B13 - Tire widths & wheel widths - Page 2

bahearn · Jul 17th, 2002, 05:29 PM

Well, that's what's on the car but it sits in the garage unregistered and uninsured. I've retired it from street duty to convert it into an SCCA ITS car. I bought the wheels and tires in October 2001 and parked the car last month.

dho · Jul 17th, 2002, 05:36 PM

Are you going to keep your 205/50/15's? I could use them in the future if you were just going to get rid of them. (If there's any tread on them, lol)

What does all the offset stuff mean? I'm wondering what my 15x6.5" enkei RS6's are. When I had 205/50/15 Kumho 712's it rubbed in the wheel well even with the fenders cut and tucked.

bahearn · Jul 17th, 2002, 06:15 PM

Tire Rack has a very good explanation of offset (known as back-spacing to the Detroit crowd). You want something in the 30 mm to 38 mm range. I can easily assist you indetermining your current offset if you have a rim with no tire on it. A rim with a tire poses a slightly messier procedure.

As for the Potenzas, I have no use for them other than something on which to roll the car around. They have about 2,000 miles on them, so lots of tread remain. I could be persuaded to sell them and could bring them the next time I'm in D/FW area. I'd want about $400 for 'em, though.

dho · Jul 18th, 2002, 01:33 AM

The 16x7" version has 42mm offset and their 17x7" version has 38mm offset. I can't find the offset for the 15" though. Do you think it's a 44mm offset? The online discount tire place says, "15X6.5 4-100/114 38S"

Man, I wish I could afford them things. I've got $300 going to the Hypercoils for the B13 (300/200). I need a job

Thanks for your help!

dho · Jul 18th, 2002, 02:05 AM

Anyone know if 215's or 225's will fit in the rear? What offset, backspacing, wheel size, and with a 1" lowering with the hyperco's will allow them to fit or not fit? When going from factory 13" wheels with those 175/65 or whatever to 205/50/15's does that affect the turning radius a great amount? What things really matter for the street?

Maybe I should just be happy with what I have!

Thanks everyone!

bahearn · Jul 18th, 2002, 11:51 AM

I had 215/40-16 on my SE-R at one time, so they fit if you don't lower the car much, and those Hypercoils better have at a rate of at least 150 lb/in or your rear wheels will rub when you carry passengers in the back seat. As I mentioned before, stick to offsets in the 30 to 38 mm range. Higher offsets will require spacers to clear the strut <Mr. Mackey>Spacers are bad, m'kay.</Mr. Mackey>. Shorter offsets put the outside edge of the tire against the fender liner.

Turning radius should be affected very little, if at all...that's determined by the steering rack and tie rods. Scrub radius is affected, but I wasn't too bothered by the little extra kick-back in the steering over one-wheel bumps.

For the street, wider is is usually better, but pay attention to offset and rolling circumference. Manipulate wheel diameter and tire aspect ratio to maintain stock circumference so that your speedometer is not affected. B13 SE-Rs came with 185/60-14, so that would be your "Plus 1" sizing. "Plus 2" would be 205/50-15 to maintain speedo accuracy (not 195 as most would lead you to believe), "Plus 3" would be 215/40-16 though 205/45-16 is close enough to not make much difference. I don't recommend 17" or 18" for a driver's car as wheel weight gets excessive; for posing, the bigger wheels are mandatory. 225mm tires can be stuffed under the car if stock ride height is maintained and springs are stiffer to keep the tires off the fender liners.

Russellc · Jul 18th, 2002, 02:22 PM

I believe that most consider the 195 to be the same circumference as the original because in fact it is, on the sentras with thirteen inch wheels. I use mich. xalto 195 50 15 on my sentra and they are as close to dead on original height as can bbe had, 205 size being just slightly taller. The ser of my same vintage came with larger wheels, so the 195 on a fifteen inch wheel would not be the same. As you may already know, there is a nifty plus size chart in the technical info, I believe it refers to plus sizing the thirteen inch wheel cars, which probably are not the same height.

bahearn · Jul 18th, 2002, 02:27 PM

That may be so for the GA16 cars. I started with a B13 SE-R and it came with 185/60-14 as OEM. I presumed that would be "Plus 1" for dho. "Plus 1" for me was 205/50-15 and plus 2 was "215/40-16". I know all about the tire sizing thing and have quite a spreadsheet with a bunch of different combinations.

dho · Jul 19th, 2002, 12:57 AM

Quote:

Originally posted by bahearn
I had 215/40-16 on my SE-R at one time, so they fit if you don't lower the car much, and those Hypercoils better have at a rate of at least 150 lb/in or your rear wheels will rub when you carry passengers in the back seat. As I mentioned before, stick to offsets in the 30 to 38 mm range. Higher offsets will require spacers to clear the strut <Mr. Mackey>Spacers are bad, m'kay.</Mr. Mackey>. Shorter offsets put the outside edge of the tire against the fender liner.

