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BoP Lab / Classes / SRF

SRF vs F6 vs FB vs F5 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-SpecEPvsF5×vsF6×FAvsFB×FCFE2FFFPFVFXGT1GT2GTXHPPP2SMSMXSRF×SRF3STLSTUT1T2T3T4Show 47 inactive classes
Series
Reference · what % is measured against
Tracks · untick to narrow

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 · F5 90.2% of SRF Matthew Strand, Daytona International Speedway Runoffs 2015 race

1:201:402:002:202 rule changes between Runoffs 2018 and Runoffs 20192 ▾11 rule changes between Runoffs 2019 and Runoffs 202011 ▾9 rule changes between Runoffs 2020 and Runoffs 20219 ▾9 rule changes between Runoffs 2021 and Runoffs 20229 ▾3 rule changes between Runoffs 2022 and Runoffs 20233 ▾10 rule changes between Runoffs 2023 and Runoffs 202410 ▾5 rule changes between Runoffs 2024 and Runoffs 20265 ▾SRF race best at Runoffs 2015: 2:16.700 (Cliff White)SRF race best at Runoffs 2016: 1:37.621 (Todd Harris)SRF race best at Runoffs 2017: 1:53.769 (Todd Harris)SRF qualifying best at Runoffs 2015: 2:14.306 (Cliff White)SRF qualifying best at Runoffs 2016: 1:37.344 (Mike Miserendino)SRF qualifying best at Runoffs 2017: 1:51.573 (Thomas Kirchman)F6 race best at Runoffs 2023: 1:58.816 (Calvin Stewart)F6 race best at Runoffs 2024: 2:18.840 (James Weida)F6 race best at Runoffs 2026: 2:20.255 (James Weida)F6 qualifying best at Runoffs 2023: 1:57.437 (Calvin Stewart)F6 qualifying best at Runoffs 2024: 2:19.106 (Calvin Stewart)F6 qualifying best at Runoffs 2026: 2:18.489 (Calvin Stewart)FB race best at Runoffs 2015: 1:51.616 (J R Osborne)FB race best at Runoffs 2016: 1:21.015 (Jeremy Hill)FB race best at Runoffs 2017: 1:33.702 (Alex Mayer)FB race best at Runoffs 2018: 1:31.189 (J R Osborne)FB race best at Runoffs 2019: 1:57.688 (Pete Frost)FB qualifying best at Runoffs 2015: 1:50.711 (J R Osborne)FB qualifying best at Runoffs 2016: 1:19.886 (Alex Mayer)FB qualifying best at Runoffs 2017: 1:33.746 (Gary Hickman)FB qualifying best at Runoffs 2018: 1:28.612 (J R Osborne)FB qualifying best at Runoffs 2019: 1:54.469 (Pete Frost)F5 race best at Runoffs 2015: 2:03.298 (Matthew Strand)F5 race best at Runoffs 2016: 1:29.853 (Steven Thompson)F5 race best at Runoffs 2017: 1:42.860 (Wiley Clinton McMahan)F5 race best at Runoffs 2018: 1:42.491 (David Lapham)F5 race best at Runoffs 2019: 1:57.572 (Wiley Mcmahan)F5 race best at Runoffs 2020: 2:21.391 (James Weida)F5 race best at Runoffs 2021: 1:43.140 (Sven de Vries)F5 race best at Runoffs 2022: 2:21.862 (Sven de Vries)F5 qualifying best at Runoffs 2015: 2:01.824 (W. Clint McMahan)F5 qualifying best at Runoffs 2016: 1:28.528 (Calvin Stewart)F5 qualifying best at Runoffs 2017: 1:43.136 (Wiley Clinton McMahan)F5 qualifying best at Runoffs 2018: 1:41.807 (Jeff Jorgenson)F5 qualifying best at Runoffs 2019: 1:57.361 (Wiley Mcmahan)F5 qualifying best at Runoffs 2020: 2:20.954 (Calvin Stewart)F5 qualifying best at Runoffs 2021: 1:42.619 (Ryan Mayfield)F5 qualifying best at Runoffs 2022: 1:57.689 (James Weida)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2026R2026
SRFF6FBF5solid race · dashed qualifying · slower is lower
80%85%90%95%100%2 rule changes between Runoffs 2018 and Runoffs 20192 ▾11 rule changes between Runoffs 2019 and Runoffs 202011 ▾9 rule changes between Runoffs 2020 and Runoffs 20219 ▾9 rule changes between Runoffs 2021 and Runoffs 20229 ▾3 rule changes between Runoffs 2022 and Runoffs 20233 ▾10 rule changes between Runoffs 2023 and Runoffs 202410 ▾5 rule changes between Runoffs 2024 and Runoffs 20265 ▾SRF race best at Runoffs 2015: 100.0% of SRF's (Cliff White)SRF race best at Runoffs 2016: 100.0% of SRF's (Todd Harris)SRF race best at Runoffs 2017: 100.0% of SRF's (Todd Harris)SRF qualifying best at Runoffs 2015: 100.0% of SRF's (Cliff White)SRF qualifying best at Runoffs 2016: 100.0% of SRF's (Mike Miserendino)SRF qualifying best at Runoffs 2017: 100.0% of SRF's (Thomas Kirchman)FB race best at Runoffs 2015: 81.7% of SRF's (J R Osborne)FB race best at Runoffs 2016: 83.0% of SRF's (Jeremy Hill)FB race