why marks on tires?

burger16b · 05-08-2011, 07:46 AM

ok so it may be a dumb question but why do people put what looks to be paint or chalk marks on there tires while racing? iv'e seen it on drag cars and auto-x but don't know why its done

1fastbmw · 05-08-2011, 08:13 AM

I believe the reason is so you can see wheel spin, usaully at the drag strip someone is watching to see if the tires break loose on launch, I can only guess auto-x is simular.

aisthetes · 05-08-2011, 08:46 AM

In autocross you mark edge of the tire tread to check how much tire rollover you're getting around turns. If the chalk wears off, you need more air pressure to maximize your tire contact patch.

ucbsupafly · 05-08-2011, 12:18 PM

Quote:

Originally Posted by aisthetes

In autocross you mark edge of the tire tread to check how much tire rollover you're getting around turns. If the chalk wears off, you need more air pressure to maximize your tire contact patch.

What he said. White shoe polish usually gets the job done.

burger16b · 05-11-2011, 07:46 PM

thanks always was curious

MrBlonde · 05-12-2011, 09:00 AM

The chalk mark on drag racing slicks is to see how much the slick is rotating inside the bead locks (ie slick moving inside the rim).

and 1 · 05-12-2011, 12:08 PM

the title of this thread made me wonder why star specs have those red and yellow dots (1 of each) on the sidewall

Clap135 · 05-12-2011, 02:14 PM

Quote:

Originally Posted by TrackRat

The tires should not be slipping on the wheel. They beadlock replaces the screws they use to use to prevent the tire from slipping or dismounting in the case of a loss of air.

I guess you havnt seen a honda idiot at 7psi spinning the wheel inside the tire have you? usually people mark this to make sure the mark still lines up at the end of the run.

chili555 · 05-20-2011, 04:54 PM

If you are a bit scientific, in road racing, you'd like to see how many heat cycles it takes for a DOT race tire to go from very grippy to kinda grippy to slick as a brick. Budget allowing, you'd like to look at the tires with five or so hash marks on them and march over to the tire vendor's trailer for replacements.

What, you didn't mark your tires after every session? Well, I guess for Sunday afternoon's 45 minute race that decides the regional championship, you'll be racing on...God knows what. Myself, I have a set safely tucked away at the back of my trailer with but one mark on them; known in the larger world as scuffs.

See you on the grid!

Eddy@ApexWheels · 05-20-2011, 06:33 PM

Quote:

Originally Posted by and 1

the title of this thread made me wonder why star specs have those red and yellow dots (1 of each) on the sidewall

That is there to aid in proper balancing of the wheel/tire during install. One of the dots is lined up with the valve stem to help compensate for the high/low spots of the tire as they are not perfectly molded.

bradford · 05-21-2011, 09:05 AM

Skip the shoe polish and use the triangles molded into the tire as the manufacturer intended.

and 1 · 05-23-2011, 11:08 AM

Quote:

Originally Posted by bradford

Skip the shoe polish and use the triangles molded into the tire as the manufacturer intended.

only tough part with that is gauging intermittent wear. you can see how far you've worn down in general, but tough to tell in between runs as you adjust pressures

Quote:

Originally Posted by paintpro21

That is there to aid in proper balancing of the wheel/tire during install. One of the dots is lined up with the valve stem to help compensate for the high/low spots of the tire as they are not perfectly molded.

either of the dots?

MrBlonde · 05-24-2011, 07:20 AM

Quote:

Originally Posted by TrackRat

The tires should not be slipping on the wheel. They beadlock replaces the screws they use to use to prevent the tire from slipping or dismounting in the case of a loss of air.

Exactly, that's why they use the marks, to ensure the aired down slicks are NOT rotating inside the rim.

JimD · 05-24-2011, 07:47 AM

I do not know about drag racing but there is an interesting piece in the Roundel several months back for determining tire pressure for track days (including autocross). I used the white stuff they sell at autoparts stores for marking windshields when you are selling a car. It's cheap. You mark the sidewall where the little triangles are moulded into the sidewall to mark the edge of the tread. You want the tread on the pavement, not the sidewall. I determined I need to be about 40 psi front and back for autocross. Less pressure and the white was removed from the sidewall.

