BoP Lab / Classes / SRF

SRF vs FB vs F6 vs BSpc pace at every track

Lap times across years say as much about the weather as the class. % of SRF is each class's best lap as a share of SRF's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.

Class · click a class to switch, + to compare alongside (up to 4: remove one to add another)

ASB-SpecvsBSpc ×EPvsF6 ×FAvsFB ×FCFE2FFFPFVFXGT1GT2GTXHPPP2SMSMXSRF×SRF3STLSTUT1T2T3T4Show 47 inactive classes

Series Runoffs Super Tour Both

Reference · what % is measured against

Tracks · untick to narrow Auto Club Speedway Barber Motorsports Park Blackhawk Farms Raceway Buttonwillow Raceway Park Circuit of St. Louis (formerly Gateway Motorsports Circuit of the Americas Daytona International Speedway Grattan Raceway Hallett Motor Racing Circuit Homestead-Miami Speedway Indianapolis Motor Speedway Laguna Seca Michelin Raceway Road Atlanta Mid-Ohio Sports Car Course New Jersey Motorsports Park NOLA Motorsports Park Pacific Raceways Pittsburgh International Race Complex Portland International Raceway Pueblo Motorsports Park Road America Sebring International Raceway Sonoma Raceway Summit Point Raceway Thunderhill Raceway Park Virginia International Raceway Watkins Glen International Willow Springs Raceway

Closest to the field: SRF 100.0% of SRF Cliff White, Daytona International Speedway Runoffs 2015 race · FB 81.7% of SRF J R Osborne, Daytona International Speedway Runoffs 2015 race