best at Runoffs 2017: 82.4% of SRF's (Alex Mayer)FB qualifying best at Runoffs 2015: 82.4% of SRF's (J R Osborne)FB qualifying best at Runoffs 2016: 82.1% of SRF's (Alex Mayer)FB qualifying best at Runoffs 2017: 84.0% of SRF's (Gary Hickman)F5 race best at Runoffs 2015: 90.2% of SRF's (Matthew Strand)F5 race best at Runoffs 2016: 92.0% of SRF's (Steven Thompson)F5 race best at Runoffs 2017: 90.4% of SRF's (Wiley Clinton McMahan)F5 qualifying best at Runoffs 2015: 90.7% of SRF's (W. Clint McMahan)F5 qualifying best at Runoffs 2016: 90.9% of SRF's (Calvin Stewart)F5 qualifying best at Runoffs 2017: 92.4% of SRF's (Wiley Clinton McMahan)Daytona International Speedway · Runoffs 2015R2015Mid-Ohio Sports Car Course · Runoffs 2016R2016Indianapolis Motor Speedway · Runoffs 2017R2017Sonoma Raceway · Runoffs 2018R2018Virginia International Raceway · Runoffs 2019R2019Road America · Runoffs 2020R2020Indianapolis Motor Speedway · Runoffs 2021R2021Virginia International Raceway · Runoffs 2022R2022Virginia International Raceway · Runoffs 2023R2023Road America · Runoffs 2024R2024Road America · Runoffs 2026R2026
SRFF6FBF5solid 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
EventSRFF6FBF5
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 20262026-09-282:18.489Calvin 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
  • SRF GCR Rain/Brake Light Correction #40579suspension & brakes
  • SRF SRF3 Spark Plugs #39899other
  • SRF Add HD Oil Cooler #38979other
  • SRF Driver Safety & Comfort #37966other
  • SRF Update SADEV transmission specs #37992other
Road America Runoffs 20242024-10-012:19.106Calvin Stewart · fastest of 22 · top 5 within 1.3s2:18.840James Weida · fastest of 22 · top 5 within 1.0s147.6Calvin Stewart
10 rule changes (SRF: 10)3 suspension & brakes · 3 tyres & wheels · 1 weight · 1 wording · 2 othershowhide
  • SRF Update SRF3 Air Filter Rule #36681other
  • SRF Update SRF Brake Rotor Thickness #36687suspension & brakes
  • SRF Hoosier Tire Decal Placement #36739tyres & wheels
  • SRF Protest Fee Clarification #36540wording
  • SRF Update to Letter 36619 with new Hoosier Contingency Decal Info #36624tyres & wheels
  • SRF Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheels
  • SRF Update SRF Rain / Brake Rule #34706suspension & brakes
  • SRF Update SRF Brake Light Rule v1 #34853suspension & brakes
  • SRF SRF / SRF3 Rule Updates #35268weight
  • SRF SRF Radiator Rule Update #34805other
Virginia International Raceway Runoffs 20232023-09-231:57.437Calvin Stewart · fastest of 9 · top 5 within 4.7s1:58.816Calvin Stewart · fastest of 9 · top 5 within 3.6s144.0Calvin Stewart
3 rule changes (SRF: 3)2 tyres & wheels · 1 suspension & brakesshowhide
  • SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheels
  • SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheels
  • SRF Update SRF Brake Rule #33469suspension & brakes
Virginia International Raceway Runoffs 20222022-09-241:57.689James Weida · fastest of 11 · top 5 within 3.9s+0.328s (+0.28%)2:21.862Sven de Vries · fastest of 10 · top 5 within 14.3s+24.290s (+20.66%)142.9Calvin Stewart+0.1 mph (+0.1%)
9 rule changes (SRF: 3, F5: 6)2 engine · 2 induction · 1 suspension & brakes · 1 tyres & wheels · 1 weight · 2 othershowhide
  • F5 Intake Boots Correction #33028induction
  • F5 Ensure availability of ECU for Rotax engines #32695engine
  • F5 Clarify stepped exhaust header references #32743engine
  • F5 593 carb boot availability and oil pump clarification #32527induction
  • SRF SRF Tire Rule Update #32614tyres & wheels
  • SRF Brake, seal, and air filter clarifications #32670suspension & brakes
  • F5 E&O class name #32194other
  • F5 Data Box Mounting Plate #31638other
  • SRF Three Updates to SRF Rules #31523weight
Indianapolis Motor Speedway Runoffs 20212021-09-251:42.619Ryan Mayfield · fastest of 22 · top 5 within 1.6s-0.517s (-0.50%)1:43.140Sven de Vries · fastest of 20 · top 5 within 1.7s+0.280s (+0.27%)144.4James Weida
9 rule changes (SRF: 6, F5: 3)3 engine · 2 tyres & wheels · 1 suspension & brakes · 1 weight · 1 wording · 1 othershowhide
