Bike models › Road
Giant Defy 3 (2015): specs, upgrades and what fits
Giant's best-selling aluminum endurance road bike with a composite fork, Shimano Sora 9-speed STI, a 50/34 compact crank, an 11-32 cassette and Tektro dual-pivot rim brakes; Giant listed it at $970. The 2014 Defy 3 is close. Best for: Long road rides and fitness.
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My take, from the specs
A good used road bike for long rides and fitness, with an aluminum frame, composite fork and a relaxed endurance position. The Sora 2x9 with a 50/34 crank and 11-32 cassette gives easy climbing gears. It runs rim brakes on 25 mm tires, so on a used one check the rim brake tracks for wear, the chain and cassette, and the shifters for sticky shifts.
Sizes: XS: 5′2″–5′7″ (157–169 cm) · S: 5′5″–5′9″ (165–175 cm) · M: 5′7″–5′11″ (171–181 cm) · M/L: 5′10″–6′2″ (177–187 cm) · L: 6′0″–6′4″ (183–193 cm) · XL: 6′2″–6′6″ (189–199 cm)
Stock specs
| Type | Road |
|---|---|
| Year | 2015 |
| Price when new | $970 |
| Sold at | Giant dealers (discontinued; common used) |
| Wheels | 700c × 25 mm tires |
| Gears | 2×9 · 50/34T · 11–32T |
| Brakes | Tektro R312 dual-pivot |
| Fork | Giant Composite, alloy OverDrive steerer (rigid) |
| Rear derailleur | Shimano Sora (9-speed) |
| Shifter | Shimano Sora, 2x9 |
| Crank | Shimano Sora compact (two-piece est.) |
| Bottom bracket | External-cup BB (BSA) |
| Axles | Quick release |
| Seatpost | 30.9 mm |
| Sizes | XS, S, M, M/L, L, XL |
| Stock colors | Black/Red/Silver, Blue/White/Green |
Upgrade limits
How far each part can go on this frame, and why. Measure your own bike to confirm the estimated ones.
| Part | Limit | Why |
|---|---|---|
| Widest tire (current wheel size) | 25 mm | Unknown until measured. Your 19 mm internal rims suit roughly 28–49 mm tires. |
| Other wheel sizes | 700c only | Rim brakes are set to the rim height, so the wheel size cannot change. |
| Tubeless | Not recommended | Tubeless needs a rim built to seal (bead hook + channel) and tubeless-ready tires. |
| Valve type | Presta | Decides which tubes and pump heads fit. Presta tubes fit Schrader rims with a grommet; not the other way. |
| Replacement wheels | Quick release · 100/130 mm | Any wheel matching axle type, spacing and brake mount fits. Rear also needs the right freehub. |
| Biggest rear cog | 32T (now 32T) | Set by the rear derailleur (Shimano Sora (9-speed)): max low sprocket 32T, total capacity ?T. A hanger extender can add a few teeth (hit-or-miss on non-Shadow derailleurs); a new derailleur is the reliable way to get more. |
| Brake pads (rim) | Road cartridge or road pads (dual-pivot caliper) | Rim brake pads are sorted by how they mount, which depends on the brake: threaded post with a nut (V-brakes, U-brakes), smooth post in an eye bolt (cantilevers), road cartridges (dual-pivot calipers) or short threaded pads (side-pull calipers). Any compound… |
| Front gears | 2x (50/34T) · needs 37T capacity | A 2x drivetrain needs a front derailleur and left shifter. Your rear derailleur must take up (biggest − smallest ring) + (biggest − smallest cog) = 37T. Going 1x drops the front derailleur: simpler and quieter, with a slightly smaller range. |
| Chainring size | Unknown (now 50T) | Estimated from similar frames. Measure the chainring-to-chainstay gap to confirm. Check whether your ring is bolted or riveted. Spindle length (? mm) sets chainline; a big change in ring size may need a different BB spindle. |
| Gear count upgrades | 9-speed (HG body) | Shimano HG 8/9/10-speed freehub: takes 8, 9 or 10-speed cassettes, Shimano 11-speed MTB and CUES/LinkGlide cassettes (7-speed needs a 4.5 mm spacer; most 11/12-speed road cassettes need an 11-speed road freehub, though the 11-34 HG700/HG800 fit). Shifter,… |
| Cranks & bottom bracket | External-cup BB (BSA) | Match crank spindle to BB type. |
