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-   Suspension, Brakes, Drivetrain (https://www.miataturbo.net/suspension-brakes-drivetrain-49/)
-   -   Conflicted help! (https://www.miataturbo.net/suspension-brakes-drivetrain-49/conflicted-help-41784/)

jacob300zx 12-05-2009 12:45 PM

Conflicted help!
 
15x8 6ul's or 15x8 tr motorsports and a gopro HD? I can only pick one. The 6ul is 12.4lbs and the tr's are 14.8lbs. I've wanted 6ul's since 2007 they are the boss wheel for the miata, but the tr's and the new gopro HD are pimp too. Either way I go these are for the track car. Help me decide....dammit this sucks.

Bond 12-05-2009 12:52 PM

1.Gopro and tr wheels.

Moar bang for the buck, and we all love to bang.

y8s 12-05-2009 01:30 PM

you wont see the wheels while you're driving or watching the videos...

magnamx-5 12-05-2009 01:39 PM

well given that the shit is damn near 15 lbs i say 6 uls. your handeling will apreciate it.

jacob300zx 12-05-2009 02:04 PM

Not so much worried about the bling factor all though the 6UL's are dope. The 2.5lbs per corner is the big difference. One advantage other than price the TR Motorsports has is the +20 offset vs the 6UL +36 for a wider track.

ScottFW 12-05-2009 03:58 PM

Think about how you would actually use the video footage, and maybe that will help you decide. I have an Aiptek HD camera and built some better external mics for it because I thought it would be dope to put all kinds of track shit on youtube. It turns out that I usually end up burning the footage to DVD, and maybe watching it once or twice again for review, but mostly the DVDs sit collecting dust. Maybe I should upload some of those vids of my stock Miata embarrassing no-talent drivers in expensive cars, but I guess I'm just lazy. After a track weekend, messing with video just seems boring, unless it's something really fantastic that MUST be shared with the world. Of course, race footage would be generally more exciting than the HPDEs I do now.

As for the wheels, I lean towards getting the best parts that fit in my budget to make a track car faster. An extra 2.5 lbs of unsprung rotating mass per corner is not going to help you go faster. Looks are subjective, but every time I look at my car I think "My wheels are the shit and if I was still single I'd be getting tons of bitches." :laugh: I also lean towards buying expensive stuff when you can afford it, and saving up and getting the cheaper stuff later, especially with electronics. You've wanted 6ULs for two years. In 2011, 6ULs will still be awesome and there will be some new whiz-bang video camera on the market.

miata2fast 12-05-2009 04:10 PM

Fail not acceptable.

6ul's.

cueball1 12-05-2009 05:04 PM

Are your fenders rolled or pulled? That tr 8" wide with a 20 offset is gonna be close.

jacob300zx 12-05-2009 05:27 PM

rolled and pulled

Nagase 12-05-2009 05:44 PM

How, exactly, is wider track an improvement?

jacob300zx 12-05-2009 06:59 PM


Originally Posted by Nagase (Post 491287)
How, exactly, is wider track an improvement?


I would imagine it gives you slightly better turn in response with the tradeoff being slightly less high speed stability.

Nagase 12-05-2009 07:10 PM

Not to say "don't do it", but you would want to look into how that change in offset would change how the car handles under braking, how steering wheel angle changes camber, how steering wheel feel is affected...

Changing offset that wildly will change your suspension behavior. Good or bad? You decide.

jacob300zx 12-05-2009 07:54 PM

You really need to understand offsets to get this. A 9" rim is 228.6mm and a 8" rim is 203.2, now lets divide those numbers in half to get a 0 offset.

114.3 and 101.6

Now take a 9" 6UL that is a +36 offset. We add the +36mm to 114.3 to get 150.3 which is the distance from the rotor in. We then take that 114.3 and minus 36mm to get the rotor to outer wheel lip distance which is 78.3. Since we know that the 949 6UL is about as large as you can go on our car, well inboard that is, then we really want to stay smaller than the 150.3 inner and as close as you can or smaller than the 78.3 outer or risk a big fender pull. The 8" Tr has a inner mm of 121.6 and an outer of 81.6. So the TR has around 30mm of inner clearance compared to the 9" 6UL and the outer is only 3.3mm wider in track than the 9" 6UL. I doubt that 3.3mm will make my car unstable and launch me into a tire wall.

Jake

Nagase 12-05-2009 08:04 PM

I didn't say anything about clearances or launching you into a tire wall. I didn't even say not to do it. Spazzy and can't read... nice combination.

The track isn't even directly what affects the suspension components I mentioned earlier. It's another aspect you change by altering your offset. Scrub radius. You'd be changing your scrub radius to a positive, by quite a bit. That would increase steering wheel feedback, bump steer, may give you inconsistant camber gains as the steering wheel turns, would make the car less stable under braking... in race cars, positive scrub radius is usually seen as a positive, in street cars, negitive scrub radius is usually a positive (strong positive scrub radius is an effective anti-yaw under braking). Zero is seen as "perfection" by some, but it has merits and minuses of its own.

Understand, then attack.

jacob300zx 12-05-2009 08:25 PM


Originally Posted by Nagase (Post 491348)
I didn't say anything about clearances or launching you into a tire wall. I didn't even say not to do it. Spazzy and can't read... nice combination.

