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 Most makers do not publish it, so I assume 15 mm and add 6 mm to the band, which on its own is enough to hold an answer at "probably" rather than "fits".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
Yoeleo Altera G21 DB
Gravel · 7 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
- Yoeleo Altera G21 DB · Gravel · 7 sizes · integrated cockpit
- Geometry
- yoeleo.com, fetched 29 Aug 2026, re-checked, no differences
- Cockpit
- H21 CARBON INTEGRATED HANDLEBAR, the maker's spec
- 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)not published | Standover (mm)not published |
|---|---|---|---|---|---|---|---|---|
| 45cm | 512 | 373 | 69 | 75 | 79 | 433 | ||
| 49cm | 531 | 373 | 69.5 | 75 | 98.5 | 433 | ||
| 52cm | 549 | 379 | 70 | 74 | 107 | 433 | ||
| 54cm | 566 | 383 | 70 | 73.5 | 134 | 433 | ||
| 56cm | 586 | 387 | 71 | 73 | 145 | 433 | ||
| 58cm | 611 | 390 | 71 | 73 | 171 | 433 | ||
| 60cm | 640 | 396 | 71 | 73 | 200 | 433 |
The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The 54cm 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. A dashed tube is a number the maker left out (est.).
The maker's cockpit
What each size is solved on unless you choose another bar on the sheet.Yoeleo H21 CARBON INTEGRATED HANDLEBARStockstem -10.2 · reach 80 · drop 120 · lengths 80-110 · widths 400-440
Yoeleo H9 integratedVendor-listedstem -7 · reach 80 · drop 125 · lengths 90-120 · widths 380-440
In the maker's words
Kept whole, as I read it off yoeleo.com.Frameset ships as "G21 Frame, Fork, Handlebar, Seatpost".
Cockpit and seatpost, in the maker's words · 406 words
Frameset ships as "G21 Frame, Fork, Handlebar, Seatpost". DEFAULT COCKPIT = H21 CARBON INTEGRATED HANDLEBAR (one-piece bar/stem, T800; yoeleobike.com spec table row "Handlebar: H21 carbon integrated handlebar"): stem 80/90/100/110 mm x hood width 400/420/440 mm (all 12 combinations are SKUs on https://www.yoeleo.com/products/h21-carbon-integrated-handlebar), angle -10.2 deg, reach 80 mm, drop 120 mm, flare 30.4 deg total per the H21 geometry drawing (https://www.yoeleo.com/cdn/shop/files/H21_geometry.jpg; the page copy calls it "15.2 deg flare", i.e. per side), drop-end width 460/480/500 mm for hood width 400/420/440, 28.6 mm steerer, weight 375-376 +/-15 g (the yoeleobike.com spec table says 360 +/-15 g for 420x90 - discrepancy), "comes with Computer Holder, Spacers for rounded 1-1/8 inch (28.6mm) steerer, Top cap and outer cable bearing cover"; H21 fits a 52 mm headset bearing diameter. H21 stem stack height NOT published. OPTION 2 = H9 integrated (listed on the G21 page under Handlebar Options): stem 90/100/110/120 mm x width 380/400/420/440 mm, angle -7 deg, reach 80 mm, drop 125 mm. OPTION 3 = ST1 stem + H25 gravel bar (two-piece): H25 hood width 400/420/440 mm (drop width 500/520/540 mm), reach 74 mm, drop 114 mm, 31.8 mm clamp, 240 g; ST1 carbon stem 90/100/110/120 mm, -10 deg, stack height 30 mm, 28.6 mm steerer, 140 g (specs from https://www.yoeleo.com/products/best-gravel-carbon-handlebar and https://www.yoeleo.com/products/carbon-stem-st1). OPTION 4 = "Without Handlebar": the frameset then comes with a bearing cover that accepts a traditional bar with internal cabling. The yoeleo.com frameset configurator only has Frame Size and Color options (no cockpit choice, no per-size default stem length or bar width), so stock_stem_length and stock_bar_width are null. SPACERS: yoeleobike.com frameset spec table "Handlebar Spacers: 3mm x1, 5mm x1, 10mm x2; Headset Bearing Cap 10mm x1" (i.e. 28 mm of spacers supplied above a 10 mm bearing cap); the yoeleo.com box list just says "Handlebar Spacer*1"; the separately sold "Yoeleo Standard Spacer Set" is a 10 mm bearing cover + 3 + 5 + 10 mm spacers + 10 mm top spacer. Maximum spacer height NOT published; top cap height NOT published. HEADSET: straight 1-1/2 in head tube, fork 1-1/8 to 1-1/2 in tapered, "Headtube Bearings*2" in the box (spares sold as "7mm Headset Top Bearing" and "8mm Headset Bottom Bearing", no dimensions given). SEATPOST: YOELEO Pro-Flex seatpost, round 27.2 mm (changed from the previous G21's D-shape), 95.2 g without clamp, seatpost clamp included, accepts third-party or dropper posts; seatpost length and offset/setback NOT published (the R11/G21 Seatpost spare page has no spec text).
