MatraSport Forum

Each model => Murena => Topic started by: macaroni on November 30, 2006, 10:50:05 am

Title: Tyres
Post by: macaroni on November 30, 2006, 10:50:05 am
I am going to replace my horrid Firestone tyres and after much research, I'm going to try some Bridgestone Potenza RE720s. I can get a full set, in both sizes (55 section fronts) fitted for £216.

I have some on the front of my 205 and they are very good and lots of 205 racers swear by them.

I know Roy G is trying some Uniroyal Rallye 550s, but I don't fancy them at all.

I'll let you know the results.
Title: Re: Tyres
Post by: Anders Dinsen on November 30, 2006, 11:31:04 am
Quote from: macaroni on November 30, 2006, 10:50:05 am
I'll let you know the results.

Yes that will be very interesting!! The more info we can gather on tyres on the Murena the better as it's difficult (impossible?) to apply info from FWD front engined cars to our RWD mid engined racer ;)

My bit of experience is that the Murena likes tyres with lots of grip! Which is why I have winter tyres on her ;D
I know you guys in Britain would never spend money on that, if you'd try, I'm sure you will be converted! Winter tyres are NOT only for snow.
Title: Re: Tyres
Post by: Lennart Sorth on November 30, 2006, 07:46:06 pm
Indeed sharing tyre-experiences on the forum is essential.

I have always thought there ought to be some place where you could borrow a set of a specific tyres, and go for a short drive, just to try them out on THAT car. Preferably at a small track. I wouldn't mind to pay a little either - its just such a gamble to fork out 200-300£, and if the tyres happen to perform less than optimal, how many actually bin them, and buy another set?

One thing we must be very careful about is that our cars might be slightly different, - some even quite unoriginal. My car e.g. has a different power/weight ratio, but I still run with the standard suspension (springs/shocks)

SUMMER
AlloyTyreFRONTREAR
15" Azev-AMichelin Pilot Exalto PE2195-50-R15205-50-R15
WINTER(anything lower than +5C):
AlloyTyreFRONTREAR
14" CompomotiveGoodyear Ultragrip 5185-60-R14195-60-R14

Yes, steel rims would be better in the winter, but these Compomotives are worn anyway, and look better :-)

Both tyres are absolutely great, - but when it is 5C or lower, the change to the narrower, softer and slightly higher profile Goodyears is remarkable. Suddenly I have loads of grip again, - and on top of that, the roadnoise is MUCH reduced, and ride comfort is as nice as the Michelin's were in the summer. (which is brilliant).

As I remember from a skidpan curve-test with the Goodyear Ultragrip 5 tyres, I had problems getting the car sideways at all - they are fantastic in the wet. None of the tyres help me much when braking in  a straight line on the skidpan - where you simply cannot feel if the tyres are blocked or still rotating. Slight movements of the steeringwheel does help a little bit, but should you need to brake (or even drive at all) in completely icy conditions, my advice is to gently pump the brake - that way there should be a chance of getting the tyres rotating, and retain friction to the ground/ice.

The only problem with the Goodyears is that they easily squeal (on dry surface), so it is a bit too easy to scare the old ladies, just by taking a corner *slightly* quicker than other cars.

Ambient temperature really makes a huge difference on the performance of tyres, and I would never try to save money by selecting a cheap tyre. Well, not if selected because of the price - however, I'm fully aware that some cheap tyres actually perform well. That would be an interesting experiment for my imaginative tyre-tryout arrangement. Actually the cheap-tyre  manufacturers should be interested in sponsoring such a place .. hmmm

Using different tyres summer/winter isn't more expensive, as you obviously only wear them half a season each. Of course that could give problems with tyres becoming too old, if you don't do enough mileage. There is of course a great solution to that: DRIVE MORE! :-)

Such a set of tyres cost about 250£, and if you go 50kkm on them, it is actually a small price to pay for safety and enjoyment.

/Lennart
Title: Re: Tyres
Post by: lewisman on December 03, 2006, 02:57:16 pm
As yet my murena is not ready for the road but even hen it is it will probably stay at home when it is snowing.  I change the alloys on my own and my wife's Alfas around November, partly to save the good alloys from road salt and partly to change to winter tyres.  I only have winter tyres on the front just now - I couldnt justify the money for a set of four when the other two on eac car were almost new and to be honest it is less of a problem with front wheel drive cars.

The Vredestein Giugiaro winter tyres are very impressive so far but I have only had one small flurry of snow to test them out roperly ;D
Title: Re: Tyres
Post by: roy4matra on December 31, 2006, 04:13:13 pm
Quote from: macaroni on November 30, 2006, 10:50:05 am
I am going to replace my horrid Firestone tyres and after much research, I'm going to try some Bridgestone Potenza RE720s. I can get a full set, in both sizes (55 section fronts) fitted for £216.

I have some on the front of my 205 and they are very good and lots of 205 racers swear by them.

