
Ford Sierra mk1/Cosworth 3-door Polycarbonate Windows
Create your ideal windows below, or contact the team if you have a specific requirement.
Customise your windows:
Note: Unless stated, all windows are sized to fit into rubber seals. If you need bolt-in sizing, then please contact us.
Shipping calculated at checkout.
Orders ship in 3 weeks (5 for hard-coated). Delivery in 3–17 business days, depending on location.
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Product information
Race Plastics polycarbonate windows are handcrafted to order by our expert UK team. Designed for motorsport and high-performance use, they’re lightweight, tough, and completely shatterproof—unlike glass or standard acrylics, which can crack under stress.
Our standard windows use 4mm polycarbonate to meet Motorsport UK regulations. We also offer 5mm options that are FIA compliant, plus hard-coated variants for added durability and resistance to scratching.
All windows are available in clear, bronze, or grey tint to suit your vehicle’s design. You can also add window sliders to either or both front doors, depending on your setup.
Window Sliders
Each slider kit is made from the same polycarbonate as your chosen windows. Designed for both driver and passenger sides, these sliders are reliable, practical, and easy to install.
Choose between:
- Three-position locking with a smooth, rattle-free action
- Simple two-position setup for fast and secure use
Sliders are engineered to avoid scratching and sit flush with your window kit. Ideal for improving airflow on track days or road builds. More info is available on our Window Slider Kits page.
Shipping times
Once your order’s confirmed, we’ll get started. Most standard orders are manufactured and dispatched within 3 weeks. Custom or hard-coated versions may take a little longer—we’ll contact you with a lead time. If you need your order by a specific date, let us know and we’ll aim to meet it.
Can I fit the windows myself?
Yes, installation is usually straightforward. There are helpful videos online, and our windows are designed to fit into standard rubber seals unless otherwise noted. If you need bolt-in variants, just contact us.
Can I collect my order?
Collection from our UK facility is available by arrangement. Most international orders are shipped, but we’re happy to sort collection if needed—just get in touch.
Want to change your order?
Reach out as early as possible. We’ll always try to accommodate changes, but if manufacturing has already started, there may be a charge.
Key product info:
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Expertly crafted in the UK
All of our windows and sliders are hand made to order by our team in the UK.
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Motorsport compliant
Our standard windows are made from UK compliant 4mm Polycarbonate.
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FIA & hard-coated options
We also offer FIA compliant 5mm & hard-coated options.
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Road legal warning
Always check your local vehicle regulations before fitting.
Not found what you need?
Need a single window, or have a special requirement, no problem. Just let us know what you need.
The Ford Sierra mk1/Cosworth 3-door rally car
The Ford Sierra Mk1, introduced in the early 1980s, revolutionized the rally scene with its aerodynamic design and advanced engineering. Unlike its predecessors, the Sierra Mk1 featured a sleek, modern look with its distinctive sloping rear end, which significantly reduced drag and improved high-speed stability. The car's rear-wheel-drive layout and innovative independent rear suspension provided excellent handling and balance, crucial for the demanding twists and turns of rally stages. The Sierra Mk1 was initially equipped with a range of engines, but it was the high-performance versions like the RS Cosworth that truly shone in rallying. With a turbocharged 2.0-liter engine, the Sierra RS Cosworth delivered up to 224 horsepower, allowing it to compete fiercely against the top rally cars of its era.
In the rallying world, the Ford Sierra Mk1 made a significant impact, particularly in the Group A category. Its competitive debut was marked by its participation in various European and World Rally Championship (WRC) events. The Sierra RS Cosworth's reliability and robust performance made it a favourite among both factory teams and privateers. The car's success was highlighted by its notable victories and consistent top finishes in major rallies, showcasing Ford's engineering prowess and commitment to motorsport excellence. Drivers appreciated the Sierra Mk1 for its power, handling precision, and the sheer thrill of driving it on the edge. Today, the Ford Sierra Mk1 remains an iconic figure in rally history, remembered for its role in elevating the standards of rally car design and performance.

Thought about a slider kit?
Our easy retro fit window slider kits are the essential addition to your racing windows with standard and advanced kits available.
Need Glue for your New Windows?

Windscreen Bonding Adhesive - Primerless & Drive within 1 hour

Let customers speak for us
from 7 reviewsVery helpfull
Nicely finished, very well packed, arrived on time and great value. Thanks!
Windows are easy to fit and look good
Would highly recommend Race plastics. I have used them now on 3 occasions, their products and their customer service are the best I have used, Thank you R.P....
Perfekt fitting, fast delivery.
Thank You.
Want some Window Advice?
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Why Polycarbonate Windows?
Find out whyLearn about what polycarbonate windows are, what benefits they offer and why you should use them.
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Perspex or Polycarbonate Windows?
Find out which oneFind out which you should use for your race windows, why, and which one will protect you the most whilst racing.
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Our Frequently Asked Questions
Find out moreGet the answers to key questions on products and services, including deliveries, collections and timescales.
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