IndyCar veteran Graham Rahal shared a heartwarming message for his sister-in-law, Brittany Force, after she announced her NHRA retirement on Friday. The two-time Top Fuel world champion, nicknamed 'Queen of Speed', revealed the reason behind retiring as wanting to start a family with husband Bobby Lyons, whom she married in November 2024.Force went on a record-breaking spree in the 2025 NHRA season. She broke her Top Fuel speed record of 338.94 mph this season and breached the 340 mph mark, which no driver had done in the category's history, an impressive 10 times. Graham Rahal, who is married to Courtney Force, a former NHRA drag racer and Brittany Force's younger sister, reacted to the 39-year-old's retirement. In a post on the social media platform X, the Rahal Letterman Lanigan Racing driver wrote:"The Queen of Speed. Proud of my sista B. She’s a great example of how you can be so successful, yet humble and kind to those around you. I cannot wait for what’s next for you, Bob and Bro. We love you B."Brittany Force, who drove for John Force Racing, a team founded by her 16-time NHRA champion father, John Force, won a record 18 races in her 13-year NHRA Top Fuel career, tied with Shirley Muldowney at the top.Graham Rahal's wife Courtney Force's reaction to sister Brittany Force's retirement announcementCourtney Force and Brittany Force at the NHRA Toyota Nationals - Source: GettyGraham Rahal's wife, Courtney Force, the youngest of John Force's four drag racer daughters, retired from NHRA in 2019 to start a family. She was the winningest female driver in Funny Car history and at the top of her game when she retired.As her sister Brittany followed suit six years later, Courtney shared a sweet message for her. She reshared a collaborative Instagram post by John Force Racing and Brittany Force on her story and wrote:"So proud of my sister @brittanyforce and all she has accomplished throughout her career. But excited for her next chapter!"A snapshot of Courtney Force's Instagram story (@courtneyforce)Graham Rahal and Courtney Force have two daughters, Tinley and Harlan, and are expecting a third child this IndyCar offseason. Elder daughter Harlan was born in November 2020, and the couple welcomed Tinley in September 2022.The IndyCar veteran had a volatile 2025 season, witnessing some unexpected highs and many lows. A P6 finish at the IMS road course in May and a P4 finish in Portland, his sole Top 5 of the season, were among the highlights. However, Rahal felt Rahal Letterman Lanigan Racing made significant progress in their on-track performance, especially in qualifying, and that the team was on the cusp of something big.RLL will continue with its three drivers, Graham Rahal, Devlin DeFrancesco, and Louis Foster, who won the 2025 Rookie of the Year award, in 2026.