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In another thread, http://www.m5board.com/vbulletin/showthread.php?t=46497, I wrote about having the Dinan JRZ Stage III suspension installed, and I said I would try to post before/after pictures of the tires. If I've done this correctly, they're attached below. The "after" pics represent two days of track use at Lime Rock. The track is nearly all right hand turns, so I've taken pictures of the left front tire, which takes most of the abuse. Thanks in advance for your feedback!

How'd the outside shoulder hold-up, relatively speaking, with -1.5 negative camber?
Before:


After:




Another question: my front rotors have a bluish band around them, I presume from heat. Anything to be concerned about? They're not vibrating or doing anything strange. Possibly, the brakes don't have quite the same amount of bite they did before the track use (I'm using Axxis Ultimate pads on the street).


Last question: These Hawk HT-10 pads have about 5 tracks days on them. They're showing some surface cracking. That's fine, right?

 

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Great post. My take:

1) Your suspension mods worked wonders. I scrubbed WAY more off the outside edge of my outside front tire at Sears Point in 1/2 day of tracking with the stock suspension. Looks like you were using the whole tire - a good thing - without too much rollover. If i were you I'd see if i could get away with even lower tire pressures next time. As long as the sidewall isn't rolling over too much you will get better grip with lower pressures.

2) I'm not so comfortable with the wear pattern on the rotors - to me it looks like the pad's backing plate isn't stiff enough - so you're only getting good pressure immediately under the piston. But this is a wild guess and if Dave Z chimes in, listen to him - he has much more experience than me in this area!

3) Surface cracking on the pads is OK. General rule of thumb I have always heard is to replace track pads no later than when they are down to 1/3 of original thickness.
 

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Discussion Starter #3
Thanks Greg. Some additional info I should have mentioned --
Tires are Dunlop 8080s in OE sizes. Tire pressure was 40-41 hot; tire temps increased 8-9 psi from cold to hot. The track days were overcast and cool, probably no warmer than mid/high 50s both days.
 

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Ed,

I agree with Greg. It looks like your fronts were wearing well; however, I'm wondering just how hard you pushed the car also. Would you say that you ran 9.5/10th's and sometimes 10/10th's? Actually, what really matters is if you had fun and enjoyed the experience. The tire wear looks nice.

Re the discs -- I'm sure Dave would have an informed opinion with experience well beyond mine. It appears that it may be possible that the pads/rotors were not both new when the pads were installed? I'm thinking that perhaps there were high spots on the rotor that locally overheated that portion of the pad resulting in pad material breakdown and deposits onto the rotor -- just a guess.

By the way, if you are at -1.5 camber up front with the Dinan Stg3, then I think you are within their expected zone. My car measures out stock to -0.5 degrees camber, and I believe Dinan quotes an approximated -1.0 change in camber with their plates.

I haven't driven Lime Rock since the BMWCCA Octoberfest in 1982 :( , but I recall that downhill corner onto the front straight as being potentially pretty hairy. I loved Big Bend (think that is what it was called) and that uphill right hander in the back part of the course. :)

Chuck
 

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CSBM5 said:
Would you say that you ran 9.5/10th's and sometimes 10/10th's? Actually, what really matters is if you had fun and enjoyed the experience. The tire wear looks nice.
Chuck
I hope you weren't going 9.5-10/10th at a drivers school! :eek:oohhh:

FWIW, my pilot sports have had similar wear since doing the dinan stage 3 suspension, and i'm also in the 1.6 negative camber range. Then again, i'm not exceeding 6-7/10, of my brain's driving ability.
Mike
 

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amazed by the state of your tyres. ive been twice on track and both times taken the edges right down wiht that typical hot rubber finish you seem to get just after the days over.

I would try less pressure if you go again or alternatively put your foot down on the gas a little more
 

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shimmy said:
I would try less pressure if you go again or alternatively put your foot down on the gas a little more
I don't think you can acurately assume Ed was pussyfooting the car around the track. If you are a smooth driver, and have some negative camber, your front tires will last. I've done 5 days of track time with my car with pilot sports (275's at the front, which helps, and the suspension) and they don't look too bad at all (and this is in the instructor group). I've seen many students tear up their front tires as they plow into corners too hot, and then blame it on the car "understeers like a ...". They'd not only save the equipment, but they'd go faster as well if they's slow a bit before the corner, so they could be back on the throttle before the apex.
my $0.02.
Mike
 

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not presuming anything just thought it would be one or the other. Ive pussyfooted around a track with the worst of them when I cared about my rims and was worried about the barrier being a little too close.
 

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Discussion Starter #9
Thanks for the feedback guys. I'm glad to hear that the tire wear looks relatively even, which was my only question re: the tires. I wasn't trying to start a Red Badge of Courage thread. I did the stage III suspension upgrade, in large part, because I wanted my tires to last longer than a handful of events. With the debate over adjustable front camber and how much is enough, I hope others will find the information useful.

To provide a point a reference, I drove in BMWCCA intermediate groups this year, and will move up a group next year. For those familiar with Lime Rock, I'm doing 1:08-1:10s and reaching 125 on the front straight. For others, these weren't parade laps, but I was driving relatively conservatively. The car was sliding in turns, but I'm not dancing with it at the limits. At this point, I'm really focusing on basics like keeping my eyes up and making smooth steering/brake/throttle inputs. I had eight 20 minute track sessions over two days, though one session lasted only about 5 minutes due to an early wreck, and another session was very slow due to traffic.
 
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