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Discussion Starter #1
Okay folks, I've decided on a wheel swap (even before getting my darn car!) for some Bonspeeds (Intense 5).

Decided to stick w/20s with 40-series tires. This car is a daily driver for the wife, so I can't fathom 22s with 35 or 30-series tires w/o her squaking about the ride. Nor I can't fathom her banging up some 22" $1k+ forged rims.

So...good compromise is to go for some one-piece billet (not cast) 20 inchers. True, not as light as forged, but not as heavy as cast.

I want to run 255/40-20F, 295/40-20R tires. The rears are BARELY taller than the stock 255/45-20 tires. But a heck of a lot wider!

So...for an 8.5, I want the LEAST amount of offset so I can have a decent lip PLUS to avoid contact w/those Brembo calipers. I think the stock, 20x9 SRT8 wheel is a +25. With a slightly narrower wheel, I figure maybe a +15 (to maintain outside dish)?

For the rears...who has exp. with 10" wide rims? I figure I can't have too much dish (small offset) as I will NOT be running 30 or 35-series tires. Again, stock offset for the 9" rear is +25. With an extra inch of width, don't know how I can go an extra .5" on either side, but maybe. So keep the +25 offset?

Bonspeeds are custom made, so I have to be CERTAIN what to have made.

I definitely did not want a CHROME wheel, so I think a polished 5-spoke would be nice.

Only $500/each including shipping. Not shabby IMHO.

 

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Discussion Starter #2
Bump.

Anyone?
 

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Teahead --you may have seen my post on this from the other forum. In case you didn't here is a cut and paste:

Boze specs (wedge5) were in terms of backspacing, but from that we can calculate offset. The fronts are 8.5x20's with 5.5" backspacing (+1.25" offset), the rears are 10x20's with 6.375" backspacing (+1.375" offset).

At the risk of too much info here is some more stuff on the wheel measurements.

Stock 9" wide wheel has 25.5 mm (which equals 1") positive offset. (Positive offset means the mounting surface of the rim is towards the outside half of the wheel). So then, for the stock wheel, the edge of the wheel is 3.5" from the hub. (To further explain, if there was zero offset, the edge of the stock 9" wheel would be 4.5" from the hub.)

The new fronts are 8.5" wide with a 1.25" offset. So the edge of the wheel is 3" from the hub. (middle of wheel is 8.5/2=4.25. Subtract 1.25" offset = 3"). The new front wheels should sit 1/2" more inside the fender. I didn't really notice this when it was on the car --I was happy with how it looked.

The new rears are 10" wide with a 1.375" offset. So the edge of the wheel will be 3.625" from the hub. (middle of wheel is 10/2=5.00. Subtract 1.375" offset = 3.625"). The new rears will sit 1/8" more towards the outside the fender. It did look to me that the rear rim did stick out farther than stock.

Given the size of the SRT brakes, offset may not be everything. You have to consider the curve profile of the wheel spokes and the lip size. In my case Boze like things tight! About 4 to 5mm brake clearance tops. The spoke of the wheel sort of curves around the back edge of the caliper. As an aside, the holes for the wheel lugs are also *just* large enough to fit a 13/16" deep socket into. The factory lug nuts work fine.

The rims are forged aluminum, BTW.

re Tires - I would like to go with a 295/40/20 rear tire, which is very close to the same overall diameter as the 255/45/20 stock rear tire . Currently though, I cannot find a max perf summer tire in that size that has a corresponding 245/45 or 255/45 size for the front! The only one is the Goodyear RSA all season -- and I want a higher performing tire for the summer than that. Hopefully the tire companies will come out with better sizes when I go through this first set of F1's

Also - here is an old link on SRT8 wheel measurments:

http://www.300cforums.com/forums/sr...400-srt8-wheel-stuff-long-multiple-posts.html
 

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Discussion Starter #4 (Edited)
Looky what I found:



TO CONVERT OFFSET TO BACKSPACING:

For positive offset wheels: (Wheel Width +1)/2 + (offset * .03937)

For negative offset wheels: (Wheel Width +1)/2 - (offset * .03937)

TO CONVERT BACKSPACING TO OFFSET:

Backspacing (in inches)*25.4 – (Wheel Width + 1)/2 * 25.4 = offset

Round this result to the nearest milimeter. If the answer is a negative number the wheel has negative offset, if positive then a positive offset.
 

