Sparecog

Planning tools for bikepacking: gearing for loaded climbs, frame fit, tire clearance, trail food and a packing list. Everything runs in your browser.

Compare two drivetrains: how easy the lowest gear is for loaded climbs, and how fast the highest gear goes. Speeds are at the pedalling pace you choose.

Setup A

Setup B

Wheel and cadence

Turns of the cranks per minute. Around 60–80 is typical on a loaded bike, 90 if you spin quickly.

Every gear, easiest to fastest

Each dot is one gear. Dots to the left are easier for climbing, dots to the right are faster. Gaps between dots are the jumps you feel when shifting.

Full gear tables and other measures

On 2x setups, struck-through gears use the chain at a steep angle (big ring with the biggest cogs, small ring with the smallest). They work, but they wear the chain and you can usually find the same gear on the other ring.

Estimate how long a climb takes at a given power, or what power you need for a target time. Uses a standard physics model with rolling resistance, air drag and drivetrain loss.

The climb

Rider and bike

Solve for

Where the watts go

On steep climbs almost everything goes into lifting you and the bike, which is why weight matters more than aero here. On flatter grades, drag takes over.

What 1 kg is worth

Model: no wind, constant grade, 2.5% drivetrain loss, air density from altitude. Real climbs vary in gradient, so treat results as a pacing guide.

Power zones from your FTP (7-zone model) and heart-rate zones from your lactate threshold heart rate (Friel cycling zones).

Power

A 20-minute result is multiplied by 0.95 to estimate FTP.

Heart rate

Your average heart rate over the last 20 minutes of a 30-minute solo time trial.

Power zones

Heart-rate zones

Enter your height and the geometry of the sizes you're considering, copied from the maker's geometry chart. Each size is compared with typical stack and reach for a rider your height, and the closest one is recommended.

You

Bike type

To measure inseam, stand barefoot against a wall, press a book up between your legs like a saddle, and measure from the floor to the top of the book. Leave it blank to estimate it from your height.

Your targets

Typical values for your height and bike type. Flexibility, arm and torso length, and riding style all shift these, so a professional fit beats any formula.

Sizes to compare

SizeSeat tubeTop tubeStackReachFitRemove

All lengths in millimetres, the way geometry charts list them. Stack and reach matter most; seat tube and top tube are used when they're missing. Seat tube is measured differently by each maker, so it counts for little.

Plan food and water for multi-day rides: how much energy a day takes, what to eat and drink each hour on the bike, and how much weight to carry between resupply points.

Your riding day

Effort
Temperature

Carrying

Each hour on the bike

Start eating within the first hour and keep going in small amounts. Little and often is easier on your stomach than big meals on the bike.

Where the energy goes

To carry until resupply

Estimates for planning. Riding energy uses your power if given (1 kJ of work ≈ 1 kcal burned), otherwise typical values for the effort level. Most people can't eat everything they burn on long days, so pack enough and eat steadily. Needs vary a lot with body, terrain, altitude and sweat rate.

A checklist of common bikepacking gear. Pick the conditions you expect to add the right extras, tick things off as they go in the bags, and add anything personal.

Packed

0of 0

Conditions

Add an item

Start over

Check whether a tire fits a frame, using each maker's stated maximum. Pick your wheel and tire, and see every frame it fits, or check one frame.

Your tire

Or type the width printed on the tire, like 700 x 45 or 29 x 2.4.

Check one frame

All frames

FrameMax tireRoomFit

These are the makers' stated maximums, which already allow some safety margin. Real widths vary: the same tire can measure 2–4 mm wider on a wide rim, and some brands run large. Mud needs extra room, and on some bikes the chain or front derailleur limits clearance before the frame does.

Load a route from Ride with GPS to see its distance and climbing, split it into riding days, and estimate food for each day.

Trip

Load one of my Ride with GPS routes

For the site owner. Also lets you load your private routes.

Or load a route file

Works for private routes and offline. To get the file from Ride with GPS:

  1. Open the route and choose Export.
  2. Pick GPX Track (.gpx) and download it.
  3. Load that file here.

Your pace, loaded

Riding time = distance ÷ flat speed, plus climbing ÷ climbing rate. On a loaded bike, 300–500 m of climbing per hour is typical. Days are split so each has about the same riding time.

Elevation

Day by day

Set a start date to check daylight and weather for each day.

Daylight compares sunrise-to-sunset with riding time plus about 30% for breaks. Food per day uses your settings on the Bikepacking food tab. Weather from Open-Meteo.

Resupply and water

Searches OpenStreetMap for grocery and convenience stores, gas stations, cafés, water taps and springs within about 1 km of the route.