Which size or configuration labels have geometry for the 2012 Trek 3900 Disc?

Geometry is listed for XS, S, M, ML, L, and XL.

What is the head tube angle of the 2012 Trek 3900 Disc?

The head tube angle is 70.5 degrees in every size.

What does the 2012 Trek 3900 Disc ship with?

The stock build includes Trek Alpha, SR Suntour XCM, Shimano EF-51, and Formula DC-20.

Which years of the Trek 3900 Disc are on Quiver?

Quiver has the Trek 3900 Disc for 2012, 2013, 2011, and 2010.

2012

2012 Trek 3900 Disc

The 3900 Disc build comes with Shimano Altus shifting and Formula DC-20 wheels.

Compare geometry

Source: trekbikes.com. Checked Oct 22, 2026.

Key facts

Brand: Trek
Model: 3900 Disc
Model year: 2012
Geometry labels: XS, S, M, ML, L, and XL
Drivetrain: Shimano Altus
Fork: SR Suntour XCM
Wheels: Formula DC-20
Geometry: Complete for every size
Source: trekbikes.com
Checked: Oct 22, 2026

Geometry by size

2012 Trek 3900 Disc geometry by size
Measurement	XS	S	M	ML	L	XL
Head tube angle(°)	70.5	70.5	70.5	70.5	70.5	70.5
Effective top tube(mm)	524	550	565	580	590	600
Chainstay length(mm)	430	430	430	430	430	430
Wheelbase(mm)	1019	1040	1057	1068	1079	1084
BB drop(mm)	46	42	60	60	60	38
BB height(mm)	287	291	293	293	293	295
Standover(mm)	705	738	772	799	827	857
Seat tube length(mm)	330	406	457	495	533	572
Head tube length(mm)	110	110	130	150	170	190

How to read a geometry chart

Stock build

12 parts

Frame

Trek Alpha

Frame

Suspension

SR Suntour XCM

ForkFront axle / spacing 15x110 (Boost)

Drivetrain

Shimano EF-51

Shifter

Shimano Altus

DerailleurActuation type Mechanical

Shimano Acera M360

Derailleur

Shimano HG31

Cassette

Shimano M171 TX

Crankset

Wheels & Tires

Formula DC-20

Wheelset

Bontrager LT3

Tire

Brakes

Tektro Novela

Brake

Seatpost & Saddle

Bontrager SSR

Seatpost

Bontrager SSR

Saddle

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Quick answers

Which size or configuration labels have geometry for the 2012 Trek 3900 Disc?: Geometry is listed for XS, S, M, ML, L, and XL.
What is the head tube angle of the 2012 Trek 3900 Disc?: The head tube angle is 70.5 degrees in every size.
What does the 2012 Trek 3900 Disc ship with?: The stock build includes Trek Alpha, SR Suntour XCM, Shimano EF-51, and Formula DC-20.
Which years of the Trek 3900 Disc are on Quiver?: Quiver has the Trek 3900 Disc for 2012, 2013, 2011, and 2010.