Velopedia Bicycle Archive
2025 Salsa Blackthorn 125 C GX Transmission
Mountain bicycle from the Velopedia specification archive.
- Original MSRP
- $6,499.00
- Sizes
- S, M, L, XL
- Colors
- Slate/Citrus
- Weight
- 31 lb. 9 oz.
- Geometry
- 4 manufacturer sizes · Ride analysis
- Archive ID
- 900000391
Current market
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Velopedia analysis
What the specifications mean
Suspension is concentrated at the fork, so fork setup and rear-tire pressure are the main tools for balancing front and rear behavior. Both 27.5- and 29-inch wheels appear in the record, but it does not establish a mixed front/rear build; confirm the correct diameter for the selected frame size. Electronic shifting removes the usual shift cable but adds a separate battery and controls, while the 520% cassette range describes how much gearing is available.
Suspension setup
Front only
Fork settings affect the front while rear-wheel behavior remains dependent on tire and wheel setup.
Wheel system
27.5 / 29 options
Both diameters are documented, but the archive does not prove a mixed front/rear setup.
Drivetrain
Electronic · 520% range
Shift-system battery state joins derailleur setup and sprocket compatibility as a troubleshooting variable.
Frame material
Carbon / composite
Look for impact damage and clamp marks rather than metal-style dents or rust.
Used-bike inspection
If you’re buying this bike used
Before any test ride: both brakes should stop the bike firmly and release cleanly; both wheels should run true and be securely attached; tires should have no casing damage; and the headset, handlebar, stem, cranks and pedals should have no looseness or play.
Follow the full used-bike inspection order →- FrameInspect the frame in bright light, especially around the head tube, bottom bracket, chainstays and clamped areas. Look for cracks, ripples, crushed sections or signs of a previous impact.Inspect the frame and fork →
- BrakesTest each brake separately and confirm it stops firmly and releases cleanly. Inspect the pads and braking surfaces for wear or contamination, and check the cables or hoses for damage.Inspect the brakes →
- SuspensionAsk when the fork was last serviced. Check the stanchions for damage, look for oil at the seals and make sure the fork moves smoothly without bushing play.Evaluate the suspension →
- DrivetrainConfirm every shift-system battery charges, every shift control works and the derailleur moves cleanly across the cassette. Make sure the matching shift-system charger is included, then measure chain wear and inspect the cassette teeth.Check drivetrain wear →
- Wheels & tiresSpin both wheels and watch the rims for side-to-side or vertical movement. Check for dents, cracks, loose or uneven spokes and hub play, then inspect both tire casings for cuts, cracking or exposed threads.Check wheels and tires →
Bike-specific inspection checklist 20 checks based on 6 archived component groups Open checklistClose checklist
This checklist uses the archived equipment for this bike. It cannot confirm the condition, service history or later component changes of the example in front of you.
Identity and fit
Follow the full used-bike inspection order →Archived: 2025 Salsa Blackthorn 125 C GX Transmission · Mountain · Published sizes: S, M, L, XL
Frame and fork
Inspect the frame and fork →Archived: Frame: Carbon · Fork: Fox 36SL Performance Elite Float X2, 140mm
Suspension
Evaluate the suspension →Archived: Fork: Fox 36SL Performance Elite Float X2, 140mm
Drivetrain
Check drivetrain wear →Archived: Shifters: SRAM AXS Pod controller, Right, w/ MatchMaker X Clamp · Rear derailleur: SRAM GX Eagle AXS Transmission · Crankset: SRAM GX Eagle Transmission, 30t w/ MRP 1x iO SL ISCG-05 aluminum bashguard · Bottom bracket: SRAM DUB BSA 73mm MTB Wide · Cassette: SRAM GX Eagle Transmission, 10–52t, 12-speed · Chain: SRAM GX Eagle Transmission Flattop
Brakes
Inspect the brakes →Archived: Brakes: Brake Calipers: SRAM Code Bronze Stealth; Brake Levers: SRAM Code Bronze Stealth; Rotors: SRAM CenterLine 2.0 (6-bolt, 200mm front, 180mm rear)
Wheels and tires
Check wheels and tires →Archived: Wheel size: 29"; 27.5" · Rims: WTB ASYM i30 TCS, 28h · Hubs: (F) WTB Frequency 15 x 110mm / (R) WTB Frequency 12 x 148mm · Front tire: Teravail Clifty, 29 x 2.5", Durable casing, WTB TCS Sealant Included · Rear tire: Teravail Drawpoint, 29 x 2.5", Durable casing, WTB TCS Sealant Included
Controls and contact points
Archived: Headset: FSA Orbit 1.5E ZS NO.57E · Handlebar: Race Face Turbine · Stem: Salsa 35.0 Guide Trail, 40mm · Seatpost: TranzX REVERSE w/ GL Stealth MMX Lever, SM: 160mm travel; MD: 180mm travel; LG–XL: 210mm travel · Saddle: WTB Solano, Medium, Steel SL, Fusion Form
Before and during the test ride
Follow the full used-bike inspection order →Interpretation based on the archived manufacturer specifications. Confirm exact fit and standards before ordering parts or performing service.
