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Best eMTB frame size for a 5'1" woman — where do I start?
- Thread starter daffodil
- Start date
At 5'1" (155cm) you're firmly in Small territory for nearly every brand — but the size on the box matters far less than two numbers: reach and standover/seat tube length. Let me explain why those two save you from a bike that fits on paper but fights you on the trail.
Reach — aim for roughly 410–435mm
For your height that's the sweet spot. eMTBs carry a lot of inherent stability from the weight and longer wheelbase, so you can comfortably run a slightly shorter reach without the bike feeling nervous — the consensus on here (see @Plummet's sizing notes) is that shorter reach is more forgiving on an ebike than on an analogue trail bike. Too long a reach is the classic mistake: it stretches you out, kills your ability to weight the front, and makes steep stuff genuinely scary.
Seat tube length and standover — this is the one that actually catches shorter riders
eMTBs hide a chunky battery in the down tube and often a tall motor housing, which pushes seat tubes and standover up. Plenty of "Small" frames still won't let a 155cm rider slam a dropper post far enough. Two things to check before buying:
• Seat tube length — short enough that you can run a 150mm+ dropper at full insertion with the saddle at your pedalling height.
• Standover — you want clear, confident clearance over the top tube flat-footed.
Don't lean on reach alone to compare across brands
As @knut7 pointed out in an older sizing thread, effective top tube (ETT) gives a truer picture of how stretched-out you'll feel, because seat angle and front-centre vary between bikes. A 420mm reach on a slack seat-tube bike can feel very different from the same number elsewhere.
Practical advice:
• Get a test ride or at least a standover check in person — sizing charts have typos more often than you'd think (the 2020 Kenevo chart was a famous offender).
• If you're between Small and a brand's "XS", and the XS exists, it's usually worth trying — several brands now build genuine XS eMTB frames with shorter cranks (160–165mm) which also helps pedal clearance and fit.
• Watch crank length and bar width too — narrower bars (740–760mm) suit smaller frames better.
If you tell me which bikes you're shortlisting and your inside-leg measurement, I'll pull the actual reach and seat tube numbers and tell you straight which size to go for.
Reach — aim for roughly 410–435mm
For your height that's the sweet spot. eMTBs carry a lot of inherent stability from the weight and longer wheelbase, so you can comfortably run a slightly shorter reach without the bike feeling nervous — the consensus on here (see @Plummet's sizing notes) is that shorter reach is more forgiving on an ebike than on an analogue trail bike. Too long a reach is the classic mistake: it stretches you out, kills your ability to weight the front, and makes steep stuff genuinely scary.
Seat tube length and standover — this is the one that actually catches shorter riders
eMTBs hide a chunky battery in the down tube and often a tall motor housing, which pushes seat tubes and standover up. Plenty of "Small" frames still won't let a 155cm rider slam a dropper post far enough. Two things to check before buying:
• Seat tube length — short enough that you can run a 150mm+ dropper at full insertion with the saddle at your pedalling height.
• Standover — you want clear, confident clearance over the top tube flat-footed.
Don't lean on reach alone to compare across brands
As @knut7 pointed out in an older sizing thread, effective top tube (ETT) gives a truer picture of how stretched-out you'll feel, because seat angle and front-centre vary between bikes. A 420mm reach on a slack seat-tube bike can feel very different from the same number elsewhere.
Practical advice:
• Get a test ride or at least a standover check in person — sizing charts have typos more often than you'd think (the 2020 Kenevo chart was a famous offender).
• If you're between Small and a brand's "XS", and the XS exists, it's usually worth trying — several brands now build genuine XS eMTB frames with shorter cranks (160–165mm) which also helps pedal clearance and fit.
• Watch crank length and bar width too — narrower bars (740–760mm) suit smaller frames better.
If you tell me which bikes you're shortlisting and your inside-leg measurement, I'll pull the actual reach and seat tube numbers and tell you straight which size to go for.