The dream build.

Bike-leg calculator · priced at your speedThe pros' most-raced gear, tallied All 45 pros' full setups

When an ad says a wheelset “saves 8 watts,” that was measured around 45 km/h (28 mph) — pro speed. Most of us ride closer to 30 km/h (19 mph), where you'd get about a third of those watts. Punch in your current split, mark what you ride NOW and what you DREAM of, and see what the money really gets you — at your speed.

01 / Your ride now — before upgrades

Climbing · mFlorida, Barcelona

Bike split · now

Rider weight

= 30.0 km/h

02 / The build sheet

NowDream

Bike & position

NowDream

Road bike, hands on hoods—
Road bike + clip-on aero bars$120$120
Aero road bike + clip-ons$4,800$4,800
Triathlon / TT bike$6,500$6,500

This swap−9:12 alone · $6,500

At your 30 km/h19.3 W

e.g. Canyon Speedmax, Trek Speed Concept. Age-grouper TT CdA ≈ 0.28 vs 0.36 on the hoods — mostly position, not frame. Assumes a decent fit.¹ ² ³ ⁴ ⁷

Wheels

NowDream

Box-section alloy wheels—
Deep carbon wheels (50–65 mm)$1,900$1,900
Deep front + rear disc$4,500$4,500

This swap−1:02 alone · $4,500

If you averaged 45 km/h8.0 W

At your 30 km/h2.3 W

e.g. Zipp 858 + Super-9 disc. Straight-line tests put a disc 2–3 W @ 45 km/h under a deep rear (crosswinds widen it; the maker's own box-vs-disc claim is ≈5× our entire wheels row). Least-documented public number on this sheet — hence the wide range. Check your race allows discs.⁵ ⁶

Tires

NowDream

Puncture-belt training tires—
Fast race tires$150$150
Fastest TT race tires$220$220

This swap−7:38 alone · $220

At your 30 km/h17.6 W

e.g. GP5000 TT TR, Vittoria Corsa Speed. Fastest measured: Crr ≈ 0.0031–0.0038 with butyl tubes. Per pair; flat-prone — run sealant.⁸ ¹⁰ ¹⁶

Tubes & setup

NowDream

Butyl inner tubes—
Latex or fast TPU tubes$40$40
Tubeless + sealant$60$60

This swap−2:03 alone · $60

At your 30 km/h4.6 W

e.g. Any tubeless-ready wheel + tire. Same BRR test: tubeless runs ≈2 W per tire under a 100 g butyl tube at 29 km/h; BRR measures it 0.2 W per tire under latex (our encodes: ≈0.35). Needs tubeless-ready rims and tires.¹³

Helmet

NowDream

Standard vented road helmet—
Aero road helmet$300$300
TT helmet$600$600

This swap−0:49 alone · $600

If you averaged 45 km/h6.0 W

At your 30 km/h1.8 W

e.g. Giro Aerohead, POC Procen. Tunnel tests: 3–9 W @ 45 km/h — heavily head- and fit-dependent. Test before race day.¹

Race suit

NowDream

Loose top + shorts—
Fitted tri suit$200$200
Sleeved aero race suit$500$500

This swap−0:59 alone · $500

If you averaged 45 km/h7.0 W

At your 30 km/h2.2 W

e.g. Castelli PR, Roka Gen II. Sleeved textured suits: 10–20 W @ 45 km/h vs loose clothing; some tunnel tests report up to 25.¹ ¹⁷

Lower legs

NowDream

Bare legs, unshaved—
Shaved legs$10$10
Shaved + aero calf sleeves$60$60

This swap−1:39 alone · $60

If you averaged 45 km/h12.0 W

At your 30 km/h3.6 W

e.g. WYN republic CDA, Compressport R2 Aero. Sleeves add ≈1–2 W @ 45 km/h over a shaved leg in our encode — published sock and sleeve claims run 2–8 W; we take the low end because the shave is already banked. Includes the shave. Check race uniform rules.¹ ¹²

Drivetrain

NowDream

Typical lubed chain—
Race-waxed chain + clean drivetrain$60$60

This swap−0:47 alone · $60

At your 30 km/h1.7 W

e.g. Hot-melt wax, clean cassette. Friction testing: ≈1.8–3.5 W under a typical lubed chain at 250 W (we encode less than the marketing quotes; wax sellers claim 6–8 W vs neglected chains) — scales with your power, not speed.¹⁵ ¹⁶

Hydration setup

NowDream

Round bottles on the frame—
Clean cockpit: between-the-arms bottle$80$80

This swap−0:33 alone · $80

If you averaged 45 km/h5.0 W

At your 30 km/h1.2 W

e.g. Torpedo BTA, bare frame. Win Tunnel: frame bottles cost ≈5 W; a BTA bottle tests neutral or better.¹²

Projected bike split · Half / 70.3 (90 km)

2:34:39

was 3:00:00 · same 161 W engine

Time saved−25:21
Typical range−17:29 to −34:20
Upgrade bill$12,580
Cost per minute$496/min
Best valueFastest TT race tires · $29/min
Speed30.0 → 34.9 km/h
ProfileFlat

No wind, no drafting, constant power. Hills are steady climb–descent segments with a 62 km/h descent cap — which is why aero buys less on a hilly course. Single swaps don't sum to the combined figure — savings interact.

