Compare: 2023 BXT BX-Road-145 Pro-145 54 vs 2025 SL8 Specialized Bicycles Tarmac sl8 Pro 172.5mm

Insights

Average stack and reach vs trend of performance road bikes

Stack	541mm	544mm +3mm
Reach	384.8mm	384mm -0.8mm
Stack to Reach Ratio	1.41:1	1.42:1
Seat Tube Length, C-T	500mm	—
Seat Tube Length, Unknown	—	473mm
Top Tube Length, Effective/Horizontal Center	543mm	541mm -2mm
Top Tube Slope	6.6deg	9.9deg +3.3deg
Head Tube Angle	73deg	73deg +0deg
Seat Tube Angle	73.7deg	74deg +0.3deg
Head Tube Length	131mm	137mm +6mm
Bottom Bracket Drop	70mm	72mm +2mm
Bottom Bracket Height	269mm	265mm -4mm
Chainstay Length	410mm	410mm +0mm
Chainstay Length Horizontal	404mm	403.6mm -0.4mm
Front-Center	580mm	579mm -1mm
Front-Center Horizontal	575.8mm	574.4mm -1.4mm
Wheelbase	979.8mm	978mm -1.8mm
Fork Offset/Rake	45mm	44.1mm -0.9mm
Fork Length (Axle-To-Crown)	375mm	—
Fork Length, Unknown	—	370mm
Trail	56.6mm mid/neutral	57mm +0.4mm mid/neutral
Mechanical Trail	54.1mm	54.5mm +0.4mm
Wheel Flop	15.8mm	15.9mm +0.1mm
Standover Height	—	768mm
Tire to Pedal Spindle	71mm 170 mm cranks	72mm +1mm 170 mm cranks
Pedal Spindle to Ground Clearance	99mm 170 mm cranks	95mm -4mm 170 mm cranks

Wheel Size	700C/29 in 622 mm BSD	700C/29 in 622 mm BSD
Tire Width	28mm	26mm -2mm
Tire Outer Diameter	678mm	674mm -4mm
Bike Length with Tires	1657.8mm	1652mm -5.8mm
Handlebar Width	—	400mm
Stem Length	—	100mm
Suspension Type	Rigid, non-suspension corrected	Rigid, non-suspension corrected
Bar Type	Drop Bar	Drop Bar
Frame Material	Carbon/Composite	Carbon/Composite
Fork Material	Carbon/Composite	Carbon/Composite
Brake Type	Disc	Disc

Actions	Collection I've Ridden	Collection I've Ridden
Source	https://www.bxtcycle.com/bxt-road-145_p75.html	https://www.specialized.com/us/en/tarmac-sl8-pro-ultegra-di2/p/4274935?color=5430657-4274935
Brand	BXT	Specialized Bicycles
Bike	2023 BX-Road-145 Pro-145	2025 SL8 Tarmac sl8 Pro
Size	54	172.5mm
Category	Performance Road	Performance Road