Bike models › Road
Polygon Strattos S4 Disc: specs, upgrades and what fits
An aluminum endurance road bike with a tapered carbon fork, 12mm thru-axles, Shimano Tiagra 2x10 with ST-R4720 levers and BR-4770 flat-mount hydraulic disc brakes on 140mm 6-bolt rotors, and tubeless-ready rims. Best for: All-weather road riding, gran fondos and commuting.
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My take, from the specs
A solid all-weather road bike, with Shimano Tiagra 2x10, flat-mount hydraulic disc brakes, 12mm thru-axles and a tapered carbon fork. It is reasonably light at about 9.9 kg and the rims are tubeless-ready. The 140mm rotors are on the small side for long descents, and the 34x28 low gear can feel tall on steep climbs.
Sizes: XS: 5′1″–5′5″ (154–164 cm) · S: 5′4″–5′7″ (162–170 cm) · M: 5′6″–5′9″ (168–176 cm) · L: 5′9″–5′11″ (174–181 cm) · XL: 5′11″–6′2″ (180–187 cm)
Stock specs
| Type | Road |
|---|---|
| Year | 2025 |
| Price when new | $1200 |
| Sold at | Bikes Online US (bikesonline.com) |
| Wheels | 700c × 28 mm tires |
| Gears | 2×10 · 50/34T · 12–28T |
| Brakes | Shimano BR-4770 flat mount |
| Fork | Polygon ACX full carbon, tapered 1-1/8 to 1-1/2, 12x100 thru-axle, flat mount |
| Rear derailleur | Shimano Tiagra RD-4700-SS, direct attach |
| Shifter | Shimano Tiagra ST-R4720 hydraulic, 2x10 |
| Crank | Shimano Tiagra FC-4700, 50/34T (arm length not listed) |
| Bottom bracket | Shimano BB-RS501, BSA threaded 68mm |
| Axles | Thru-axle |
| Seatpost | 27.2 mm |
| Weight | 21.8 lb (9.9 kg) |
| Sizes | XS, S, M, L, XL |
| Stock colors | White |
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) | 28 mm | Unknown until measured. Your 19 mm internal rims suit roughly 28–49 mm tires. |
| Other wheel sizes | 650b up to ~35 mm | Disc brakes don't care where the rim sits, so a 650b wheel with a fatter tire fits. A 650b × 47 is about the outer size of a 700 × 28, so the bottom bracket sits about 12 mm lower than on 700 × 40 (watch pedal strikes). |
| Tubeless | Yes (tubeless-ready) | 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 | Thru-axle · 100/142 mm · 6-bolt disc | Any wheel matching axle type, spacing and brake mount fits. Rear also needs the right freehub. |
| Biggest rear cog | 28T (now 28T) | Set by the rear derailleur (Shimano Tiagra RD-4700-SS): max low sprocket 28T, total capacity 33T. 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. |
| Front gears | 2x (50/34T) · needs 32T capacity | A 2x drivetrain needs a front derailleur and left shifter. Your rear derailleur must take up (biggest − smallest ring) + (biggest − smallest cog) = 32T; yours handles 33T. 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 (24 mm) sets chainline; a big change in ring size may need a different BB spindle. |
| Gear count upgrades | 10-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". |
| Brake pads | SHIMANO L | Disc pads only fit calipers with the matching shape. |
| Rotor size | 140/140 mm now · front 160 (flat mount: check fork) | 6-bolt rotors. Going bigger needs a caliper adapter: flat-mount adapter, and many flat-mount forks are rated 160 mm max. Most steel forks allow 180 mm; check the fork if a max rotor is printed on it. |
| Caliper upgrades | Hydraulic system | Hydraulic: match the brand of lever and caliper. |
| 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 | 27.2 mm | 27.2 mm is the most common size: suspension posts and external-cable dropper posts are easy to find. Internal droppers need internal routing the frame does not have. |
| Racks, fenders, bottles | No rack · No fender · 2 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 Polygon Strattos S4 Disc 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
Comfort
- 35° rise 60 mm stem, $. tapered" steerer matches · Get the 31.8 mm clamp version for your bar
- Suspension seatpost 27.2 mm (budget), $$. 27.2 mm post ↔ your 27.2 mm seat tube
- Redshift ShockStop suspension seatpost 27.2, $$$$. 27.2 mm post ↔ your 27.2 mm seat tube
- WTB Volt saddle, $$. 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
- Ritchey Comp 2-Bolt alloy seatpost 27.2 mm, $$. 27.2 mm post ↔ your 27.2 mm seat tube
- Thomson Elite seatpost 27.2 x 330 mm, $$$. 27.2 mm post ↔ your 27.2 mm seat tube
- Ergon CF Allroad Pro Carbon flex seatpost 27.2 mm, $$$$. 27.2 mm post ↔ your 27.2 mm seat tube
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 27.2 mm (LR or XR spring), $$$$. 27.2 mm post ↔ your 27.2 mm seat tube
- Redshift ShockStop suspension stem 31.8 (±6° or +30°), $$$. tapered" steerer matches · Threadless stem ↔ your threadless steerer
- Redshift ShockStop PRO suspension stem 31.8 (±6°), $$$$. tapered" steerer matches · Threadless stem ↔ your threadless steerer
Control
- External dropper post 27.2 mm, 100 mm drop + remote, $$$. 27.2 mm post ↔ your 27.2 mm seat tube
- 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), $$$. Cup-and-cone bearings are fully serviceable and last for years. Shoes with a 2-bolt SPD cleat sold separately.