Running total−25:21$12,580$496/min

From the register

This calculator is a side room of RACEKIT: the race-day setups of 45 pro triathletes, cataloged part by part with sources. The dream picks above aren't hypothetical — the register shows who actually races them.

The count — every brand on the start line, tallied by category.
Gear register — 302 items on file, and who races each one.
Start list — every athlete's full spec sheet, swim to run.

The fine print

Model: P = ½·ρ·CdA·v³ + Crr·m·g·v, plus drivetrain loss (2.5% baseline; your drivetrain pick can lower it). Your power is inferred from the split you enter on the setup you mark as current — or, in watts mode, is exactly the steady average watts you type, with the split computed from it — then held constant across every what-if: same engine, different equipment. Per-swap watts are rider watts (drivetrain loss included) computed from our encoded value — where that encode differs from the ad's claim (usually by being more conservative), the two bars disagree even at 45 km/h. That gap is deliberate. Rows with no hollow claim bar are parts that aren't marketed with a watt figure at all (position, tires, tubes, wax) — nothing to re-price, only the tested number.
Fewer watts is not fewer minutes. At your speed a swap delivers a fraction of its claimed watts, but you are on course longer and your total power is smaller, so each saved watt buys more seconds — a slower rider banks similar or even more time from the same part. What shrinks at your speed is the watt number on the box, and that is the number the ads sell.
Constants: air density 1.225 kg/m³ (sea level, 15 °C), bike + kit fixed at 9 kg, no wind, no drafting. Weight is held fixed on purpose: at constant power this model prices a 1 kg lighter bike at ≈41 s over the hilliest preset half (≈14 s flat) — real, but small next to the position and tire swaps here, and per-part weight data is too inconsistent to price honestly. If grams matter on your course, spend there after the aero.
Course profiles are modeled as steady flat–climb–descent segments: the course's total climbing (preset per profile, or type your own) at a representative 4–5% gradient — steepened when a typed gain is too big to fit the distance at 4–5% — with descents capped at 62 km/h / 39 mph (brakes and nerve, not power). That is why aero upgrades buy less on a Lake Placid than a Florida — more time at slow climbing speeds where drag is small, and the descent gives little back. Tire savings survive hills: rolling energy is paid per kilometer, not per unit of speed. One edge of the cap: once both setups descend at 62, the descent pays nobody — heavier riders on steep courses can see aero savings step down as they cross it.
The card's “same N W engine” figure is the constant power that rides your split on the setup marked NOW — it is not a power-meter average. On hilly courses a meter reads meaningfully lower than the steady-state equivalent: real riders coast descents, carry momentum through rollers, and pace climbs above average power, none of which the segment model does — and GPS total-ascent figures run high. Treat the absolute watts as an upper bound on hills; the before-vs-after savings compare like-for-like regardless.
Part numbers are the midpoints of published wind-tunnel and roller bands (rounded toward the conservative end) — not our own tunnel session. Body and position dominate drag, so read every figure as an estimate; the “typical range” on the card runs the same physics at both ends of each published band.
Combining parts sums CdA deltas that were measured in separate tests on separate riders, and real interactions (helmet × position, wheels × yaw) can move individual numbers either way. The per-swap figures are the defensible core; the full-build total is the roughest number on this page — that is exactly what the typical range is for.
Tire Crr comes from standardized drum tests. Drums flatten the tire more than a road does, so absolute watt figures can run optimistic — the relative differences between tires hold.
Baseline anchor: an age grouper on road-bike hoods at CdA ≈ 0.36 m²; category baselines are the first option in each row.
Model checks against the published rules of thumb — every one of these reproduces from the equations above: 0.01 of CdA costs ≈31–46 s over 40 km at 35–41 km/h / 22–25 mph for starting rigs from full-TT (CdA ≈ 0.28) to road hoods (≈ 0.36) — published rule of thumb: 40–60 s, so our model sits at the conservative end; training tires with butyl tubes → TT tires run tubeless saves ≈27 W for an 84 kg system at 36 km/h / 22 mph (published extreme-swap band: 10–30 W; SILCA quotes ≈26 W for the tire change alone — we only reach ≈27 W with the tubeless step included); clip-ons→TT bike saves ≈3.7–3.8 min over 40 km at 210 W, tire choice moving it within that band (published: low single-digit minutes). Don't take our word for it — punch the same CdA/Crr/mass into the independent calculator in source 11 and compare.
No ads, no affiliate links, no email capture on this page. Anonymous usage analytics only (PostHog: which presets and parts get picked, never who you are) so we know which categories to improve. Every outbound link below points at the published test it cites.

Sources

A number off? Send a correction — sources welcome.