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 Most makers do not publish it, so I assume 15 mm and add 6 mm to the band, which on its own is enough to hold an answer at "probably" rather than "fits".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 hands sit than your saddle. On a riser bar I count the bar's rise, so the drop is that much less than it is to the clamp.
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
Cannondale Topstone Carbon
Gravel · 6 sizes
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This is the bike I ride
No account is needed to read the table. Report a wrong number · Correct this bike
- Bike
- Cannondale Topstone Carbon · Gravel · 6 sizes
- Geometry
- cannondale.com, fetched 20 Oct 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
- 22 October 2026 · 686 bikes, 74 makes, 3,984 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) |
|---|---|---|---|---|---|---|---|---|
| 47 | 554 | 364 | 69.9 | 73.1 | 97 | 420 | 1009 | 716 |
| 51 | 561 | 373 | 70.7 | 73.1 | 101 | 420 | 1012 | 741 |
| 54 | 579 | 378 | 70.7 | 73.1 | 123 | 420 | 1026 | 772 |
| 56 | 597 | 383 | 70.7 | 73.1 | 142 | 420 | 1036 | 800 |
| 58 | 615 | 389 | 70.7 | 73.1 | 164 | 420 | 1050 | 831 |
| 61 | 646 | 397 | 70.7 | 73.1 | 196 | 420 | 1069 | 864 |
The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The 56 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 per size47 70 mm, 51 70 mm, 54 80 mm, 56 90 mm, 58 90 mm, 61 100 mm. The maker publishes no bar width per size.
Frame facts
read from the maker's words, not a table: cannondale.com- Tyre clearance
- not recorded yet
- Bottom bracket
- not recorded yet
- Axles and brakes
- not recorded yet
- UDH
- not recorded yet
- Seatpost
- 27.2 mm round
- Frame weight
- not recorded yet
In the maker's words
Kept whole, as I read it off cannondale.com.Two-piece cockpit on the Topstone Carbon 2 GRX 2x: handlebar "Cannondale 2 ShortDrop, 7050 alloy, 12 deg flare drop" (widths per size not printed on this build); stem "Cannondale C1 Conceal, Alloy, 31.8, -6 deg: 70mm (47-51m), 80mm (54cm), 90mm (56-58cm), 100mm (61cm)" ("47-51m" sic).
Cockpit and seatpost, in the maker's words · 66 words
Two-piece cockpit on the Topstone Carbon 2 GRX 2x: handlebar "Cannondale 2 ShortDrop, 7050 alloy, 12 deg flare drop" (widths per size not printed on this build); stem "Cannondale C1 Conceal, Alloy, 31.8, -6 deg: 70mm (47-51m), 80mm (54cm), 90mm (56-58cm), 100mm (61cm)" ("47-51m" sic). Fork "1-1/8" to 1.5" steerer, 55mm OutFront offset" (round steerer). Seatpost "Cannondale 2 Carbon, 27.2x350mm (47-58), 400mm (61)" (offset not printed).
OFFICIAL SOURCE: Cannondale GB product pages for the Topstone Carbon 2 GRX 2x (SalsifyId 3884-COLL2025) and the Topstone Carbon 1 Lefty AXS (3892-COLL2025), MY2025 in the product data feed. Source: image_table (official Cannondale GB product page, "Geometry" section is a single image
How I read the maker's table
both show the same geometry image, cy25_topstonecarbon_geotable, so the maker gives one table for the rigid-fork and the Lefty builds (the Lefty's own fork numbers are not printed separately). The data feed carries Geometry null for every variant, so the image is the only table. SIZE LABELS: the table header prints 47.0/51.0/54.0/56.0/58.0/61.0; the shop's size selector says 47/51/54/56/58/61, which is what size_label holds. UNITS: lengths printed in centimetres to one decimal; every length here is the printed value x 10, angles as printed. No Wheel Size row; 700c from the spec. The 47's stack (55.4) sits only 7 mm below the 51's (56.1) on a 4 mm shorter head tube at a 0.8 deg slacker angle; as printed. STACK DATUM: O is drawn to a horizontal through the top of the head tube where G starts. MAKER INCONSISTENCY in the spec (not the table): the tyre is named "WTB Riddler TCS Light, 700x45c" while the feed's TireSize field says 37; tyre_width_mm takes the named 45. stock_stem_length is the C1 Conceal stem length per size from this build; stock_bar_width is not printed (null).
Source: image_table (official Cannondale GB product page, "Geometry" section is a single image: https://www.cannondale.com/-/media/images/my25/bikes/road/gravel/topstone-carbon/pdps/cy25_topstonecarbon_geotable.ashx, 2000x2992 px, diagram + table headed "Topstone Carbon"; numbers read from the image by the collector, image NOT stored)