| Pedal thread | 9/16" × 20 | Every adult multi-piece crank uses 9/16". One-piece kids/cruiser cranks use 1/2". |
| Stems & bars | tapered steerer · 31.8 mm bar clamp | Any stem for a tapered steerer with a 31.8 mm clamp fits. You can cut a bar narrower but not wider. |
| Seatposts | 30.9 mm | Buy posts in exactly this diameter. |
| Racks, fenders, bottles | No rack · No fender · 0 bottle | Threaded eyelets at the dropouts and seat stays take a rack and fenders. Fork leg mounts take cargo cages. |
| Max load (rider + cargo) | Unknown | Wheels are usually the weak point under heavy loads. Stay under this with rider plus luggage. |
Best upgrades by area
Three options that fit the Giant Defy 3 (2015) as-is in each area, from budget to best. ★ marks the one most worth the money. How we pick. Typical US prices, checked October 2026. They change often: check the price at the store.
Upgrades that fit as-is
Brakes
- Shimano R55C4 road cartridge pads (2 pairs), $$. road caliper pads ↔ your rim brakes
- Shimano R50T2 road caliper brake pads (2 pairs), $. road caliper pads ↔ your rim brakes
- Kool-Stop Dura 2 salmon road brake pads, threaded (2 pairs), $$. road caliper pads ↔ your rim brakes
- SwissStop Full FlashPro Original Black road pads with holders (2 pairs), $$. road caliper pads ↔ your rim brakes
- Shimano Sora BR-R3000 dual-pivot rim brake calipers (pair), $$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
- Shimano Tiagra BR-4700 dual-pivot rim brake calipers (pair), $$$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
- Shimano 105 BR-R7000 dual-pivot rim brake calipers (pair), $$$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
- Tektro R539 long-reach dual-pivot rim brake calipers (pair), $$$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
Comfort
- 35° rise 60 mm stem, $. tapered" steerer matches · Get the 31.8 mm clamp version for your bar
- WTB Volt saddle, $$. Medium-width shape that suits most riders. Measure sit bones if comfort is the goal.
- Brooks C17 All Weather saddle, $$$. Vulcanized rubber top that flexes like a hammock, and this All Weather version is fully waterproof. No break-in like leather. Firm, not padded: made for long…
- Bikeroo oversized comfort saddle, $. Wide, soft and sprung for short upright rides on cruisers and hybrids. On rides over an hour wide padding can chafe; a firmer saddle that fits your sit bones…
- Cinelli Cork Ribbon bar tape, $. Made for drop bars ↔ your drop bar
- Selle Royal Respiro Moderate saddle, $$$. Made for a 60° "moderate" back angle (most flat-bar hybrids). Very upright cruisers suit the wider Respiro Relaxed. Standard round steel rails.
- Fizik Terra Argo X5 saddle (150 or 160 mm), $$$. Pick 150 mm for narrower sit bones, 160 mm for wider. Round 7 mm alloy rails fit every standard clamp.
- Ergon SR Allroad Core Comp saddle (men's or women's), $$$. Comes in S/M and M/L widths (measure your sit bones) and men's and women's shapes. Round CroMo rails; 120 kg rider limit.
- Lizard Skins DSP V2 bar tape 2.5 mm, $$. Made for drop bars ↔ your drop bar
- Lizard Skins DSP V2 bar tape 4.6 mm, $$. Made for drop bars ↔ your drop bar
- SR Suntour NCX suspension seatpost 30.9 x 350 mm, $$$. 30.9 mm post ↔ your 30.9 mm seat tube
- Redshift ShockStop Endurance suspension seatpost 30.9 mm, $$$$. 30.9 mm post ↔ your 30.9 mm seat tube
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 30.9 mm (LR or XR spring), $$$$. 30.9 mm post ↔ your 30.9 mm seat tube
- Redshift ShockStop suspension stem 31.8 (±6° or +30°), $$$. tapered" steerer matches · Threadless stem ↔ your threadless steerer
- Redshift ShockStop PRO suspension stem 31.8 (±6°), $$$$. tapered" steerer matches · Threadless stem ↔ your threadless steerer
Control
- Race Face Chester composite flat pedals, $$. Big platform with pins. Feet stay put on bumps and in rain. Install with an 8 mm hex key (no wrench flats).
