jimlab

Just curious what the maximum wheel width and offset is for the FD before aftermarket trailing arms become necessary.

I believe Manny stated at one time that the maximum backspacing in the rear was 7.5" without going to aftermarket trailing arms and coil-over springs. In the picture below, you can see my 17x9, +45mm wheels (backspacing ~6.75") and the clearance to the stock trailing arm. My 19x10s will have 7.5" backspacing, but the rim lip will be a little farther away from the trailing arm because of the increase in diameter. So at what point do aftermarket trailing arms become absolutely necessary?

The reason I ask is because I have a pair of K2RD trailing arms, but I also have custom pillow-bushings for the stock trailing arms that would accomplish the same thing, and I need to decide which I'm going with before I send my rear suspension components out for polishing.

Thanks!

dclin

iTrader: (4)

I'll be mounting my 19x10s shortly - at least when I find or buy a replacement for the lug lock key I, umm, misplaced. I've got 19x10 +45 for the rear, but I'll be able to measure clearance and then you can calculate from there for your 19x10 +50(ish?).

jimlab

Thanks Daniel. What are your specs for the front wheels? I'll be going with 19x8.5, +45mm.

I considered going +45mm offset on both front and rear, since that would put an even amount of the extra width of the rear wheel on either side of the mounting pad, but I was worried that it would have a very noticeably staggered look to it.

19x10, +45mm = 7.25" backspacing, 3.75" frontspacing
19x8.5, +45mm = 6.5" backspacing, 3" frontspacing

19x10, +51mm = 7.5" backspacing, 3.5" frontspacing

To quote Manny...
"Front space limits are 3.5 +/- 0.1 inches for front wheels, 4 +/- 0.1 inches for the rear wheels. Back space limits are 7.5 inches for fr/rr given that you have 2.5 inch coil springs. You could go 7.75 inches back space for the rear position if you have tubular rear trailing arms and at least 18 inch wheel diameter."

Obviously there shouldn't be any problem in the front or rear with the +45/+51mm combination, since I have coilovers, and backspacing for the front is an inch under the maximum. Those offsets would put frontspacing 0.5" under the maximum, front and rear.

The only question I have is whether an aftermarket trailing arm would be required to clear in the back, or if as Manny stated above, a tubular trailing arm is only required for 7.75" backspacing with an 18. With a 19" wheel and only 7.5" backspacing, there's probably plenty of clearance, but I just want to be sure my math is correct.

93 R1

Not sure if it helps any but I have 18x9.5 +50, and there is plenty of room.

bkapold@aol.com

Kevin Wyum has 17 x 11's (R) and 17 x 10's (F)

Brad

SleepR1

Kevin's car had M2 trailing arms...

maxcooper

I have 18" wheels with 7.5" of backspacing and they fit fine with the stock arms. Never rubbed. 17" wheels with 7.5" backspacing will rub a bit, and 19" should give even more clearance than the 18".

From the pic that is floating around, I think Wyum's car had aftermarket trailing arms, mounted as far inboard as possible (look at the position of the ball joint at the body end), and it was still very close.

-Max

jimlab

Yep, and even then, he had to space them over as far as they'd go with a nut and some washers...



Brad, I'm well aware of who Kevin is and what's been done to his car. I've known him since shortly after I bought my FD in April of '97.

jimlab

Thanks Max, that's what I needed to know.

Yep, that's the one I posted from my private stash.

dclin

iTrader: (4)

Yes, you might remember the picture I post of my Gewalt Evolutions that were 18X8.5 +44 and 18X10 +44. The result was a slightly tucked in look on the front wheels ('slight' is the operative word as that it seemed like I was pretty much the only one that noticed hehe).

Part of the effect may have been the slightly narrower tires I had on there (225/40/18s, while I was waiting on the 245/35/18 to come back in stock), but it was still enough to bug me to where I took that under consideration when chosing this latest set (of 19's).

The set I got in this past week are 19X9 +45 and 19X10 +45. That extra 1/2" (1/4" added to the front spacing, and 1/4" added to the back spacing - compared to my previous 18X8.5 +44) pushes the 'face' of the front wheel out again to keep the wheel 'face'/fender lip distance (more) equal front and rear.

While mine has about 1/4" more front spacing front and rear compared to yours (pushed out more), we both maintain equal wheel 'face-to-fender edge distance front to rear - so your thinking is right. Whether or not anybody (except me) notices is another matter.


