Question 1

Do I need an adapter to mount my bike on a trainer?

Accepted Answer

It depends on your dropout. Quick-release bikes usually need no extra adapter — they clamp in the trainer’s standard cups. Thru-axle bikes need end-cap adapters matching their axle; 25 of 27 direct-drive trainers in our database include them.

Question 2

Do trainers come with thru-axle adapters?

Accepted Answer

Most do: 25 of 27 direct-drive trainers in our database ship thru-axle adapters in the box (typically 12×142 and 12×148 Boost). A few sell them as an extra — check each trainer’s page.

Question 3

I have a quick-release bike — what do I need?

Accepted Answer

Quick-release frames (130 mm road or 135 mm MTB/disc) mount with the trainer’s standard QR cups, so no extra adapter is normally required. You will, however, usually need a cassette and the right freehub body.

Question 4

What about 12×148 Boost thru-axle?

Accepted Answer

Boost (12×148 mm) is the wide MTB thru-axle standard. Most current direct-drive trainers support it with an included or optional end-cap adapter — check the trainer’s page to confirm the adapter is in the box.

Question 5

My adapter isn’t included — what now?

Accepted Answer

Buy the manufacturer’s thru-axle adapter kit for your axle size. The trainer’s page lists whether the adapter ships in the box or is a separate purchase, so you know before you buy.

Rear dropout	Adapter you need
130 mm quick-release	Standard quick-release cups (no extra adapter on most trainers)
135 mm quick-release	Standard quick-release cups (no extra adapter on most trainers)
12 × 142 mm thru-axle	Thru-axle end-cap adapter sized for your axle (often included)
12 × 148 mm Boost thru-axle	Thru-axle end-cap adapter sized for your axle (often included)
12 × 135 mm thru-axle	Thru-axle end-cap adapter sized for your axle (often included)
10 × 135 mm thru-axle	Thru-axle end-cap adapter sized for your axle (often included)

Thru-axle & quick-release adapter finder

Your dropout → what you need

Frequently asked questions