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teahead said:
Looky what I found:


ok-- my logic must be mixed up somehow. the offsets i gave 2 posts above DO NOT correspond to this table. I'm going to have to do some more research to figure this out
 

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Discussion Starter #6
Yeah, I don't think you're front 8.5" wheel (1.375"???) would have MORE offset than the stock SRT8 9" wheel (1"). More likely less.

I'm guessing you're running maybe a +15mm offset with a backspacing ~5 3/8".

The rears, I'm guessing you're running maybe a +25mm offset. This would make the 10" wide wheel ~.5" stickout closer to the street from the stock SRT8 wheel. I bet that's the most you can do w/o rubbing. I think some folks are running a +20mm offset, but this would stick you out about 11/16" closer to the street.
 

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I'm wondering what would be the offset if i try to do 22x11 rear and 22x10 in the front and is it possible. I'll be thankful for any kind of help you could provide.
 

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Discussion Starter #8
Lilperez23 said:
I'm wondering what would be the offset if i try to do 22x11 rear and 22x10 in the front and is it possible. I'll be thankful for any kind of help you could provide.
Those are pretty darn extreme for these LX cars.


I would do NO MORE than 9.5" wide in the front. 10.5"s are doable, but you're talking a 25-series tire (295/25-22). If you can handle that on the streets where you live, more power to ya.

For the 9.5s, a +18 is ideal. For the 10.5s, I think a +30 would work. Contact GS Motorsports; they've fitted suched wheels.
 

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now I know how you are "managing" while the car sits on the dealer's lot in Michigan...
it's not for you!
This car is a daily driver for the wife

I was seriously perplexed as to how calm you have been waiting for "your" car...
that explains everything...
you a good man, teahead...
hooking the lady up with a sweet ride...
so what does the teahead drive then?
 

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Discussion Starter #10 (Edited)
cbutler32 said:
now I know how you are "managing" while the car sits on the dealer's lot in Michigan...
it's not for you!
This car is a daily driver for the wife

I was seriously perplexed as to how calm you have been waiting for "your" car...
that explains everything...
you a good man, teahead...
hooking the lady up with a sweet ride...
so what does the teahead drive then?
Trust me, I am "managing" a lot better than my wife, whose notoriously type-A and impatient. I've been having to deal with a LOT lately :argue:

Yes, she needed a new commuter car, but I wanted something we can BOTH enjoy, as she hands me the keys on the weekends and road trips.

Honestly, she doesn't enjoy driivng and would rather be a passenger, but I think once she gets the new ride, that will change.

She initially didn't want the SRT8; "too big," "too boxy" and she had her heart on the Lexus IS350.

I had to do a lot of convincing to finally decide on the "8". More room for our family and friends. More horsepower, more exclusivity (although it's difficult for the lay person to distinguish from other 300s); overall better value. :fing02:

Also, she'll let me mod it (she liked the Bonspeeds I picked out), as long as as it doesn't drive harshly (stuck w/keeping 20s; not 22s) and make it too loud. Hence, the decision to keep the exhaust stock and maybe add headers later. So...she succombed and now excited as heck to get it. :kiss:

But two months of waitinng is not helping the relationship much.:twak:

My DD is a '90 300zx Twin Turbo. I HAVE to drive a stick shift and I absolutely love the car. It's at the Stage V level (CAI, downpipes, hi-flow cats, 3" catback, chip, boost controller) making ~360 crank HP. It's a blast and I like driving sports cars preferably. I also love the glass t-tops; one of its bets traits.:headbang:



Gotta love those indiglos!