The only concern maybe with the sway bar linkage on the rear, but should be ok. I recall asking Johnny about his 18X10 +50, and he related that it was close - similar to what Steve Ciriani spoke of when he did the 17X10 CCWs (though I never figured out what the effective offset was after the spacer Steve had to use). I'm guessing that the larger diameter of the 19's will help with clearance (of the sway bar linkage), but will not know how close it is until I get my stock wheels off.

My wheel lock keys should be here by the end of the week, so I'll 'plumb bob' off the fender edge to see how equal the space is front to rear (from wheel 'face' to fender edge), along with seeing exactly where the 19" rim lip sits in relation to the swaybar linkage. I'll take pics then.

BTW, you getting one of the new tuner wheels from Boyd's?

http://www.bcforged.com/home/frame/

jimlab

I'm also the type of person who'd notice something like that... go figure.

The only reason I've been reluctant to use a 9" wheel in the front is because I haven't liked the look of 245s on a 9" wheel in the past. Too much wheel, too little tire.

Then again, the bead width of my S03 245s is 9.5" (uninstalled), and the 285s are 10.5" and I plan to put them on 10" rims, so maybe I'm worrying about nothing. A 19x9, +45mm would have a backspacing of 6.75" and frontspacing of 3.25, so when compared to the rear 19x10, +51mm, there'd only be a quarter inch difference in the front of the wheels. The rest of the width of the rear would be on the inside. Sound reasonable?

That's the plan. We're talking to Boyd Jr. about a one-off and kicking around ideas on the design.

bkapold@aol.com

Jimlab: i was only informing you of his wheel and tire size.... and I also know what he has on car, we shared a garage for a year, and BTW: he still has his car.. He does have wheels spacers and longer studs too but the point is he fit 315's in a stock body. Lots of people said I couldn't get 275's on 91 TII but I did it without any spacers or mods...

anyway......

Brad

SleepR1

Jim,

I'm loving the BC02s in standard satin finish. http://www.bcforged.com/home/frame/

These are light eh?

9.5 x 17, 50-mm offset, set of FIVE. How much will that set me back??

7racer

Sleep!!!

u wheel *****

SleepR1

yeah, you got that right hee hee...seriously, the BC02 is happening...10 x 17, 21 lbs, $475 each. I wonder if they'll do a 9.5 wide?

dclin

iTrader: (4)

I know what you mean - the tire-pulled-tight-over-the-rim look that Japanese drifters and US low-riders adore. I'm actually thinking that this phenomenon depends also on the make/model of tire as well - it seems some tires maintain the upright sidewall on wider wheels better then others.

Been micro-analyzing my tire selection as I usually do with most things, and noticed that some tires appear to maintain a 'more' vertical sidewall - like the AVS Sports.

Looking at the specs on this Porsche:

http://www.miaminightout.com/spotlig...02/index.shtml

it lists the tires as AVS Sports 235/35/19 on 19X9 front and 275/30/19 on 19X11 rear. I would expect the tires to be noticeably 'stetched', but the sidewalls appear to maintain a pretty good vertical profile, considering. Though it's hard to see, I'm guessing more of the rim lip is expose rather then if they had used a wider tire, irregardless.

I noticed this again in the September '03 issue of Import Racer (I was bored at my local B&N, ok? ) on the (allegedly) 700hp 3 series BMW - they list the wheels to be AVS Sport 235/35/19 on 19X8.5 front and 265/30/10 on 19X10 rear.

http://www.importracermag.com/

Like the Porsche above, the 265/30/19s on the 19X10 maintained a surprisingly vertical sidewall (No pics on their website, but the issue should be out now at the local B&N to look at).

Toyo T1s on the other hand, appear to have an exaggerated 'stretched' look when fitted to increasingly wider wheels.

In this article, this BMW appears to have Toyo T1s 235/35/19 on 19X9 front and 265/30/19 on 19X10 rear.

http://www.ridejudge.com/featured/May01/

(It's not very clear the exact size of the Toyos as that they mention two different sets wheels and tires, but looking at Toyo's size list: http://toyo.com/tires/tire_specsheet.cfm?id=2 , the narrowest 19" tire 235/35/19. Looking closely at the pics of the sidewall, the pictures are with the Toyos mounted - and not the other brand mentioned. The tread pattern is also a give-away.)

The stretched look is very noticeable here, where the difference between the Toyos and the AVS is dramatic (again, both 265/30/19 on 19X10):

http://www.ridejudge.com/featured/may01/show.jpg

In my search for info on the T1S, I've read (on a BMW or Audi forum IIRC) other people mention the exagerated 'stretched' look of the T1S on wider wheels as well.

