23–24 January 2027 · Veliky Novgorod
ЗИМНИЕ ВЫХОДНЫЕ ВЕЛОКРОССА · 3ВВ
Два дня ТИПАЦИКЛОКРОССА: Cyclocross, Gravel, Fixed gear, МТБ и беговой кросс. Один день или оба.
FRAME GEOMETRY COMPARISON
To the calculatorsDrive in the numbers of two or three frames from the manufacturer's tables — you will get a table with deltas, STR, trail, front center and human output: how many spacers, what kind of takeaway and what will change in the behavior of the steering wheel.
How to compare geometry before buying
What we count
STRTrailFront centerWeight distributionΔ for each sizeVerbal conclusions
In A and B there are numbers-examples, so that the page opens alive — replace them with your own. There is no base of frames here and there will not be: you drive in the numbers from the official table of the manufacturer. Lying with numbers out of your head is the worst thing such a calculator can do.
The link to the page stores everything you entered — you can throw it into the chat and argue about geometry in a substantive way.
Frame A
The frame we're comparing to: your current one or the one you already like.
Fill in at least stack and reach — let's count STR, trail, and front center.
Frame B
Candidate for purchase. All deltas in the table are considered relative to frame A.
Fill in at least stack and reach — let's count STR, trail, and front center.
Frame C · optional
Third frame — optional. Can be left blank.
Fill in at least stack and reach — let's count STR, trail, and front center.
Comparison table
Rows are parameters, columns are frames. In columns B and C, there is a Δ value relative to frame A.
| Parameter | Frame A | Frame B | Frame C |
|---|---|---|---|
| Stack | — | — | — |
| Reach | — | — | — |
| STR (stack/reach) | — | — | — |
| Top Tube (ETT) | — | — | — |
| Head tube angle (HTA) | — | — | — |
| Seat tube angle (STA) | — | — | — |
| Steerer tube | — | — | — |
| Fork rake | — | — | — |
| Trail (trail removal) | — | — | — |
| Chainstays (chainstay) | — | — | — |
| Wheelbase | — | — | — |
| Front center | — | — | — |
| Front center share in the base | — | — | — |
| Carriage drop | — | — | — |
Visually
Lengths in scale: stack, reach, Wheelbase, Feathers. The longest frame occupies the entire strip.
What does it mean on the road
Fill in two frames — and a verbal analysis will appear here: spacers, take-out, steering behavior.
How to read it
STR = stack / reach — the main indicator of the genre. Below 1.40 — racing frame, 1.40–1.50 — endurance, 1.50–1.60 — gravel and comfort, above 1.60 — very high fit for touring and luggage.
Trail (trail removal) = (wheel radius × cos HTA − fork reach) - sin HTA. We take the radius according to ETRTO: π × (rim + two tire widths) ÷ 2π. More trail — the steering wheel is calmer and keeps a straight line itself, less — sharper in turns. The difference of more than 8 mm is felt immediately.
Front center ≈ wheelbase − the length of the feathers. Its share in the base shows the weight distribution: the larger it is, the more the weight is shifted back and the less the front wheel is loaded.
We translate the glass into spacers by 7mm: 10 mm stack ≈ 1.5 spacers. Reach — in take-out: 10 mm reach ≈ take-out is 10 mm shorter or longer. One degree of the seatpost at a saddle height of about 700 mm is 8-10 mm of horizontal displacement of the saddle, played out by rails or a seatpost with another offset.
Everything is calculated by the numbers from the tables: if the manufacturer measures stack and reach from another point, the comparison will go. Make sure you take the numbers for the same size and the same fork.