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Frameset
| Frame Construction | Carbon |
|---|---|
| Frame Material | Carbon Fiber |
| Fork | Fox 36SL Performance Elite Float X2, 140mm |
Drivetrain
| Shifters | SRAM AXS Pod controller, Right, w/ MatchMaker X Clamp |
|---|---|
| Front Derailleur | N/A |
| Rear Derailleur | SRAM GX Eagle AXS Transmission |
| Crankset | SRAM GX Eagle Transmission, 30t w/ MRP 1x iO SL ISCG-05 aluminum bashguard |
| Bottom Bracket | SRAM DUB BSA 73mm MTB Wide |
| Cassette | SRAM GX Eagle Transmission, 10–52t, 12-speed |
| Chain | SRAM GX Eagle Transmission Flattop |
Brakes
| Brakes | Brake Calipers: SRAM Code Bronze Stealth; Brake Levers: SRAM Code Bronze Stealth; Rotors: SRAM CenterLine 2.0 (6-bolt, 200mm front, 180mm rear) |
|---|
Cockpit & Contact Points
| Headset | FSA Orbit 1.5E ZS NO.57E |
|---|---|
| Handlebar | Race Face Turbine |
| Stem | Salsa 35.0 Guide Trail, 40mm |
| Saddle | WTB Solano, Medium, Steel SL, Fusion Form |
| Seatpost | TranzX REVERSE w/ GL Stealth MMX Lever, SM: 160mm travel; MD: 180mm travel; LG–XL: 210mm travel |
Wheels & Tires
| Hubs | (F) WTB Frequency 15 x 110mm / (R) WTB Frequency 12 x 148mm |
|---|---|
| Rims | WTB ASYM i30 TCS, 28h |
| Spokes | Butted steel, black |
| Front Tire | Teravail Clifty, 29 x 2.5", Durable casing, WTB TCS Sealant Included |
| Rear Tire | Teravail Drawpoint, 29 x 2.5", Durable casing, WTB TCS Sealant Included |
| Wheel Size | 29"; 27.5" |
Size-specific frame data
Geometry
Manufacturer-published geometry normalized for consistent archival comparison. Effective top tube and reach remain separate measurements because they describe different aspects of fit.
| Measurement | Small | Medium | Large | X-Large |
|---|---|---|---|---|
| Seat tube | 405 mm | 430 mm | 455 mm | 480 mm |
| Effective top tube | 587 mm | 609 mm | 631 mm | 653 mm |
| Head tube | 100 mm | 110 mm | 120 mm | 130 mm |
| Head-tube angle | 64.7- 64.4 | 64.7- 64.4 | 64.7- 64.4 | 64.7- 64.4 |
| Seat-tube angle | 78.3- 77.9 | 78.3- 77.9 | 78.3- 77.9 | 78.2- 77.9 |
| Chainstay / rear center | 432 mm | 432 mm | 432 mm | 432 mm |
| Wheelbase | 1211 mm | 1236 mm | 1260 mm | 1283 mm |
| Bottom-bracket drop | 32 mm | 31 mm | 31 mm | 31 mm |
| Bottom-bracket height | 344 mm | 345 mm | 345 mm | 345 mm |
| Reach | 462 mm | 482 mm | 502 mm | 521 mm |
| Stack | 605 mm | 614 mm | 623 mm | 632 mm |
| Standover height | 736 mm | 736 mm | 737 mm | 737 mm |
| Fork offset / rake | 43 mm | 43 mm | 43 mm | 43 mm |
| Fork length / axle-to-crown | 551 mm | 551 mm | 551 mm | 551 mm |
| Crank length | 165 mm | 165 mm | 170 mm | 170 mm |
| Stem length | 40 mm | 40 mm | 40 mm | 40 mm |
| Handlebar width | 760 mm | 800 mm | 800 mm | 800 mm |
Geometry source: Manufacturer HTML geometry table ↗ Measurements can vary by configuration, wheel size, or flip-chip position where noted by the manufacturer.
Geometry interpretation
What this geometry means
The archived table contains multiple manufacturer geometry states. Velopedia preserves source order and analyzes each state separately rather than averaging the published values.
