Cannondale Topstone Alloy Geometry & Bikepacking Bag Fit2026
A retailer listing — this frame is not on the manufacturer's current site, so the specs may lag a model year.
We may earn a commission if you buy through this link, at no extra cost to you.
Cannondale Topstone Alloy frame geometry, drawn to scale
Every tube angle and length below is from the published chart, not an illustration. The front triangle area is the number that decides which frame bags fit — and it changes a lot across sizes.
What this frame gives a loaded bike
Chainstay length is the gap between the seat tube and the rear axle, which a rack, panniers and your heels all have to share. Bottom bracket drop is how far the cranks sit below the axles. Both are compared against the median across every current frame we hold.
435mm chainstays, about the median for the 65 current frames here. Bottom bracket drop 75mm, 5mm more than the 70mm median. The fork publishes cargo mounts, and the frame publishes bottle or accessory mounts. A rear rack bolts straight on. Widest published tire 45mm on 700c / 29in. It takes a dropper post.
Every figure above is the manufacturer's, computed against the rest of the database. It says what the frame allows, not how it feels — nobody here has ridden it.
What it can carry
Mount provision and clearance, as Cannondale publishes it.
Cannondale's wording: “45mm”
Builds
As Cannondale lists them. Prices are MSRP at our last check and move around — treat them as a reference point, not a live quote.
| Build | Drivetrain | MSRP |
|---|---|---|
| Topstone 3 | microSHIFT Sword 1x10 | $1,599 |
| Topstone 2 1x | Shimano CUES 1x11 | $2,199 |
| Topstone 1 | Shimano GRX | $2,699 |
Geometry
All figures in millimeters except angles. Effective top tube and seat tube are the two that decide frame bag fit.
| Size | Eff. top tube | Seat tube | Standover | Head tube | Stack | Reach | Chainstay | Wheelbase | BB drop | Head angle | Seat angle |
|---|---|---|---|---|---|---|---|---|---|---|---|
| XS | 533 | 410 | 703 | 86 | 518 | 368 | 435 | 1016 | 75 | 70° | 73.1° |
| S | 544 | 458 | 744 | 115 | 549 | 377 | 435 | 1027 | 75 | 71° | 73.1° |
| M | 557 | 505 | 784 | 147 | 579 | 385 | 435 | 1045 | 75 | 71° | 73.1° |
| L | 572 | 553 | 824 | 180 | 610 | 394 | 435 | 1065 | 75 | 71° | 73.1° |
| XL | 587 | 600 | 864 | 212 | 640 | 402 | 435 | 1083 | 75 | 71° | 73.1° |
Bottom bracket height
Roughly 300mm off the ground. Cannondale doesn't publish this directly — we derive it from their BB drop and a typical 75cm tire diameter, so treat it as indicative rather than exact. It changes with the tire you fit. Lower means more stable and more pedal strikes; higher means the opposite.
Source — retailer listing (this model's geometry isn't on the manufacturer's current site, so specs may lag a model year): https://www.rei.com/product/208190/cannondale-topstone-1-bike — checked 2026-08-16. A dash means the figure isn't published; we leave it blank rather than estimate.
Note: Geometry from the current REI Topstone Alloy table, which matches Cannondale’s own chart on every measurement. seatAngle is Cannondale’s published effective seat angle of 73.1 degrees, not the 71.8 in REI’s Seat Tube Angle row — that row is the actual angle, and using it makes the published reach, stack and effective top tube contradict each other by 18-25mm. Cannondale chart: c22_topstone_alloy_geo_table_v2.
How the Topstone Alloy compares
Against the frames people actually cross-shop it with — both charts held together, on the specs that decide what the bike carries.
Questions people ask about this frame
Answered from what Cannondale publish. Where they publish nothing, that is what it says.
Does the Topstone Alloy take fork cargo cages?
Rack mounts, not cage mounts. The fork mounts Cannondale publish are for racks or fenders, and a lowrider eyelet won't take a cargo cage. That doesn't rule cages out — it means nobody has said.
What is the widest tyre the Topstone Alloy takes?
45mm on 700c / 29in. That is the frame figure rather than the fork's, and it is what limits a loaded bike.
Will a seat pack work on the Topstone Alloy?
The dropper is the problem, not the pack. This frame publishes dropper routing, and a dropper and a seat pack want the same space — fitting one rules out almost every strap-on seat pack and leaves rail-mounted bags at a fraction of the volume. Run a rack or a saddle-rail bag if you want both.
Which frame bags fit
Every frame bag we track, checked against this frame's published geometry. Pick your size.
Checking 16 frame bags against a 557mm effective top tube and 505mm seat tube. 16 fit.
Frame bag fit is calculated from Cannondale's published geometry, so it's as reliable as their chart. Seat packs and handlebar rolls depend on your exposed seatpost and bar width, which no geometry table lists — the bag finder covers those once you add your own measurements.