BFG KDW's vs Dunlop Direzzas vs something else

[phucheneh]

I had a thread about a turbo'd Lexus I was messing with.

Long story short...this car is the source of my current stance of 'yes, you CAN have too much power.'

This is not my car, but my name's kinda on it, so to speak. I've been quite involved in its resurrection and was definitely involved in wrecking it slightly (I'm gonna...not go into depth on that).

Anyhoo...I'm replacing some bodywork, and trying to look at it as a 'better me than you' type of thing (i.e. this car was destined to wipe out at the drop of a hat and I got very lucky). In addition to making the street tune less aggressive, I am very heartily recommending a wheel/tire change. Current setup is 18" wheels (somewhere in the 8.5-9.5" range) with 255/35 rear, 225/40 front. KDW's.

In addition to the wheels just not really fitting that well (fronts need spacers to clear upgraded brakes)...it desperately needs more traction. I was eyeing the Dunlop DII's mentioned in another thread, but dunno if the rears would really make that much difference.

I'm leaning towards saying 17x8's all around are probably going to be the best best. 9-9.5" wheels are also fine, but not needed. 17" is minimum for brake clearance.

Then a set of 245/45/17's (little more sidewall and a slight decrease in rolling diameter to help front tire clearance). The question then becomes...rear traction...is it possible?

Talking about 5-600whp with batshit insane turbo spool here. I think it needs some kind of track tire on the back. It will be driven on the street, but probably not more than 5k a year, if that.

Thoughts?

...exdeath? What does your satanmobile have on it, again?

 

[jlee]

Exdeath has 315-series Mickey Thompson ET Streets. They hook leikwhoa.

I've also read good things about the Toyo Proxes R888's, hooking up with 700whp Cobras. You definitely need some serious tire...KDW's are not gonna cut it at all. Dunlop Direzza ZII's would likely be way better than what's on there now, but I'd step up to a drag radial (or R compound tire) if you truly want evil amounts of warm-dry-weather-only grip. Though the R888's can be ran in rain, I think, it'd still be useless with that much power.

 

[phucheneh]

He knows as well as me that clutch-side-stepping, front-end-raising traction only leads to broken drivelines. That's the main reason I had previously discouraged sticky tires.

The main concern is being able to hit the gas in third or fourth and not end up in an uncontrollable 720 degree spin (*I did this).

I too think the Direzzas would help. But also that other tires would be a lot better. I've seen the Toyo R888's, and also a comparable Yoko (A048, apparently). Both seem to be geared more toward a sticky, short-wearing track tire than the Dunlops, and way past the KDW's, but I can't find any reviews on them.

Past that, Hankook and Kumho both make an affordable dry-only DOT sticky. Any idea what treadwear on these is like on the street? Gotta at least be able to get 3-5k on them.

And even further, there's front-vs-rear combinations. I can't see putting track tires on the front, as well. The car just doesn't handle well enough to warrant full racing tires on it all the time. It just needs to be able to hook in at least third or higher. Second would be nice. I'm thinking something like the Toyos in the front and a real sticky in the rear.

I'd say DII's in front, but if they can't be rotated it's hard to ask them to get 10k+ miles. Might as well go for the extra stickiness.

 

[jlee]

So build a driveline that won't break.

Can't IS300's cut 1.6 second 60ft times on the stock rear diff? What's the first failure point?

 

[phucheneh]

I'm gonna guess the diff or a CV axle.

That's ignoring the fact that it already has a noisy output shaft bearing and probably needs U-joints. But those are from gradual wear.

If something was gonna snap, I would 100% say rear axle area.

 

[exdeath]

MT ET Street Radial II 315/35/17 #3744R

 

[tcG]

Why get only 8" wide wheels? I say get the widest you can fit and put the meatiest, stickiest summer tires you can.

Suspension changes would help, too.

EDIT: Didn't read whole thread... hmmm.

 

[exdeath]

I wouldn't worry about breaking anything on the street. Streets are covered in dirt and grime not VHT.

 

[cbrsurfr]

Past that, Hankook and Kumho both make an affordable dry-only DOT sticky. Any idea what treadwear on these is like on the street? Gotta at least be able to get 3-5k on them.

I don't believe you'll see 3-6K out of a 30-40 UTQG rated tire. How about Michelin Pilot Sport Cup? 80 UTQG and many reviews have people getting 5K+ out of them. R888's should last within that range as well.

 

[JCH13]

You want more grip to not spin, but less grip to not break drive-line components? edit: I guess you want 'just the right amount' of grip?

Possibly consider some RS3 tires. Stickier than ZIIs I'd bet, not as sticky as the MTs. Maybe the Kumho Ecsta XS is worth considering too.

