cbender

Thanks to CoralDoc for sharing some in-car footage with me of his friend at Robeling Road

Roebling looks like an easy track to drive at 8/10ths, and a very difficult one to drive at the limit. Lots of subtle changes in mid-corner which means that the typical strategy of braking-on-entry and driving hard to the apex is probably inappropriate (and likely to be slow). Here's what I read into the video CoralDoc sent. Does anyone care to share some reaction to it? And I won't take it personally, if you think I'm plain wrong here. There are real limitations to learning a track on a computer screen. I'll divide the track into sections, rather than using corner numbers, as I don't know how the track is numbered:

Front straight to the double-apex right-hander: it seems as if you can't carry much speed in mid-corner (between the two apexes) and still make the final apex, so the trick to this corner seems to be to carry as much speed as you can into the corner, lose some speed in mid-corner, and then get on it on exit. But the section between the first apex and mid-corner, where you track out, seems the tricky stretch. Gearing: finish the front straight in 5th, downshift to 4th at entry, downshift to 3rd just past the first apex in preparation for the exit.

Long left-handed sweeper: this seems reasonably straightforward with an entry at track-right followed by a late apex. Neutral throttle on entry but otherwise very light positive throttle through the rest of the corner. Seems as if the exit on this turn is compromised to better set up for the entry into the next right-hander. Gearing: entry in 4th, downshifting very late to 3rd at the end of the turn in preparation for the next right-hander.

Long right-hander: this also seem reasonably straightforward, although the entry

CoralDoc

You're welcome . I'm glad that you found the video to be so useful and have taken the time to comment. Here are my additions.

First of all, my friend Scott has an excellent sense of speed and car control. While it's instructive to see his line and approach to the turns, there is no way that I can emulate them. He is several seconds faster per lap than I am, though his car is nicely set up with aftermarket coilovers. He's running on Kumho V700s.

Your analysis of the course is spot-on, and I'll add a few pointers.
Turns 1 & 2.
Be careful with the 4-3 downshift because it's easy to unsettle the car unless you perfectly rev-match. I suggest taking this turn in 4th until you get a feel for the line.
Turn 3
Scott's line hugs the inside of the turn more than the line most drivers follow. The benefit is that the outside of the turn is slightly off-camber, but you have to be careful about too much speed messing up your entry into turn 4.
[QUOTE]Long right-hander:

cbender

Roebling looks to be a very interesting track -- and an unusual one in that many of the corners involve throttle transitions (neutral on entry followed by positive throttle on exit) which has got to make it a very difficult track to drive quickly. The presence of runoff and the lack of things to hit, however, is comforting.

I'll be instructing for Maurice (the family friend who's offering up the use of his NSX for the day), so I'm trying to do as much advance preparation as I can. Thanks, again, Joshua, for your comments/suggestions and for the video. It's really helpful, and I'll be much better prepared for it.

Best,
Christopher

mistervlus

Take a look at www.seat-time.com, there is a good write-up of a lap on there that has pictures of the corners.

What I noticed about Roebling, which may be hard to detect from the video of Scott, is that the track surface has been repaired many times and the level of adhesion can change mid corner (especially true between the apexes of 1 & 2), so you may have to adjust your line accordingly.

Roebling is a great track, and I think your line "Roebling looks like an easy track to drive at 8/10ths, and a very difficult one to drive at the limit" about sums it up pretty well. A perfect lap can be pretty elusive.

Have fun and be safe.

Lee

cbender

Thanks, Lee. I'll check out the URL....

cbender

A couple of things are more clear in the photographs than in the video. First (to Lee's point) the pavement's taken some abuse. Second, there's some subtle elevation gain/loss that I suspect I'll only appreciate once I'm at the track. Third, corner entry is just impossibly slow in a number of turns, particularly 3, 4, and 7. Finally, the turn in for 8, onto the front straight, seems to lack any sort of a landmark, other than it's just after the crest, perhaps parallel with the big tree at track-right?, and it's also a very slow entry. I'm getting excited. For me, half the fun lies in the preparation, but this is starting to seem like a very subtle track...

CB

S2k Dude

cbender, I'm by no means much of a driver or have much experience at Roebling Road other then the one event the Atlanta club did this past summer but I'll tell you what, it was a blast.

I had the toughest time getting the right line through 3-4 which sometimes also screwed up turn 5. Something that I'm sure would improve with more practice.

I also had a hard time waiting 'till that last few hundred feet to start braking from 115-120 mph. I tended to hit my top speed just after the start/finish line and was wanting to brake way early. But hey I can accept that I'll never be much of a driver and move on.

Just enjoy the day and be careful of the pit wall. The track manager get's PO'd when someone hits it and he has to paint it again.

mistervlus

Here's another good video of a Spec Miata race. Although the Miata's do take a slightly different line it definately seems to work as these guy's are putting down 1:27's for lap times. I don't know who the driver is but he's pretty damn good, he goes from last to 2nd. Because the lines are all over the place you get a much better view of the track surface. Later in the race he puts down some impressive laps.

Oh, and its just good fun to watch this guy totally destroy to field.

CoralDoc

Sounds like an interesting video - but I don't see a link in your post.

mistervlus

Oops.

http://gdjenkins.com/images/TBurasSIC.wmv