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The car mechanic reduced the tyre pressure, and the car became grippier in the wet !

Here is the longer verson. My Subaru Outback has a placard saying the tyre pressure is supposed to be 28/29 PSI, and the speed rating should be at least "S". I run my current tyres Dunlop LM703 (H speed) at a pressure of 36 PSI (cold). I found the car got responsive handling just like a passenger car.

I took my car for service, and the car mechanic reduced the pressure to what I estimate to be 32 PSI. The car started to wallow around the corners, and lost the crisp handling. However, I noticed that it became noticeably grippier when cornering in the wet weather ! And the squeal threshold moved by maybe 5 km/h up.

This is surprising to me as I experimented with the pressure 34 PSI, and I found the car got a worse grip when cornering in dry. I thought: "That's understandable. All articles advise to increase pressure in order to increase the tyre's grip, so that the tyre does not excessively deform and hold the whole ptach pressed against the road". I bumped the pressure back.

However, I think this was why the reducing of the pressure increased the grip. As was already mentioned on this thread, cornering changes the geometry of the car. The wheels tend to ride on the tyres' edges instead of on the whole surface. Deflating the tyre helps to align the contact patch better in parallel to the road.

valerian wrote: P.S. I wrote an email to Yokohama Australia and received a reply that they had no plans of importing G055 into Australia. He said even if this happened the tyres would not arrive this year. Oh well, maybe we could get the gray import...

Well, what do you know... the Yokohama Geolandar SUV G055 is now sold in Australia by Bob Jane,
http://webcache.googleusercontent.com/s ... clnk&gl=au
(That's 215/70R16 for $219.)

That's performance summer SUV tyre, 100% on tar. It is an "eco" variety, so that I am not sure...

Today I went to Bob Jane, and got quoted $180 for the Yokohama Geolandar SUV G055 tyre in the size 205/70R15. The sales rep showed me the tyre of a different size 215/60R16.

The sidewall is firm as is supposed to be in an H-speed tyre, or maybe slightly less firm. The tread seems to be made of many small blocks. The rubber is rather soft. The tread blocks are squirmy, especially the middle rib. The shoulders have much more rubber on them than a passenger tyre. The UTQG rating is 600, traction is B and temperature is A. Made in Thailand. The tyre does not have an appearance of a high build quality product.

My conclusion is that the tyre will understeer when cornering due to squirmy blocks. More than I am prepared to tolerate. It will probably feel at home on dusty unsealed road. They had to put lots of sipes and edges probably because the rubber is not grippy ("B traction"). The EU Tyre Labelis C for wet grip, which is a middle of the road. The wet grip probably drops after the tyre is partially worn.

About Yokohama Geolandar SUV G055. The Australian Yokohama website is dismal. They say the tyre is quiet and long-wearing, and is suitable for strapped on cash parents. Clearly an attempt to appeal to a segment of the market by the "marketologist" from the same segment. The website says nothing about the performance of the tyres.

So that I had to take it into my hands, and found a Japanese review:

Really, I was surprised to see the article in comparison with GEOLANDAR H / T ー S which was revealed after the test drive. Maneuverability and stability in dry road pylon slalom measure the improvement in the near 10%, 2% improvement in lap times of wet course. As also previously presented braking performance. Has improved dry, wet, snow, and ice, with all surfaces.

This, yet they coexist firm "and 16% decrease rolling resistance." In the Freelander also have tried dry roads, not to grip any anxiety. From said grip is better than H / TS would also dry road off-road, it's true as long as you do not bring in mud terrain, and surpasses the H / TS in most performance.

In other words, what the author is saying, in the dry road slalom test ("witches hats"), it took 10% less time to finish it compared to the tyres H/T-S G051. And he says that G055 performs better than G051 in any area.

Highly HIGHLY reccomend Toyo Teo Plus. Grip like shit, and dont squeal with my outback. They are also wearing quite nicely too.

I think they are around the $200 a corner mark.

EDIT: And for a H/T they are INCREDIBLE offroad for sandwork.