But like I said, I can't wait to get the hands on "my wife's car" and feel what a torque monster this car is (which my twin turbo don't have so much). She even is looking forward to getting a helmet and taking it to the track! She's cool.:wavey:
 

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teahead said:
Yeah, I don't think you're front 8.5" wheel (1.375"???) would have MORE offset than the stock SRT8 9" wheel (1"). More likely less.

I'm guessing you're running maybe a +15mm offset with a backspacing ~5 3/8".

The rears, I'm guessing you're running maybe a +25mm offset. This would make the 10" wide wheel ~.5" stickout closer to the street from the stock SRT8 wheel. I bet that's the most you can do w/o rubbing. I think some folks are running a +20mm offset, but this would stick you out about 11/16" closer to the street.
Teahead -- thanks very much for that chart (a few posts up). It explains a lot of things. I was wrong by 1/2" (front) and 3/4" (rear) on my previous offset calculations!

Using the chart, my Front 8.5x20 with 5.5" backspacing has a +19mm offset.
This puts the edge of the wheel (relative to the fender) very close to stock, and indeed it looks just the same. I'm glad about this because the wheel is 1/2" narrower than stock and I did not want it to look 'pushed in'. Boze did a good job. See attached pic.

The rear 10x20 with 6.375" backspacing, using the chart has +16mm offset.
This puts the edge of the wheel (relative to the fender) a bit farther out than stock. This would have to be the case since the new wheel is 1" wider than the stock wheel. But I did not want the new one to protrude past the fender. It does stick out from stock, but IMO is just at the edge of the fender. Again Boze did a good job, especially since this was done on the phone 3000 miles away! See attached pic. (The stock rear 255/45/20 tire looks a bit stretched for the 10" rim -- I'll be going to something wider when the these wear out.)

A couple more pics are attached. I had the Boze Wedge5 wheels installed with the summer tires just for the pics, the stock wheels with winter tires are back on the car now.
 

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teahead said:
Trust me, I am "managing" a lot better than my wife, whose notoriously type-A and impatient. I've been having to deal with a LOT lately :argue:

Yes, she needed a new commuter car, but I wanted something we can BOTH enjoy, as she hands me the keys on the weekends and road trips.

Honestly, she doesn't enjoy driivng and would rather be a passenger, but I think once she gets the new ride, that will change.

She initially didn't want the SRT8; "too big," "too boxy" and she had her heart on the Lexus IS350.

I had to do a lot of convincing to finally decide on the "8". More room for our family and friends. More horsepower, more exclusivity (although it's difficult for the lay person to distinguish from other 300s); overall better value. :fing02:

Also, she'll let me mod it (she liked the Bonspeeds I picked out), as long as as it doesn't drive harshly (stuck w/keeping 20s; not 22s) and make it too loud. Hence, the decision to keep the exhaust stock and maybe add headers later. So...she succombed and now excited as heck to get it. :kiss:

But two months of waitinng is not helping the relationship much.:twak:

My DD is a '90 300zx Twin Turbo. I HAVE to drive a stick shift and I absolutely love the car. It's at the Stage V level (CAI, downpipes, hi-flow cats, 3" catback, chip, boost controller) making ~360 crank HP. It's a blast and I like driving sports cars preferably. I also love the glass t-tops; one of its bets traits.:headbang:



Gotta love those indiglos!





But like I said, I can't wait to get the hands on "my wife's car" and feel what a torque monster this car is (which my twin turbo don't have so much). She even is looking forward to getting a helmet and taking it to the track! She's cool.:wavey:

Tea,
first, you my friend are a lucky guy...
what a wonderful wife to have...
two, nice 300! - the letters are "off" a little though...
nice HP output...
third, hang in there man!
fourth,
good choice on passing on the exhaust...
my wife likes it...
but on my car...
know what I mean...
once you do get the vehicle...
man it will so worth it...
Take care,
Sincerely,
Chris
 

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Teahead, nice choice of rims, please let me know how they turn out. By the way, had a 90 300Z myself and miss it a lot (but a lot less after this car, that's for sure).
 

