Alex’s custom-specced Marin Alpine Trail E2 ebike

By Alex Evans

Published: Monday, 09 May 2022 at 12:00 am

When Marin launched its first electric mountain bike, the Alpine Trail E2, at the very tail end of 2020, I was lucky enough to swing a leg over one of the first test samples in the country to bring you all a full review.

I was seriously impressed with the Californian brand’s debut attempt at electrification.

Its top-notch spec, reasonable price tag and awesome performance meant I awarded it 4.5 stars in my Marin Alpine Trail E2 review, which in turn earned it a place in our list of the best electric mountain bikes currently on sale.

Of course, I wouldn’t be a technical editor if I didn’t think there was some room for improvement.

This edition of BikeRadar Builds kicks off with the Alpine Trail E2’s already stellar performance, and looks to build on it with a number of choice upgrades and changes designed to coax out every last drop of available performance, and make this ebike truly mine.

Welcome to BikeRadar Builds

BikeRadar Builds is our occasional look at the team’s personal bikes, including custom rigs, commuters, dream builds, component testbeds and more.

This is our chance to geek out about the bikes we’re riding day-to-day, and explore the thinking (or lack of it!) behind our equipment choices.

The perfect starting point

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The E2 looks similar to Marin’s Alpine Trail XR.
Alex Evans / Our Media

Having raved about the bike in my review, I put my money where my mouth is and purchased this Alpine Trail E2 from Marin with my hard-earned cash.

Along with using my heating even less to finance the purchase, it also meant I had a great starting point from which to begin my customisation journey.

At the heart of the E2 is Shimano’s DU-EP800 motor and large 630Wh capacity battery. Heavy-hitting parts such as Fox’s venerable 38 fork and DHX2 rear shock also feature, bolstering the Marin’s exceptional value.

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The EP8 motor has plenty of power, but is also impressively frugal.
Alex Evans / Our Media

The frame boasts internally-routed cables, chain slap protection and space for a water bottle within the front triangle.

It has a linkage-driven single-pivot rear suspension system offering 150mm of rear wheel travel, and is roughly 17 per cent progressive.

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The E2 uses a linkage-driven single pivot suspension design.
Alex Evans / Our Media

All these elements are combined with near-Goldilocks mountain bike geometry.

The head angle is around 63 degrees, while the seat tube angle sits at 78 degrees.

The size large I own has a 485mm reach figure and 435mm chainstays. These combine with a 1264mm wheelbase and a seriously low 686mm standover height, plus a short seat tube with a large insertion depth for long-travel dropper posts.

A full bike, modified

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This spec and build meets all of my gravity-focused needs.
Alex Evans / Our Media

From the first time I rode an Alpine Trail E2 I was convinced it had more to give, and being able to buy one has given me the perfect opportunity to make all the modifications and changes I wanted to prove that theory.

Mullet massacre

Let’s start with the biggest and most important change first.

In an attempt to provide full disclosure I wouldn’t say I dislike mullet bikes (29in front, 27.5in rear), and I’ve certainly loved riding several in recent times (keep your eyes peeled for our 2022 Ebike of the Year reviews, which include loads of mullet-wheeled monsters).

But if given a choice, I’d always fit 29in wheels front and back to one of my personal bikes.

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Like all of Marin’s alloy full suspension bikes, it’s made from the brand’s Series 4 aluminium.
Alex Evans / Our Media

The wagon-wheel setup is arguably quicker, gives more grip and provides a smoother more stable riding character.

I’d also argue the mullet setup doesn’t ‘create the best of both worlds’ (in terms of stability and agility) because a bike can only really be one thing. It’s either stable, agile or somewhere in between, but can’t be simultaneously the most stable and agile.

And that’s why I went feet-first into tuning up Alpine Trail E2’s pet hate of mine: its 2.8in wide, 27.5in diameter rear tyre and wheel.

I swapped out the stock wheels for a set of Roval’s Traverse Alloy 29in wheels front and back, with the latter fitted with a normal-sized 2.5in wide Maxxis High Roller II, to de-mullet it.