The track isn't even directly what affects the suspension components I mentioned earlier. It's another aspect you change by altering your offset. Scrub radius. You'd be changing your scrub radius to a positive, by quite a bit. That would increase steering wheel feedback, bump steer, may give you inconsistant camber gains as the steering wheel turns, would make the car less stable under braking... in race cars, positive scrub radius is usually seen as a positive, in street cars, negitive scrub radius is usually a positive (strong positive scrub radius is an effective anti-yaw under braking). Zero is seen as "perfection" by some, but it has merits and minuses of its own.

Understand, then attack.

Spazzy? Can't Read? Understand, then attack?
Really? Because I explained offset...


Originally Posted by Nagase (Post 491318)
Changing offset that wildly will change your suspension behavior. Good or bad? You decide.

Don't get all butt hurt cuz I hitz you wid da nawlegdgz kid...word. :jerkit:

Nagase 12-05-2009 08:32 PM


Originally Posted by jacob300zx (Post 491359)
Spazzy? Can't Read? Understand, then attack?
Really? Because I explained offset...

Cliffnotes: Knowing where the wheels are (offset) is different than knowing how they affect your suspension and steering (scrub radius).


Originally Posted by jacob300zx (Post 491359)
Don't get all butt hurt cuz I hitz you wid da nawlegdgz kid...word. :jerkit:

This just doens't make sense... scrub radius tuning is a preference, not a good or bad thing. It's not "butt hurt" of me to say "it's your car, do which option you like better."

magnamx-5 12-06-2009 12:00 AM


Originally Posted by Nagase (Post 491364)
Cliffnotes: Knowing where the wheels are (offset) is different than knowing how they affect your suspension and steering (scrub radius).



This just doens't make sense... scrub radius tuning is a preference, not a good or bad thing. It's not "butt hurt" of me to say "it's your car, do which option you like better."

ahem actualy he is explaining how his outbored offsett will change in a miniscule amount and give his car a 3 mm wider track the very fact that he knows this means he is not some newb wanting to show his ricer buddys how cool his sretched 160's on a 10 inch rimm look. So your advice is rather vague and well just underparr with the knowledge being thrown around. Seeing as how he tracks the car and probably has his suspension set pretty stiff i think the wider stance will indeed benefit him however i think the extra inertia from the heavier wheels will make mid corner upsets rather more starteling. But at the end of the day both wheels are essentialy even, so the real question he has to ask himself is how much is a in car camera worth to him? Becouse for my money get the lighter 6uls and be happier. Gl jacob

Nagase 12-06-2009 12:29 AM


Originally Posted by magnamx-5 (Post 491473)
ahem actualy he is explaining how his outbored offsett will change in a miniscule amount and give his car a 3 mm wider track

Yes, that's obvious, and it's been repeated already.


Originally Posted by magnamx-5 (Post 491473)
the very fact that he knows this means he is not some newb wanting to show his ricer buddys how cool his sretched 160's on a 10 inch rimm look.

I didn't say that he was.


Originally Posted by magnamx-5 (Post 491473)
So your advice is rather vague and well just underparr with the knowledge being thrown around.

Underpar? He's talking about changing offset and only considering track width. That's like getting an alignment and only being concerned about camber.


Originally Posted by magnamx-5 (Post 491473)
Seeing as how he tracks the car and probably has his suspension set pretty stiff i think the wider stance will indeed benefit him

If you really want to know about track width, read this:

Track Width vs. Everything else - Corner-Carvers Forums

Also, you can use this skidpad simulator to see how 3mm extra track can affect your cornering forces: (not much, but useful for anyone interested in putting flares on their car)

Page 29

jacob300zx 12-06-2009 01:28 AM

Nagase that link you posted sucked.

FYI
Pros
increased dynamic camber gain
slower instance of center migration
slower weight transfer
Could be pro or con depending:
effective spring rate softer (higher wheel rate)
Cons:
increase scrub radius
increase load on already over loaded front bearings
think increase caster jacking

Keeping the (static design) scrub radius a little bit positive is better than zero because it keeps the state the same as the tire squirms from normal road irregularities and minor steering corrections... you don't want the scrub radius constantly flopping from pos to neg as you drive, alternately loading the joints in different directions when you just want to go straight.


Anyways picked up some more noob parts today.

http://inlinethumb58.webshots.com/36...600x600Q85.jpg

http://inlinethumb34.webshots.com/43...600x600Q85.jpg

magnamx-5 12-06-2009 05:39 AM


Originally Posted by jacob300zx (Post 491522)
Nagase that link you posted sucked.

FYI
Pros
increased dynamic camber gain
slower instance of center migration
slower weight transfer
Could be pro or con depending:
effective spring rate softer (higher wheel rate)
Cons:
increase scrub radius
increase load on already over loaded front bearings
think increase caster jacking

Keeping the (static design) scrub radius a little bit positive is better than zero because it keeps the state the same as the tire squirms from normal road irregularities and minor steering corrections... you don't want the scrub radius constantly flopping from pos to neg as you drive, alternately loading the joints in different directions when you just want to go straight.


Anyways picked up some more noob parts today.

Oh man what newb parts to buy :drool: wish i had some myself


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