- ROCKBROS aluminum flat pedals, $$. Budget metal platform with pins. A big step up from stock plastic.
- Shimano PD-M520 SPD clipless pedals (cleats included), $$. Nearly indestructible two-sided SPD pedals. You also need SPD (2-bolt) shoes, about $60–100 more. Set the release tension low and practice unclipping before…
- Crankbrothers Stamp 2 aluminum flat pedals (small or large), $$$. Sized by shoe: small for US men's 5–10, large for 10 and up. Grease the threads and tighten to about 35 Nm.
- OneUp Components Aluminum flat pedals, $$$. Bearings and bushings can be serviced with a cheap kit instead of replacing the pedal. Grease the threads and tighten to about 35 Nm.
- Shimano PD-EH500 dual-sided SPD / flat pedals (cleats included), $$$. Comes with SM-SH56 multi-release cleats, which are easier to get out of in a panic. You still need 2-bolt SPD shoes to clip in.
- Shimano Deore XT PD-M8100 SPD pedals (cleats included), $$$. Cup-and-cone bearings are fully serviceable and last for years. Shoes with a 2-bolt SPD cleat sold separately.
- KS eTen-R external dropper 30.9 mm, 100 mm drop + KS Southpaw remote, $$$. 30.9 mm post ↔ your 30.9 mm seat tube
- TranzX YSP22 external dropper 30.9 x 410 mm, 125 mm drop, remote included, $$$. 30.9 mm post ↔ your 30.9 mm seat tube
- KS LEV external dropper 30.9 mm (100–150 mm drop) + KS Southpaw remote, $$$$. 30.9 mm post ↔ your 30.9 mm seat tube
Utility
- USB rechargeable front + rear light set, $$. Daytime flashing lights cut collisions. Required by law at night.
- Pletscher adjustable kickstand, $$. Handy for errands. Check it clears the rotor and chainstay.
- Lisen clamp-style handlebar phone mount, $. Cheap and tool-free for maps on paved rides. On rough gravel or trails a locking mount (Quad Lock or Peak Design, about $45–70 plus a case) is much safer.
- Topeak TopLoader top tube bag (0.75 L), $$. Keeps snacks, keys and a multi-tool within reach. Straps on, with a rain cover. Check your knees do not rub it when you stand up.
- Knog Oi Classic bell, $. Slim ring bell that wraps the bar. Large fits 23.8–31.8 mm bars; Small fits 22.2 mm kids and BMX bars. Required by law in some places.
- Planet Bike Beamer 200 + Blinky Squared USB light set, $$. USB rechargeable, tool-free mounts. Use flash mode in daylight. Rear light is 30 lumens: good for town, modest on fast roads.
- Cygolite Metro Plus 800 + Hotshot Pro 150 USB light set, $$$. Nine headlight modes including a daytime flash. Aim the beam slightly down so you do not blind oncoming riders.
- Trek (Bontrager) Ion Pro RT + Flare RT light set, $$$. Daytime-running flash modes on both lights. ANT+ lets a Garmin or Wahoo show battery and switch them. Full power runs about 1.5 hours; medium lasts much longer.
