[19bwb67]

I know you hard core guys are not running much stock stuff on these cars. <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" /> Does anyone have any experience or advice for us 16 in rim guys? Is there any advantage be seen on 16 in rims by going to 225/50 r16 fronts and 245/45 r16 rears. Are there any other configs people like? What are the trade offs. I usually assume Porsche went through the trouble of finding the perfect combos for each car. Thanks

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[Greimann]

There should be no issue with bumping the size a bit. They will help fill out the fenders. Porsche also offered optional 17's on the 968 and put 18's on the turbos. The target of each option package was to meet different needs for performance.



Look at it this way, 16's was once state of the art and people went, and do, go very fast on 16's. The type and brand of tire has more to do with the handling than the wheel diameter.

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[flash]

yeah - the biggest difference in handling that happens when you go to a bigger diameter is that you also generally simultaneously decrease profile and increase width - that give less flex and a larger contact patch area which makes for tighter handling



the downside is that you lose a small amount of the cush of the ride because the lower the profile, the firmer the tire

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[bbranch]

I just (tonight) got a set of Toyo T1S tires at the larger size. I figured that moving to the lower ratio tires meant lower profiles and therefore less flex without the expense of 17" wheels which I can't afford right now. I know I am not getting all the advantage of a 17" wheel, but I thought I'd give the 245/45/15, 225/50/16 sizes a try.

Impression driving home - I'm not sure if its the tire sizes, the tire brand, or just that they are new (I hope its because they are new), the tires cause the car to have more action, seems to be moving/floating around more and seem to drift through corners. For comparision I have driven on Yoko AVS Sports, which I thought were great, but didn't hold up enough for a daily driver, when I last replaced the tires I got Bridgestone RE750s, which I thought were great. A nice compromise between grip and handling (they performed really well) and treadwear life.

I live in area dominated by Les Schwab, and I can say I have always gotten excellent service from them (I can give you some nice stories if you want - off topic). They push the Toyos, hence why they are now on my car. When I bought the 750s I made them get them for me even though they don't normally carry them :-)



Slight hijack of the thread, but related since I also am trying the size the original poster was asking about, and might also e interested in this question/answer - Anyone have any feedback on Toyo T1S? Did I make a mistake? Should I go back to the Bridgestones? (I have about a week to take 'em back - Les Schwab offers a satisifaction guarantee). Or should I wait until tomorrow and let them "break in"?

:-)



-Brett

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[BruceWard]

Different tires need different pressures to be tuned in. I suggest that you try adding and removing pressure from the tires until they feel right to you.



For the street I have more pressure in the rear than in the front which provides understeer. For autocross I run with more pressure in the front to provide oversteer.



I would start by adding two to three psi to both the front and rear with two to three psi less in the rear than the front. See if that feels better, if so add a little more, if not perhaps drop a few psi and see if that is better.



I was surprised that the new P Zero Neros that we installed on the Jetta did not bite until 39 to 40 PSI. The old Goodyears were best around 36.

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[968Z]

bbranch - I'm sure you have already done this, but verify that the correct size tires were put on your car. About a year ago I had new stock tires put on my 16" rims. I noticed fairly quickly that the ride was much softer and it tracked poorly thru corners. At one point, I had my father in the car and he commented how surprised he was that a sports car rode as soft and smooth as his '88 420 SEL. I didn't even think to look at the actual tires sizes; I assumed the shop had installed the correct sizes. As it turned out, they installed the 225/50s on the front, and a completely wrong size on the rear. After new tires were installed correctly, everything was fine, and handling was restored.

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[Greimann]

Also, new tires do need time to scrub in. Give it at least a hundred miles before you make the final determination.

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[bbranch]

I'm at 65 miles on them so far, and they still feel loose. For points above:

- Les Schwab put the tires at 40psi, max is 44. Since it still feels soft, I would think an increase, rather then a decrease in pressure would be in order, except that I'm only 4lbs from max already...?

- It does have 225/50/16s on the front, as opposed to the "correct" size since I wanted to go wider/lower then stock thinking it would give better stablity. Despite the tires larger size, OD went from 24.9 to 24.8, a mere tenth of an inch, but in the right direction. I figure a decrease in sidewall height should make the ride firmer, not softer. It has 245/45/16s in the rear. This is what 19bwb67 was originally asking about as well.



This morning when I got out of the car at work after driving the winding-over-the-mountian route to work and not liking the feel of the tires, on a whim I rocked the car by pushing on the roof. I could see action in the tires by doing that. With the Bridgestones you would get a little movement on the suspension (our cars are fairly firm) but I don't recall any tire movement/action from a slight hand rocking. I don't know if 1) it could be cured by running the tires at max pressure, 2) it is due to the larger tire size, even if sidewall is decreased (this doesn't make sense to me though - the rim widths are actually what is recommended for these larger tire sizes, so I don't think they should be introducing flex), or 3) Toyo Proxes T1S have weak sidewalls and suck.



I am 80% inclined, since I don't like inconvieniencing the tire guys too much and keep playing with tire sizes, to eliminate both variables and go back to the Bridgestones at the stock sizes. Thoughts?

