My bike is about five years old. It's a Giant Trance 27.5, it's been a great bike. It's still a great bike. But after years of mates telling me e-bikes are the way forward, and a teenager who has now taken de facto ownership of the bike I've finally decided to look into and eMTB as an option.
So here's the question. If I want to go electric but keep the same kind of riding I already do, what does that actually look like? What changes, what stays the same, and what should I expect from a modern e-trail bike compared to an older analogue one?
It reminded me of a trip to a trail centre years ago. We walked into the shop and asked the manager for the "lowest amount of uphill climb" for the "biggest amount of downhill fun". He looked at us and said, "You lads need motocross bikes." Fair point at the time. But e-MTBs now fill exactly that gap perfectly.
The bike I'm comparing against
My 2019/20 Giant Trance 27.5 (Medium): 435mm reach, 591mm stack, 67° head angle, 140mm rear travel, 150mm fork, 27.5" wheels front and rear, around 13.5kg without pedals.
The e-MTB equivalent at Sprockets Cycles is the Trek Powerfly FS+ 4 Gen 4 at £4,150. Full-power Bosch motor, 130mm front and 120mm rear travel, 800Wh battery, 29" wheels. Same category, different package.
The geometry has moved on, motor or no motor
This is the bit a lot of people miss. Even if you took the motor out of the equation, modern trail bikes have evolved significantly in five years. Reach numbers are longer, head angles are slacker, seat tubes are shorter, droppers are longer.
For context, in a size Medium:
- Old Trance 27.5: 435mm reach, 591mm stack, 67° head angle, ~150mm dropper
- Modern Powerfly FS+: longer reach, considerably taller stack, slacker head angle, 170mm dropper
The reach is broadly similar across the trail category. The big differences are a taller front end, a slacker head angle for more confident descending, and a longer dropper for genuinely getting the saddle out of the way.
None of that is down to the motor. That's just what modern trail bikes look like now. The Powerfly's travel is slightly less than my old Trance (130/120 vs 150/140) but the modern geometry more than makes up for it. Sizing-wise, if you're a Medium on the old bike, you'll likely be a Medium on the new one. Reach is the number to match.
Wait, what does "reach" actually mean?
This caught me out, and it's worth explaining because it's not what most riders think it means.
In bike industry terms, reach is the horizontal distance from the bottom bracket (where the cranks meet the frame) to the top centre of the head tube (where the bars sit). It's a measurement taken with the bike empty, no rider, no saddle position factored in. It describes how much room you've got when you're standing up on the pedals.
What I thought reach meant, and what I suspect a lot of riders assume, is the distance from the saddle to the handlebars. The bit that determines how stretched out you feel when you're sitting down pedalling. That's a different measurement entirely, called effective top tube length (ETT). Most geometry charts list it as a separate number.
The two are linked, but not the same. A bike can have a longer reach than my old Trance but a shorter effective top tube, because the seat tube angle has changed.
The seated position is genuinely different
I noticed this when I started comparing pictures of my Trance with the Powerfly side by side. The reach numbers came out fairly similar, but the saddle on the new bike clearly sits closer to the handlebars. I prefer the longer stretch I'm used to. Turns out this isn't accidental.
Old trail bikes (mine included) had slacker seat tube angles, around 74-75°. The seat tube leans back from vertical, so as the saddle rises out of the frame, it travels backwards as well as up, sitting you further behind the bottom bracket. Modern e-MTBs run 76-78° seat tubes. More vertical, saddle pushed forward, sitting you almost directly over the cranks.
Why? Two reasons. First, a more upright seated position is more efficient for the kind of steep, technical climbing the motor lets you attempt. Second, motor and battery packaging in the down tube forces design choices that pretty much require the steeper angle to keep weight distribution right.
I looked into whether there's a modern e-MTB still running a slacker seat tube to give that older-style stretched-out cockpit. Short answer: no. I checked Trek, Giant, Whyte, Santa Cruz, Marin, GasGas, Velduro, every full-power e-MTB at Sprockets sits in the 76-78° range. The industry has moved as one. There's no e-MTB you can buy today that recreates the seated position of a 2019 trail bike.
That's worth knowing before you walk into a demo. The new position isn't wrong, it's just different. You will adapt within a few rides. But if you want to claw back some of the seated reach, the practical fixes are sliding the saddle backwards on its rails (most have 20-30mm of fore/aft adjustment) and fitting a slightly longer stem. Past that, you accept the new normal.
