Guest KraZ4spd Posted September 5, 2001 Share Posted September 5, 2001 I found some wheels by Complete Custom Wheel in Florida that look like Fiske's. They are custom made to fit. This guy seems to have a problem with 17" wheels. I told him that I was going to run 245/45/17's and he said that 16's would hook up better. What difference is there between 245/45/17 and 245/45/16? To me the tire is the same in proportion with the wheel. It doesn't make any sense to me as to what he is talking about. To me a 17 should hook up fine, I mean Porsche uses a 245/45/17 on the back of the new Carrera's. Dazz showed me this wheel and said that a 17x8.5 would work on my 240 with a 5mm spacer on the back. Any input? Quote Link to comment Share on other sites More sharing options...
johnc Posted September 6, 2001 Share Posted September 6, 2001 John Perner runs Complete Custom Wheel. He's very knowledgeable and also very opinionated. And, he's right. A 15 or 16" wheel works better on a 240/260/280Z. Look at all the racers who compete in classes (GT2, BSP, SM) with no wheel size restrictions. Almost all run 15 or 16" wheels even though custom 17" have been available from Bogart, Taylor, Monocoque, CCW, Kiezer, and others for years. I don't know the theory behind the "why." The previous owner of the 240Z I bought tried a 17" racing wheel and DOT race tires (Hoosier) and the car was very unpredictable. One minute it would understeer and the next it would oversteer. The problem was with the rear suspension and no amount of caster, camber, and toe adjustment could get it to be predicable. Swapping back to 16" rims and tires instantly cured the problem. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted September 6, 2001 Share Posted September 6, 2001 The taller sidewall will make for better launching than a narrower sidewall will. He is referring to the change in aspect ratio relative to the rim size--the 16 inch rim has a taller (or wider) sidewall in this case even though the width of the tire remains a 245. Sometimes this is hard to understand, but if you could see the tire and wheel setups side by side, we could measure them and it would all make good sense. Did you tell him you would be doing any drag racing or street racing with it? If not, maybe he assumed you would be. Davy Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted September 6, 2001 Share Posted September 6, 2001 "He is referring to the change in aspect ratio relative to the rim size--the 16 inch rim has a taller (or wider) sidewall in this case even though the width of the tire remains a 245." OK, Davy, I'll bite...how is a 245/45/16 sidewall taller than a 245/45/17 sidewall? overall wheel diameter is 1" larger with 17's but tire sidewalls are numerically (ignoring manufacturer's differences) the same. If he was working to achieve the same overall diameter then sidewalls would differ. The 17 with same tread spec (ie. 245/45)as 16 would ideally have a 'longer' contact patch which is something I haven't seen discussed much (I can hear Pete typing away already I'd choose 16's myself simply for the weight savings (in rims and tires) and more reasonably priced tires/rims.....17's are typically stepped to when you're going wider than the 16" treads are available in or for their appearance IMHO. I have a camaro roadracing friend who's spent thousands on his Z28 but has been running the same heavy 17" OZ wheels for years....he's finally coming around to the idea of lighter wheels equals greater acceleration AND deceleration.....(we had to to cement 10 lb gloves to his arms and make him walk like an ape for a week before he believed us ) Many 17" rims are literally 8-10lbs heavier than easily available OEM 16's weighing 15-17lbs. Quote Link to comment Share on other sites More sharing options...
Guest confuZed Posted September 6, 2001 Share Posted September 6, 2001 I think the point DavyZ was trying to make is the aspect ratio. When you go with a 17 you might want 245/45/17's but if you went with 16s you would change the tire size to equal the same Outside Diameter. so that would be what 245/55/16's?? Don't feel like doing the math. But in this you would gain sidewall. The reasons the new porche's use 17's is because they go with what 285 wide tires? put an aspect ratio of 40 or 45 series and it's still quite thick. You need the tires to ply a little otherwise you bust a bead or could slip a bit easier as well. This is of course my unedumacated humble opinion. jared Quote Link to comment Share on other sites More sharing options...
johnc Posted September 6, 2001 Share Posted September 6, 2001 Longer vs. wider contact patch in braking (my cross post from and earlier IZCC discussion.) The same applies to acceleration. I've just spent some time re-reading Chapter 2 - Tire Behavior in Milliken's "Race Car Vehicle Dynamics." While all sections in the chapter are relevant, I think Section 2.3 - Longitudinal Force helps explains the issue above. There's a lot of fundamental information that's need as background, but I ain't about to type all that. Go buy the book and read Chapter 2 yourselves... A tire's footprint under braking (and acceleration for that matter) experiences shear stress. This is because the tire's radius is forced to change as the tire tread (and sidewall) elements enter the footprint. For a constant angular velocity, the linear velocity at the circumference of the tire decreases as the radius changes resulting in rearward stress. Under braking, the footprint is moved rearward relative to the axle centerline, compressing the elements in the rear half of the print and stretching the elements in the front half. As more and more elements enter the footprint (which occurs as braking force increases) and move aft under increasing load, the longitudinal shear force builds up linearly. As the footprint unloads toward the rear, sliding occurs between the tread elements and the road. In a tire with a long footprint, the longitudinal shear forces build up quicker and reach higher values than a comparable shorter tire with a wider footprint. Why? 1. The tires' overall radius change is greater so you get a higher linear velocity number. 2. The stress force distribution is more concentrated through the footprint. 3. The sliding velocity is higher in the rear part of the footprint. (you need to see Figure 2.14 on page 34 to see the velocity curves and the shear force distributions) Due the items 1, 2, and 3 above (and probably some other things that I don't understand), more of the taller, narrower tire's potential braking force is used overcoming the greater longitudinal shear force. So, even though both a tall narrow and a short wide tire put pretty much the same amount of rubber on the ground, the short wide tire uses less of its potential braking force overcoming longitudinal shear forces. Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 6, 2001 Share Posted September 6, 2001 Thanks John. I need to save up for that book - it's been on my wish list for years. It's over $100US, isn't it? Great stuff, thanks for writing that! Quote Link to comment Share on other sites More sharing options...
