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

The Trek Fuel EX Aluminium is a mtb bike available in 4 sizes, from S to XL. Stack ranges from 610 to 651 mm and reach from 431 to 510 mm. Its position sits between racing and endurance.

Stack610–651mm

Reach431–510mm

Head angle64.5–64.6°

Chainstay length437–447mm

Steep seat anglePlantedCalm steeringHigh BB

What size Fuel EX 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 610 · R 431

MS 624 · R 460

LS 638 · R 485

XLS 651 · R 510

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	610	624	638	651
Reach	431	460	485	510
Effective top tube	548	583	617	651
Head tube length	95	110	125	140
Head angle	64.6°	64.5°	64.5°	64.5°
Effective seat angle	78.7°	78.3°	77.4°	76.9°
Actual seat angle	72.7°	72.6°	72.6°	72.6°
Chainstay length	437	437	442	447
Wheelbase	1,187	1,225	1,262	1,298
Front centre	754	791	822	854
BB drop	34	35	35	35
BB height	340	339	339	339
Fork offset	44	44	44	44
Trail	129	129	129	129
Standover	748	744	747	758
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 LX Carbon · M2026±0 mm±0 mmCompare →

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

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

Cube Reaction C:68X SLX · L2026−2 mm−3 mmCompare →

KTM Scarp LT · M2027−4 mm+1 mmCompare →

Trek Fuel MX Aluminium · M2026+3 mm−4 mmCompare →

Fuel EX Aluminium or Fuel LX Carbon? In size M they have exactly the same stack and reach (624 / 460 mm): the difference is in the frame and build, not the position.

Frequently asked questions

What size Fuel EX 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 610/431 mm in size S to 651/510 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 EX Aluminium in size M?

Stack of 624 mm and reach of 460 mm, with an effective top tube of 583 mm and a head angle of 64.5°.

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

In between. In size M its stack-to-reach ratio is at percentile 39 of mtb bikes: neither very low nor very tall.

Does it have the same geometry as the Fuel LX 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.