Buying guide · 2026
7 min read
Bike size guide — how to choose the right size
Bike sizing is not one height chart fits all. Standover, reach, and intended riding style change the right size — especially between brands like Marin, Mondraker, and Basso. Use this guide as a starting point, then confirm in store or book a bike fitting.
Rider height vs frame size
Manufacturer size charts (S/M/L/XL) translate inside leg and height to frame size. They are starting points — two riders the same height may need different sizes based on arm length and flexibility.
Reach and cockpit
Reach affects how stretched you feel on descents and flats. Too long causes neck and lower back strain; too short feels twitchy at speed. Stem length and handlebar rise fine-tune fit after frame choice.
Mountain bike sizing notes
Mondraker Forward Geometry often suits sizing by reach rather than seat tube alone. Marin trail bikes follow conventional charts on product pages. When between sizes on an e-MTB, consider battery weight and standover for mounting.
Road and gravel sizing
Basso road bikes reward professional fitting — saddle setback and bar drop matter for long rides. Gravel bikes may size like endurance road frames; check tyre clearance if you plan mudguards for commuting.
Why buy from Stretton Bikes?
Stretton Bikes is an independent bike shop in Ashby-de-la-Zouch, Leicestershire. We stock Marin, Mondraker and Basso, offer workshop servicing, professional bike fitting, and honest advice for riders across the East Midlands — from trail centres in Derbyshire to road loops in Leicestershire.
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Frequently asked questions
Yes — kids bikes size by wheel diameter and inside leg. Bring your rider to the shop for a standover check on Marin or Mondraker kids models.
Not sure on size?
Visit us in Ashby-de-la-Zouch or book a fitting session — we will measure reach, saddle height, and cockpit setup on the bikes you are considering.
Book a bike fitting