% of SRFLap times

SRFFBF6BSpcsolid race · dashed qualifying · slower is lower

SRFFBF6BSpcsolid race · dashed qualifying · each class's best lap as a share of SRF's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	SRF			FB					F6					BSpc
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs SRF	% of SRF	Qual best	Race best	Trap	vs SRF	% of SRF	Qual best	Race best	Trap	vs SRF	% of SRF
	Road America Runoffs 20262026-09-28									2:18.489Calvin Stewart · fastest of 13 · top 5 within 4.2s-0.617s (-0.44%)	2:20.255James Weida · fastest of 13 · top 5 within 2.0s+1.415s (+1.02%)	143.0Calvin Stewart-4.5 mph (-3.1%)
5 rule changes (SRF: 5)1 suspension & brakes · 4 othershowhide 2026-09-01 SRF GCR Rain/Brake Light Correction #40579suspension & brakes 2026-03-01 SRF SRF3 Spark Plugs #39899other 2025-10-01 SRF Add HD Oil Cooler #38979other 2025-04-01 SRF Driver Safety & Comfort #37966other 2025-04-01 SRF Update SADEV transmission specs #37992other
	Road America Runoffs 20242024-10-01									2:19.106Calvin Stewart · fastest of 22 · top 5 within 1.3s	2:18.840James Weida · fastest of 22 · top 5 within 1.0s	147.6Calvin Stewart
10 rule changes (SRF: 10)3 suspension & brakes · 3 tyres & wheels · 1 weight · 1 wording · 2 othershowhide 2024-10-01 SRF Update SRF3 Air Filter Rule #36681other 2024-10-01 SRF Update SRF Brake Rotor Thickness #36687suspension & brakes 2024-10-01 SRF Hoosier Tire Decal Placement #36739tyres & wheels 2024-09-01 SRF Protest Fee Clarification #36540wording 2024-09-01 SRF Update to Letter 36619 with new Hoosier Contingency Decal Info #36624tyres & wheels 2024-08-01 SRF Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheels 2024-01-01 SRF Update SRF Rain / Brake Rule #34706suspension & brakes 2024-01-01 SRF Update SRF Brake Light Rule v1 #34853suspension & brakes 2024-01-01 SRF SRF / SRF3 Rule Updates #35268weight 2023-10-01 SRF SRF Radiator Rule Update #34805other
	Virginia International Raceway Runoffs 20232023-09-23									1:57.437Calvin Stewart · fastest of 9 · top 5 within 4.7s	1:58.816Calvin Stewart · fastest of 9 · top 5 within 3.6s	144.0Calvin Stewart
17 rule changes (SRF: 17)5 suspension & brakes · 5 tyres & wheels · 3 weight · 2 engine · 2 othershowhide 2023-06-01 SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheels 2023-05-01 SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheels 2023-03-01 SRF Update SRF Brake Rule #33469suspension & brakes 2022-06-01 SRF SRF Tire Rule Update #32614tyres & wheels 2022-06-01 SRF Brake, seal, and air filter clarifications #32670suspension & brakes 2021-12-01 SRF Three Updates to SRF Rules #31523weight 2021-08-01 SRF SRF Wet Tires #30849tyres & wheels 2021-08-01 SRF SADEV-SRF3 Transmission #30926other 2021-08-01 SRF SRF Update Maintenance, Repairs and Seals #30961engine 2021-06-01 SRF SRF3 Alternator Pulley #30684weight 2021-03-01 SRF Mandatory identification: #30223engine 2020-12-01 SRF SRF Shocks, Springs and Ride Height. #29688suspension & brakes 2020-05-01 SRF SRF Bump Stop Correction #27019suspension & brakes 202-01-01 SRF SRF Rain / Brake Rule - BoD approved as follows #34958suspension & brakes 2019-12-01 SRF SRF Tire Warmer Rule #27622tyres & wheels 2019-12-01 SRF SRF / SRF3 Nose Weight Reduction #27706weight 2019-12-01 SRF SRF / SRF3 Majors & Regional Class Updates #27723other
	Virginia International Raceway Runoffs 20192019-10-05				1:54.469Pete Frost · only car	1:57.688Pete Frost · only car	145.9Pete Frost
1 rule change (SRF: 1)1 othershowhide 2019-07-01 SRF SRF Dash Windscreen Kit #27028other
	Sonoma Raceway Runoffs 20182018-10-10				1:28.612J R Osborne · fastest of 7 · top 5 within 3.3s	1:31.189J R Osborne · fastest of 7 · top 5 within 3.7s	140.5J R Osborne
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s	1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s		1:33.746Gary Hickman · fastest of 18 · top 5 within 3.3s	1:33.702Alex Mayer · fastest of 17 · top 5 within 3.0s		-20.067squal -17.827s	82.4%qual 84.0%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s	1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s		1:19.886Alex Mayer · fastest of 10 · top 5 within 1.5s	1:21.015Jeremy Hill · fastest of 10 · top 5 within 1.2s		-16.606squal -17.458s	83.0%qual 82.1%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	2:14.306Cliff White · fastest of 39 · top 5 within 1.2s	2:16.700Cliff White · fastest of 38 · top 5 within 0.5s		1:50.711J R Osborne · fastest of 20 · top 5 within 1.1s	1:51.616J R Osborne · fastest of 19 · top 5 within 2.1s		-25.084squal -23.595s	81.7%qual 82.4%

By track

Track	Events	Typical % of SRF	Best	Latest
Road America	2	0 of 2 with SRF
Virginia International Raceway	2	0 of 2 with SRF
Daytona International Speedway	1	100.0%	100.0%Runoffs 2015	100.0%Runoffs 2015
Indianapolis Motor Speedway	1	100.0%	100.0%Runoffs 2017	100.0%Runoffs 2017
Mid-Ohio Sports Car Course	1	100.0%	100.0%Runoffs 2016	100.0%Runoffs 2016
Sonoma Raceway	1	0 of 1 with SRF

About this data

Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of SRF's best on the same day: the weather and the day cancel out, so one figure compares across years where lap times cannot; a class that suits one track more than another still reads differently there. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.