Tissot · Chrono XL Classic and Supersport Chrono

Tissot T1166171609200 vs Tissot T1254171104100

9 published specifications differ between these two, and 3 are identical. Every figure below is what the manufacturer states for that reference; nothing is inferred from the other watch.

What differs

Specification	Tissot Chrono XL Classic 45mm, quartz, leather strapT1166171609200	Tissot Supersport Chrono 42mm, PVD-coated steel, blue dialT1254171104100
Case	316L stainless steel, 45.00 mm	316L stainless steel with PVD coating, 42.00 mm
Diameter	45 mm	42 mm
Thickness	11.02 mm	11.27 mm
Lug to lug	45 mm	42 mm
Crystal	Sapphire	Sapphire with one antireflective coating on bottom side
Dial	Green, with Arabic indexes and Super-LumiNova on the hands	Blue, with index markers and Super-LumiNova on the hands
Bracelet	Leather, reference T600041655; front in alligator-style grained cowhide, back synthetic; strap length 120.00 mm at 6 o'clock and 75.00 mm at 12 o'clock; interchangeable quick release	Stainless steel, reference T605052437, interchangeable quick release
Clasp	Standard buckle	Butterfly clasp with push-buttons
Movement notes	Battery voltage 1.55 volts. EOL battery end-of-life indicator, 30-minute and 1/10 second counters, central 60-second chronograph hand, ADD and SPLIT functions. Date. Total weight 75.00 g. Country of manufacture given as Switzerland, with a stated two-year warranty.	Battery voltage 1.55 volts. Battery end-of-life warning, thirty-minute and tenth-of-a-second counters, centre chronograph seconds hand, ADD and SPLIT. Date. Total weight 165.00 g. Country of manufacture given as Switzerland, with a stated two-year warranty.

What is identical

Worth knowing as much as the differences: these are the specifications you cannot use to tell the two apart.

Lug width: 22 mm
Water resistance: Water-resistant up to a pressure of 10 bar (100 m / 330 ft)
Movement: Quartz chronograph PowerDrive

Stated for one, not the other

These rows cannot be compared, because one maker publishes the figure and the other does not. An empty cell is a gap in the manufacturer's documentation, not a gap in the watch — and not a licence to fill it in from the other column.

Bezel	not stated	Stainless steel with an aluminium bezel ring

What the differences cost you

Each note below follows from the published figures in the tables above — what they mean for intake, for a listing, and for the handover. Nothing here estimates a price or a margin.

One of these is the harder fit

Lug to lug is 45 mm on the T1166171609200 against 42 mm on the T1254171104100 — a 3 mm difference across the wrist. Diameter is what buyers ask about; lug to lug is what decides whether a case sits flat or overhangs. Ask for a wrist measurement before shipping the T1166171609200, and put the figure in the listing rather than the diameter alone.

These reach different buyers

45 mm on the T1166171609200 against 42 mm on the T1254171104100. Diameter is a poor predictor of how a watch actually sits, but it is the field buyers filter on, so the two land in front of different people. Do not let one listing's photographs or copy stand in for the other.

What to check on each

T1166171609200

Use the published strap lengths of 120 mm and 75 mm to answer fit questions before shipping. Tissot states both halves, which is more than most makers give, and a 45 mm watch on a fixed-length strap either fits or it does not.
Read the strap construction carefully: the front is alligator-style grained cowhide and the back is synthetic, so describe it as grained calf rather than as alligator.
Test the ADD and SPLIT functions, not just start and stop. Both are listed for this movement and neither is exercised by a simple timing run.

T1254171104100

Examine the PVD coating at every edge and corner for breakthrough to the steel beneath. Coating wear is permanent, polishing removes more of it, and a bright patch on a dark case is the first thing a buyer sees.
Grade the aluminium bezel ring for fading and denting rather than for scratches, which is how aluminium wears.
Confirm the bracelet is the coated one and matches the case. A replacement steel bracelet against a PVD case is an obvious mismatch and a common bodge on coated watches.

Sources

Not affiliated with Tissot. Specifications are read from each manufacturer's own published documentation on the dates shown and may change; the manufacturer's current documentation governs.