BayCEER Workshop 2025

Quantifying the abrasion of microplastic from bicycle tires

Introduction

Microplastics (MPs) are significant pollutants in our ecosystems. Current research focuses on detecting MPs in environmental samples but often overlooks their sources and spatial distribution. While tire wear particles (TWP) from cars are known to be a major source of MPs (Thompson et al., 2004), little to none is known about bicycle tire abrasion. Mountain biking, a popular outdoor sports in Germany (IfD Allensbach, 2023; Mountainbike Tourismusforum Deutschland e.V., 2022), produces abrasion particles through direct tire-environment interaction. This potentially significant but underexplored source of MPs requires thorough investigation to identify intervention points and reduce global MP emissions. Our research quantifies microplastic abrasion from mountain bike tires in real-life usage.

Methods

We measured the weight loss of bike tires in a real-life use scenario to quantify abrasion throughout their lifecycle. Over 90 subjects tracked the routes via GPS ridden with provided tires to calculate weight loss with distance. This follows a similar approach tested for quantifying tire abrasion of motorized vehicles (Kreider et al., 2010; Silvestro & ADAC Technik Zentrum, 2022).

Results

We found an average abrasion rate from 0.36 (road bike, front tire) to 2.05 grams (mountain bike, rear tire) per 100 kilometres and tire. Over At every measurement point for all tire sets the rate was higher for the rear compared to the front tire. These values are comparatively low to abrasion rates between 11 up to 95 grams per 100 kilometres from motorized vehicles.

Discussion

Overall, the method of gravimetrically measuring weight loss proved to be an effective way to quantitatively assess the microplastic abrasion emitted by bike tires. Tire abrasion quantities between different tire types could be explained by tire attributes (e.g. different compounds, contact area and ridden tire pressure). Different abrasion quantities of individual tires of the same type could be explained by rider/bike attributes (e.g. system weight, riding style, suspension) and environmental attributes (e.g. surface type, incline/decline, surface moistness, temperature).

Outlook

In the next step we will calculate the influence of different parameters (environment and rider/bike) on bike tire abrasion. Following we will try to model the load and spatial distribution of bicycle tire-based MPs in the environment. With this research the global MP cycle can be better understood, and our data could help find solution to protect the environment from pollution.

Literatur

IfD Allensbach. (2023). Anzahl der Personen in Deutschland, die in der Freizeit Mountainbike fahren, nach Häufigkeit von 2019 bis 2023 (in Millionen). Statista. https://de.statista.com/statistik/daten/studie/171142/umfrage/haeufigkeit-von-mountainbike-fahren-in-der-freizeit/

Kreider, M. L., Panko, J. M., McAtee, B. L., Sweet, L. I., & Finley, B. L. (2010). Physical and chemical char-acterization of tire-related particles: Comparison of particles generated using different methodolo-gies. Science of The Total Environment, 408(3), 652–659. https://doi.org/10.1016/j.scitotenv.2009.10.016

Mountainbike Tourismusforum Deutschland e.V. (2022). Der Mountainbike-Monitor – Die Basis für erfolgrei-chen Mountainbike-Tourismus. https://www.mountainbikeforum.de/mountainbike-wissen/marktforschung-grundlagen-untersuchung-mountainbike-monitor-2022/

Silvestro, D., & ADAC Technik Zentrum. (2022). Tyre wear particles in the environment. https://www.adac.de/rund-ums-fahrzeug/ausstattung-technik-zubehoer/reifen/reifenkauf/reifenabrieb-mikroplastik/

Thompson, R. C., Olsen, Y., Mitchell, R. P., Davis, A., Rowland, S. J., John, A. W. G., McGonigle, D., & Russell, A. E. (2004). Lost at Sea: Where Is All the Plastic? Science, 304(5672), 838–838. https://doi.org/10.1126/science.1094559