Jim

05-08-2011, 07:46 AM	#1
burger16b Second Lieutenant 13 Rep 256 Posts Drives: 135i Join Date: Sep 2010 Location: LI, NY, CT iTrader: (0)	why marks on tires? ok so it may be a dumb question but why do people put what looks to be paint or chalk marks on there tires while racing? iv'e seen it on drag cars and auto-x but don't know why its done
	Appreciate 0 Tweet Quote

05-08-2011, 08:13 AM	#2
1fastbmw Second Lieutenant 23 Rep 215 Posts Drives: 2009 135i Join Date: Feb 2010 Location: Chesterfield, MI iTrader: (4) Garage List 2009 135i [10.00]	I believe the reason is so you can see wheel spin, usaully at the drag strip someone is watching to see if the tires break loose on launch, I can only guess auto-x is simular. __________________ JB4 l Berk AB l AP Mids l PLM DP's l RSD CP l Injen CAI l BSH OCC l ETS FMIC l Koni FSD's l BMW Performance Springs l Complete M3 Frt & Rear l Dinan Shock Mnts & Camber Plates l Quaife LSD l Morel Speakers l Zapco Amps l BMW SS Pedals l Pearlescent Brake Handle l 30% Tint l ICarbon Dry Diffuser l Matte / Gloss Grills l Black 135i emblem l P3 V2 Gauge l SF-71's l Conti DW's 235/265-19's l LCI Tails l Lux H8
	Appreciate 0 Quote

05-08-2011, 08:46 AM	#3
aisthetes First Lieutenant 13 Rep 340 Posts Drives: 2013 M3 Competition Join Date: Sep 2008 Location: Colorado iTrader: (0)	In autocross you mark edge of the tire tread to check how much tire rollover you're getting around turns. If the chalk wears off, you need more air pressure to maximize your tire contact patch.
	Appreciate 0 Quote

05-11-2011, 07:46 PM	#5
burger16b Second Lieutenant 13 Rep 256 Posts Drives: 135i Join Date: Sep 2010 Location: LI, NY, CT iTrader: (0)	thanks always was curious
	Appreciate 0 Quote

05-12-2011, 09:00 AM	#6
MrBlonde Colonel 122 Rep 2,695 Posts Drives: Audi TTRS, M Coupe, 1299 Join Date: Jan 2008 Location: Merewether iTrader: (0)	The chalk mark on drag racing slicks is to see how much the slick is rotating inside the bead locks (ie slick moving inside the rim). __________________ .-=[ Kenny ]=-. 1999 BMW M Coupe 10.775 @ 134.35 mph w/1.600 60' (Best 136.07 mph) 25th August 2004. +2010 X5 35D+ Check out the 1Addicts Drag Racing Standings and Drag Racing 101.
	Appreciate 0 Quote

05-12-2011, 12:08 PM	#7
and 1 winter mode 62 Rep 2,057 Posts Drives: 08 135i, 88 M3 Join Date: Aug 2008 Location: Somerville, MA iTrader: (0) Garage List 1988 BMW M3 [0.00] 2008 135i [7.50]	the title of this thread made me wonder why star specs have those red and yellow dots (1 of each) on the sidewall __________________ 88 M3: BMWCCA J Sport 08 135: because streetcar
	Appreciate 0 Quote

05-20-2011, 04:54 PM	#9
chili555 Private First Class 13 Rep 107 Posts Drives: M3 DCT coupe Join Date: Feb 2011 Location: South Carolina, USA iTrader: (0)	If you are a bit scientific, in road racing, you'd like to see how many heat cycles it takes for a DOT race tire to go from very grippy to kinda grippy to slick as a brick. Budget allowing, you'd like to look at the tires with five or so hash marks on them and march over to the tire vendor's trailer for replacements. What, you didn't mark your tires after every session? Well, I guess for Sunday afternoon's 45 minute race that decides the regional championship, you'll be racing on...God knows what. Myself, I have a set safely tucked away at the back of my trailer with but one mark on them; known in the larger world as scuffs. See you on the grid!
	Appreciate 0 Quote

05-21-2011, 09:05 AM	#11
bradford Major 28 Rep 1,035 Posts Drives: 2008 SGM 135i Join Date: Jul 2007 Location: Chicago > * iTrader: (4)	Skip the shoe polish and use the triangles molded into the tire as the manufacturer intended.
	Appreciate 0 Quote

05-24-2011, 07:47 AM	#14
JimD Brigadier General 368 Rep 3,547 Posts Drives: 128i convertible Join Date: Apr 2009 Location: Lexington, SC iTrader: (0)	I do not know about drag racing but there is an interesting piece in the Roundel several months back for determining tire pressure for track days (including autocross). I used the white stuff they sell at autoparts stores for marking windshields when you are selling a car. It's cheap. You mark the sidewall where the little triangles are moulded into the sidewall to mark the edge of the tread. You want the tread on the pavement, not the sidewall. I determined I need to be about 40 psi front and back for autocross. Less pressure and the white was removed from the sidewall. Jim __________________ 128i Convertible, MT, Alpine White, Black Top, Taupe Leatherette, Walnut, Sport Ordered 5/22/09, Completed 6/4/09, At Port 6/9/09, On the Georgia Highway 6/13/09, Ship Arrived Charleston 6/24/09 at 10pm, PCD 7/21/09
	Appreciate 0 Quote