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Old 01-22-2009, 03:47 PM   #1
thereplacement
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Default To shave or not to shave? Direzza Star Specs for auto-x (STX) and street use

Let me preface this by saying I've never bought new performance tires for my car, I ran some used r-comps in the past that were already well broken in. I'm planning on getting a set of the Z1 star specs (235/40/17) primarily for running local events in STX this year. I'm looking for recommendations on whether or not to get them shaved, along with anything else I should or shouldn't do.

While it would be really nice to use these as my primary street tires throughout the entire summer I did run r-comps before so I'm used to changing tires at every event and I'm not opposed to it if there are some real benefits. What benefits could you expect by shaving them and conserving them purely for autocross and maybe driving to/from events; would you get more "competitive auto-x miles" out of them shaved than not, would it potentially take seconds/tenths/hundreths off your times? (I realize this differs by the individual, but in general...) If I use these for daily driving for 6 months or so (maybe 7k miles) is shaving them out of the question?

If anyone has used these tires, either shaved or not, let me know what experience you had with them, how long did they last (street miles and/or auto-x/HDPE events), and if they weren't shaved did you have any "chunking" issues when racing on them. Opinions?
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Old 01-22-2009, 04:07 PM   #2
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What benefits could you expect by shaving them and conserving them purely for autocross and maybe driving to/from events; would you get more "competitive auto-x miles" out of them shaved than not,
Shaved tires in rain... not a good idea.

--kC
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Old 01-22-2009, 04:44 PM   #3
jamesohoh7
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I've had a set on my car since like Sept. '08. Unshaved. They sort of chunked up a bit when new and so on, but have 'stabilized' since.

I would say I daily drive on them, b/c they've been on the car constantly since October'ish, but I don't daily drive the STi that much. I did daily-drive it a lot in Oct-Nov though.

I probably have ... 7 events on 'em?.. maybe 8. Still lots of useful life, though the grip is not quite what it was when new.

I'm cheap though, and never shave tires. I know the conventional wisdom says 'shave them', but I hate the thought of tossing that good rubber in the trash. Goofy, for sure... but oh well.



Cliffs: my z1-ss's were never shaved, and seem to have lasted quite well.
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Old 01-22-2009, 04:50 PM   #4
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I would recommend you get them at full tread.

I ran 1 set of full treads from April last year-September. Auto-x only. They were my rains and drys.......... and I think their ability to perform is well documented.

You should only use them for auto-x as Dunlops have some funky wear characteristics. Which is magnified when they are full tread. I never experienced chunking, overheating, yes.

You would probably only get 15-20K out of them DD, add the abuse of auto-x and that would quickly degrade.


Don't shave and rotate front to back every event.

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Old 01-24-2009, 03:44 PM   #5
thereplacement
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Well it's looking like leaving full tread is the way to go. Not too sure about how much I'll street them though, on one hand I'd be happy to get one year of a dozen or so auto-x's plus a few thousand street miles, though if I could get more than just one season that would be nice.

Mccannix, how much life was left in them after a season of autocross?
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Old 01-24-2009, 04:39 PM   #6
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Originally Posted by thereplacement View Post
Mccannix, how much life was left in them after a season of autocross?
Possibly another season of auto-x. They were around 5-7/32 at the end of the year. The wear is strange though.
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Old 01-24-2009, 08:09 PM   #7
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I suggest a light shave to 7/32 on a WRX. Your tires will wear more evenly if shaved. Uneven, accelerated wear for the first few events is a result from the tall tread blocks deforming under high loads.

On a BMW, or with wider sizes and lower profiles, I would say go full tread. But FWD and AWD will overload the relatively narrow tires.

I'm on my 5th set and noticed it more on 245/45s, compared to 245/40s.

Rick
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Old 01-24-2009, 08:18 PM   #8
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PSM Bugeye in cleveland! YA!!!!!
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Old 01-24-2009, 08:18 PM   #9
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I ran mine full tread last year, roughly 25 events plus 10-15K road miles before they died in November. I wouldn't bother with shaving them.
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Old 01-24-2009, 09:37 PM   #10
thereplacement
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Based on the mileage/use mccanixx and wagonan have mentioned I'm sure I could stretch these out over a couple of seasons, I'm not out every weekend, and would be limiting street miles.

Quote:
Originally Posted by Evoracer View Post
I suggest a light shave to 7/32 on a WRX. Your tires will wear more evenly if shaved. Uneven, accelerated wear for the first few events is a result from the tall tread blocks deforming under high loads.
Out of curiosity I'm gonna check with tirerack on how much a shave to 7/32 goes for, I trust info from someone on their 5th set!... though you've got to be going back to the previous version of the direzzas with that many sets, right?, not sure how much different the Z1's are from the previous but I thought these just came out last year.

The wet performance after shaving concerns me a bit, but it's not like these are like r-comps where entire tread is shaved away.




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PSM Bugeye in cleveland! YA!!!!!
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Old 01-24-2009, 11:23 PM   #11
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Quote:
Originally Posted by mccanixx View Post
Possibly another season of auto-x. They were around 5-7/32 at the end of the year. The wear is strange though.
There are a couple considerations here; surface and number of drivers. I'm not sure what Greg usually runs on, and I'm assuming he's usually driving by himself.