What's actually different
Weight
My old Trance is around 13.5kg. The Powerfly FS+ is around 24kg. That's nearly 11kg extra, the equivalent of strapping a full crate of beer to the frame. The motor and battery do all the work going up, so you won't feel it on the climbs. You will feel it in the air, on tight switchbacks, and when lifting the bike onto a roof rack.
Cranks and saddle height
The Powerfly runs 165mm cranks. My old Trance came with 175mm cranks as standard in size Medium, typical for trail bikes of that era. The shorter cranks on the e-bike give you ground clearance for the steep, technical climbs the motor opens up, climbs you'd previously have walked. With shorter cranks, your foot doesn't drop as low at the bottom of the pedal stroke, so raise your saddle by around 5-10mm compared to your old setup to keep the same leg extension.
Wheels
My old bike is full 27.5". The Powerfly is full 29er. The bigger wheels roll over obstacles better and feel more planted on rough terrain, with the trade-off of slightly less low-speed playfulness. Most riders coming off older 27.5 trail bikes find it a positive change.
So is it worth it?
If you've been on an older trail bike and you're starting to feel its age (or your age), a modern e-trail bike feels like a complete upgrade in two directions at once. The geometry alone would make a difference. The motor on top makes it transformative. An 800Wh battery is good for a full day in the Galloway Forest or Glentress, with enough left for a cheeky bonus lap.
This post covered the like-for-like swap. If the motor opens up bigger terrain and you want a bigger bike to match, that's a different conversation, longer travel, slacker angles, a much taller and longer bike. That's the subject of Part 2: From an Older Trail Bike to a Modern Enduro E-MTB.
One last thing
Numbers on a page only get you so far. Reach figures, stack heights and crank measurements are a starting point, but they don't tell you how a bike feels under you on actual trails. The only way to really know if a bike fits is to get a leg over it. Come down to the shop in Kilmarnock, book a demo, or browse the full electric mountain bike range online and we'll talk you through your options.
Quick answers
What does reach mean on a mountain bike? Reach is the horizontal distance from the centre of the bottom bracket to the top centre of the head tube. It's a frame measurement that describes how much room you have when standing up on the pedals, not how stretched out you feel when seated.
Is reach the distance from the saddle to the handlebars? No. Reach is a frame measurement from the bottom bracket to the head tube. The saddle-to-handlebar distance is called effective top tube length (ETT), and it's a separate number on a geometry chart.
Why does the saddle feel closer to the handlebars on a modern e-MTB? Modern e-MTBs run steeper seat tube angles, typically 76-78° compared to 74-75° on older trail bikes. The steeper angle pushes the saddle forward over the bottom bracket, which shortens the seated cockpit even when the reach measurement stays similar.
Do I need to buy the same size e-MTB as my current mountain bike? Match the reach number rather than the size letter. Reach has stayed broadly similar across the trail category over the last five years, so if you ride a Medium analogue trail bike, you'll most likely be a Medium on a modern e-trail bike.
How much heavier is an electric mountain bike than a regular one? A full-power e-MTB weighs around 22-24kg, roughly 8-10kg heavier than a comparable analogue trail bike. The motor and battery do the work on climbs so you won't notice the weight pedalling uphill, but you will feel it on switchbacks, in the air, and when lifting the bike onto a roof rack.
Why are the cranks shorter on an e-MTB? E-MTBs typically ship with 160-165mm cranks instead of the 170-175mm cranks fitted to older trail bikes. The shorter length prevents pedal strikes on the steep, technical climbs the motor lets you attempt. Raise your saddle by 5-10mm compared to your old setup to maintain the same leg extension.
Why is the front end taller on a modern mountain bike? Stack heights have grown across the trail category in the last five years, regardless of whether the bike has a motor. A taller stack puts you in a more centred riding position with less weight over the front wheel, which improves stability on descents.
Can I still get an e-MTB with traditional, slacker geometry? No. Every current full-power e-MTB sits in the 76-78° effective seat tube angle range, including Trek, Giant, Whyte, Santa Cruz, Marin, GasGas and Velduro. The motor and battery packaging force this design choice. If you prefer the older stretched-out seated position, the practical options are to slide your saddle backwards on its rails, fit a slightly longer stem, or simply adapt to the new position over a few rides.
Will the motor make me a lazy rider? No. Modern e-MTBs only provide assistance when you pedal, so you still put in the work. The motor lets you cover more ground, do more laps, and finish less broken at the end of a ride.