Track width confusion

#1

My understanding has always been that the rear track is about 10mm wider than the front. I am/was using 15mm h&r spacers with 25mm offset team dynamics wheels. Here’s the weird part. Rear track was 1/4" under (good) but front track was 1/2" over (bad). Took off the front spacers and now all is legal but im confused. (Interestingly i kinda liked the handling with that setup but i still want to figure it out).

#2

Front track width in stock configuration is 1405 mm, rear is 1399 mm. These are from the shop manual:

[attachment=2075]fronttrackwidth.JPG[/attachment]

[attachment=2076]reartrackwidth.JPG[/attachment]

#3

Hmmm conflicting info out there on the interwebs but ill go with yours. So how can you get max track with spacers and 25mm offsets and still stay hub centric?

#4

I always chalked that up to German over-engineering. Sure, on a street car the belt-and-suspenders approach of lug nuts and centering ring make sense. On a race car where lugs are torqued to spec each session, the friction between wheel and spacers and hub suffices.

But don’t take my word. I am the 2011 Inaugural Track Width Disqualification Champion.

#5

IIRC from the struggle that we had when RR’s caused some DQ’s, a 12mm spacer is good and 15mm spacer is borderline. That’s with OEM wheel offset which is 15 or 25mm, I can’t remember which.

Lots of spacers have hubcentric designs, just have to look around.

I’d stay with hubcentric. My perception is that folks that don’t have a hubcentric setup have more studs fail.

Those RR DQs years ago were, imo, not fair. The CCR put us in new shoes that year but failed to account for their increased width in the trackwidth spec. So cars that had been legal, suddenly weren’t. The DQ was not Steve’s fault. It was the fault of a CCR revision author that missed a predictable consequence of his rule change.

#6

I highly recommend treating studs as wear items. Replace them each winter or if you’ve taken a good whack to a wheel, had one fail, etc.

I appreciate the sentiment, but disagree. It was an easy rule to read and an easy measurement to check. I was grabbing for all the track width I could get. My car was not legal as raced. Patton and the others were trying to figure out any justification to let it slide but the rule was crystal clear, if unintentionally narrower than the prior year.

#7

Thanks, Steve. I don’t remember all of the details, but if we tried to get it “legal” and worked for the racer that was/is important.

RP

#8

I highly recommend treating studs as wear items. Replace them each winter or if you’ve taken a good whack to a wheel, had one fail, etc.

I appreciate the sentiment, but disagree. It was an easy rule to read and an easy measurement to check. I was grabbing for all the track width I could get. My car was not legal as raced. Patton and the others were trying to figure out any justification to let it slide but the rule was crystal clear, if unintentionally narrower than the prior year.[/quote]
Lol, we rarely agree you and I.

The CCR authors have a responsibility to prevent “gotcha’s”. They simply missed this one and you took the heat. Robert was constrained because he was obligated to support the rule as written.

#9

[quote=“Steve D” post=79781]Front track width in stock configuration is 1405 mm, rear is 1399 mm. These are from the shop manual:

[attachment=2075]fronttrackwidth.JPG[/attachment]

[attachment=2076]reartrackwidth.JPG[/attachment][/quote]

Thank you for the data. There is a “woops” here with the way I have been stringing cars, albeit a 3mm oops. I was under the impression the front and rear hubs had the SAME track width.

Fred, Chuck, are you reading this? 3mm=1/8" so the string should be a tad wider at the rear.?. With the string wider at the rear the car that was set at 0 is now toed out just a tad.

Hell, I’ll have to go measure Laura’s car to see. Fred’s car doesn’t matter and Chuck’s is work in progress?

McKay sez 1/4 toe out is the hot set-up. HA Ha

RP

RP

#10

[quote=“Ranger” post=79792]Lol, we rarely agree you and I.
[/quote] I disagree.:stuck_out_tongue:

#11

I run 10mm offset drag DR41. At the front they are absolutely the maximum you could legally run. They could pass or fail depending on how much tension you put on the tapes. In back I could probably use a 5mm spacer. The centering rings are not a source of worry.

#12

I thought it had been clear for a couple years now. A +10 mm effective offset is going to be borderline, and a +15 mm offset should keep you legal. I run the Kosei K1 +25s with the 10 mm spacer that Tire Rack gave me for my two sets of Kosei K1 +38s that I use for rains and older RRs.

#13

Are you hub centric?

#14

Yeah the Tire Rack spacers that came with my Kosei K1 +38s are hub centric.