New Tyres for the QP

[Gixerboy]

Hi all

Looking to replace all 4 Tyres on the QP Sport

Currently it runs
Front 245/35
Rear 285/30

I recall I think it was BJL who had gone up a size on the side wall to add a little more compliance??

Any suggestions, Re Size & make?

Cheers

Dave

 

[TridentTested]

Read something about that on the USA forum once and when I went back to try and find the post I couldn't and thought I must have imagined it.

I would be curious to know more.

 

[BJL]

P Zeros do a 245x40x20 for the fronts and a 295x35x20 for the rears.
No noticable difference in handling but a lot more compliant and no more damaged wheels on continental roads.
I set the pressures at 30 all round which works well plus the rolling circumference is in balance so no traction issues.
The set up fills the arches a lot better and the overall gearing is raised about 4% but testing mine on a dead straight and level road at 100mph on the speedo gps confirmed within 1% accuracy so presumably it was slightly over reading before.

I had Meridien set the geometry to neutral bias with maximum negative camber on the rear which put an even footprint down giving even wear across the tread.

Anything else I can answer please ask. It works well for me and has caused no issues.

 

[npaskin]

That's really useful to know. Mine will probably be due a new set in spring or summer, and I'll seriously consider going down this same route. Dave, if you do get it done, please post any feedback here too.

 

[Gixerboy]

Barrie , that's great, as you can probably yell I've worn the backs out already!

Regards

Dave

P Zeros do a 245x40x20 for the fronts and a 295x35x20 for the rears.
No noticable difference in handling but a lot more compliant and no more damaged wheels on continental roads.
I set the pressures at 30 all round which works well plus the rolling circumference is in balance so no traction issues.
The set up fills the arches a lot better and the overall gearing is raised about 4% but testing mine on a dead straight and level road at 100mph on the speedo gps confirmed within 1% accuracy so presumably it was slightly over reading before.

I had Meridien set the geometry to neutral bias with maximum negative camber on the rear which put an even footprint down giving even wear across the tread.

Anything else I can answer please ask. It works well for me and has caused no issues.

 

[BJL]

One other side benefit I've found is because the tyres are obviously a tad more compliant they seem to wear a lot better. I'm getting at least 10k from the rears and 20k from the fronts doing pretty rapid touring. I suppose track work would be a lot different.

 

[Gixerboy]

Thanks Barrie, going to order them on Monday, I've been quoted £1090 all in fitted & balanced..
(deep breath) but the car deserves it!
( This car will be a good buy for someone if I ever decided to sell..

Dave

 

[BJL]

Not a bad price. My local tyre company who do all ours quotes £235 for the fronts and £270 for the rears so not much in it.

 

[BJL]

Fitted but not balanced I should have added as I do my own on the Hoffman I bought a while back. Anyone who wants theirs wheels balanced to 1/2 a gram just pop on down.

 

[Gixerboy]

So, after a bit more research, I have just replaced all 4 with Bridgestone Potenza S001s AMR
Went for
Front 245/40 20 99Y
Rear 295 / 35 20 105Y

These have a rim protector ridge on the sidewalls which means scraped wheels will become a dim & distant memory..
As suggested by BJL the rear camber has been set to max neg (which to achieve the same on the concentric bolts gave -2degrees). The Fronts are now at -1.4 with a toe in of 2.40mm.
Car feels more compliant & less prone to bump steer.

Excellent & can recommend to the change ton fellow QP & GT owners!

Dave

 

[TridentTested]

These have a rim protector ridge on the sidewalls which means scraped wheels will become a dim & distant memory.

That would be nice.

Let us know if it works.

 

[BJL]

Glad it works for you..we can compare notes at the next Ace meet.
Can't do this one as I'm away.
Thanks for the update report.

 

[Brainsick]

I just went with the Falkens for the fronts on my QP based upon a recommendation from Migliore. About to finish our 2000 Km jaunt through Europe and am more than happy with them. There are some relatively new P Zeros on the back that didn't need replacing before the trip, but may be getting on a bit now after a few high speed runs down the autobahn and the extra mileage.

One interesting thing to note is the when compared to the GPS my speedo is optimistic by about 3.5% at 150 Kph. I suppose it will help me avoid any speeding tickets.

