Understeer...
07-16-13, 05:23 PM
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Understeer...
Okay, while running on a road course and auto-x this weekend. My car had pretty severe understeer. I'm running 2* camber up front, 5* caster and 1.5* camber out back. Stock bars f/r.
Is it a tire balance issue, running 255's up front vs my 275's out back? Or something else? Or am i asking too much of what i consider a street tire in the NT05? They got greasy on my after about a dozen hot laps up front(air temps low 90's, track temps to match a clear sunny day that hot) and actually put me in the grass when i lost my front. Might have been able to save it, but chose 4 off in control vs fighting the car and likely dropping 2 out and hoping i stay pointed the right direction.
You can actually see me lose my front grip in this vid, good turn in and suddenly car pushed wide badly putting me in a bad spot.
RX 7 off - YouTube
At auto-x i noticed it pretty badly again, had 5-6 seconds left in the car if i had more front grip.
Do i need more tire or better tire or?
Any input is welcome.
Jason
Is it a tire balance issue, running 255's up front vs my 275's out back? Or something else? Or am i asking too much of what i consider a street tire in the NT05? They got greasy on my after about a dozen hot laps up front(air temps low 90's, track temps to match a clear sunny day that hot) and actually put me in the grass when i lost my front. Might have been able to save it, but chose 4 off in control vs fighting the car and likely dropping 2 out and hoping i stay pointed the right direction.
You can actually see me lose my front grip in this vid, good turn in and suddenly car pushed wide badly putting me in a bad spot.
RX 7 off - YouTube
At auto-x i noticed it pretty badly again, had 5-6 seconds left in the car if i had more front grip.
Do i need more tire or better tire or?
Any input is welcome.
Jason
you're probably hitting your bump stops in corners...
07-17-13, 10:29 AM
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It was a combo, got distracted by the corner guy and seeing that red car spin, turned ina little early(its a fast decreasing radius) and it literally pushed itself wide. I remember having plenty of time to think about it....lol
Jason
Jason
07-17-13, 11:42 AM
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Stock-ish suspension with staggered tires will understeer a bit. Your suspension settings seem reasonable, as long as toe in's are set right as well.
Going into a corner too hot and trying to turn can also feel like understeer - I haven't done that since last weekend's autocross. Slow in, fast out as they say. Understeer is safer than snapping the tail out tho - as you voted by doing.
I'm not familiar with the springs you are running, but it sounds worth considering an upgrade.
Going into a corner too hot and trying to turn can also feel like understeer - I haven't done that since last weekend's autocross. Slow in, fast out as they say. Understeer is safer than snapping the tail out tho - as you voted by doing.
I'm not familiar with the springs you are running, but it sounds worth considering an upgrade.
07-18-13, 07:18 AM
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What tyre pressures are you running? Do you drop the pressure after the tyres heat up? After a dozen or so quick laps the pressure would have come up a lot, maybe too much?
07-18-13, 08:55 AM
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30f and 27r when hot as best I could manage. I set the pressures after my previous runs when the tires were still pretty hot. Ended up dropping about 7-8lbs of air out of them through the day.
Jason
Jason
07-19-13, 08:02 PM
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Yeah, it happens. Been years since I've been on a track. And watching that red car go round really distracted me. I knew i was off my line before opting to cut the grass, figured it was the safest option considering where i was on the track. Might have been able to bring it back on, but wouldnt have been very smooth and if i dropped two might have been pretty dramatic.
Still understeered horribly at auto-x. How much better is the 93 rear bar vs the 94/5 bar?
Jason
Still understeered horribly at auto-x. How much better is the 93 rear bar vs the 94/5 bar?
Jason
07-19-13, 09:11 PM
#9
Yes, you know what you need to do.
Stock FD understeers a bit and then you added staggered wheels and tires making it worse.
I hated the understeer when I raced my FD in stock class, but now it is banished with even front/rear spring rates and maintaining a square wheel/tire fitment with more width.
Stock FD understeers a bit and then you added staggered wheels and tires making it worse.
I hated the understeer when I raced my FD in stock class, but now it is banished with even front/rear spring rates and maintaining a square wheel/tire fitment with more width.
09-08-13, 11:44 PM
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The Ohlins R&T series (with their DFV) are a great road and track shock, and will get rid of the understeer, as they have equal spring rates of 11k front and rear. You might even have to deal with oversteer like me with my new set!