Small geometry
Configuration
Riding position
A 462 mm reach paired with 605 mm of stack gives this size a moderate frame proportion: roomy enough when standing without pushing strongly toward either a very low or very upright front end. Its 78.3° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.7° head angle combined with a 1211 mm wheelbase points to stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 2, this configuration steepens the head angle by 0.3°.
Archive context
Its reach of 462 mm sits toward the longer end. The seat angle of 78.3° sits toward the steeper end. Its wheelbase of 1211 mm sits somewhat longer than typical.
Riding position
A 462 mm reach paired with 605 mm of stack gives this size a moderate frame proportion: roomy enough when standing without pushing strongly toward either a very low or very upright front end. Its 77.9° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.4° head angle combined with a 1211 mm wheelbase points to strongly stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 1, this configuration slackens the head angle by 0.3°.
Archive context
Its reach of 462 mm sits toward the longer end. The seat angle of 77.9° sits toward the steeper end. Its wheelbase of 1211 mm sits somewhat longer than typical.
Medium geometry
Configuration
Riding position
With 482 mm of reach and 614 mm of stack, the frame has a relatively long, low proportion that should leave plenty of room when standing and put the front end toward the lower side of modern mountain-bike fit. Its 78.3° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.7° head angle combined with a 1236 mm wheelbase points to stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 2, this configuration steepens the head angle by 0.3°.
Archive context
The seat angle of 78.3° sits toward the steeper end. Its reach of 482 mm sits toward the longer end. The chainstay of 432 mm sits somewhat shorter than typical.
Riding position
With 482 mm of reach and 614 mm of stack, the frame has a relatively long, low proportion that should leave plenty of room when standing and put the front end toward the lower side of modern mountain-bike fit. Its 77.9° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.4° head angle combined with a 1236 mm wheelbase points to strongly stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 1, this configuration slackens the head angle by 0.3°.
Archive context
Its reach of 482 mm sits toward the longer end. The seat angle of 77.9° sits toward the steeper end. The chainstay of 432 mm sits somewhat shorter than typical.
Large geometry
Configuration
Riding position
With 502 mm of reach and 623 mm of stack, the frame has a relatively long, low proportion that should leave plenty of room when standing and put the front end toward the lower side of modern mountain-bike fit. Its 78.3° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.7° head angle combined with a 1260 mm wheelbase points to stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 2, this configuration steepens the head angle by 0.3°.
Archive context
The seat angle of 78.3° sits toward the steeper end. Its reach of 502 mm sits toward the longer end. Its stack of 623 mm sits somewhat lower than typical.
Riding position
With 502 mm of reach and 623 mm of stack, the frame has a relatively long, low proportion that should leave plenty of room when standing and put the front end toward the lower side of modern mountain-bike fit. Its 77.9° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.4° head angle combined with a 1260 mm wheelbase points to strongly stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 1, this configuration slackens the head angle by 0.3°.
Archive context
Its reach of 502 mm sits toward the longer end. The seat angle of 77.9° sits toward the steeper end. Its stack of 623 mm sits somewhat lower than typical.
X-Large geometry
Configuration
Riding position
With 521 mm of reach and 632 mm of stack, the frame has a relatively long, low proportion that should leave plenty of room when standing and put the front end toward the lower side of modern mountain-bike fit. Its 78.2° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.7° head angle combined with a 1283 mm wheelbase points to stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 2, this configuration steepens the head angle by 0.3°.
Archive context
The seat angle of 78.2° sits toward the steeper end. Its reach of 521 mm sits toward the longer end. Its stack of 632 mm sits somewhat lower than typical.
Riding position
With 521 mm of reach and 632 mm of stack, the frame has a relatively long, low proportion that should leave plenty of room when standing and put the front end toward the lower side of modern mountain-bike fit. Its 77.9° effective seat angle places the seated rider relatively forward, a layout that generally helps keep body weight centered on steep climbs.
Handling tendencies
A 64.4° head angle combined with a 1283 mm wheelbase points to strongly stability-oriented steering and chassis behavior. The longer the chassis and slacker the front end, the more the bike tends to favor composure over very quick direction changes.
Configuration changes
Compared with Configuration 1, this configuration slackens the head angle by 0.3°.
Archive context
Its reach of 521 mm sits toward the longer end. The seat angle of 77.9° sits toward the steeper end. Its stack of 632 mm sits somewhat lower than typical.
Geometry describes frame proportions and likely tendencies, not a ride test. Rider proportions, cockpit setup, tires, suspension settings, wheel configuration, and component choices can materially change how a bicycle fits and feels.
Gallery
Specifications are presented as a reference. Components may vary by market, size, production run, or later manufacturer revisions.