Stack and reach
How high and how far forward the top of the head tube is, from the bottom bracket. They are the two numbers that decide whether a frame can be set up like yours.
BB, or bottom bracket
The axle your cranks turn on, in the middle of the frame. Every number on this site is measured from it, because it is the one point that sits in the same place on every bike.
Headset cover
The little cap on top of the head tube, under your spacers. Most makers do not publish it, so I assume 15 mm and add 6 mm to the band, which on its own is enough to hold an answer at "probably" rather than "fits".
Stem clamp, and its centre
The collar on the steerer that your stem bolts to. I need the middle of it. Where a maker gives only the height, I assume halfway up and say so on the answer.
Steerer
The tube coming up out of the fork. The cover, the spacers and the stem all sit on it, and it is the thing a mechanic cuts to length.
Bar reach
How far forward the hoods sit from the middle of the bar. Two bars on the same stem can put your hands 20 mm apart, which is why I ask.
Setback
How far your saddle sits behind the bottom bracket.
Drop
How much lower your bar is than your saddle.
Rails, and the rail centre
The two rods under your saddle, and the middle of the straight part of them. That midpoint is the point I use, because it is the one you can find with a tape.
The band
How far out I could be, in millimetres, and why. It is a straight sum of everything I had to assume rather than a clever average, so it errs wide on purpose.
wb, stand, trail
Wheelbase, standover and trail: how long the bike is, how high the top tube is where you straddle it, and how steady the steering feels. I show them against your bike, and I leave them out when the maker does not publish them.
est.
Estimated: a number I worked out rather than read off the maker's table. Anything marked this way can move if the maker publishes the real one.
Close Escape closes it. The measuring guide has the pictures. Open the measuring guide
Giant Defy Advanced SL / Advanced Pro / Advanced
Endurance road · 6 sizes
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This is the bike I ride
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- Bike
- Giant Defy Advanced SL / Advanced Pro / Advanced · Endurance road · 6 sizes · integrated cockpit
- Geometry
- giant-bicycles.com, fetched 29 Aug 2026, re-checked, no differences
- Cockpit
- Generic stem and bar, assumed
- Solved with
- cover 15 mm (assumed), max spacers 40 mm (assumed), stem clamp centre 20 mm (assumed), so every verdict carries ±10 mm at the bar
- Sheet
- 6 September 2026 · 210 bikes, 43 makes, 1,262 sizes in the catalogue
Geometry, every size, from the maker's table
The tinted row is the size drawn beside it. Press a size to draw it.| Size | Stack (mm) | Reach (mm) | Head angle (deg) | Seat angle (deg) | Head tube (mm) | Chainstay (mm) | Wheelbase (mm) | Standover (mm) |
|---|---|---|---|---|---|---|---|---|
| XS | 527 | 369 | 70.5 | 74.5 | 125 | 420 | 995 | 705 |
| S | 541 | 375 | 71.8 | 74 | 135 | 420 | 994 | 733 |
| M | 558 | 380 | 72.5 | 73.5 | 150 | 420 | 998 | 762 |
| ML | 577 | 384 | 72.5 | 73 | 175 | 420 | 1010 | 796 |
| L | 596 | 393 | 72.5 | 73 | 195 | 420 | 1025 | 814 |
| XL | 615 | 402 | 72.5 | 73 | 215 | 420 | 1040 | 841 |
The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The ML drawn to scale from the table, with no build on it. Stack and reach run from the bottom bracket to the top of the head tube; every size is solved from those two. One square is 100 mm.
The maker's cockpit
No stock cockpit I can name, so every size is solved on a generic stem and bar unless you choose one on the sheet.Generic stem and barAssumedNo bar is listed for this frame.
Stock stem and bar per sizeXS 80 x 400, S 90 x 400, M 100 x 420, ML 100 x 420, L 110 x 440, XL 110 x 440 (stem length x bar width, mm)
In the maker's words
Kept whole, as I read it off giant-bicycles.com.Defy Advanced SL 0 (2025): Giant Contact SLR Aerolight one-piece bar/stem (widths 400/400/420/420/440/440 mm, lengths 80/90/100/100/110/110 mm per size, rows N and O); the Advanced Pro and Advanced builds use the Contact SLR / Contact SL stem and bar in the same schedule.
Cockpit and seatpost, in the maker's words · 55 words
Defy Advanced SL 0 (2025): Giant Contact SLR Aerolight one-piece bar/stem (widths 400/400/420/420/440/440 mm, lengths 80/90/100/100/110/110 mm per size, rows N and O); the Advanced Pro and Advanced builds use the Contact SLR / Contact SL stem and bar in the same schedule. Stem angle, spacers and top-cover height not published on the bike page.
OFFICIAL SOURCE: Giant UK page for the Defy Advanced SL 0 (2025). Source: html table (official Giant UK product page, "Sizing Guide and Geometry" section, HTML table with mm and inch spans; the mm values were taken; fetched 2026-08-29
How I read the maker's table
the Defy Advanced Pro 0 (2025) and Defy Advanced 1 (2025) pages (fetched, https://www.giant-bicycles.com/gb/defy-advanced-pro-0-2025 and /gb/defy-advanced-1-2025) print identical tables in every row including the seat tube, so this is the platform table for all three tiers of the current Defy (launched 2023 as MY2024). The URL /gb/defy-advanced-pro-0-2023 redirects to the 2025 page, so Giant UK no longer serves the previous Defy generation. Model year 2025 (page title). Angles are printed to one decimal.
Source: html table (official Giant UK product page, "Sizing Guide and Geometry" section, HTML table with mm and inch spans; the mm values were taken; fetched 2026-08-29, HTTP 200)