Polygon Sierra Deluxe Sport Men City Bike

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If you're looking for a bike that's simple, practical and super comfortable, the Polygon Sierra Sport 21-Speed Gents City Bike should be hovering at the top of your list. With its classic, European-styled lightweight aluminium frame, reliable Shimano Altus / Tourney gear set and highly functional full fenders and dynamo front light, the Sierra Deluxe is the perfect ride for quick trips around town or to work and back.

Key Features

  • Alutech 6061 alloy frame is lightweight, sturdy and comfortable
  • SR Suntour NEX commuter suspension fork delivers a responsive feel for the road
  • Shimano Altus / Tourney 21 Speed groupset giving you all the gears you need to ride with ease
  • Tektro Alloy V brakes handle stopping duties
  • Lightweight and handy rear carrier rack included
  • Front and rear mudguards and chain guard protect your clothes from getting dirty while riding
  • Front light provides reliable lighting
  • Selle Royal Rodesia Plus gel saddle provides extremely comfortable riding
  • 700c Rigida Alloy Double Wall wheels with Schwalbe Citizen 700x40c tires provide a comfortable, stable and responsive ride
  • 16.4kg including pedals. 
  • LIFETIME Warranty on Frame.
  • Full manufacturer’s warranty on parts 





Alutech Alloy Citybike


SR Suntour NEX, Travel 63MM


Alloy, 680mm


Alloy, Adjustable, 110mm


Selle Royal Nuvola Gel


Alloy, 27.2x350mm with spring


Sealed cartridge bearings


SHIMANO FC-TY501 48X38X28T, 170MM




Shimano Tourney MF-TZ21 14-28T


Shimano Tourney ST-EF41


Shimano Tourney FD-TY510


Shimano Altus RD-M310


Tektro Alloy, V-Brake


VP Component, VP-195E, Alloy


Schwalbe Citizen 700x40C


Araya TX-733 Alloy rim, Double Wall, alloy hub

City bike frames are measured in centimetres, and the recommended heights are listed below.


Seat Tube length

Rider Height













Sizes (A) Stack (mm) (B) Reach (mm) (C) Head Tube Angle (D) Head Tube Length (mm) (E) Head Tube Diameter (mm) (F) Seat Tube Angle (G) Seat Tube Length (C-T) (mm) (H) Top Tube Actual (mm) (I) Top Tube Effective (mm) (J) Front Center (mm) (L) Rear Center (mm) (M) BB Height (Ground Clerance) (mm) (N) BB Height (BB Drop/Rise) (O) Stand Over Height (mm)
48 606.1 410.5 69 135 50/44 73.5 480 568 590 669 460 301 50 Drop 772.9
52 648.2 408 69 180 50/44 73.5 520 578 600 682 460 301 50 Drop 815.5


We understand how important shipping is once you click "buy now", that's why we have the following policies

Australian Warehouse

All products are in stock and ready to ship from our Sydney warehouse (with the exception of preordered bikes, which have the dispatch date illustrated)

Next day dispatch

All orders received by 5 pm AEST will usually be dispatched the following business day. If an order is placed on the weekend or public holiday, please note dispatch will usually be the next working day. For tracked shipments, please allow 12 hours for tracking to begin.

Shipping of Parts, Accessories and Apparel

Economy Shipping

There is free delivery available on all small parcels Australia wide using tracked services of Australia Post or Fastway, no minimum order value required! Estimated delivery time is 4-9 business days. 

Express Shipping

We do also offer Express Shipping for a small additional fee on parts, accessories and apparel orders. Estimated delivery time on Express Shipping is 1 to 4 business days.

Shipping of Bikes

Shipping of bikes and other bulky goods is free to 85% of residences in Australia. However, some postcodes incur a surcharge starting from $29. 

Once shipped you will be issued a consignment number which can be used to track your parcel. We use Direct Freight Express for deliveries and you can track your delivery by calling 1300 347 397 or online at www.directfreight.com.au


We’re so confident that you’ll love our extensive range of bikes, that we’ll let you ride one as your own for a full 14 days and if you don’t like it, simply e-mail us at sales@bicyclesonline.com.au and we’ll pick it up from you, free of charge! Just make sure you keep the box so it can be re-used to send it back. Click here for more information. 

All of our bicycles come with a Free Pro Build valued at $99. This means that your bicycle will be pre built by our professional mechanics. For your convenience, safety and comfort all our bikes are fully assembled prior to delivery. The bike is then packaged back into a box for secure shipment.


When your bike arrives, all you have to attach is the front wheel, the handlebar and pedals, everything else has been done – the headset has been adjusted, wheels trued, pedals and seat post greased, brakes and gears calibrated, and the tyres have been pumped up (please note upon arrival, in some cases you may need to add more air to tyres).

Most companies simply sell you the bike as it comes from the factory, which will require significant know-how to get your bike on the road. Currently we are the only Australian company providing this service, and have the 14 day test ride to back it up.

Whilst your new bicycle will have already gone through our Pro Build process, you will still need to complete some minor final assembly steps when you take your bicycle out of its box.

Please follow the video playlist below to correctly complete the setup of your new bike:


Assembly Time:

  • 10-15min - You have assembled bikes before
  • 15-25min - You are mechanically handy
  • 30-40min - Never assembled a bike and working with tools isn't your thing


Unboxing your bike:

Start by carefully opening the top flap to expose the contents. You will see the bike with plenty of protective packaging and next to the rear wheel, the saddle & seat post, a small cardboard box where your pedals, tools, bell and reflectors are. If you ordered any other products with the bike, it is likely they were placed on the bottom of the box as well. Remove all the loose items before pulling the bike out of the box and gently placing it on the floor.

Keep the box and all the protective packaging found on the bike in case you choose to change frame sizes, upgrade/downgrade the bike, or return the bike for a full refund under the 14 Day Test Ride Policy.


How to install a quick release front wheel:



How to install a quill stem handlebar:


V-Brake Setup:


How to install pedals on your bike:


Congratulations on your Purchase

This bicycle is backed by a LIFETIME factory warranty on frame and full manufacturer’s warranty on parts. Lifetime warranty refers to the lifetime of the original owner.

Warranty is valid only for bicycle that has been properly and well-maintained under the following conditions:

Warranty includes:

  • All damaged or fractured or broken frame / fork / component which was caused by manufacturing or assembling error in factory.
  • Non functioning mechanism caused by manufacturing error in factory.

Warranty is NOT valid for:

  • Incorrect assembly, i.e pedals installed in the wrong crank arm. 
  • Normal degradation caused by frequent use, such as degrading brake shoe, deflated tire, etc
  • Surface defects, such as stained, marred, defaced, etc
  • Damaged caused by misuse or accident
  • Other damages which are not caused by factory error
  • Bicycle which has been sold to other party
  • Bicycle used in commercial, such as rented
  • Bicycle which has not been well-maintained

For any damages which is guaranteed by the brand as the first condition above, the brand will repair or replace damaged frame / fork / component with the one of the same brand or similar.

Warranty is valid for all Polygon and Marin bicycles to the original owner only, by showing the purchase invoice.  

To make a claim click here.

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