Guys, do you commonly find that if your tires spin, or rather slip a little at the starting line and not 'dead hook', that your reaction time is a little longer?

When I raced last Sunday, throughout time trials and in the first round of competition my drag truck ran pretty consistently, varying by only a few thousandths from pass to pass. My reaction times were .05 to .08; unremarkable.

But I lost in the second round when my truck ran nearly 3 hundreths of a second off-dial and my 60' was off by about .02 second.
My reaction time was .120. Though my opponent cut a .130 light, I was too far off dial to win.

I could have sworn that I left the starting line at the same point on the tree. I initially blamed my loss on my sleeping at the tree.
Perhaps I can somewhat blame it on tire spin.

My weather station didn't seem to indicate a change in the atmosphere.

Could I have lost that much at the tree with a little spin?

I did look through the archives on this forum to see if my question has already been covered.

Thanks!
Troy

If I had to guess here I'd say 99% of it was you and 1% tire spin that caused that late of a light. Forget it and move on.

Are you foot-braking, or T-Brake/Box?
I would say Top38 is probably right, (although maybe I would go 95%-5%)
Lot of potential causes. Sometimes you don't want to over-think things.
As a friend of mine likes to say: Flush, wipe, and go on.

As you well know, concentration is 100% of the rule. But never over think it. Never heard of a driver that nerves don't come into play. Drive your own race. This takes years as you know. An example, Friend of mine put together a new motor for his rack. First couple times out he has too much going on in the ****pit.Thinks he is getting it done 7.40 car. I knew he was not in the right frame of mind.Well lets put a camera on the back i tell him. Looking at the throttle response when your on the 2 step. Watching that throttle cable go back and forth ever so slightly. Now looking at the throttle cable response on his voyage to the 1320 was eye opening. See, what did i tell you, your 2 stepping it. He never believed it until he watched the video facing the carbs. Race your own race and don't beat your self at your own race.Troy you will be fine. Give it time.

I see too many times where one is worried about the other lane. Don't.....

This message has been edited. Last edited by: TD3550,

The question was about tire slippage at launch affecting r/t.
Seems to me if car is stationary while tire spins, of course it's going to affect reaction time by same amount of time it takes car to trip lights after initial spin starts and car doesn't move.
O.P. says 60' off by .02 and r/t and et off by similar amount. Yes, I'd be suspicious.

The answer is yes it could.

Thanks, guys; all helpful answers.

My local track has very questionable track prep. There are times when many struggle to hook and it does effect the RT but you can generally feel it in the car when you leave. My car will vibrate a little with slicks, it will rattle like a funnycar on radials if it spins. Are you feeling anything?

Thanks, Eman.
My own track usually has pretty good prep.
You know, I can't say that I feel anything unusual, but perhaps I'm not sensitive enough?

But I reckon that my tires only need to slip just a little bit to slow me down by .03 second or so in the quarter mile.

FWIW, I 'think' I can usually tell if I hit the tree right or not.

Lol, I wish I were some sort of electronics guru and could invent a gadget that could compare the track surface speed to the tire speed, to detect and report slippage. ;^)

There is its called a data logger, you can see tire slippage there in the form of drive shaft RPM. I was told you can even see it in the shock travel if you monitor that also. They are expensive, but as one racer puts it if you don't have data your just another racer with an opinion.

https://drr.infopop.cc/eve/foru...55-DC3BC3B84E39.jpeg
If it works here is an example of tire slippage on a data logger where as this is tire chatter/shake you can still see the difference in drive shaft RPM going up and down. In you case it would go up a short time then down and start a smooth upward climb until the shift then down and slowly back up again.

Thank you, Ron.
I suppose I should think about investing in a data logger. Maybe get to the money rounds more often, heheh.

I have to wonder how it detects slippage via driveshaft RPM; would it not need something like ground speed to compare that to?

Anyway, another feature of the data logger I've heard of too is that it can report your rear tire temp. I'm trying however to figure out a way of giving me a direct reading of tire temp via some gauge on my dash.

Slippage is detected but the sudden change in driveshaft rpms. All it does is show driveshaft rpms which on a normal run is a slow climb, not a spike on the graph.

Here is an illustration of tire slippage on a loose track versus no slip. I only have the driveshaft speed turned on in this pic. Now, the loose pass is low gear leave and the other is high gear only though.

quote:

Originally posted by CURTIS REED:
Here is an illustration of tire slippage on a loose track versus no slip. I only have the driveshaft speed turned on in this pic. Now, the loose pass is low gear leave and the other is high gear only though.

Curtis that looks like a dirt road not a loose track.....geez

On this graph I assume the x-axis is time. I cant quite make out the scale but say reaction time is changing from .015 to .035 or higher can you see that small on the scale provided to determine tire slippage? How many magnets on the DS collar? Some simple math with tire roll out and rear gear should determine how precise the measurement would be.

Just curious as I haven't invested in a logger yet either.

Dale

quote:

Originally posted by CURTIS REED:
Here is an illustration of tire slippage on a loose track versus no slip. I only have the driveshaft speed turned on in this pic. Now, the loose pass is low gear leave and the other is high gear only though.

No you aren't going to see that about your reaction times. My collar has 4 magnets.

Let's see if I can make this larger.

quote:

Originally posted by Big Steve:


Curtis that looks like a dirt road not a loose track.....geez

That’s just roadster life.