Yokohama AVS ES100's on 930/911 - Tail Happy?

[jrl]

Last week I replaced the rear (only) SO3's on my '86 930 with Yokohama AVS ES100's; fronts are still SO3's (stock f/r 16" Fuchs). It felt like the car was immediately more tail happy / wiggly on the new tires (I'm a pretty conservative driver who takes a corner fast when the opportunity arises.)

I increased rear tire pressure a few pounds, which seemed to help a small bit. Is the 930/911 that sensitive to tires, or am I just imagining things with these new ones? Grip is very good with the AVS's.

Thanks,
John

[fintstone]

New tires will do that sometimes...it usually goes away after a few hundred miles.

[450knotOffice]

Yep. I've only run S03's on my car and when I replaced the worn out rears with new ones (still S03's, btw) my car was really nervous in back for a few hundred miles. Mine needed to be scrubbed in. It'll get better for you soon enough.

[DARISC]

Yep - same slipperiness for a while when I put them on my SC.

I've heard comments that perhaps this particular tire is manufactured using an excessive ammount of mold release that doesn't get cleaned off the tread before going to market.

I dunno, but after not too many miles mine stick quite well. I'll be buying another set when these wear out.

[sfoster13]

I've found that at the track my ES 100's are very sensitive to tire pressure. If I run above 38/39 (hot) in the rears things get very interesting.

[PorscheGuy79]

Whoa, Whoa, Whoa, Whoa, Whoa...

If I understand what you are saying, the front 2 tires are S03s and the rears are ES100s? That would be causing your issue right there. The ES100 isnt really that great of a performance tire, where the S03s are one of the best (this is based on observations and conversations with local track guys who have run ES100s). I think your tail happy nature has a combination to do with the fact that they are new but mostly that the front and rear tires are different, they have different grip levels. This could be very dangerous based on my assumption that an ES100 tire will lose traction before a SO3, hence the back end will swing out every-time.

My advice would be to match the front and rear wheels, but you can let others chime in.

[nostatic]

I wouldn't mix-and-match two tires with very different performance levels like that...at least not on a car I was going to drive hard.

Right now I have RA-1s on the rear and Yoko AO48s on the front of my car, and I think the car is a tad unsettled at the limits (on the track)...and those are both R-compound tires. Only reason I did it was that I couldn't find a matched set in either tire at the time.

[PorscheGuy79]

Check out how they stack up on Tire Rack...they are very different tires with very different dry traction levels.

The AVS ES100s

The SO3s

[jrl]

In the process of choosing tires, I noticed that Tire Rack no longer shows the SO3's for the 930 with 16" wheels. What are its nearest alternates?

[PorscheGuy79]

I use Kuhmo MXs and they seem to work preatty close to my fathers S03s, but im not sure if they come in 930 widths.

If you have 9s in the rear I think you can use 245s, which I believe the S03s come in...Oops no just looked, they dont show 245s, im not sure if that means you cant get them cause I swear they come in 245s. Maybe someone will chime in on a place other than Tire Rack to get 245 S03s...

Good luck jrl, im bored at work and will try and look at some other sites for them.

BTW its not that you cant run the ES100s, just buy a matching front set would be my suggestions. Or try and find some S03s laying around. Or if you really wanna spend the cash move up to 17s and they have great tire selection.

[Emission]

I mixed tires on my 930... and it was a nightmare. I ended up buying new fronts to bring back the "neutral" handling ("neutral" isn't the correct word for a 930, but you get what I mean).

[robhamster]

I have the Yoko AVS all around on my '84. They handle better than the Bridgestones and Pirelli's I have tried in the past and seem to be lasting longer.

[Nine9six]

Originally posted by PorscheGuy79
Whoa, Whoa, Whoa, Whoa, Whoa...

If I understand what you are saying, the front 2 tires are S03s and the rears are ES100s? That would be causing your issue right there. The ES100 isnt really that great of a performance tire, where the S03s are one of the best (this is based on observations and conversations with local track guys who have run ES100s). I think your tail happy nature has a combination to do with the fact that they are new but mostly that the front and rear tires are different, they have different grip levels. This could be very dangerous based on my assumption that an ES100 tire will lose traction before a SO3, hence the back end will swing out every-time.

My advice would be to match the front and rear wheels, but you can let others chime in.

Hmmm, now there's a thought.
I may not go as far as to say that "is" the reason for the issue.
I would say, it certainly "could" be some, or part of the reason for the issue.

[SLO-BOB]

I think the young Jedi is correct. I have had ES100s on my car and like them. BUT-I wouldn't mix them the way you have. Sounds like a disaster in the making. At this point I would get some ES100s for the front to bablance things out.

That said, new tires always seems squirmy to me on our tail happy cars.

[dentist90]

JRL (John)
Ditto on your experience with Yoko ES100 on rear. I got my car with new ES100s on front and very bald Yoko 520 on rear (tire out of production now). Made total sense to go ES100 all around. The day I drove my car home from the tire shop... what a difference (not good)! Wasn't a lack of grip, but more like body sway. Car had an extra little wiggle when you finished a sharp turn (or slalom move). The tires were no where near the limits of their traction. This happened immediately after changeover. I appreciate that I went from 'slicks' to full tread depth so there will be a little more tread squirm, but I think it is in the sidewall construction. When parked I give the car a firm side-side push and the only thing flexing is the tire sidewalls. Bearings, sway bar bushings, everything in the suspension is tight. Hopefully the tires will improve as they wear. Stock sizes on car: 205/55/16 and 225/50/16. I have these tires on my Talon (215/50/17) and they are fantastic, but 17" rims make a difference too.

[PorscheGuy79]

Thats the big bummer about 16s, a little lackluster on the sidewall support. Sometime in the future I would like to move up to 17s...

[bmgmd]

jrl-

As a comment to PorscheGuy79's reply:

I don't know what size rears you have but if you have the 245/45s, it is one of the few ES100s with steel sidewall inserts.

Check out the pdf from Yokohama's website:

http://www.yokohamatire.com/pdf/avses100.pdf

It's shown on the second page with the Part No. starred referring to the steel inserts.

If you have something else, it may not have the added support.

Brian

[PorscheGuy79]

Very interesting, I didn't know they had a steel insert.

The sidewall comment was more about the better compounds and technologies available in larger wheels sizes because performance 16" tire choices are not common anymore.

[jrl]

dentist90 -

You described my experience exactly--the tail wiggles around as if the sidewalls are flexing. Very noticeable even twitching the steering wheel on a straight highway. Grip is actually very good in hard turns, but as you said, there's always that extra wiggle on exit. The old SO3's had maybe 1/16" tread left.

My tire size is 245/45 16; front is 205/55 16, stock 7"/9" Fuchs. Agree fully that significantly mismatched tires on a 911 could be a disaster at the limit, but this is happening under more benign conditions.

[bmgmd]

Matthew-

You are absolutely correct. In about 5-10 years, the only choices we'll have are snow tires and all-seasons!