C5 X7 Canberra wheel swap? - you get bigger diameter, wider wheels!

JulianEdgar

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Long shot I know.

I have just bought a 2011 C5 X7 with 245/45 tyres on factory 18 inch rims.

The profile is a bit thin for my roads and I am wondering if anyone nearby wants to 'upgrade' to these wheel and tyres from their higher profile / smaller diameter rims, by a direct swap?

I'd have to check the smaller wheels still clear the brakes, have the same offset, etc

Am also open to buying the wheels.

(Haven't been here since I owned a Pug 405 about a decade ago. But that email/password no longer works, so explaining post count of 1.)
 

Sans_sagesse

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Welcome back Julian.

I can't help with the wheels, but did own a C5 X7 Comfort HDi that came with the factory 17in alloy wheels. I haven't driven a C5 with the 18in wheels, but on the 17s the C5 would still crash over some bumps. Typically these were bumps that transmitted a sharp shock through the suspension, such as a pothole or sharp raised ridge in the road. Even some speed humps. it was such a shock, pardon the pun, because ride was so lush in any other circumstance.

What I'm saying in a round-about way is the taller-tyred 17in C5 rims such as mine had will undoubtedly absorb road shocks better that the 18s, but I'm not sure if it would be a dramatic improvement. I think compliance in the suspension bushes might be an issue regardless of which tyre sidewall you go with. It could also be the bushes were on the way out in my car, but I drove another identical C5 that was much the same.

Perhaps others will chime in with more experience of driving on the different wheel options, but from I've read the 19in wheels can be particularly harsh, the 18s not so much.
 

CC1701

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..... just bought a 2011 C5 X7 with 245/45 tyres on factory 18 inch rims.

The profile is a bit thin for my roads and I am wondering if anyone nearby wants to 'upgrade' to these wheel and tyres from their higher profile / smaller diameter rims, by a direct swap?

We've recently replaced the 245/45-R18's on our C5 X7 Tourer to Michelin Primacy 4 in 235/50-R18.
Much better low speed ride, doesn't crash over bumps at low speed.
Its a costly size >$1000 a set but cheaper and much easier than swapping wheel sizes for a similar result.
We did a similar change on the wife's DS5 and also got an excellent result.
Highly recommended to go for a good touring tyre, down a width and up a profile.
The Primacy 4 seems made for the C5 X7, especially in 50 profile.
 

Whippet

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Welcome Julian. Your contribution on this forum would be appreciated.

I have read and enjoyed many of your articles for auto speed. Even though I was a latecommer to that website, much of your thinking and approach resonates with my own understanding for vehicles, efficiency and approaches to performance.

There have been some recent posts here about tyre sidewall heights and the aesthetic race to larger and larger rim diameters and low profile tyres, with I consider, diminished driving enjoyment on typical passenger vehicles on Australian roads. 4CVG might also comment on the gains for increased sidewall height from 18" to 17" rims.
 

4cvgordini

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What would be the 17" tyre size? What is the current tyre model?

cheers! Peter
 

JulianEdgar

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Welcome Julian. Your contribution on this forum would be appreciated.

I have read and enjoyed many of your articles for auto speed. Even though I was a latecommer to that website, much of your thinking and approach resonates with my own understanding for vehicles, efficiency and approaches to performance.

There have been some recent posts here about tyre sidewall heights and the aesthetic race to larger and larger rim diameters and low profile tyres, with I consider, diminished driving enjoyment on typical passenger vehicles on Australian roads. 4CVG might also comment on the gains for increased sidewall height from 18" to 17" rims.
Thanks, but AutoSpeed was a long time ago now. These days I do videos and write books.
 

JulianEdgar

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We've recently replaced the 245/45-R18's on our C5 X7 Tourer to Michelin Primacy 4 in 235/50-R18.
Much better low speed ride, doesn't crash over bumps at low speed.
Its a costly size >$1000 a set but cheaper and much easier than swapping wheel sizes for a similar result.
We did a similar change on the wife's DS5 and also got an excellent result.
Highly recommended to go for a good touring tyre, down a width and up a profile.
The Primacy 4 seems made for the C5 X7, especially in 50 profile.
Thanks for that.
 

