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 Most makers do not publish it, so I assume 15 mm and add 6 mm to the band, which on its own is enough to hold an answer at "probably" rather than "fits".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
Look 765 Optimum
Endurance road · 5 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
- Look 765 Optimum · Endurance road · 5 sizes
- Geometry
- lookcycle.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.The table runs on to the right: 6 more columns after Reach. Scroll it sideways to read them.
The M 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.
Frame facts
read from the maker's words, not a table: lookcycle.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 lookcycle.com.Two-piece on the 765 Optimum 105 Di2: Handlebar "LOOK LS3 Alloy", Stem "LOOK LS3 Alloy" (per-size lengths and widths not printed).
Cockpit and seatpost, in the maker's words · 30 words
Two-piece on the 765 Optimum 105 Di2: Handlebar "LOOK LS3 Alloy", Stem "LOOK LS3 Alloy" (per-size lengths and widths not printed). Seatpost "LOOK LS1 Carbon Superlight 27.2 mm 350 mm".
OFFICIAL SOURCE: https://www.lookcycle.com/fr-en/products/bikes/road-bikes/endurance/765-optimum-105-di2-r50d. Source: html table (official Look product page "765 Optimum 105 Di2 / R50D", Geometry table; fetched 2026-10-20
How I read the maker's table
Look prints decimals with both commas and points (486,2 and 525.2) in one row; converted by script, numbers unchanged. No stack datum is stated in words (stack_datum null). Table heading "765 Optimum". The head tube row is lettered "K2 - Head tube" (117/142/170/195,3/223,4). Head angle 70.8 and seat angle 74 on every size, trail 67 and offset 50 on every size. Rows kept here only: L - Fork 385.5 on every size. Stock tyre "HUTCHINSON Fusion 5 Tubeless Ready 700x30" (tyre_width_mm 30). Model year not printed.
Source: html table (official Look product page "765 Optimum 105 Di2 / R50D", Geometry table; fetched 2026-10-20, HTTP 200)