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Old 08-25-2005, 02:07 PM   #1
zoomfactor
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Default Inside Front Tire Wear - No Lift -- suggestions needed

I have been experiencing pretty nasty inside front tire wear - primarily as a result of wheel spin. At no time am I seeing lift, and no lift has been reported by others. This is only during auto-x. I've only got a modest power (in the STX-ESP range).

In another thread, KC indicated that it was an easy fix -- alignment and stiffening things up

I believe that the alignment is spot on-based on measured tire temps and the fact that I have "cloned" several of the settings used by the Nat'l folks. -2.5 Front (0-1/8 toe for auto-x), -1.5 to -1.7 rear. Where I differ is in spring rates (on Tein RA's) ~450 front ~400 rear. 22mm FSB/22-24mm RSB.

I favor the front biased spring rates due to the great high-speed balance it gives the car... as well as my planned schedule of increasing track duty. I am also introducing my kids to auto-x this fall - so I don't want a rotational monster - just a better balanced one.

1. Will a front diff solve my problems without requiring me to stiffen the rear spring rates?
2. Would a stiffer RSB help without stiffening the rear spring rates?
3. Or...am I just an ass? <----just put those 9-12 springs on the back and sut-up?

We've got a few test days coming up and I'd like to get some feedback before I ruin another set of tires.
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Old 08-25-2005, 02:15 PM   #2
trhoppe
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Quote:
1. Will a front diff solve my problems without requiring me to stiffen the rear spring rates?
Yes

Quote:
2. Would a stiffer RSB help without stiffening the rear spring rates?
Yes

Quote:
3. Or...am I just an ass?
Yes?

-Tom
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Old 08-25-2005, 03:24 PM   #3
zoomfactor
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Man you are too much
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Old 08-25-2005, 09:01 PM   #4
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I agree with Tom on #1 and #2. Oddly enough, I've seen the most inside tire spin and inner edge wear around -2.5 on the camber scale. Going to more, I've typically seen less. Haven't quite figured out why yet but so far those have been my results.

I'm going to see if I can replicate that with a different set of shocks and springrates but I have a hunch that it would come out about the same. Quite befuddled as to why really but thought I would share regardless.

-Biggly
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Old 08-25-2005, 10:00 PM   #5
zoomfactor
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I'm used to seeing a slight amount of increasing of wear as you move to the edge - but what I've got looks like the gremlins put the wheel on a router and shaved off rubber at almost a 30 degree angle at the extreme inside edge.

I'm going to tighten down the rear sway bay a notch. No front diff at this point, but if I've got to crack the case open I'll be replacing everything. ..the purchase of a new STi is now looking like a more "reasonable" outlay of cash
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Old 08-25-2005, 10:38 PM   #6
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what is the loose nut behind the wheel doing? that much tire wear says to me that the car is pushing horribly and you're just cranking in steering input and throttle. not saying 100% that's the case here, but from the limited information given that would be my first guess.

btw, a local civic with a quiafe that runs in STX has the exact same tire wear patterns i have without a diff. this is with all of 125whp in my car and maybe 110whp in his. the ackerman combined with toe out, lots of camber, and aggressive launches are likely the cause of the wear. just a data point that would indicate that a front diff won't necessarily SOLVE the problem, but it may (and likely will) minimize it.
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Old 08-25-2005, 10:44 PM   #7
ChrisDP
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I'm not really getting much of any weird inside wear patterns, can't say that I did with -2.5 camber or -3 to -3.5 like I've been playing with recently. I've got a lot of toe out right now which is putting a bit of an angle on the inside blocks, but it's nothing major. I think more rear bar will help pin the inside front down some.
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Old 08-25-2005, 10:46 PM   #8
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Speaking of which.. what's your front toe?
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Old 08-26-2005, 02:14 AM   #9
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he said zero to 1/8th ...

Are you sure the wear isn't coming from the inside tires inside edge being dragged across the corners ...

Perhaps you should try your oem FSB ... so that the inside wheel can droop down to get better purchase.
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Old 08-26-2005, 07:09 AM   #10
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Quote:
Originally Posted by makofoto
he said zero to 1/8th ...

Are you sure the wear isn't coming from the inside tires inside edge being dragged across the corners ...

Perhaps you should try your oem FSB ... so that the inside wheel can droop down to get better purchase.
oem FSB == bad call.

-Tom
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Old 08-26-2005, 11:36 AM   #11
zoomfactor
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While I have a tendancy to overdrive a bit I don't think that is the problem. The current set-up suits my driving style and turn-in is sharp. The problem seems to be post-apex as soon as I roll on throttle I get enough spin to smell tire.

I really didn't think 50# difference in spring rates front-to-back would be that much of a problem. I think I need to try even spring rates.

Anybody got a set of Tein 8 kg/cm springs they want to get rid of
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Old 08-26-2005, 01:13 PM   #12
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yes ... I believe they are the 200 mm long ones ... from the rear of my Tein Flex's ... $50 including shipping. PM me your address if you're interested. I've used them on the rear and front of my Flex's. Front ones standard are 175 mm

If you have stiff enough springs ... you can go with lighter sway bars ... ioho :-)
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Old 08-26-2005, 05:53 PM   #13
rex n effect
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I had tire wear like that on my last set of tires. I think more caster and less toe helped the problem. I got a little better at teh driving also.
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Old 08-27-2005, 09:23 AM   #14
zoomfactor
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Well Update...

Going up just one slot (23->24) on the RSB seems to have fixed the lift. Now I just need fatter rubber

Turn-in is scary fast




Mako - PM sent
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