Drivetrain
- KMC X9 9-speed chain with Missing Link, $$. 9-speed chain ↔ your 9-speed drivetrain
- Shimano CN-HG53 9-speed chain (116 links), $. 9-speed chain ↔ your 9-speed drivetrain
- Shimano CN-HG93 9-speed chain (XT/Ultegra level, 116 links), $$. 9-speed chain ↔ your 9-speed drivetrain
Tubes
- Continental Race 28 Wide 700x25–32 Presta 60 mm tubes (pair), $. 700c wheel size matches · Presta valve ↔ your Presta rims
- RideNow TPU road tubes 700x18–32 Presta 65 mm (pair), $. 700c wheel size matches · Presta valve ↔ your Presta rims
- Pirelli P ZERO SmarTUBE 700x23–32 Presta 60 mm (pair), $$$. 700c wheel size matches · Presta valve ↔ your Presta rims
Wheels
- Shimano WH-RS100 700c rim-brake wheelset, QR 100/130, 8–11 speed, $$$. 700c wheel size matches · 100/130 mm hubs ↔ your frame
Fits with small changes (18)
- Suspension seatpost 27.2 mm (budget), $$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- Redshift ShockStop suspension seatpost 27.2, $$$$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- External dropper post 27.2 mm, 100 mm drop + remote, $$$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- Ritchey Comp 2-Bolt alloy seatpost 27.2 mm, $$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- Thomson Elite seatpost 27.2 x 330 mm, $$$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- Ergon CF Allroad Pro Carbon flex seatpost 27.2 mm, $$$$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 27.2 mm (LR or XR spring), $$$$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- KS eTen-R external dropper 27.2 mm, 100 mm drop + KS Southpaw remote, $$$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- PNW Components Pine external dropper 27.2 mm (90 or 110 mm) + PNW Loam lever, $$$$. Your seat tube takes 30.9 mm: needs a 27.2→30.9 shim.
- Continental Ultra Sport III 700x25 folding (pair), $$. Outside the ideal range for your 19 mm rims (28–49 mm): it will mount, but the shape is less stable.
- Michelin Power Cup 700x25 clincher (pair), $$$. Outside the ideal range for your 19 mm rims (28–49 mm): it will mount, but the shape is less stable.
- Continental Grand Prix 5000 700x25 clincher (pair), $$$. Outside the ideal range for your 19 mm rims (28–49 mm): it will mount, but the shape is less stable.
- Stan's NoTubes tire sealant 16 oz, $. In tubes: needs tubes with removable valve cores (Presta or Schrader to match your rims).
- Orange Seal Endurance tubeless sealant 16 oz, $. In tubes: needs tubes with removable valve cores (Presta or Schrader to match your rims).
- SILCA Ultimate Tubeless Sealant 16 oz, $. In tubes: needs tubes with removable valve cores (Presta or Schrader to match your rims).
- Kalloy Uno SP-602 alloy seatpost 25.4 x 350 mm, $. Your seat tube takes 30.9 mm: needs a 25.4→30.9 shim.
- Thomson Elite seatpost 25.4 x 330 mm, $$$. Your seat tube takes 30.9 mm: needs a 25.4→30.9 shim.
- Sunlite adjustable suspension seatpost 25.4 mm, $$. Your seat tube takes 30.9 mm: needs a 25.4→30.9 shim.
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Buying one used? Fair prices
Worked out from the price new ($970), age and condition, not live market data. If it needs tires, a chain or brakes, take off what fixing them would cost.
| Condition | Today (2015 model) |
|---|---|
| Like new | $245–$325 |
| Good | $220–$285 |
| Fair | $180–$235 |
| Needs work | $135–$180 |
See what these really sold for on eBay · Other used bike prices
Geometry (size M (50 cm))
| Stack | 566° |
|---|---|
| Reach | 377 mm |
| Head angle | 72.5° |
| Seat angle | 73.5° |
| Chainstay | 420° |
| Wheelbase | 995 mm |
| Head tube | 165 mm |
| Standover | 777° |
Compare with
- Trek Domane AL 2 Gen 4 · compare frames side by side
- Giant Contend 3 · compare frames side by side
- Specialized Allez (Shimano Claris) · compare frames side by side
- Schwinn Volare 1300 700c Drop Bar · compare frames side by side
Sources: Giant bike archive: 2015 Defy 3 (spec, geometry, colours, $970) · Bicycle Blue Book: 2015 Giant Defy 3 (lists MSRP $950)