Getting close to needing tyres on my Outback again, roughly 25,000kms on my Bridgestone Ecopia EP100's. They still have tread in the middle, but they are almost bald on the edges. I put that down to the number of corners on my way to work on a country road, plus a roundabout and 3kms of urban driving.

Bridgestone is the only tyre place that is convenient for me to leave my car at during the day while Im at work. There is a Goodyear about 15kms away, but I've heard bad things about their wheel alignment machine.

I was thinking about the Turanza ER300, but I really dont want to be replacing them next year if they wear as quick as the Ecopias did

Davidov wrote:Highly HIGHLY reccomend Toyo Teo Plus. Grip like shit, and dont squeal with my outback. They are also wearing quite nicely too.

I think they are around the $200 a corner mark.

EDIT: And for a H/T they are INCREDIBLE offroad for sandwork.

yes, got these in 235/45/17 on my passat.

inceridibly smooth and quiet

alex

Davidov wrote:Highly HIGHLY reccomend Toyo Teo Plus. Grip like shit, and dont squeal with my outback. They are also wearing quite nicely too.

I think they are around the $200 a corner mark.

EDIT: And for a H/T they are INCREDIBLE offroad for sandwork.

+1 i have them on forester have had them on for 35,000ks so far and have been very grippy, quiet, and looking like i will get 50-60ks from them and i am fairly harsh

Davidov wrote:Highly HIGHLY reccomend Toyo Teo Plus. Grip like shit, and dont squeal with my outback.

Do they squeal when you are pushing them to the limit of grip, e.g. around corners ?

valerian wrote:Do they squeal when you are pushing them to the limit of grip, e.g. around corners ?

Why should that be a defining factor? They squeel very very quietly.

I had marangonis on my liberty and they out handled my current pirellis but they squeeled loudly when pushing hard.

Teos are very quiet, very smooth and pretty precise. Bloody brilliant tyre.

Sent from my Motorola RAZR HD

The new tyres to consider:

Bridgestone Ecopia EP850
General Grabber GT

Alex wrote:Teos are very quiet, very smooth and pretty precise. Bloody brilliant tyre.

I checked via carsales.com.au -- the Toyo Teo Plus appeared in my size. However, I got Michelin XM2 (and it is coming to an end of its life now).

I read a comment somewhere that if the price for Toyo and Michelin is the same, then one should get Michelin, as it is much better.

I have Bridgestone Turanza Serenity Plus on the Forester and I'm really happy with them

Bridgestone Turanza Serenity Plus looks like a good tyre, however it is not available in the SUV size for me.

I'd be wary of Bridgestone. Lots of people get them & say how grippy they are, but then dont notice them slowly lose grip as the rubber hardens. All tyres harden with use & age but Crapstone tend to do it more than any other tyre. Its a very sneaky ploy they have to "wow" people with their grip when they first get them, but to harden up significantly to give good tread life, which they are known for.

Remember, its a choice... good grip OR good wear. You cant have both!

valerian wrote: I got Michelin XM2 (and it is coming to an end of its life now).

About a year has passed since that comment, but my XM2 tyres are still coming to an end of their life . It looks like I will be getting 5k km more thus bringing the mileage to 60k km. And, what's more, the tyres keep a good wet grip and a low noise. I am impressed, and I am now a Michelin believer

An update. I got another set of the Michelin XM2 tyres. The old ones have done 56k km, and I could probably keep them until 60k km. What I noticed, though, is that they easily pick up nails. Over 2 years, I had two puncture repairs. My previous tyres Dunlop LM703 were hard, and I never had problem with punctures from nails, including driving on rocky country roads. The Michelin tyres have a soft compound, and they are designed to enswathe the small features on the road which gives them their superior grip. But this makes easy for the nail to get into tyre, too. A few days ago, I discovered two small nails in one tyre, and another tyre was getting bold at the edge.. so that I decided to get the new tyres now.

Costco was selling the tyres at $20 below RRP, and they gave a discount of $70 from the set of 4. I asked the local Bob Jane to match the price. After installing I discovered that they did not provide free lifetime balancing and rotation like Costco did. I am not going to them anymore... in fact, this was what I told myself 6 years ago.