I know Roy G is trying some Uniroyal Rallye 550s, but I don't fancy them at all.

I'll let you know the results.

Thanks for pointing out they now do the RE720 185 x 14 in 55 profile.  Last time I checked they didn't.  Since I wanted the same tyres all round, and decided to change after 20 years of Pirellis on my Murena, I didn't want to spend a lot on my 'gamble' in case they didn't work out.  (I got my 550's pretty cheap!)  I will be interested to see how these Uniroyal perform when I get the car back on the road, but agree those RE720's look good too and Bridgestones have a good reputation.  I will be interested to hear how they perform on your car.

Roy
Title: Re: Tyres
Post by: macaroni on January 02, 2007, 11:31:09 am
Well, so far the tyres are very good. I have much more confidence braking hard in the wet, although I do still lock up the offside front.

The rear is much better behaved too. The whole car feels much more planted than with the Firestones.
Title: Re: Tyres
Post by: Anders Dinsen on January 02, 2007, 01:45:49 pm
Quote from: macaroni on January 02, 2007, 11:31:09 am
Well, so far the tyres are very good. I have much more confidence braking hard in the wet, although I do still lock up the offside front.

The rear is much better behaved too. The whole car feels much more planted than with the Firestones.

How old were the Firestones?

I have the same experience as you with my new set of  (winter) tyres (mixed Pirelli and Conti): My confidence in the car is much improved. Breaking isn't really my primary priority (hard breaking also causes the right front wheel to lock up first on mine, it must be the weight distribution) as I've experinced a 180 degrees (or was it 360, Roy?) spin where my rear lost traction.

- Anders

Title: Re: Tyres
Post by: macaroni on January 02, 2007, 02:45:59 pm
They were about a year old, with good tread left, not that you'd notice.

Interesting to hear about your front right locking up. I read an old road test, from 1983 or something and the tester found it impossible to lock the front wheels under heavy braking. I guess he wasn't trying hard enough!
Title: Re: Tyres
Post by: Anders Dinsen on January 02, 2007, 06:13:44 pm
Quote from: macaroni on January 02, 2007, 02:45:59 pm
They were about a year old, with good tread left, not that you'd notice.

Only one year!? I would call that tyre close to new then...Maybe I missed it earlier... why did you replace them? Wear? Or because you felt they were'nt good for the car?

Quote
Interesting to hear about your front right locking up. I read an old road test, from 1983 or something and the tester found it impossible to lock the front wheels under heavy braking. I guess he wasn't trying hard enough!

Sounds very very odd, I can easily (well it takes some speed, of course) lock up all four wheels if I push hard enough. Of course we don't know which pads he was using or whether the brakes were in fact already fading when he did it - I'm running EBC GreenStuff, and have no reason to complain about stopping power.

- Anders
Title: Re: Tyres
Post by: macaroni on January 04, 2007, 12:01:24 pm
The handling was very wayward and the first port of call is tyres.
They were still legal, but I drive 25 miles to work on winding roads and need confidence.
Title: Re: Tyres
Post by: roy4matra on January 06, 2007, 03:25:48 pm
Quote from: macaroni on January 02, 2007, 02:45:59 pm
They were about a year old, with good tread left, not that you'd notice.

Interesting to hear about your front right locking up. I read an old road test, from 1983 or something and the tester found it impossible to lock the front wheels under heavy braking. I guess he wasn't trying hard enough!

To be brutally honest, I don't think anyone whom I've known who bought Firestone tyres for a Murena has ever had a good word to say about them, except maybe they were cheap (at least in the U.K.) - but you only get what you pay for!  I would never recommend them.

If you or Anders (or anyone else) has one wheel locking before another, but not just occasionally as might be caused by say a slippery patch of road or a that wheel having only a light contact owing to say a bump; then it suggests a slightly sticking caliper.  Even though my Murena corning weighting is lightest on the right front (and heaviest on the left rear) which I suspect may be the case with most Murena driven solo, it locks up evenly in extremes.  It will usually only lock on a dry road when slamming them on hard as in an emergency, and usually they lock up all round about the same time.

The road tester you mention was reasonably correct I feel, since what he meant by heavy braking is not the same as an emergency stop.  In normal use I can brake very hard if necessary and not have to worry about locking brakes.  I even track tested my Murena at Cadwell Park without ever locking a brake, and I was really trying!  However, in the ultimate emergency situation, then yes you can.
Title: Re: Tyres
Post by: Lennart Sorth on January 06, 2007, 11:41:46 pm
Quote from: roy4matra on January 06, 2007, 03:25:48 pm
it locks up evenly in extremes.

I think there could be a difference because we drive in the other side of the road here - thus the right side possibly has more dirt between tyre and tarmac. In all the cars I have driven in Denmark, I have had the impression that you could lock up the right front slightly before the left.

That is the actually best argument I have ever heard for driving on the left - the Murena corner weight balance benefits! :-)

Good thing I'm on the way there in 3 weeks time! :-)

/Lennart