 

[zoros]

Try this for size:

http://www.kouki.co.uk/utilities/visual-tyre-size-calculator

The visual tyre size calculator is on the right.

Z

 

[justhb]

Hi everybody,

Has anybody got any reviews on the Kumho tyres? I know that I am probably going to be seen as a bit tight, but as I can get them for about £150 a corner instead of up to £350 for Michelin sports, added to the fact that the car is only used in the dry and occasionally, it does seem a better deal.

Thanks

J

 

[Parisien]

http://www.tyrereviews.co.uk/Tyre/Kumho/

P

 

[zoros]

Hi everybody,

Has anybody got any reviews on the Kumho tyres? I know that I am probably going to be seen as a bit tight, but as I can get them for about £150 a corner instead of up to £350 for Michelin sports, added to the fact that the car is only used in the dry and occasionally, it does seem a better deal.

Thanks

J

JustHB: There is an enormous amount of ignorance and snobbery attached to tyre choice. Most drivers haven't a clue what tyre performance does or doesn't do for them, they just want to be seen with the "right tyres" on their car.
If you 'track race" your car, or drive it ******* A roads through the Alps for instance, you will notice the difference - most definitely. But if, like 90% of joe average, you drive (normally) around British main roads then as long as you stick to the OEM standards (for insurance reasons mainly), you won't go far wrong.
Some turn this product into a science and some retailers have attuned to this - thus making a big fuss of the more profitable ones. [They drone on about hardness/road noise/assymetry, etc].
Go to the cheapest tyre web site, type in the OEM requirements and then stick with the household names: Michelin/Vreds/Dunlop/Kuhmo; etc etc....Nobody is going to stop and stare at your tyre walls and snigger!!! The only half decent (bolt on) might be a protective raised rim to look after those occasional close parking manouevres by the kerb . Spend your savings on a decent alignment and balance.

Start altering the rolling radius and this is where you could come unstuck. If you drift too far from the correct rolling radius, thus imposing a 'delta' between what your indicated speed is and what you are actually doing, then you will have to constantly remind yourself by comparing your GPS speed with your speedo to stay within the law! Tyre wall specifications are also noticeable when you change them. If your suspension settings are already 'hard' or sport mode, a lower ratio tyre wall aspect (say a drop from 35% to 30%) is very noticeable and the journey will remind you how hard too! You might even notice that you can't even get your jack under the **** car!

Nitrogen: As a medium, is another market 'con'. A lot of retailer garages 'sell' it for £1 per wheel!!! The ONLY benefit that joe average will "see" is that if the day is very hot or very cold, or the car is driven hard and the tyres get 'warm'; then tyre pressure will more or less stay constant with nitrogen in it. Plain old air in the tyres allow the tyre pressure to fluctuate with the changing environment.

I've done a significant amount of track day driving over the years. We still do 'workshops' with various experts from various areas in the motoring fraternity - one of the better presentations recently was from a tyre manufacturer (won't mention their name) - who enlightened us!
I used to trackday my M3 with Kuhmo 39's on it and they stood up very well to harsh treatment compared to the 'best' the market could buy...on other cars tracking with me. As I said, it's mainly snobbery or ignorance.

 

[justhb]

Hi Zorros,
That is probably the most reasoned and sensible advice possible. I tend to agree with you and just wanted to check that my quietly held opinion was right. It is all too easy to get wrapped up in hype and spend huge amounts of money on something that is not necessary - I would note that the car itself could be a case in point !!! Hey, life is short but tyres are not where I will waste money! All I can save will go towards the impending clutch change. Thanks
J

 

[drewf]

I've mentioned before that Bridgestone in Poland are a client. Less than 50% of the tyres leaving that factory say Bridgestone on the sidewall.

I've used Kumho on another car, and they were excellent.

 

[CatmanV2]

I've mentioned before that Bridgestone in Poland are a client. Less than 50% of the tyres leaving that factory say Bridgestone on the sidewall.

I've used Kumho on another car, and they were excellent.

Nearly completely agree. I did have some tyres on my 156 once that were really bloody awful, but they weren't a well known brand.

C