Turning radius should be affected very little, if at all...that's determined by the steering rack and tie rods. Scrub radius is affected, but I wasn't too bothered by the little extra kick-back in the steering over one-wheel bumps.

The Hypercoils are supposed to have 300f/200r spring rates. My turning radius felt like it was bigger than 34 ft or whatever the factory was before and after I put in my 2.7 rack & pinion with the 15" wheels. I miss doing U-turns in a residential street... I've been doing 3 point turns ever since I had the 15"s.

bahearn · Jul 19th, 2002, 12:36 PM

2.7 rack and pinion? What's that? Are you saying you replaced the steering rack? With one that has a different ratio than what came on the car?

dho · Jul 19th, 2002, 12:42 PM

Yes I did replace my rack & pinion and the Texas Steer shop replaced the 3.2 or whatever the original gear with a 2.7 gear. I'm needing to take back my rack & pinion because I was in an accident and I need to get it fixed. I might upgrade it to a 2.5 for better turnin. Anyone think this is tooo tight for street?

Going from the 1.6L 94.5 Sentra LE with that 3.27 lock-to-lock ratio to the 2.7 was an awesome improvement. It's kept me from over steering while avoiding road debris and accidents.

Does the lower ratio mean higher Turning Diameter? I noticed the SE-r's come factory with 2.7 but the non se-rs have 3.2 or so but the Se-r have a 34.1 turning diameter but the non se-r's have 30.2.

Newer corvettes have a 2.66 lock-to-lock ratio.

bahearn · Jul 19th, 2002, 01:00 PM

Steering rack numbers indicate number of turns required by the steering wheel to go lock-to-lock. It shouldn't affect turning radius.

Lower numbers mean fewer turns and faster steering response. It will have no bearing on actual handling but it should improve driver control.

I have no idea what the SE-R turning radius is...it was never an issue for me.

Was the 2.7 rack physically shorter than the 3.27? If so, that would explain the larger turning radius.

dho · Jul 19th, 2002, 01:08 PM

Quote:

Originally posted by bahearn
Was the 2.7 rack physically shorter than the 3.27? If so, that would explain the larger turning radius.

I honestly do not know. Thank you for your help though.

dho · Jul 19th, 2002, 06:14 PM

bahearn - In the future, if I get a job and some $$, I'd like to get some 12 lb. wheels. I've seen a lot of 15x6.5" miata aftermarket wheels that have a 40mm offset. Will these fit okay? I know you said 30-38mm but I was just checking. At this website the gentleman talks about either the 38mm or the 40mm being more driveable.. which one is he talking about? Would the 40mm only work with the 195/50/15's and not the 205/50/15's? Is it better to have a 4lb lighter rim or to have wider tread & better tire options?

Skinny G · Jul 20th, 2002, 12:24 AM

Quote:

Originally posted by dho
At this website the gentleman talks about either the 38mm or the 40mm being more driveable. Which one is he talking about?

That would be me.

I understand that the factory offset is 40mm. The wheels I am currently running on the street happen to have 38mm offset (hey, they were on sale).

My recommendation on running as close to factory offset as possible is based on my experience with very different offset aftermarket wheels on the Sentra and other projects. Since many of the engineered suspension angles were designed to use 40mm wheels, sticking to that dimension will make the car steer very much like the stock car did.

Either 38 or 40 mm will be fine - there is negligable difference. Going to my 25mm offset race wheels makes steering much more difficult, and it needs a bit of help returning to centre at times.

I would recommend 40mm. If you can only get 38mm, don't sweat it - it will still work out just fine. I have zero clearance problems with 15x6.5 38mm offset and 1.375 (or so) drop.

Miata rims (are they 15" now?) are a great idea, but you will most likely have to get the hub centres machined to fit the larger Nissan hub.

Greg