  • F5 Clarify allowable assisted shifting systems #30871wording
  • F5 Request to correct terminology #30976tyres & wheels
  • SRF SRF Wet Tires #30849tyres & wheels
  • SRF SADEV-SRF3 Transmission #30926other
  • SRF SRF Update Maintenance, Repairs and Seals #30961engine
  • F5 Request to Allow Rotax 593 HO Engine #30712engine
  • SRF SRF3 Alternator Pulley #30684weight
  • SRF Mandatory identification: #30223engine
  • SRF SRF Shocks, Springs and Ride Height. #29688suspension & brakes
Road America Runoffs 20202020-10-022:20.954Calvin Stewart · fastest of 16 · top 5 within 1.8s2:21.391James Weida · fastest of 14 · top 5 within 1.5s143.2Aaron Ellis
11 rule changes (SRF: 5, F5: 6)2 engine · 2 suspension & brakes · 1 induction · 1 tyres & wheels · 1 weight · 4 othershowhide
  • F5 Request to Update Suzuki Engine Years for F500 #29453engine
  • F5 Request for Cockpit Adjustment of External Jetting Devices #28359other
  • F5 Two Stroke Motors (reply to #28359 WDYT) #28816engine
  • F5 Re letter requesting driver adjustable carb mixture #28840other
  • F5 #28359 WDYT Request for Cockpit Adjustment #28875other
  • SRF SRF Bump Stop Correction #27019suspension & brakes
  • F5 Change 600cc restrictor size #27883induction
  • SRF SRF Rain / Brake Rule - BoD approved as follows #34958suspension & brakes
  • SRF SRF Tire Warmer Rule #27622tyres & wheels
  • SRF SRF / SRF3 Nose Weight Reduction #27706weight
  • SRF SRF / SRF3 Majors & Regional Class Updates #27723other
Virginia International Raceway Runoffs 20192019-10-051:54.469Pete Frost · only car1:57.688Pete Frost · only car145.9Pete Frost1:57.361Wiley Mcmahan · fastest of 15 · top 5 within 3.8s1:57.572Wiley Mcmahan · fastest of 15 · top 5 within 4.0s142.8Eric McRee
2 rule changes (SRF: 1, F5: 1)1 weight · 1 othershowhide
  • F5 Request for Weight Increase for Motorcycle Powered Cars #27214weight +25 lbs
  • SRF SRF Dash Windscreen Kit #27028other
Sonoma Raceway Runoffs 20182018-10-101:28.612J R Osborne · fastest of 7 · top 5 within 3.3s1:31.189J R Osborne · fastest of 7 · top 5 within 3.7s140.5J R Osborne1:41.807Jeff Jorgenson · fastest of 5 · top 5 within 6.6s1:42.491David Lapham · fastest of 5 · top 5 within 9.5s113.3David Lapham
No rule changes on record between these events
Indianapolis Motor Speedway Runoffs 20172017-09-251:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s1:33.746Gary Hickman · fastest of 18 · top 5 within 3.3s1:33.702Alex Mayer · fastest of 17 · top 5 within 3.0s-20.067squal -17.827s82.4%qual 84.0%1:43.136Wiley Clinton McMahan · fastest of 38 · top 5 within 1.4s1:42.860Wiley Clinton McMahan · fastest of 37 · top 5 within 1.6s-10.909squal -8.437s90.4%qual 92.4%
No rule changes on record between these events
Mid-Ohio Sports Car Course Runoffs 20162016-09-191:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s1:19.886Alex Mayer · fastest of 10 · top 5 within 1.5s1:21.015Jeremy Hill · fastest of 10 · top 5 within 1.2s-16.606squal -17.458s83.0%qual 82.1%1:28.528Calvin Stewart · fastest of 14 · top 5 within 3.9s1:29.853Steven Thompson · fastest of 12 · top 5 within 4.5s-7.768squal -8.816s92.0%qual 90.9%
No rule changes on record between these events
Daytona International Speedway Runoffs 20152015-09-212:14.306Cliff White · fastest of 39 · top 5 within 1.2s2:16.700Cliff White · fastest of 38 · top 5 within 0.5s1:50.711J R Osborne · fastest of 20 · top 5 within 1.1s1:51.616J R Osborne · fastest of 19 · top 5 within 2.1s-25.084squal -23.595s81.7%qual 82.4%2:01.824W. Clint McMahan · fastest of 16 · top 5 within 3.0s2:03.298Matthew Strand · fastest of 15 · top 5 within 4.9s-13.402squal -12.482s90.2%qual 90.7%

By track

TrackEvents Typical % of SRF Best Latest 
Road America30 of 3 with SRF
Virginia International Raceway30 of 3 with SRF
Indianapolis Motor Speedway2100.0%1 of 2 with SRF100.0%Runoffs 2017100.0%Runoffs 2017
Daytona International Speedway1100.0%100.0%Runoffs 2015100.0%Runoffs 2015
Mid-Ohio Sports Car Course1100.0%100.0%Runoffs 2016100.0%Runoffs 2016
Sonoma Raceway10 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.