Letters J and K are absent from this table (on Yoeleo's R12 table they are front centre and wheelbase), so wheelbase, front centre, standover and trail are NOT published for the Altera G21 and are null. Source: html_table
How I read the maker's table
STACK/REACH DATUM: drawing D is a vertical from the BB centre up to the level of the head tube top, C a horizontal from that vertical to the head tube top centre - i.e. the usual BB centre to head tube top-centre convention. TOP TUBE: labelled "TOP TUBE LENGTH(mm)" with no "effective" qualifier; drawing B is a horizontal from the head tube top to the seatpost line, so recorded as effective - uncertain. HEAD TUBE ANGLE DISCREPANCY: the frameset table (yoeleo.com, and the identical table on https://www.yoeleobike.com/products/altera-g21-gravel-frameset) gives G = 69/69.5/70/70/71/71/71 deg, but the maker's own complete-bike page https://www.yoeleobike.com/products/racing-bikepacking-carbon-gravel-bike ("Altera G21 DB Gravel Bike 12S", same table otherwise) gives 72.2/72.3/72.6 deg for 56/58/60. I recorded the frameset page's values and flag the alternative; see collector_notes for a consistency check. SIZE NAMES: sizes are named by nominal seat tube length in cm (45, 49, 52, 54, 56, 58, 60; product options "45cm" etc.). Official rider-height row in the same table: 45 = 160-168 cm, 49 = 165-175, 52 = 172-180, 54 = 177-185, 56 = 182-190, 58 = 187-196, 60 = 193-201. MODEL YEAR: not stated on the page; the brand distinguishes "G21 2023" (previous generation, D-shaped post; the fork spare page says "Fork for G21 2023 and Altera G21 frameset") from the Altera G21, whose yoeleobike.com product was published 2025-04-10, whose yoeleo.com product record dates 2025-09-12 (a store migration date shared by every product), whose geometry image asset is v=1758162507 (2025-09-18), and whose blog "The Story Behind YOELEO ALTERA G21" is dated 2026-01-10; page live and table current when fetched. Treat as the 2025-launched generation, but model_year is left null because no year is published. FRAME FACTS: Toray T800 UD carbon, T47 inboard-bearing BB (86.5 mm on yoeleo.com, 85.5 mm on yoeleobike.com), straight 1-1/2 in head tube, 12x142 rear / 12x100 front thru axles, UDH, flat mount, 1x max 42t (44t wide spindle), 700x53 mm or 650Bx2.1 in max tyre (1x setup), 4 bottle mounts, mudguard and rack compatible, top-tube and down-tube storage, frame weight Champagne 1170 g / raw 1050 g (yoeleo.com) or raw 1150 g (yoeleobike.com) size 56, fork 480 g, rider weight limit 125 kg, UCI approved (yoeleobike.com), price USD 1420 all sizes (2026-08-28). Colours: Champagne, Prism Blue, Artisan Black, Panda Purple (separate product pages, same table), Custom Painting.