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Author Topic: New tiress for my Murena  (Read 144 times)
Matra_Hans
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Owner of Bagheera, Rancho, Murena & Espace


« on: October 26, 2019, 12:37:45 pm »

The new wheels for my Murena:
I lost control and made a spin with my Murena on a rainy day a few weeks ago, I wanted to overtake a car in heavy trafic going out of a roundabout, luckly there was just enough space in the trafic for me to spinn around with other motorist staring at me in misbelive.
That was a reminder to me that it was time to change the almost 20 years old tires to somthing new and due to turbo engine also wider tires.

So a found the rims which i bought back in 2011 and ordered some tires.
Rims: Keskin KS1 7,5x16 Et 39 (not 100% sure of the ET)
Tiers: Falken ZIEX in front 205/50 16, rear 225/50 16
I like that the wheels are now filling out the wheel wells.
The wheel size is most likely the biggest that can be used on a Murena with standard body work. During hard driving the tires touches the
bobywork just a little but nothing serious, A sligthly lower profile migth be an adwantage.
The new wheels also increases the gearing and the ride hight, I see the taler gearingas a benefit due to my more powerfull engine (Turbo 200hp).
(I already have the long 5th gear).
Further a previous owner has lowered the car (maybe a little too low). I used to 140 mm clearance under the LAMM
front spoiler now I have a clearance under the spoiler of 160 mm.
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Anders Dinsen
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« Reply #1 on: October 26, 2019, 02:51:54 pm »

The new wheels for my Murena:
I lost control and made a spin with my Murena on a rainy day a few weeks ago, I wanted to overtake a car in heavy trafic going out of a roundabout, luckly there was just enough space in the trafic for me to spinn around with other motorist staring at me in misbelive.
That was a reminder to me that it was time to change the almost 20 years old tires to somthing new and due to turbo engine also wider tires.

Shocked

First and only time I tried that in my Murena was on a track (on old tyres, but still). She can be a tricky lady, turbo or not, as she has so much traction - until it's gone. Everyone should try it - in a safe place, of course, not on the road!

I'm not sure your wider tyres will help, but they sure look cool  Cool

I'm happy you're ok! (the car too)

/Anders

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'82 Murena 2.2 prep 142
'01 Grand Espace 24v
'08 Smart Fortwo 0,8 cdi
matramurena
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« Reply #2 on: October 26, 2019, 09:07:14 pm »

I have had the back break out in a corner driving onto the motorway once. Brand new tyres, but that does not help much. There just is loads of grip right untill you get to the limit and then it is gone.....

BTW, nice rims you got there.
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1983 Matra Murena V6 (AR engine)
2003 Matra Avantime 2.0T Expression
2003 Matra Avantime V6 Privilege
JV
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« Reply #3 on: October 27, 2019, 12:27:33 pm »

The torque of the turbo askes for prudence on roundabouts even with new tyres.
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Jan Verdam
roy4matra
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« Reply #4 on: November 06, 2019, 05:21:17 pm »

I have had the back break out in a corner driving onto the motorway once. Brand new tyres, but that does not help much. There just is loads of grip right untill you get to the limit and then it is gone.....

There area few points to make here if I may.  First you say they were 'brand new tyres' but I hope you had run them in for around 300 kms at low speed first?  Brand new tyres always have some of the coating still on them that allow the tyres to be easily released from the molds, and this makes them slippery.  The running in process at low speeds should get rid of all that whilst also allowing the carcase to settle properly.

Since they were brand new tyres, if they weren't exactly the same as you had on previously, then you should always treat them with respect until you have learnt how they perform and grip, because different tyres will have different characteristics.

Next, it is really important that the Murena has the correct tyre pressures on them, especially the rears, and if you are running standard wheels and tyre sizes then the front should be 1.9 bar but the rear MUST be 2.4 bar for a 1.6 or 2.5 bar for a 2.2 model.  If the rear tyres are less than these then it will break away more easily than it should.

Also a mid-engined car has a low polar moment of inertia, which should give it a higher cornering capability than other types of layout (front engine rear drive, or rear engine rear drive) but one inherent trait of a mid-engined car is that when it does break away, it snaps very quickly!  It will also snap-oversteer if you lift off suddenly when cornering quickly, so that should be avoided at all costs.  Always bring the speed down before entering the corner and power through it, increasing the power as you exit.

Finally, if/when you change wheel and tyre sizes for something different, you need to check the relative tyre patch size and adjust the pressures accordingly.  Bigger tyres does not necessarily mean more pressure.  It might even be less.

Roy
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