JulianEdgar

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Welcome back Julian.

I can't help with the wheels, but did own a C5 X7 Comfort HDi that came with the factory 17in alloy wheels. I haven't driven a C5 with the 18in wheels, but on the 17s the C5 would still crash over some bumps. Typically these were bumps that transmitted a sharp shock through the suspension, such as a pothole or sharp raised ridge in the road. Even some speed humps. it was such a shock, pardon the pun, because ride was so lush in any other circumstance.

What I'm saying in a round-about way is the taller-tyred 17in C5 rims such as mine had will undoubtedly absorb road shocks better that the 18s, but I'm not sure if it would be a dramatic improvement. I think compliance in the suspension bushes might be an issue regardless of which tyre sidewall you go with. It could also be the bushes were on the way out in my car, but I drove another identical C5 that was much the same.

Perhaps others will chime in with more experience of driving on the different wheel options, but from I've read the 19in wheels can be particularly harsh, the 18s not so much.

I see the C5 X7 as having two issues with ride.

The first is that, as you describe, the impact over sharp-edged bumps. A pothole, for example, causes a real crash through the car and also makes me think it would be easy to dent a rim. So higher tyre profile should help fix that.

The other issue, especially in Normal mode (ie in contrast to Sport mode) is that the roll accelerations are much higher than the bump accelerations. In Normal mode, they're about 50 per cent higher, in fact (based on my measuring bump and roll natural frequencies). In Sport mode, they're much closer in magnitude and so for me, Sport mode rides better than Normal mode. The roll accelerations are caused by the anti-roll bars - did C5 X7 models come with different thickness anti-roll bars?
 

Sans_sagesse

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I see the C5 X7 as having two issues with ride.

The first is that, as you describe, the impact over sharp-edged bumps. A pothole, for example, causes a real crash through the car and also makes me think it would be easy to dent a rim. So higher tyre profile should help fix that.

The other issue, especially in Normal mode (ie in contrast to Sport mode) is that the roll accelerations are much higher than the bump accelerations. In Normal mode, they're about 50 per cent higher, in fact (based on my measuring bump and roll natural frequencies). In Sport mode, they're much closer in magnitude and so for me, Sport mode rides better than Normal mode. The roll accelerations are caused by the anti-roll bars - did C5 X7 models come with different thickness anti-roll bars?
Not sure about the roll bars; but surely the (presumably heavier) V6 had a thicker one or two?

I didn't mind normal mode during freeway use, but on some secondary roads Sport felt more controlled. But I got used to the normal mode's wafting along approach. I never pushed the C5 hard though corners, except maybe on circular freeway on-ramps, where it quickly became obvious these are not the most dynamic of cars.

The other thing I forgot to mention if you haven't discovered it already is the front suspension's tendency to top-out passing over some bumps where a fair bit of sudden compression and rebound were involved (eg some speed bumps). Lack of rebound control, lack of downward travel or both - I don't really know the reason but again, it was surprising when it topped out with an almighty bang because it seemed totally out of character with how well the suspension behaved on more gentle surfaces.

From memory, this platform was shared with the steel-spring Peugeot 407 (and some C5s also sold on steel springs). Maybe some compromises with the hydraulic suspension was a result.

I just loved that it was a very relaxing and efficient point-to-point long-distance freeway tourer. For that purpose, it rated among the best cars I have ever owned.
 

jaahn

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Hi Julian :)
I have a Renault Captur which came fitted with optional low profile tires on mag rims standard. I got sick of the sh*t ride on suburban streets and as new tires were due just recently I fitted rims off a Clio, two sizes down, and tires two profiles up.
I have been happy enough with the change as it takes the edge off the sharp bumps and holes. It does not transform the ride to a hydraulic Citroen equivalent, but has enabled me to stop thinking of selling the car due to the poor bumpy ride. What were they thinking ???? :rolleyes:
IMHO the marketing people and the spin merchants have taken over from 'common' sense.
Jaahn
 