Switching to an open rear diff might really help with the 'spinning around' situation. What sort of diff is in it now?

other edit: with that much power it wouldn't be a bad idea to go with a staggered setup, i.e. wider tires out back.

 

[phucheneh]

You want more grip to not spin, but less grip to not break drive-line components? edit: I guess you want 'just the right amount' of grip?

I'm saying the desire is 'as much grip as possible,' but that I'm not worried about first gear launches.

The reason for not caring about stagger or >8" wheels is simply that 245's are about the limit. I could probably get a 265-275 under the back if I wanted, but the difference is negligible and it limits options. 255/40 or 245/40 are pretty much what's available.

 

[JCH13]

I'm saying the desire is 'as much grip as possible,' but that I'm not worried about first gear launches.

The reason for not caring about stagger or >8" wheels is simply that 245's are about the limit. I could probably get a 265-275 under the back if I wanted, but the difference is negligible and it limits options. 255/40 or 245/40 are pretty much what's available.

I see.

Obviously you need a set of these. :awe:

But seriously now, the Toyo RA1 or ProxesR888 might work well.

 

[JoLLyRoGer]

I see.

Obviously you need a set of these. :awe:

But seriously now, the Toyo RA1 or ProxesR888 might work well.

HoHo's! Hell Yeah!!

Seriously though, no tire is going to be all things for all conditions. Grip is obviously a priority here for you so Direzza's, Toyo Proxes, Ecsta's, Hankook RS3's are all VERY good street tires that will deliver. (Obvioulsy the Puple Crack is gonna work too in the sticky gumball dept. ).

But.. here is one you might not have considered yet that will cost you considerably less than what has been mentioned.

http://www.nittotire.com/tire/nt05

These are not an all out R-Comp so don't expect them to be.. But they're more than an average street tire too. The treadwear rating is stated as 200. I've got a set I use for AX/Track days and while they are not going to deliver like R6's, (or even some of the fastest "street tires") they do stick very well, wear like iron, can take a fair amount of heat before they get greasy, do OK in the rain for what they are, and are very predictable to drive at the limit. In a word, they're fun, but don't expect to take the podium with them.

For my setup they were also about $40.00 per tire cheaper than RS3's and I'd say for the money they are one of the best bang-for-buck performance tire out there. I really wish Grassroots would pick them up and do another tire shootout because I'd be a lot of people would be surprised.

On an unrelated note: To jlee and exdeath.. Where do you hail from? I'm rep-ing Sierra Vista, AZ myself...

 

[XavierMace]

HoHo's! Hell Yeah!!
On an unrelated note: To jlee and exdeath.. Where do you hail from? I'm rep-ing Sierra Vista, AZ myself...

Phoenix/Tucson. Not that you care, but I'm in Mesa.

Regarding the tires.... The reviews I've read of the R888's have all been extremely positive both in regards to traction and lifespan.

See: http://www.svtperformance.com/forum...-r888-best-rear-tire-ive-ever-used-stuck.html

Why would you want to run 245's up front?

 

[JoLLyRoGer]

....Why would you want to run 245's up front?

He's got a good point... OP, If you're gonna step up to a 9.5" rim why wouldn't you go wider? Say 275's at all four corners?

I say stuff as much tire under the wheel wells that you can possibly fit without rubbing.. I'm probably gonna try and fit 305's all around next time I'm due for new rubber! HA

 

[phucheneh]

Why would you want to run 245's up front?

I dunno. Why not?

I don't get the 'stagger' fascination. If the biggest widely-available rear size you can fit will also fit in the front...why not?

edit: If someone knows of a 17-18" tire size bigger than 245-255 with lots of 'sticky' options, I'm all ears.

Said 245/255's are going to be the limit for the front. Not sure what maximum rear size is...I'm guessing 275-295 would be pushing it. Unfortunately, 'Lexus enthusiasts' don't seem to have done the legwork and figured out a 'standard' for the biggest tires you can shove under one of these. Something like exdeath's Mustang is a little easier to shop for, as I'm sure you can hop on some forums and get info on the optimal width/offset combo for the rear.

One of the reasons I was looking for non-exotic wheels was that (assuming I can do math) there are tons of choices in an 8" wheel. +45 offset should be the sweet spot, and that's the most common choice. Biggest issue is the damn front brakes...there is no way to measure if a wheel will clear; it's not actually in the offset, but more in the design of the spokes.

 

[phucheneh]

http://www.clublexus.com/forums/is-first-generation/297455-wheel-offset-2.html

That pic of the car with the stretched tires on 9.5" wheels is helpful (the gold ones). His setup is retarded; but the info is helpful.