For me, I normally run on fairly grippy concrete and I was running another driver for most of last season. Starting with full tread back in May and flipping front to back every event, I'm guessing my tires will be toast by the time the first 3 events of this season are done (again 2 drivers)

Still though, that's pretty decent wear considering the circumstances.
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Old 01-25-2009, 01:38 AM   #12
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Several people have commented on Dunlops having "funky wear". What exactly does this mean?
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Old 01-25-2009, 09:32 AM   #13
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It's nothing bad, but the edges of the tread blocks will get this crazy lip on them on the inside edge. Best I can tell it's from the tread block pressing over during cornering, which wears the outside edge and top but leaves inside edge. After competition you've then got this thin lip that sticks up from the tread block on the inside edge. If you're using them for street duty also, they should wear themselves even pretty quickly I'd think.
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Old 01-25-2009, 09:57 AM   #14
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It was hard to tell with mine, my alignment decided to become dynamic about half way through the year, so the toe was off. The comments about full tread blistering is true, at least at first. It does seem to settle down after a couple events, and if sprayed, it does stay in check.

Our first events are always on cool/cold days, so the blistering is kept to a minimum.
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Old 01-25-2009, 01:52 PM   #15
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Quote:
Originally Posted by Evoracer View Post
I suggest a light shave to 7/32 on a WRX. Your tires will wear more evenly if shaved. Uneven, accelerated wear for the first few events is a result from the tall tread blocks deforming under high loads.

On a BMW, or with wider sizes and lower profiles, I would say go full tread. But FWD and AWD will overload the relatively narrow tires.

I'm on my 5th set and noticed it more on 245/45s, compared to 245/40s.

Rick
Good advice from 1 fast racer =)
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Old 01-25-2009, 04:39 PM   #16
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Originally Posted by williaty View Post
Several people have commented on Dunlops having "funky wear". What exactly does this mean?
They really don't wear much different than any tire with a tall tread block. If the tire is overdriven it wears like Aaron mentioned. With a light shave you will get better intail wear.

Unless there is deep standing water, I use the shaved tires in wet AX conditions.

Quote:
The comments about full tread blistering is true, at least at first. It does seem to settle down after a couple events, and if sprayed, it does stay in check.
The tread does not blister, a lot of us ran Dunlops at the Wendover ProSolo in 100+deg consecutive runs with good results. Blistering happens on overheated race slick tires.

Last edited by Evoracer; 01-25-2009 at 04:48 PM.
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Old 01-25-2009, 09:52 PM   #17
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Originally Posted by Evoracer View Post
The tread does not blister, a lot of us ran Dunlops at the Wendover ProSolo in 100+deg consecutive runs with good results. Blistering happens on overheated race slick tires.
Good point my friend
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Old 01-26-2009, 09:33 AM   #18
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I bought a set last September for track use as my Victoracers were getting old and I was concerned they would cord before the events were done. I used them for 11 sessions over three days at NHMS and Pocono, with 6 of those sessions being pretty mellow (four were done by my codriving wife). The other five sessions were pushed hard until I swapped over to the Victoracers. Left them full tread, I saw no chunking at all. They did get a bit loose when they got overworked but otherwise they were predictable and seem to have worn well.

Still much slower than old Victoracers that I pulled out of the basement.
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Old 03-03-2009, 12:59 PM   #19
thereplacement
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I'll be ordering soon and I'm prob gonna go with the light shave to 7/32 as suggested.

I do plan on driving these at least to/from events, any ideas on how they'll hold up to say 2500 street miles mixed in with 10-15 ax's (say 100ish total runs)? if I can go with a light shave and still get this I'd be very happy (of course no streeting once below 2/32's).
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Old 03-03-2009, 01:08 PM   #20
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Here's a pic of my buddies shaved direzza, next to a full-tread one. both are the same size tire, even though they look different in the pic. the shaved looks much squarer. He'll be testing them out this weekend at the track(not autox) on his m3.

http://img.photobucket.com/albums/v2...R34/tires2.jpg
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Old 03-03-2009, 01:50 PM   #21
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out of curiosity.. what kind of tire temps are you guys seeing in AutoX? and could the funky tread wear be from running too low of a pressure to generate more heat? or too much which induced wheel spin?
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Old 03-03-2009, 01:55 PM   #22
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Originally Posted by thereplacement View Post
I do plan on driving these at least to/from events, any ideas on how they'll hold up to say 2500 street miles mixed in with 10-15 ax's (say 100ish total runs)? if I can go with a light shave and still get this I'd be very happy (of course no streeting once below 2/32's).
You'll be fine driving to the event, autocrossing and driving back. But why not do what the rest of us idiots do, arrive early, wrench, autox, bitch, wrench, drive home.

Don't fool yourself. If these really are your dailys don't shave 'em.

Last edited by 68Cadillac; 03-03-2009 at 02:28 PM.
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Old 03-03-2009, 02:14 PM   #23
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You'll be fine driving to the event, autocrossing and driving back. But why not do what the rest of us idiots do, arrive early, wrench, autox, bitch, wrench, drive home.
Speak for yourself. Arrive at an OK time. Back car off trailer. Autox. Drive car on trailer. Drive home.

--kC
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Old 03-03-2009, 02:16 PM   #24
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Or do like me: Arrive at what you think is an ok time but is actually later than everyone else, end up with a work shift that is late in the day and miss out on fun runs, bitch, drive home.
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Old 03-03-2009, 02:29 PM   #25
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Speak for yourself. Arrive at an OK time. Back car off trailer. Autox. Drive car on trailer. Drive home.
[napoleon dynamite]Lucky![/napoleon dynamite]
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