- KS eTen-R external dropper 27.2 mm, 100 mm drop + KS Southpaw remote, $$$. 27.2 mm post ↔ your 27.2 mm seat tube
- PNW Components Pine external dropper 27.2 mm (90 or 110 mm) + PNW Loam lever, $$$$. 27.2 mm post ↔ your 27.2 mm seat tube
Utility
- USB rechargeable front + rear light set, $$. 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, $$$. Daytime-running flash modes on both lights. ANT+ lets a Garmin or Wahoo show battery and switch them. Full power runs about 1.5 hours; medium lasts much longer.
Tires
- Continental Grand Prix 5000 700x28 clincher (pair), $$$. 28 mm tire ↔ your ~28 mm clearance
- Continental Ultra Sport III 700x28 folding (pair), $$. 28 mm tire ↔ your ~28 mm clearance
- Michelin Power Cup 700x28 clincher (pair), $$$. 28 mm tire ↔ your ~28 mm clearance
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), $$$. 700c wheel size matches · Presta valve ↔ your Presta rims
- Tubolito Tubo-CX/Gravel-All 700x30–50 Presta 42 mm (pair), $$. 700c wheel size matches · Presta valve ↔ your Presta rims
Drivetrain
- KMC X10 10-speed chain with Missing Link, $$. 10-speed chain ↔ your 10-speed drivetrain
- Shimano CN-HG95 10-speed chain (XT level, 116 links), $$. 10-speed chain ↔ your 10-speed drivetrain
- KMC X10 EPT 10-speed anti-rust chain with Missing Link, $$. 10-speed chain ↔ your 10-speed drivetrain
Wheels
- Shimano WH-RS171 700c disc wheelset, 12x100 / 12x142 thru-axle, Center Lock, HG 11-speed road + 2 Shimano SM-RT54 160 mm Center Lock rotors, $$$$. Disc-brake part ↔ your disc brakes · 700c wheel size matches
- DT Swiss G 1800 Spline 25 700c wheelset, 12x100 / 12x142, Center Lock, Shimano HG + 2 Shimano SM-RT64 160 mm Center Lock rotors, $$$$. Disc-brake part ↔ your disc brakes · 700c wheel size matches
- DT Swiss GR 1600 Spline 25 700c wheelset, 12x100 / 12x142, Center Lock, Shimano HG + 2 Shimano SM-RT64 160 mm Center Lock rotors, $$$$. Disc-brake part ↔ your disc brakes · 700c wheel size matches
Fits with small changes (15)
- Continental Ultra Sport III 700x25 folding (pair), $$. 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).
- Shimano SM-RT56 160 mm 6-bolt rotor (1 rotor), $. Your front rotor is 140 mm: a 160 mm rotor fits with a post +20 mm caliper adapter (check your fork's max rotor size).
- Galfer Wave 160 mm 6-bolt rotor, 1.8 mm (1 rotor), $$. Your front rotor is 140 mm: a 160 mm rotor fits with a post +20 mm caliper adapter (check your fork's max rotor size).
- Shimano SM-RT86 Ice-Tech 160 mm 6-bolt rotor (1 rotor), $$. Your front rotor is 140 mm: a 160 mm rotor fits with a post +20 mm caliper adapter (check your fork's max rotor size).
- Shimano SM-RT56 180 mm 6-bolt rotor (1 rotor), $. Your front rotor is 140 mm: a 180 mm rotor fits with a post +40 mm caliper adapter (check your fork's max rotor size).
- Galfer Wave 180 mm 6-bolt rotor, 1.8 mm (1 rotor), $$. Your front rotor is 140 mm: a 180 mm rotor fits with a post +40 mm caliper adapter (check your fork's max rotor size).
- Shimano SM-RT86 Ice-Tech 180 mm 6-bolt rotor (1 rotor), $$. Your front rotor is 140 mm: a 180 mm rotor fits with a post +40 mm caliper adapter (check your fork's max rotor size).
- Kalloy Uno SP-602 alloy seatpost 25.4 x 350 mm, $. Your seat tube takes 27.2 mm: needs a 25.4→27.2 shim.
- Thomson Elite seatpost 25.4 x 330 mm, $$$. Your seat tube takes 27.2 mm: needs a 25.4→27.2 shim.
- Sunlite adjustable suspension seatpost 25.4 mm, $$. Your seat tube takes 27.2 mm: needs a 25.4→27.2 shim.
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Buying one used? Fair prices
Worked out from the price new ($1200), age and condition, not live market data. If it needs tires, a chain or brakes, take off what fixing them would cost.
| Condition | 1 year old | 3 years old | 5 years old |
|---|---|---|---|
| Like new | $675–$895 | $550–$725 | $445–$585 |
| Good | $595–$785 | $485–$635 | $390–$515 |
| Fair | $490–$645 | $395–$520 | $320–$420 |
| Needs work | $375–$490 | $300–$400 | $245–$320 |
See what these really sold for on eBay · Other used bike prices
Geometry (size M)
| Stack | 533.3° |
|---|---|
| Reach | 387.1 mm |
| Head angle | 73° |
| Seat angle | 74° |
| Chainstay | 415° |
| BB drop | 70 mm |
| Wheelbase | 984.8 mm |
| Head tube | 130 mm |
| Seat tube | 500 mm |
| Standover | 746.5° |
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: Bikes Online US: Polygon Strattos S4 Disc - Tiagra ($1,199.99, specs, 21.8 lb M) · Polygon US: Strattos S4D specs + geometry (BR-4770, TR-29 140mm, BB-RS501) · Bike Insights: Polygon Strattos S4D geometry (matches Polygon table)