Why in the hell would you mod your fenders to fit a stock tire size that would fit fine if you picked wheels with the right offset...ugh.

But if this car had 9.5's in the back with ~255's, I think +40 would be the optimal offset. That's 18mm further in than the picture, but with a tire that has a section width to match the wheel. If I went that route, we'd need to stagger, I think. If 9.5's fit in the front, it would be with stretchy tires.

 

[phucheneh]

http://www.tirerack.com/tires/tires...4WR7R888&vehicleSearch=false&fromCompare1=yes

295/30/18 is the perfect diameter. :hmm:

Once you're up to 17-18" wheels (read: not 15's), how much do you guys figure sidewall matters? I can't imagine 17's having discernibly more traction than 18's.

 

[JCH13]

The appeal of a staggered setup is reduced oversteer and generally cheaper front tires.

 

[XavierMace]

I dunno. Why not?

I don't get the 'stagger' fascination. If the biggest widely-available rear size you can fit will also fit in the front...why not?

edit: If someone knows of a 17-18" tire size bigger than 245-255 with lots of 'sticky' options, I'm all ears.

Said 245/255's are going to be the limit for the front. Not sure what maximum rear size is...I'm guessing 275-295 would be pushing it. Unfortunately, 'Lexus enthusiasts' don't seem to have done the legwork and figured out a 'standard' for the biggest tires you can shove under one of these. Something like exdeath's Mustang is a little easier to shop for, as I'm sure you can hop on some forums and get info on the optimal width/offset combo for the rear.

Because what are you gaining going from 215's to 245's in the front? Not being sarcastic, serious question. The reason for going wider in the rear is obvious but unless you are having issues with your front breaking loose, it seems pointless. Or am I missing something?

I've also been told that wider front tires = wider turning circle. No idea if that's actually true though.

Regarding the research: http://my.is/forums/f95/wheel-fitment-guide-will-these-fit-what-offset-do-i-need-413953/

That seems likes sufficient legwork.

 

[phucheneh]

Because what are you gaining going from 215's to 245's in the front? Not being sarcastic, serious question. The reason for going wider in the rear is obvious but unless you are having issues with your front breaking loose, it seems pointless. Or am I missing something?

I've also been told that wider front tires = wider turning circle. No idea if that's actually true though.

Regarding the research: http://my.is/forums/f95/wheel-fitment-guide-will-these-fit-what-offset-do-i-need-413953/

That seems likes sufficient legwork.

Well shit, I missed that thread. I'm obviously not a regular over there, I just look for good info to steal and laugh at the rest of the silly stuff.

The appeal of bigger fronts is simply better cornering/braking and interchangeability. This car is mostly straight line, but it handles competently and it might as well get proper use of its big brakes. Cost isn't really a factor unless the rears are an oddball size.

That said, if I can make this thing tuck 295's in the back, I will.

 

[exdeath]

Because what are you gaining going from 215's to 245's in the front? Not being sarcastic, serious question. The reason for going wider in the rear is obvious but unless you are having issues with your front breaking loose, it seems pointless. Or am I missing something?

I've also been told that wider front tires = wider turning circle. No idea if that's actually true though.

Regarding the research: http://my.is/forums/f95/wheel-fitment-guide-will-these-fit-what-offset-do-i-need-413953/

That seems likes sufficient legwork.

Guess you've never seen the Cobra turn a 3 pt turn into a 7 pt turn

Too wide on the front, you need rack limiters to keep the wheel from hitting things like, oh, the control arms, sub frame, etc.

Stagger setup is nice on a street car because you have traction in the rear and a bias toward understeer in the front. When the front starts to slide out first, you know to back off, or alternatively, how predictably the rear will break free, because the rears aren't that far behind. Much easier to drive hard on the street without wrecking.

Too much grip in the front is asking for trouble on a overpowered street car. Throttle and brake induced oversteer is fun in a 300 HP car, not in a 600+ HP car.

 

[XavierMace]

Guess you've never seen the Cobra turn a 3 pt turn into a 7 pt turn

Actually I think you were the one who told me that but I wasn't sure.

I think you need to hurry up and fix it though so you can demonstrate for me.

 

[exdeath]

Actually I think you were the one who told me that but I wasn't sure.

I think you need to hurry up and fix it though so you can demonstrate for me.

I hate doing rear end bearings. My garage smells like gear oil and friction modifier already and the bottles are still sealed.

 

[XavierMace]

Yeah but if I get the engine pulled on the IS before you do that, that will be a sad day for car people everywhere.