Seb Grindley is a name to watch in 2027. He is currently one of the best U23 riders in the UK, and rides for the Lidl–Trek Future Racing team. The Lidl–Trek development team acts as a feeder team into the WorldTour. Lidl-Trek provides opportunities for development riders to race alongside the WorldTour pros and Seb has held his own alongside the world’s best riders. He recently finished in the top 10 at the Philadelphia Cycling Classic (1.1), just behind his teammate Quinn Simmons. His jersey is hung up in pride of place in my fit studio. We think a lot of Seb, and he is a great supporter of Crimson Performance and Velo Edge.
I first started working with Seb in 2024. At that time he was riding for the Fensham Howes-MAS Design-CAMS team and the 2024 season was his last as a junior. It also offered a massive opportunity to step up into a bigger development team. Seb had some specifics to cover in this first session; he was experiencing left lateral knee pain as well as soft tissue discomfort with his saddle setup. Seb hadn’t had a professional bike fitting before and his physiology had changed a lot through his junior years. As with every bike fitting, I started with the screening assessment. This identified a few areas that Seb needed to work on off the bike. It also identified some areas which would help with his areas of discomfort. Seb had heavily pronated feet and required in-shoe support. He also had external rotation of both feet which was leading to wear on both crank arms.
We started with his current riding position on the fitting jig; it was quick to see that Seb’s saddle was too high and was creating instability in the pelvis as well as forward movement during higher power efforts. Seb’s saddle to bar drop was also massive: he was running a 144 mm bar drop. Quickly into the fitting I decided to fit +4 mm Shimano SPD-SL pedals to increase stance width. I also maxed out the cleat stance width and switched the float from 2° to 6°. Seb needed more stance on the bike. He was striking the cranks on most downstrokes. The cranks were a barrier for his feet to find the position they wanted to be in. I decided to increase the cleat float to see if this helped reduce tension on the left knee. These changes worked well and Seb’s knee discomfort started to improve. I then reduced the saddle height by 25 mm, positioned the saddle 5 mm forward and set the bar drop to 117 mm. These changes helped to stabilise Seb on the saddle. I used the Gebiomized saddle pressure mapping to validate the changes. I also decided to switch out the saddle to a Prologo Nago R4 147. This saddle had a narrower mid-section vs the Syncros Belcarra that Seb had been using. I wanted to clear space around the middle of the saddle as Seb had been developing sores. See the pressure shots below for a comparison:
One of the areas that we highlighted in the screening was Seb’s pronated feet. The pronation was creating instability up the kinetic chain (this was easier to see at higher power efforts). Seb was pronating at the bottom of the pedal stroke which was resulting in internal rotation of the subtalar joint and as a result more lateral movement in the knee and the pelvis. I decided to make Seb a set of Sidas Custom Pro insoles. The medial arch support was aggressive to offer enough support during higher power efforts. The introduction of the insoles was a hit! Seb felt more stability over the top of the pedal stroke and less movement in the knees. We finished the fitting with some big positional changes, and it was time to test things out on the road. Seb responded really well to the new position and a few weeks later he finished 11th at the Paris-Roubaix Juniors followed by 9th at the E3 Saxo Classic.
Seb moved up to Lidl–Trek Future Racing team in 2025 and was supported by the team with bike fit. I was able to keep in touch with him when he visited the studio for custom insoles for his race shoes. I think I have made about 6 sets of insoles for Seb. The lad has a lot of shoes! Seb had been mentioning discomfort on his Trek Madone team bike, and we decided to wait for a quieter point in the season for a positional review. This opportunity came recently just after the Philadelphia Cycling Classic. When a professional cyclist needs bike fit support during the season there is a definite reason for it. The most common issues are saddle sores, knee pain, back and neck discomfort. It is important that only necessary changes are made during bike fits mid-season. The off-season provides opportunities to test components and bigger positional changes. There is always a degree of caution about making too many changes and potentially worsening the discomfort. Seb also had a nasty crash at the 2025 National Road Race Championship where he fractured the right side of the C4 cervical vertebra and required a neck brace for 3 months. There were a few things to consider in this review, and we referred to tried and tested optimal fit data from the session back in 2024. The neck injury had created some physiological asymmetries, which Seb was receiving ongoing physio treatment for. Seb also needed to work on the right glute medius strength, which we identified in the single-leg squats. Have a look at the red line on the pressure mapping shots below. This indicates the angle of regression of the pelvis. The red line rotates in an anticlockwise manner which follows the internal rotation of Seb’s right ASIS. We finished the review session with Seb’s saddle height at 800 mm and his reach 30 mm longer than 2024 data. We also made a few small tweaks to the saddle setback and angle which improved the pressure on the saddle. See the comparison below:
Seb has some big races left before the 2026 season ends. I wish him every success moving forward and we can’t wait to see what the future holds. I can see a rider like Seb winning a monument in the future. He has all the attributes to do this. Crimson Performance will be at his side with bike fit support to make sure he has every chance to do this.
Written by Matt Hallam, IBFI Level 4 Master Bike Fitter at Crimson Performance.
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