been able to get down to under 70db in the cabin. So it does make you wonder, to get the quietest tyre in the cabin is it just about buying a premium one with the HIGHEST DB rating?


There'll be some advantages to bigger sidewalls etc, but I've never fancied it as I'd have to tell the insurers unless I dropped to 17s which are an approved size.

Agree that the ride isn't perhaps quite to the level advertised but for me it's good enough, all I'd want is a little more compliancy over slow speed ruts and a quieter ride over bad surfaces. By the way Stu, are yours marked ACO?..... apparently some E.Primacy v1 are and some arent.

I had a good look earlier in the week and there are a lot of slight tweaks in the model names of the new E.Primacy V2. It seems for the specific ones I want only Halfords seem to do them.

[DS9]

Well i just got me digital tyre depth gauge delivered and was dying to see what the actual answers were so did all 4 deep grooves and in all 4 tyres.

This is what I measured.
Nearside Rear 6.58 6.52 6.56 6.52
Nearside Front 6.37 6.36 6.34 6.33
Offside rear 6.51 6.85 7.04 6.85
Offside front 6.40 6.50 6.55 6.34

Mean average 6.54mm

So give or take they have 6.5mm on them.

[DS9]

By the way, something for C5x owners if they didn't know.

I only thought the driver headrest went up and down, yesterday I found out by pressing the button on the headrest it also moves horizontally.

Seriously, I never knew.

[Sloppysod]

There is no difference between e-primacy and primacy-5 apart from efficiency, and using Michelin spec the 'e' gives 7%, so for me, electric mode I would get an extra 2 miles range (yearly average) and an extra 4 mpg!

I'm personally going to look a Devanti when I renew.

[DS9]

I looked at the primacy 5, a very good tyre and to be honest would be my 2nd choice.

[MattBLancs]

Interesting background on the tyres thank you - the C4 tyres were not XL Extra Load rated - not sure about the C5's, but will check in the morning.

To confirm:

C5 is fitted with Goodyear Efficient Grip Performance 2 Extra Load in 225/55 R17 101W size and spec.


Correction!

Rear: Efficient Grip Performance 2,
Front: Efficient Grip Performance (so "1" in effect!)

[DS9]

if they arent both XL it might be an idea to put the Xl's on the front.

"The 2009 Citroen C5 Tourer 2.2 HDi Exclusive 173 has a front-to-rear kerb weight split of approximately 60% front and 40% rear. With a kerb weight of about 1,765 kg, this translates to roughly 1,060 kg over the front axle and 705 kg over the rear, owing to the heavy transversely-mounted diesel engine."

I'm surprised how heavy it is, about the same as my C5x hybrid which has a 58/42 split. I did think the battery was supposed to be 300kg but just looked and it says 115kg-135kg. Makes me wonder why the recommended tyre pressure on mine are 32psi front and 40psi rear.

[Sloppysod]

From blackcircles, C5X PHEV, vs C5 2.0 HDI Auto. Same load/speed rating V V97, so yes why different presures

From Duckduck.ai
"The number 97 on a tyre is the load index, which indicates the maximum weight (1,609 pounds) that a single tyre can safely support when properly inflated."

"The letter V, on tyres indicates the speed ratings: V means the tyre can safely maintain speeds up to 149 mph (240 km/h)."

[MattBLancs]

if they arent both XL it might be an idea to put the Xl's on the front.

"The 2009 Citroen C5 Tourer 2.2 HDi Exclusive 173 has a front-to-rear kerb weight split of approximately 60% front and 40% rear. With a kerb weight of about 1,765 kg, this translates to roughly 1,060 kg over the front axle and 705 kg over the rear, owing to the heavy transversely-mounted diesel engine."

I'm surprised how heavy it is, about the same as my C5x hybrid which has a 58/42 split. I did think the battery was supposed to be 300kg but just looked and it says 115kg-135kg. Makes me wonder why the recommended tyre pressure on mine are 32psi front and 40psi rear.

Sorry, was a bit shorthand with my edit - both front and rear are marked extra load, it's only Performance / Performance 2 that differs.

Yes, it's a heavy car! It's also surprising given how much aluminium is used (bonnet, but also lots of suspension components, front and rear subframe etc) it's also a very quiet car, so I put it down to plenty of "mass loading" type sound deadening materials deployed.

The 2.2 bi turbo is a great engine - it certainly overcomes the weight. I know you could get the little 1.6 HDi in the C5, I think that'd frustrate me somewhat!

[DS9]

It's a shame to meet emissions regulations etc they've stripped cars to the bare bones. I expect a car a decade old or more would have a fair bit of sound deadening swabs here and there but I know in my C5X it's virtually non existent.

Just looked and the 2.2hdi, it does look potent, the 8.6 sec 0-60 is kinda like a lie. 200+ hp and 450nm torque will make it really shift. Bet it goes like a rocket at 30-80 mph wafting along on a sea of torque.

[MattBLancs]

Maybe that's a better route to investigate - improving the sound deadening to mask the road noise rather than eliminate it through tyre choice??

There's a thread on here of someone who was doing just that. Will have a dig....



....ha ha! It's you!
viewtopic.php?p=846243#p846243

For the avoidance of doubt I'm a serenity guy

[DS9]

I thought it might be, lol. I got the DS9 in a good place but as DS never sorted the suspension knocking i always got from the front passenger wheel which annoyed me to death so I swapped for a C5X.

I've done a fair bit of sound deadening on the C5X already, in fact almost everything I want to do including the wheel wells. I just think I've messed up with the bonnet. In the DS9 I just covered the whole bonnet with a 10mm thick £40 dodmat 1 piece bonnet liner (and cut badly to size, its about a 1hr job max), before and after pics below, while on the C5X I've just put a couple of layers of butyl stuff under the bonnet liner.

The outcome. Well they have the same 1.6 engine, the C5X at 180hp and the DS9 higher at 225 hp, but should both sound the same. At idle 800rpm tickover in the DS9 you genuinely could hardly hear the engine, with everything else silent i'd have to lean forward and turn my head a bit, in the C5X I can hear it a fair bit more. Overall I'm not sure if the bulkhead was better soundproofed in the DS9 though.

Now the last 2 pieces of the puzzle are the doors which I don't think it'll ever solve, the issue is they dont sit on the sill like the DS9 but go down and wrap around the bottom of the car and the tyres. My car is all but perfect on a good surface, its so serene, but I think the tyres are rubbish on poor surfaces.