This assumption is based on the respective articles giving the correct wheel/tire specs though, and not sure how the AVS Sports can defy physics. Then again, I'm not a tire engineer hehe.

Quote:

Originally posted by jimlab

Then again, the bead width of my S03 245s is 9.5" (uninstalled), and the 285s are 10.5" and I plan to put them on 10" rims, so maybe I'm worrying about nothing.

Your point kinda hints at possible reasons of the issues mentioned above. A tire 'size' is determined by a corresponding wheel width (set by some obscure tire or engineering organization no doubt) - a 235/35/19 is designed off of a 8.5" width wheel, a 265/30/19 is designed off of a 9.5" wheel, etc.

However, given the variance in measurements from one tire to the next as seen on Tirerack's tire spec pages, there appears to be no rules as to how wide a tread is suppose to be (in relation to the overall width) or - specifically the result - what angle a sidewall must be for a certain size (on the specified rim width).

I'm willing to bet that if one was to set unmounted tires of the same size from three different manufacturers next to each other, one would find three different measurements of the bead.

Quote:

Originally posted by jimlab

A 19x9, +45mm would have a backspacing of 6.75" and frontspacing of 3.25, so when compared to the rear 19x10, +51mm, there'd only be a quarter inch difference in the front of the wheels. The rest of the width of the rear would be on the inside. Sound reasonable?

That's exactly what I measured (within +/- a bit for crude measuring toolsand methodology) just now. Post pics in a second.

dclin

iTrader: (4)

I reread this - if you are asking if the front wheel of a 19X9 +45/19X10 +51 combo will have 1/4" more front spacing on the front wheel then a 19X8.5 +45/19X10 +51 combo - then yes.

If I was to do 19X10 +51 in the rear though, I would go with a 19X9 +51ish on the front (if you wanted the wider 9"wheel instead of the 8.5"). Actually, IIRC, these are the width/offsets (or close enough) to what Johnny has - 18X9 +50 and 18X10 +50. I'll see if I can find his pics to give us another reference point (for how this wheel width/offset combo looks).

------

Tried posting pics of my wheel measurements to the Forum, but it will not take. You can see them here though:

http://www.imagestation.com/album/?id=4289403857

I put notes in the comment section so that you can figure out what you're looking at hehe.

dclin

iTrader: (4)

Ah, darnit - the pics Johnny had of them mounted on the car were linked (in the second thread), and are now represented by [img]d[/img]. I'll have to dig, but I think I have them saved somewhere.

https://www.rx7club.com/forum/showth...hlight=kinesis

https://www.rx7club.com/forum/showth...hlight=kinesis

He lists 18X9 +50 and 18X10 +50, 235/40 front and 265/35 rear AVS Sports.

jimlab

What size tires are you going with?

Thanks!

dclin

iTrader: (4)

Was planning on 265/30 front and 285/30 rear, but likely 255/30 front and 275/30 rear - I'll go into more detail tomorrow.

SleepR1

19s, are just too big on a sports car, IMHO...oh well...to each his own

ptrhahn

iTrader: (9)

Those BC wheels are gorgeous... as nice as HREs, with no stepped lip, and without the galling HRE price.... i'd prefer the BC02, BC09, or BC10 (10 being my fave).

21 lbs for a 17x10 isn't exactly setting the world on fire, i think 17" Fikses are in the teens. the 19" BCs are up around 25 lbs.

But, for a show/road car w/ 650 bhp, thats probably splitting hairs...

SleepR1

What are we worried about wheel weight for, Pete? We've got 350-hp FDs with KDR motors in them LOL

ptrhahn

iTrader: (9)

For 350 hp, i bet the difference would still be noticeable... i can certainly tell the diff between mine and stock wheels. When I need new tires (VERY SOON!) I want 18".... and i want wheels in the teens, so i don't make the sitch worse.

SleepR1

BC wheels don't come in half sizes, so 10 x 17, 2 inch offset, 7.5-inch back space for you PT...assuming you have 2.5-inch coil springs...you can run 265/40-17 all around with the Boyd Coddingtong wheels.

I'm back to the Enkei NTO3+Ms in 9.5 x 17, 44-mm offset. They're 20.5 lbs each. F1 silver looks nice enough. I just don't get the dual valve stems. Like what is a second valve stem for any way????

www.enkei.com