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The DoubleDown casing on the High Roller II tyre has proven to be sturdy.
Alex Evans / Our Media

I’ve specced the DoubleDown casing, 3C MaxxTerra compound version of the popular rubber because I feel it offers the best balance between traction, wear rate and carcass stability.

Up front, I’ve fitted an EXO+ casing Minion DHF, but had to forego the preferred 3C MaxxGrip compound as this isn’t a combination available in my preferred 29×2.5in size.

Geometry stability

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The E2 looks similar to Marin’s Alpine Trail XR.
Alex Evans / Our Media

So what has changing out the rear 27.5in wheel for a 29in hoop done to the marvellous geometry? Well, not all that much.

To get a flavour of the changes, you only need to look to Marin’s human-powered Alpine Trail XR. This bike has 29in wheels front and rear from the factory, but because the two bikes share almost identical geometry, the swap to a big wheel on the E2 brings it very close to the XR’s figures.

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Bike-Stats has an incredibly useful tool where you can compare the geometry of different bikes.
Bike-Stats

The head angle now sits at 63.5 degrees, while the wheelbase has extended to 1,283mm and BB lifted marginally to 339mm – which is still seriously low.

There’s more than enough tyre clearance at the rear of the E2 to take the 29in wheel and 2.5in rubber… it’s almost like the brand designed it to be both 27.5in and 29in compatible.

Always wanting more

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I’ve increased the travel of the Fox 38 fork to 170mm by installing a different air spring; something that can be done to any Fox 38 fork.
Alex Evans / Our Media

Not satisfied, I wanted more. But this time from the front end.

Although the 160mm-travel Fox 38 fitted to the E2 has plenty of squish, and adding an extra 10mm doesn’t seem like much, out on the trail that extra give meant a few things.

Firstly I could run the fork a bit softer than the 160mm version, while maintaining my preferred handlebar height without needing to add loads of stem stackers.

It also meant I could create a larger negative air vacuum within the fork’s lowers, by releasing air from the lower leg bleed valves while the forks were compressed, without dramatically impacting ride height.

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The GRIP2 damper has a large number of adjustments, but I found it feels best with all the settings fully open.
Alex Evans / Our Media

Releasing air from the bleeders improves small-bump sensitivity and traction, and produces similar results to increasing the negative air spring size or pressure by making the forks more eager to compress or suck down into their travel.

Swapping out the Fox 38 air spring was relatively simple, requiring only a few basic tools, some of the recommended Fox suspension fluid and a small amount of knowledge.

All Fox 38 forks can be changed between 160mm and 180mm of travel with an air spring swap. A new air spring costs £159.95.

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The extra volume air spring is one of the 38’s best features… and with 170mm of travel, it’s even better.
Alex Evans / Our Media

Of course, if you’re looking to change the fork travel on your bike, please check whether the longer distance is within your manufacturer’s recommended travel specifications before fitting them to avert voiding your warranty.

Shimano EP8 spotlight

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Shimano’s ebike display is one of the more discreet units.
Alex Evans / Our Media

Shimano’s EP8 motor offers impressive battery life, user tuneable modes, is relatively light and has proven to be seriously frugal. Combined, these virtues make me think it is the best electric mountain bike motor currently on sale.

But it’s not without its faults.

The biggest of these, in the context of the Marin E2, relate not to the motor itself but to the e*thirteen e*spec cranks fitted from the factory. These cranks have been linked to cases of EP8 bottom bracket spindle failure.

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Replacing the e*thirteen e*spec cranks with Shimano versions was a move I decided to make after reading about EP8 bottom bracket axle failure.
Alex Evans / Our Media

Not wanting to suffer from this issue, I fitted a pair of Shimano’s own EP8 compatible FC-EM600 cranks for the princely sum of £31.99.

With these cranks fitted from new, and installed according to Shimano’s instructions, my EP8 motor warranty should be preserved if the worst happened.