Owen Posted September 6, 2001 Share Posted September 6, 2001 BLKMGK, check out the last Turbo mag with the red 240Z on the cover. Those are pretty similar wheels but they are the more expensive brand name kind, Racing Harts I think. How much are these ones from Complete Custom? Owen Quote Link to comment Share on other sites More sharing options...
Drax240z Posted September 6, 2001 Share Posted September 6, 2001 Hehe, we've used that book a ton for our FSAE car, specifically for suspension design. Its really worth its weight in gold, we've started calling it 'The Bible'. (no offense intended to anyone) Mine is the budget version. Anyone who spent time in university will know what that means. Anyway, check Zdriver.com's photo gallery, I think there are some similar wheels to those on a dark metallic blue car there, so you can check out the pictures. Quote Link to comment Share on other sites More sharing options...
Guest KraZ4spd Posted September 7, 2001 Share Posted September 7, 2001 The wheels in the Turbo mag were aspecial order from japan through DAZZ. They don't have access to those wheels anymore. The Racing Harts (above) are less expensive than the ones on the magazine. posted September 06, 2001 02:38 PM -------------------------------------------------------------------------------- BLKMGK, check out the last Turbo mag with the red 240Z on the cover. Those are pretty similar wheels but they are the more expensive brand name kind, Racing Harts I think. How much are these ones from Complete Custom? Owen The ones from Complete Custom are $1100.00 for a set of 16x8 2 piece. They look more like a Fiske style 20 spoke wheel. I think I would still like the 3 piece design. John, do you know if Mr. Perner has any other custom made wheels besides the 20 spoke Fiske style? Quote Link to comment Share on other sites More sharing options...
johnc Posted September 7, 2001 Share Posted September 7, 2001 The book is $89.00 at Amazon http://www.amazon.com/exec/obidos/ASIN/1560915269/qid=999815893/sr=1-1/ref=sc_b_1/107-6869113-3129310 I have never seen any other style of wheel from CCW. That doesn't mean John has only one style. Richard Pilfold here in SoCal runs 16 x 8s on his 240Z and loves them. Most of the applications for CCW wheels are Corvettes and Vipers. Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 7, 2001 Share Posted September 7, 2001 Darnit John, you had to go and give me the link and everything! Hmm. I have a coupon for Amazon too... Thanks! Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted September 7, 2001 Share Posted September 7, 2001 KraZ - those are some very nice looking wheels you've discovered. Have you tried using somehting like Photoshop to put them on a picture of a Z to get the idea as to how they might look? I did this on a car that looked a great deal like mine until I was satisfied and it made me feel much better about ordering. Will be interested to see pics if you go for 'em as it ought to look REALLY nice. Have you decided on backspacing etc.? Not sure if our previous discussions on backspacing for 17s will apply or not but it ought to be a god starting point. Will you be running coil overs? Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted September 10, 2001 Share Posted September 10, 2001 Can't believe nobody pointed out the better overall gearing with a shorter tire. The 245/45-16 will give ~4% greater thrust at the contact patch. Plus they'll look better IMO. And of course they're cheaper. And lighter (all else being equal). No more wagon-wheeled Zs please! Quote Link to comment Share on other sites More sharing options...
jeromio Posted September 10, 2001 Share Posted September 10, 2001 I don't know that I could effectively argue the point of short/wide vs. narrow/tall. I'm a bit confused by the notion that the taller tire is going to lose fiction with the road due to increased sidewall shear forces (and there's no way I can spend $100 to find out ). But, I think with the Z car, unflared, there's not much point in the debate anyway. If you're very diligent, you can maybe stick a 9 inch wide wheel in there (8 is alot easier). So, in order to get the maximum tread to the road, you gotta go to the taller wheel. I don't see how a 16X8 wheel can give you a more effective footprint than a 17X8. Also, seems like there are more sport tires to choose from in the 17 inch diameter. That aside, if anyone wanted to trade me a set of 16X8 Panasports for my 17X8 5spokes, I'd be all over it... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 12, 2001 Share Posted September 12, 2001 Does anyone have a website or phone number to Complete Custom Wheel? Quote Link to comment Share on other sites More sharing options...
Guest jens Posted September 13, 2001 Share Posted September 13, 2001 This wheel has 6" backspace in the 16x9 or 17x9" version. The problem is that a 5 lug conversion is necessary but it would look nice. http://www.weldracing.com/ProStarXP.html Quote Link to comment Share on other sites More sharing options...
johnc Posted September 16, 2001 Share Posted September 16, 2001 http://www.ccwheel.com/ Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 25, 2001 Share Posted October 25, 2001 There is a REALLY helpfull site for looking at the different tire sizes, etc. http://www.miata.net/garage/tirecalc.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 25, 2001 Share Posted October 25, 2001 I'm on a mailing list called DealNews. Here's an Amazon coupon they found. **Amazon.com: $5 off $35** - 11:23 am Amazon.com knocks $5 off a purchase of $35 or more via coupon code "MAPAMEXSUNNY". Offer ends December 31, 2001. http://dealnews.com/newsdaily.html?article,27608 Quote Link to comment Share on other sites More sharing options...
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