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 Most makers do not publish it, so I assume 10 mm and add 6 mm to the band beside every answer.
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
Specialized Tarmac SL6 Disc
Road · 7 sizes
The Tarmac SL6 Disc on specialized.com
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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
- Specialized Tarmac SL6 Disc · Road · 7 sizes
- Geometry
- specialized.com, fetched 22 Oct 2026, re-checked, no differences
- Seat angle convention
- Calculated from Specialized's table
- Cockpit
- Generic stem and bar, assumed
- Solved with
- cover 10 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 · 879 bikes, 79 makes, 4,979 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) |
|---|---|---|---|---|---|---|---|---|
| 44 | 500 | 365 | 70.5 | 76 | 105 | 410 | 969 | 730 |
| 49 | 514 | 375 | 71.75 | 75.5 | 115 | 410 | 973 | 740 |
| 52 | 527 | 380 | 72.5 | 74 | 126 | 410 | 975 | 755 |
| 54 | 544 | 384 | 73 | 74 | 143 | 410 | 978 | 775 |
| 56 | 565 | 395 | 73.5 | 73.5 | 163 | 410 | 990 | 795 |
| 58 | 591 | 402 | 73.5 | 73.5 | 190 | 410 | 1005 | 826 |
| 61 | 612 | 408 | 74 | 73 | 210 | 410 | 1012 | 850 |
The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The 54 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 size44 70 x 360, 49 80 x 380, 52 90 x 400, 54 100 x 420, 56 100 x 420, 58 110 x 440, 61 110 x 440 (stem length x bar width, mm)
Frame facts
read from the maker's words, not a table: specialized.com- Tyre clearance
- not recorded yet
- Bottom bracket
- not recorded yet
- Axles and brakes
- 12x100 / 12x142, flat mount
- UDH
- not recorded yet
- Seatpost
- not recorded yet
- Frame weight
- not recorded yet
In the maker's words
Kept whole, as I read it off specialized.com.Tarmac SL6 Disc Sport (MY2020), Specialized US spec: Stem "Specialized, 3D-forged alloy, 4-bolt, 7-degree rise" (stem angle 7 degrees, printed as a rise); Handlebars "Specialized Shallow Drop, 6061, 70x125mm, 31.8mm clamp" (bar reach 70 mm, drop 125 mm).
Cockpit and seatpost, in the maker's words · 50 words
Tarmac SL6 Disc Sport (MY2020), Specialized US spec: Stem "Specialized, 3D-forged alloy, 4-bolt, 7-degree rise" (stem angle 7 degrees, printed as a rise); Handlebars "Specialized Shallow Drop, 6061, 70x125mm, 31.8mm clamp" (bar reach 70 mm, drop 125 mm). Stock stem length and bar width per size from the geometry table.
OFFICIAL SOURCE: Specialized US page for the Tarmac SL6 Disc Sport (code 171352), page JSON modelYear 2020, frame "Tarmac SL6, FACT 9r carbon, Rider-First Engineered, threaded BB, clean routing, 12x142mm thru-axle, flat-mount disc", fork "FACT carbon, 12x100mm thru-axle, flat-mount disc". Source: html table (official Specialized US product page for the Tarmac SL6 Disc Sport, code 171352, the "Geometry" HTML table in the page; fetched 2026-10-22
How I read the maker's table
The Tarmac SL6 on the FACT 9r frame: against the FACT 10r Tarmac Disc Expert of MY2019 (specialized-tarmac-sl6.json, OSBB and an integrated seat clamp) every stack, reach, angle, head tube, chainstay, wheelbase, BB drop and offset is the same on 49 to 61, the horizontal top tube is 3 to 4 mm longer here (49: 511 against 508; the 10r figure is the one reach + stack / tan(seat angle) gives) and the seat tube 17 to 20 mm longer (49: 451 against 431), and this page adds a 44. Seven sizes 44 to 61. Values printed with mm and degree suffixes, stripped by script. Stock tyre Turbo Pro 700x26mm.
Source: html table (official Specialized US product page for the Tarmac SL6 Disc Sport, code 171352, the "Geometry" HTML table in the page; fetched 2026-10-22, HTTP 200)