offset question

Wheels, Suspension, Brakes & Tyres questions and answers

Moderators: timk, Stu, zombie, Andrew, -alex, miata

User avatar
16bit
Speed Racer
Posts: 2346
Joined: Wed Nov 29, 2006 1:51 pm
Vehicle: NB8A - Supercharged
Location: Brisbane Southside

offset question

Postby 16bit » Wed Oct 17, 2007 9:18 am

can anyone tell me the difference between the A, B and C offsets in this chart? is it just from different points like before the centre piece and after it?

http://www.perfectrun.com.au/performanc ... Cface1.htm

btw would getting the 17 x 8 with plus 16 offset with 245/40/17 on the rear and 17 x 7 with plus 22 offset with 215/40/17 on the front need guard rolling? also do you think it would destroy the handling of just make it less likley to slide?

User avatar
Charlie Brown
Speed Racer
Posts: 2623
Joined: Mon Apr 28, 2003 11:00 am
Vehicle: NC
Location: Sydney, Just out of Dragon Territory over the bridge in the "Shire"
Contact:

Postby Charlie Brown » Wed Oct 17, 2007 9:40 am

Not sure what the difference is between A, B & C but you need atleast the +42 or +50 offset. Read up on \"bump steer\" before heading to the offset area you're thinking of. Also with the offset you are suggesting you would need to roll the front and do even more on the rear guards.

As for rim width, unless you have an NB8B or later the 8\" rim is illegal to run on the road. You can only go up 1\" in diameter and up 1\" in width and increase your track by 1\" (25mm) legally.
Image

Wakefield 1:09.13 Eastern Creek GP 1:50.198 Ext 2:17.538 Sth 1:02.9003
Phillip Is 1:58.50 Winton Short 1:10.7 Lakeside 1:05.7711 MDTC 45.20

User avatar
16bit
Speed Racer
Posts: 2346
Joined: Wed Nov 29, 2006 1:51 pm
Vehicle: NB8A - Supercharged
Location: Brisbane Southside

Postby 16bit » Wed Oct 17, 2007 10:23 am

this is part of the nopro arches grand plan so there will be ample room under the arches - however the legallity bit does seem a problem. might have to stick with these and see if i can get away with them.

http://www.perfectrun.com.au/performanc ... ngGT-N.htm

in 17 x 7 with the plus 25 offset and the gun metal centre.

User avatar
AB7
Racing Driver
Posts: 637
Joined: Thu Jun 07, 2007 2:42 pm
Vehicle: ND - 2 GT
Location: Melbourne

Postby AB7 » Wed Oct 17, 2007 11:41 am

+25 will need guard rolling, +38 is the pretty much the max for 17 X 7.

Babalouie
godfather of saké
Posts: 1457
Joined: Wed Apr 23, 2003 11:00 am
Vehicle: ND - 2 GT
Location: Sydney Australia
Contact:

Postby Babalouie » Wed Oct 17, 2007 11:58 am

The A, B and C face thing is actually pretty important to nail down to make sure you get the look that you were after in your mind's eye.

One is the more \"dished\". It's not just a matter of actual offset, but also appearance. I can't remember which is which, but one extreme (either A or C) will curve outwards to make room for big calipers, so if you want a dished look with flat spokes you need to get the other extreme.

If you choose wrongly, you can end up with wheels that are actually quite low offset (and hence stick out a lot) but stock looking appearance with no dish to the spokes and miles of air between the spokes and the actual calipers.

There is a diagram in the catalog explaining this but I can't seem to find it on the website: www.rayswheels.co.jp

And oh BTW, 7in +25 will leave a set of Nopro flares looking a little undernourished :D You'd need to start at around a zero offset if you were after the big flares :D
Image
Japanese Nostalgic Car Magazine - Dedicated to classic japanese cars

User avatar
AB7
Racing Driver
Posts: 637
Joined: Thu Jun 07, 2007 2:42 pm
Vehicle: ND - 2 GT
Location: Melbourne

Re:

Postby AB7 » Wed Oct 17, 2007 12:22 pm

Babalouie wrote:And oh BTW, 7in +25 will leave a set of Nopro flares looking a little undernourished :D You'd need to start at around a zero offset if you were after the big flares :D


Very good point, Zero Offset with flares. Looks just right :)

Image

User avatar
16bit
Speed Racer
Posts: 2346
Joined: Wed Nov 29, 2006 1:51 pm
Vehicle: NB8A - Supercharged
Location: Brisbane Southside

Postby 16bit » Wed Oct 17, 2007 1:07 pm

shite - they look great! where are those arches from? hmm - so zero offset with new arches or +25 with rolled arches.

Babalouie
godfather of saké
Posts: 1457
Joined: Wed Apr 23, 2003 11:00 am
Vehicle: ND - 2 GT
Location: Sydney Australia
Contact:

Re:

Postby Babalouie » Wed Oct 17, 2007 1:25 pm

16bit wrote:shite - they look great! where are those arches from? hmm - so zero offset with new arches or +25 with rolled arches.