JulianEdgar

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Hi Julian :)
I have a Renault Captur which came fitted with optional low profile tires on mag rims standard. I got sick of the sh*t ride on suburban streets and as new tires were due just recently I fitted rims off a Clio, two sizes down, and tires two profiles up.
I have been happy enough with the change as it takes the edge off the sharp bumps and holes. It does not transform the ride to a hydraulic Citroen equivalent, but has enabled me to stop thinking of selling the car due to the poor bumpy ride. What were they thinking ???? :rolleyes:
IMHO the marketing people and the spin merchants have taken over from 'common' sense.
Jaahn

Yes it's my belief that ride quality of normally-priced cars has just gone down and down over the last few decades. Stupidly low profile tyres is certainly part of that.
 

Buttercup

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Hi Julian :)
I have a Renault Captur which came fitted with optional low profile tires on mag rims standard. I got sick of the sh*t ride on suburban streets and as new tires were due just recently I fitted rims off a Clio, two sizes down, and tires two profiles up.
I have been happy enough with the change as it takes the edge off the sharp bumps and holes. It does not transform the ride to a hydraulic Citroen equivalent, but has enabled me to stop thinking of selling the car due to the poor bumpy ride. What were they thinking ???? :rolleyes:
IMHO the marketing people and the spin merchants have taken over from 'common' sense.
Jaahn
It all started when the car companies realised 2 things......
Every male driver wants to be Fangio.
And....
Suspension travel costs money.

So they gave us "sports" suspension, told us that body roll is bad, that tyres need to too look like they came straight from the race track, and as we drive we need to think constantly about Zoom-Zoom.

I'm VERY glad that my C5 wagon has 16" wheels.
 

4cvgordini

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The tyre model is Boto Vantage H8 (Bob Jane own brand, I think). The rolling diameter equivalent in a 17 inch tyre would be 225/55.
As I see it, the options are basically 2: stay with 18" & try to get a tyre which works better for you (see post by cc1701) or move to 17" as proposed.

The dominant variables are sidewall connected.

One is height. Your current sidewall height is 109 mm. That's not ridiculously low profile short. Going to your proposed 225/55-17 size adds 14% in sidewall height to get 124mm. Other things being equal, I suggest that 14% would be noticeable.
Mind you, one could gain sidewall height within 18", though not as much.
cc1701's 235/50 option increases sidewall height to 117 (+7%). It does overgear the car by 2.2% but I suggest that that is a slight problem.
Another 18" option is 215/55. A bit taller at 119 mm (+9.3%) & similar overgearing of 2.2%.
Each of the 18" options would be a noticeable sidewall change other things being equal but they don't have to be.
Other variables apart from type dimensions concern the sidewall structure.
One concerns the number of plies involve from bead to bead. Usually this is one ply but on so-called "extra load" variants, it is usually two. Such variants are stiffer riding than one ply siblings. The other is the treatment of the bead area. In pursuit of having the tyre quickly transmit steering inputs to tread movements, "sporty" tyres reinforce the bead area by extra fold-up plies ("flippers") &/or wedge-shaped inserts of hard "rubber" ("fillers"). Such reinforcements detract from ride. So, even within the same tyre size, improvements can be found by avoiding XL structures &/or tyres designed to be crisp & quick in turn-in response.

The Boto is a tyre type which I would be suspicious of on "el cheapo" wet grip grounds but it is unknown to me; however, there are three things to note from its BJ "blurb". One is that it is an XL type. The second is that is is supposedly sporty. Confusingly, & in tension with the sportiness claim, it also speaks of comfort. Let's focus on the first two.
cc1701's Primacy 4 tyres come in two types in 225/50. Each is a "touring" tyre & thus is not as bead area reinforced as the Boto presumably is. Moreover, although one is an XL type, one is not. Furthermore, the non-XL type is the ST variant of the P4, a variant which is more comfort orientated than the regular P4.
In short, & given cc1701's experience, staying with 18" but moving to 225/50 Primacy ST tyres sounds like a good option. I can't think of a more suitable tyre for you within that size.