(anyone have 17" CupIIs in nice shape for sale cheap? <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> )

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[flash]

it is likely that you have hit it with "c" - tires have different sidewall stiffness, and the bridgestone is a stiff one - the toyo may indeed be soft



you can call chris young at toyo at 714-236-2080 ext 2298 - he's the marketing support manager and will probably have the answer for you - i ran into him at a car show i was judging - very cool guy



the later 17" rims are CUP and not CUP 2s, as they have commonly been incorrectly referred to(i got dinged for that recently on rennlist),



i don;t have those, but i do have a very clean replica set of the earlier 17s (which are C2 Turbo and not CUP 1, as they are also commonly incorrectly referred to) - they already have S0-3s on them - pics, description and tread details are available here:



http://www.968forums.com/index.php?showtopic=398

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[bbranch]

The rims I want, whichever they are called, are these, in original finish:

http://mall.rennlist.com/scripts/featured/...query=retrieval

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[flash]

yeah - those are the Cup rims - good choice - very light for a stock cast rim - pretty tough to find in decent shape though - good luck

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[Bart]

bbranch-

The wheels you listed in your post are now for sale on ebay.



http://cgi.ebay.com/ebaymotors/ws/eBayISAP...sspagename=WDVW



They are the 993 widths. I'm not sure what differences there maybe in offset. The tires that are mounted run around $850 a set from tire rack.



Good luck!

Bart

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[bbranch]

hence why I am currently buying 16" tires <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

thanks for the name/phone # of the Toyo guy, I'll give him a call after my next meeting and discuss sidewall stiffness and tire sizes and go from there. Though I suspect he'll push the Toyo tires, and I'm really leaning to going back to Bridgestones.

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[flash]

i went with the S0-3 again - i liked them enough that they are now a sponsor of my car

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[bbranch]

How many miles do you get with the S-03? I didn't think they would last long enough for a daily driver (I put on about 20K miles a year).



For others who may be reading this thread, here's the response from Toyo on my impressions:

The tires sizes I choose, on the rim widths we have, should not be a problem at all. He thinks that the sidewalls should be even stiffer then the RE750s I liked, so he's not sure why it would feel softer. I said I'm not sure softer is the right word actually, just that the car moves around too much on the patch, and feels like it wants to drift out on the corners instead of staying tight, which could be sidewalls giving, or could just be the tire not gripping well. He suggested dropping the tire pressure to 36psi and if that doesn't work, then for sure to return the tires. I'll follow his suggestion and see what the turns are like on my drive home and post again then.

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[flash]

interesting - decreasing pressure should make it looser - hmm - well, no harm no foul - give it a try



as for mileage - i have 15k on the set that is for sale, and i still have 75% on the fronts and 60% on the rears - i do have a non-stock alignment though which gives me better tire wear



realizing that high mileage and best traction are diametrically opposed, choosing something that suits 80% of your driving needs is the best thing you can do



side note - alignment is the single most important thing for handling - make sure you have a good one, which includes correct ride height - without a good alignment, you may be chasing the wrong problem, and the old tires may just have worn such that now with the new tires the problem shows up

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[Jim Child]

I run Toyo T1-S tires on my '92 968 and like them a lot, so much so, that I'll buy another set when these wear out. They certainly don't suck. Mine are 235/40/17's front and 255/40/17's rear, so they're not directly comparable to your 16's. First of all you need to drive them enough to scrub them in a bit before you make any judgments. New tires will always feel a bit strange when they're brand new until the slick, shiny surface is scrubbed off. Second, you need to make sure you're running the right pressures. I run 35 psi cold all around in my T1-S's. Your tires might need an extra pound or two to compensate for the softer sidewalls of the 16's. Anything over 37-38 lbs is almost certainly too high.

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[bbranch]

Thanks Jim, is 65 miles (at least 15 of it through a winding road with agressive driving) too little for the tires to scrub in? I'll try decreasing the pressure, and also see if I can get it in for an alignment within the 500 mile trial period. Unfortunately most of the tire shops with quick turn-around times can't properly align our cars...

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[Jim Child]

[quote name='bbranch' date='Apr 26 2005, 11:47 PM']Thanks Jim, is 65 miles (at least 15 of it through a winding road with agressive driving) too little for the tires to scrub in?[/quote]



Maybe. Look closely at the tires and run your hand over them. Do they look and feel smooth and slick? Or instead, do they look and feel as if they've been lightly scrubbed?

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[19bwb67]

Hi Guys- I got the wider/lower yoko avs es100's and I love them compared to the yoko avs db's. I am still wondering about correct tire pressure. Tire rack said stick w/ manufacturers specs. My mechanic(who used to race-not porsches)-looked at the max pressure on them(44psi) and said to run them at 40psi. His yahoo junior mechanics put 45psi in them - I was pissed- He usually takes good care of me and is very honest, but when I saw them working on my car I wasn't Happy. They were bumbling around like idiots- they bottomed out my car getting on the lift- they almost dropped it off the lift whem backing up for a second try- they put one tire on backwards-they put a back tire on the front-etc- anyway... when test driving (at 45psi) it seem to get loose/greasy around corners- no surprise there considering!! I dropped them down to 37psi and they bite much better. I was hoping to get a consenus on tire pressure for the yokoavs es100's- Hearing from Bruce would be great as I think he is running the exact tires and config.

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