Velopedia Bicycle Archive
Surly Lowside Frameset - Blue Monday
Mountain bicycle from the Velopedia specification archive.
- Model year
- Not published by manufacturer
- Original MSRP
- $999.00
- Sizes
- XS, S, M, L, XL
- Colors
- Blue Monday
- Geometry
- 5 manufacturer sizes · Ride analysis
- Archive ID
- 900000934
- Catalog verified
- August 19, 2026
Current market
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Used-frameset inspection
If you’re buying this frameset used
Before buying: confirm the serial number and exact model, inspect frame and fork alignment, and inventory every included axle, hanger, clamp, headset part, cable guide and proprietary fitting.
Inspect the frame and fork →- FrameCheck paint chips, vent holes and the inside of the seat tube for corrosion. Also look for dents, bent tubes and cracking around welded or brazed joints.Inspect the frame and fork →
- Included hardwareInventory every axle, hanger, clamp, headset part, cable guide, frame plug and proprietary fitting included with the frameset. Confirm replacement availability before treating a missing small part as insignificant.
- AlignmentSight along the frame and fork from several directions. Confirm that the fork, rear dropouts, head tube and other visible interfaces appear straight; professional measurement is appropriate when alignment cannot be established visually.
Used-frameset inspection checklist 14 universal checks for a record with limited component data Open checklistClose checklist
The archived record does not contain enough component detail for a fully specification-informed frameset checklist. Use these universal checks on the frameset in front of you, inventory every included part and confirm exact interfaces before choosing components.
Identity and fit
Follow the full used-bike inspection order →Archived: Surly Lowside Frameset - Blue Monday · Mountain · Published sizes: XS, S, M, L, XL
Frame and fork
Inspect the frame and fork →Archived: Frame: Surly Lowside - 4130 Chromoly, Natch tubing, double-butted main triangle, TIG welded, ED coated · Fork: Surly Lowside - 4130 Chromoly, Natch tubing, double-butted tapered fork blades, TIG welded, ED coated · Steel
Alignment
Inspect the frame and fork →Frame interfaces
Inspect the bottom bracket and shell →Before accepting the frameset
Inspect the frame and fork →Have you owned this bike?Help preserve its real-world history by sharing your owner experience.
Share the details that would help another rider understand how this model fits, rides and holds up over time. Velopedia reviews every contribution before publication.
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Frameset
| Frame Construction | Surly Lowside - 4130 Chromoly, Natch tubing, double-butted main triangle, TIG welded, ED coated |
|---|---|
| Frame Material | Steel |
| Fork | Surly Lowside - 4130 Chromoly, Natch tubing, double-butted tapered fork blades, TIG welded, ED coated |
| Fork Material | Steel |
Wheels & Tires
| Wheel Size | 26" |
|---|
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 | X-Small | Small | Medium | Large | X-Large |
|---|---|---|---|---|---|
| Seat tube | 316 mm | 366 mm | 416 mm | 466 mm | 516 mm |
| Effective top tube | 570 mm | 590 mm | 610 mm | 630 mm | 650 mm |
| Head tube | 110 mm | 125 mm | 140 mm | 155 mm | 170 mm |
| Head-tube angle | 70° | 70° | 70° | 70° | 70° |
| Seat-tube angle | 74° | 74° | 74° | 74° | 74° |
| Chainstay / rear center | 425 mm | 425 mm | 425 mm | 425 mm | 425 mm |
| Wheelbase | 1068 mm | 1089 mm | 1110 mm | 1131 mm | 1152 mm |
| Bottom-bracket drop | 55 mm | 55 mm | 55 mm | 55 mm | 55 mm |
| Reach | 414.5 mm | 429.3 mm | 445.3 mm | 461 mm | 477 mm |
| Stack | 542.2 mm | 560.3 mm | 574.4 mm | 588.5 mm | 602.5 mm |
| Standover height | 700 mm | 729 mm | 762 mm | 792 mm | 823 mm |
| Fork offset / rake | 47 mm | 47 mm | 47 mm | 47 mm | 47 mm |
| Fork length / axle-to-crown | 420 mm | 420 mm | 420 mm | 420 mm | 420 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
X-Small geometry
Riding position
A 414.5 mm reach paired with 542.2 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.
Handling tendencies
A 70° head angle combined with a 1068 mm wheelbase points to quicker-steering and more responsive 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. A 425 mm rear center is compact, which tends to make rear-wheel weight shifts and tight direction changes easier than a long-rear-center layout.
Small geometry
Riding position
A 429.3 mm reach paired with 560.3 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.
Handling tendencies
A 70° head angle combined with a 1089 mm wheelbase points to quicker-steering and more responsive 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. A 425 mm rear center is compact, which tends to make rear-wheel weight shifts and tight direction changes easier than a long-rear-center layout.
Medium geometry
Riding position
With 445.3 mm of reach and 574.4 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.
Handling tendencies
A 70° head angle combined with a 1110 mm wheelbase points to quicker-steering and more responsive 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. A 425 mm rear center is compact, which tends to make rear-wheel weight shifts and tight direction changes easier than a long-rear-center layout.
Large geometry
Riding position
With 461 mm of reach and 588.5 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.
Handling tendencies
A 70° head angle combined with a 1131 mm wheelbase points to quicker-steering and more responsive 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. A 425 mm rear center is compact, which tends to make rear-wheel weight shifts and tight direction changes easier than a long-rear-center layout.
X-Large geometry
Riding position
With 477 mm of reach and 602.5 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.
Handling tendencies
A 70° head angle combined with a 1152 mm wheelbase points to quicker-steering and more responsive 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. A 425 mm rear center is compact, which tends to make rear-wheel weight shifts and tight direction changes easier than a long-rear-center layout.
Across the size range
From X-Small to X-Large, reach grows by 62.5 mm and stack by 60.3 mm, showing how the frame becomes both longer and taller through the published size range. The rear center stays essentially constant at about 425 mm across sizes, so most of the wheelbase growth happens in the front half of the bike rather than by lengthening the rear triangle.
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.