What of the other, slightly sidewall-taller (& lighter, another ride factor) 18" possibility - 215/55?
The P4 ST is again available but only in an XL variant. However, I note that Dunlop's FM800 tyre is available in a non-XL variant. If wet grip is important to you then this is a very good tyre in the wet from what I recall of a Choice test & from my experience of it at the rear of my rear-engined Renaults. I can't comment on comfort as I don't attend to that. I think that the FM800 in this size might prove to be a very good option.The option is improved by Dunlop currently offering a "4 for the price of 3" deal.

What of 17"? What's available in a "touring" & non-XL tyre of a decent sort?

The Primacy 4 ST & the FM800 are both available but not in a non-XL variant. Fortunately, a very good "touring" tyre is: Bridgestone's Turanza T005. Nothing else in this size attracts. As the T005 is sold in Europe (like the regular Primacy 4 but not the ST & not the FM800), a good suite of magazine tests is available in summary at:
https://www.tyrereviews.com/Tyre/Bridgestone/Turanza-T005.htm

Although no tests are available, some FM800 user reviews are at:
https://www.tyrereviews.com/Tyre/Dunlop/SP-Sport-FM800.htm

The Tyre Reviews site has nothing on the Primacy 4 ST variant but you could trawl the tests on the regular P4 & hunt for comments on comfort. See:
https://www.tyrereviews.com/Tyre/Michelin/Primacy-4.htm

You probably already know of it but for tyre size comparisons, see:
https://tiresize.com/comparison/

My own inclination would be to stay with 18" & try the FM800 unless 17" wheel offers fly in the door.

cheers! Peter
 

JulianEdgar

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As I see it, the options are basically 2: stay with 18" & try to get a tyre which works better for you (see post by cc1701) or move to 17" as proposed.

[snipped]

cheers! Peter

Thank you for such a comprehensive reply, Peter. I'd not realised that XL had significance for sidewall stiffness.

The Boto tyres are pretty well brand new, so I won't be buying any new tyres for a while. Surprisingly, they also seem to have decent wet and dry grip.

So I guess unless a smaller wheel swap appears, I'll stay with these tyres until they're worn out and then look at going narrower/taller as per your recommendation.
 

Ken W

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Hi Julian,
I purchased my C5X7 in the early days of the model and I still have it! I was told then that the difference in ride between the 17" and 18" wheels wasn't that noticeable but that the ride was noticeably firmer with the step upto the 19" wheels.

Cheers, Ken
 

CC1701

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got sick of the sh*t ride on suburban streets ... poor bumpy ride.
What were they thinking?
marketing ... taken over from 'common' sense.
Low profile tyres aren't well suited to our conditions, but we get sold bigger wheels and licorice strap tyres are a fashion 'Must' have.
Don't engineers and marketers test them in the real world before releasing them on the unsuspecting public.

Indeed! What were they thinking?
 

CC1701

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cc1701's 235/50 option increases sidewall height to 117 (+7%). It does overgear the car by 2.2% but I suggest that that is a slight problem.
With the 235/50-18's the speedo is nearly spot on now. 100 indicated = 100 actual road speed, 60 indicated = 58.5 actual road speed.
+7 mm in sidewall height makes it a little easier to get out of the car and the bib doesn't scrape on curbs :)
 
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MELso

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Low profile tyres aren't well suited to our conditions, but we get sold bigger wheels and licorice strap tyres are a fashion 'Must' have.
Don't engineers and marketers test them in the real world before releasing them on the unsuspecting public.

Indeed! What were they thinking?
The engineers test them and probably say 'that'll be rubbish with the soft ride of the hydro suspension'.

And then Citroen's dumb marketing department from a decade ago says "yeah but we're trying to compete with Audi RS, Merc AMG and BMW M - it's all about Nurburgring lap times! People want 'sportiness' and 'style' and the 19" wheels look awesome". There's no other explanation.

At least Citroen are offering a counterpoint to the Germans these days. It's a shame they had to ditch the hydro suspension before they realised that not everyone wants a rock hard ride from their car...
 
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