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Discussion Starter #14
Doyle said:
Teahead, nice choice of rims, please let me know how they turn out. By the way, had a 90 300Z myself and miss it a lot (but a lot less after this car, that's for sure).
Thanks. Yeah, the 300zx is a fun car. Did really crappy on the track (no traction w/those 30-series tires), but hits that traps @107+mph. So the horsepower is there. Hope to get bigger turbos on her this spring. Should be fun.

The SRT8 will definitely be a whole diff. experience and I look forward to driving that sucker on long road trips/twisties.

And of course, I can't leave well enough alone and promptly planned to change out the wheels/tires immediately. It's all bolt-on stuff; nothing that can't be reversed.
 

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Discussion Starter #15
cbutler32 said:
Tea,
first, you my friend are a lucky guy...
what a wonderful wife to have...
two, nice 300! - the letters are "off" a little though...
nice HP output...
third, hang in there man!
fourth,
good choice on passing on the exhaust...
my wife likes it...
but on my car...
know what I mean...
once you do get the vehicle...
man it will so worth it...
Take care,
Sincerely,
Chris
Thanks Chris, I think I'll keep her (the wife that is).

Hard not to mod a car when one's on these msg. boards so often. One gets mod-envy.
 

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Discussion Starter #16
hemiwagn said:
Teahead -- thanks very much for that chart (a few posts up). It explains a lot of things. I was wrong by 1/2" (front) and 3/4" (rear) on my previous offset calculations!

Using the chart, my Front 8.5x20 with 5.5" backspacing has a +19mm offset.
This puts the edge of the wheel (relative to the fender) very close to stock, and indeed it looks just the same. I'm glad about this because the wheel is 1/2" narrower than stock and I did not want it to look 'pushed in'. Boze did a good job. See attached pic.

The rear 10x20 with 6.375" backspacing, using the chart has +16mm offset.
This puts the edge of the wheel (relative to the fender) a bit farther out than stock. This would have to be the case since the new wheel is 1" wider than the stock wheel. But I did not want the new one to protrude past the fender. It does stick out from stock, but IMO is just at the edge of the fender. Again Boze did a good job, especially since this was done on the phone 3000 miles away! See attached pic. (The stock rear 255/45/20 tire looks a bit stretched for the 10" rim -- I'll be going to something wider when the these wear out.)

A couple more pics are attached. I had the Boze Wedge5 wheels installed with the summer tires just for the pics, the stock wheels with winter tires are back on the car now.
Nice ride Hemiwagn! That has an awesome stance!

Q: do you rub those rear tires at all? Say with three people in the back and luggage? It looks like the fender lip will contact the tire. Did you roll them? And if so, does it STILL rub?

Thanks for the pics! i'm still debating tire sizes. I canNOT have any rubbing whatsoever. Wife will get PO'd!:twak:
 

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rear rubbing: That day was just to see the wheels on the car and take some pics. I did not load it so, short answer, I don't know if it will rub.
I guess that will have to wait until mid april when put them on for the season and load 3 200lb buddies into it. I wish I had thought more about it at the time. Doh! I agree it does look pretty close.

If they do, I'll have to see if there is clearance for more postive offset (I'm pretty sure there is) and have the rims re-hooped. If that does not work roll the fenders. Would rather not, but like you, no rubbing is allowed! These cars deserve that.
 

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God i just did a search on the wheels on your Z, those are absolutely beautiful! I belive they are called Blitz?... Perfect for that car!
 

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Discussion Starter #19
B8B8B8 said:
God i just did a search on the wheels on your Z, those are absolutely beautiful! I belive they are called Blitz?... Perfect for that car!

Yup. Blitz Type-03. Forged three piece made in Japan. Very very nice and for $625/ea, a good buy IMHO.

Car is in desperate need for some ball bearing turbos. Hopefully this summer.:naughty:
 
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