This is +7 offset with a 14x7 rim, and on an NA, that's how far you have to go to get the rim to be flush with the wheelarch. A +25 offset would be almost a full inch further into the 'guards :)

Image
Image
Japanese Nostalgic Car Magazine - Dedicated to classic japanese cars

User avatar
16bit
Speed Racer
Posts: 2346
Joined: Wed Nov 29, 2006 1:51 pm
Vehicle: NB8A - Supercharged
Location: Brisbane Southside

Postby 16bit » Wed Oct 17, 2007 1:34 pm

so if i was to go with a +9 on an 8 inch rim it should look ok - if not i will get some wheel spacers made. this then puts me back into the legal battle. won't be till next year so i will hold tight until then. thanks for the feedback guys, atleast i know the general direction to head now.

User avatar
16bit
Speed Racer
Posts: 2346
Joined: Wed Nov 29, 2006 1:51 pm
Vehicle: NB8A - Supercharged
Location: Brisbane Southside

Postby 16bit » Fri Oct 19, 2007 5:46 pm

ok i have gone back to the drawing board and figured this out.

The stock wheels are 15 x 6 +40 offset and tyres are 195/50/15. The arches i would like to put on will be 40mm wider at the front and 50mm wider at the rear. Obviously i would like fill these.

I have calculated that if i get a 15 x 7 inch rim with a

+ 27 offset on the rear with a 20mm spacer it will be 46mm wider at the outside edge then standard (4mm clearance) and 18mm more (taking into account the 20mm spacer) clearance on the inside edge

+ 35 offset on the front with a 20mm spacer it will be 38mm wider at the outside edge then standard (2mm clearance) and a 12mm more (taking into account the 20mm spacer) clearance on the inside edge

My question is how much will the handling be effected and will you be able to align/setup the suspension so it works well or will this completely ruin the handling? I understand that with a wider stance i will probably tend to feel more stable/understeer.

I have Tein SS coil overs and all other bits are stock at the moment if that helps.

User avatar
AB7
Racing Driver
Posts: 637
Joined: Thu Jun 07, 2007 2:42 pm
Vehicle: ND - 2 GT
Location: Melbourne

Postby AB7 » Fri Oct 19, 2007 6:04 pm

You can get those flares from here

http://www.racinglifestyle.com/

Adam_NAclubman
Racing Driver
Posts: 1418
Joined: Wed Jan 25, 2006 11:39 pm
Vehicle: NA8 - Turbo
Location: Adelaide, Australia
Contact:

Postby Adam_NAclubman » Sat Oct 20, 2007 2:06 am

I don't think you'll be filling 40mm front flares with a 7 +27 with 20mm spacers if the NB is anything like a NA, a 7 +17 doesnt quite get to the outer edge of the guards on a NA and you're effectively going for 7 +7.

Maybe look at getting those rims the USA guys use that come in 8 +0, they're cheap Chinese stuff but theyre about the best way to get low offset 4x100 rims at a cheapish price

User avatar
AB7
Racing Driver
Posts: 637
Joined: Thu Jun 07, 2007 2:42 pm
Vehicle: ND - 2 GT
Location: Melbourne

Postby AB7 » Sat Oct 20, 2007 4:10 am

yep, those wheels are 16 X 8 et 0 and most of them run 205/45/16.

User avatar
16bit
Speed Racer
Posts: 2346
Joined: Wed Nov 29, 2006 1:51 pm
Vehicle: NB8A - Supercharged
Location: Brisbane Southside

Re:

Postby 16bit » Sun Oct 21, 2007 3:53 pm

Adam_NAclubman wrote:I don't think you'll be filling 40mm front flares with a 7 +27 with 20mm spacers if the NB is anything like a NA, a 7 +17 doesnt quite get to the outer edge of the guards on a NA and you're effectively going for 7 +7.

Maybe look at getting those rims the USA guys use that come in 8 +0, they're cheap Chinese stuff but theyre about the best way to get low offset 4x100 rims at a cheapish price


I am not interested in the cheap rims - i would rather pay more to get good stuff but thats not the point

If i got from a 15 x 6 +40 to a 15 x 7 + 27 with 20mm space it is an extra 46 mm wider.

use this calculator and add 20mm for the spacer.

http://marksink.com/tire_wheel_offset/offset.html

now the question is will my handling be effected and if so will i be able to setup the suspension to reduce any negative effects.

Adam_NAclubman
Racing Driver
Posts: 1418
Joined: Wed Jan 25, 2006 11:39 pm
Vehicle: NA8 - Turbo
Location: Adelaide, Australia
Contact:

Postby Adam_NAclubman » Sun Oct 21, 2007 4:00 pm

I increased my track by 41mm a side with my P1's on my NA and it still wasn't quite at the edge of the stock guards with 195's, so unless the NB is set up from stock with the outer edge of the wheels closer to the guard than the NA was, you're not going to be filling the flares at all with what you're planning on getting.

My Buddyclubs plus a 20 or 25mm spacer would get you out there though :P



edit

Oh, and yeah it does have quite an effect, steering gets quite a bit heavier and on my car there was a weird point at about 1/2 to 3/4 lock where it would scrub wide as if it had lost grip until you either backed the steering off or put more lock on, but you only ever use that much lock on really tight corners. My Volks and Watanabes sit slightly further inboard than the P1's and don't seem to have the same problem


Return to “MX5 Wheels, Suspension, Brakes & Tyres”

Who is online

Users browsing this forum: No registered users and 168 guests