Trek Fuel MX Aluminium geometryMTB · 2026 · 4 sizes, from S to XL

The Trek Fuel MX Aluminium is a mtb bike available in 4 sizes, from S to XL. Stack ranges from 613 to 654 mm and reach from 426 to 507 mm. Its position sits between racing and endurance.

Stack613–654mm

Reach426–507mm

Head angle64.2–64.2°

Chainstay length434–444mm

PlantedSteep seat angleCalm steeringHigh BB

What size Fuel MX Aluminium do I need?

Enter the stack and reach of a bike that fits you well and we will tell you which size is closest and how to set it up.

Stack in mm Reach in mm Compare on Fitbikefy →

SS 613 · R 426

MS 627 · R 456

LS 641 · R 482

XLS 654 · R 507

Enter your stack and reach to see which size fits you best.

Geometry chart by size

Measurements in mm and degrees, as published by Trek. The ones that matter most for choosing a size are in bold.

Size	S	M	L	XL
Stack	613	627	641	654
Reach	426	456	482	507
Effective top tube	549	584	618	652
Head tube length	95	110	125	140
Head angle	64.2°	64.2°	64.2°	64.2°
Effective seat angle	78.3°	77.5°	77.0°	76.6°
Actual seat angle	72.3°	72.3°	72.3°	72.3°
Chainstay length	434	434	439	444
Wheelbase	1,191	1,228	1,264	1,301
Front centre	758	795	826	857
BB drop	31	31	31	31
BB height	343	343	343	343
Fork offset	44	44	44	44
Trail	132	132	132	132
Standover	752	749	752	763
Seat tube (method not stated)	370	400	420	455

Source: Trek official website · data from 11 Nov 2026.

Stack and reach of every size

Higher means a taller front end; further right means a longer reach. The blue dot is your search.

Character of each size

Compared with other mtb bikes. Further right means more of that quality.

Positionracing → relaxed

Steeringcalm → quick

Pedallingrearward → forward

Bottom brackethigh → low

Wheelbaselively → planted

Rear endstable → agile

Bikes with similar geometry (size M)

The closest size of other mtb models, by stack and reach.

ModelΔ stackΔ reach

Trek Fuel MX Carbon · M2026±0 mm±0 mmCompare →

Cube Stereo HPC · M2026±0 mm−1 mmCompare →

Canyon Neuron AL · M2027−1 mm−1 mmCompare →

Cube Stereo C:62 · M2026−2 mm−1 mmCompare →

Cube Stereo C:62 Super · M2026−2 mm−1 mmCompare →

Cube Reaction C:68X SLX · L2026−3 mm±0 mmCompare →

Fuel MX Aluminium or Fuel MX Carbon? In size M they have exactly the same stack and reach (627 / 456 mm): the difference is in the frame and build, not the position.

Frequently asked questions

What size Fuel MX Aluminium do I need?

It depends on your position, not just your height. The most reliable way is to compare the stack and reach of a bike that fits you with those of each size (from 613/426 mm in size S to 654/507 mm in size XL). The size finder on this page shows the closest size and the stem and spacers you would need.

What are the stack and reach of the Fuel MX Aluminium in size M?

Stack of 627 mm and reach of 456 mm, with an effective top tube of 584 mm and a head angle of 64.2°.

Is the Fuel MX Aluminium a racing or an endurance bike?

In between. In size M its stack-to-reach ratio is at percentile 49 of mtb bikes: neither very low nor very tall.

Does it have the same geometry as the Fuel MX Carbon?

In size M, yes: same stack and reach. If one already fits you, the same size of the other will put you in the same position.