BH Aero TT geometryTime trial / Triathlon · 2026 · 4 sizes, from SM to XL
The BH Aero TT is a time trial / triathlon bike available in 4 sizes, from SM to XL. Stack ranges from 494 to 547 mm and reach from 409 to 443 mm. Its position sits between racing and endurance. All sizes share 380 mm chainstays.
What size Aero TT 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.
Enter your stack and reach to see which size fits you best.
Geometry chart by size
Measurements in mm and degrees, as published by BH. The ones that matter most for choosing a size are in bold.
| Size | SM | MD | LA | XL |
|---|---|---|---|---|
| Stack | 494 | 509 | 528 | 547 |
| Reach | 409 | 420 | 431 | 443 |
| Head tube length | 85 | 100 | 120 | 140 |
| Head angle | 72.5° | 72.8° | 72.8° | 72.8° |
| Chainstay length | 380 | 380 | 380 | 380 |
| Wheelbase | 970 | 983 | 1,001 | 1,018 |
| Front centre | 589 | 602 | 619 | 638 |
| BB drop | 74 | 74 | 74 | 74 |
| Fork length | 373 | 373 | 373 | 373 |
| Top tube (method not stated) | 531 | 547 | 562 | 579 |
| Seat tube (method not stated) | 510 | 525 | 540 | 560 |
| Seat angle (method not stated) | 76.0° | 76.0° | 76.0° | 76.0° |
Source: BH official website · data from 11 Nov 2026. Spot a mistake?
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 time trial / triathlon bikes. Further right means more of that quality.
Bikes with similar geometry (size MD)
The closest size of other time trial / triathlon models, by stack and reach.
Frequently asked questions
What size Aero TT 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 494/409 mm in size SM to 547/443 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 Aero TT in size MD?
Stack of 509 mm and reach of 420 mm.
Is the Aero TT a racing or an endurance bike?
In between. In size MD its stack-to-reach ratio is at percentile 45 of time trial / triathlon bikes: neither very low nor very tall.