Compare an Astra road frame with the Tarmac SL8 race platform using source-backed geometry, not an assumed conversion between their labels.
USD dealer quote required
Best for: Riders considering a taller road front end
USD quote depends on build
Best for: Road racers comparing a lower frame front end
| Aspect | Basso Astra | Specialized Tarmac SL8 |
|---|---|---|
| Example stack | 575.9 mm at 53 | 544 mm at 54 |
| Example reach | 380.4 mm at 53 | 384 mm at 54 |
| Next larger stack | 602.4 mm at 56 | 565 mm at 56 |
| Next larger reach | 382.1 mm at 56 | 395 mm at 56 |
| Source scope | Linked catalog chart; year not specified | Sourced 2023-2026 SL8 geometry |
| Measurement | Basso Astra | Specialized Tarmac SL8 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Size | 45 | 48 | 51 | 53 | 56 | 58 | 61 | 44 | 49 | 52 | 54 | 56 | 58 | 61 |
| Stack (mm) | 538.9 | 538.9 | 563.4 | 575.9 | 602.4 | 625.4 | 650.4 | 501 | 514 | 527 | 544 | 565 | 591 | 612 |
| Reach (mm) | 371.1 | 371.1 | 374.5 | 380.4 | 382.1 | 384.4 | 385.5 | 366 | 375 | 380 | 384 | 395 | 402 | 408 |
Comparing a different size or generation? Use the bike geometry comparison tool with the exact frame charts instead of assuming matching size labels mean matching fit.
Source-backed geometry used in this table
For now this pilot only covers stack and reach. We still do not have standover, top tube, wheelbase, or angle data in a verified record here, so the page stops short of making a stronger fit call.
Astra 53 is 575.9/380.4 mm stack/reach; Tarmac SL8 54 is 544/384 mm. The Astra example is 31.9 mm taller and 3.6 mm shorter at the head tube.
At the example sizes, the Astra has considerably more stack without more reach. That can matter more than the nominal frame size when transferring a known fit. Choose the exact frame and cockpit that can reproduce your position, not a general comfort or performance winner.