Which BMW models does Nitron's F20 NTR-R1 Coilover Kit fit?

This Nitron F20 NTR-R1 fits the F20 and F21 BMW M135i and M140i and the F22 BMW M235i.

Does the Nitron NTR-R1 kit fit the M235i?

Yes. The F22 M235i is covered alongside the F20 and F21 M135i and M140i.

What does a divorced rear suspension mean on the Nitron NTR-R1?

It means the rear spring and damper stay as separate parts, the way the car came from the factory. The Nitron rear damper takes the place of the original, and the rear geometry is not changed.

How is the Nitron NTR-R1 adjusted?

Compression and rebound are adjusted together through a single control at each corner, and the damper uses an internal reservoir with nothing remote to mount.

Are top plates included with the Nitron NTR-R1?

Yes. Adjustable top plates are part of the kit.

Can I order different spring rates for the Nitron NTR-R1?

Yes. Every kit is made to order, and custom rates outside the standard range are available by contacting us directly.

Description

Additional Info

Shipping policy

BP PRICING DIFFERENCE

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Description

Nitron NTR-R1 Coilover Kit for F2x BMW M135i, M140i, and M235i

The Nitron BMW F20 NTR-R1 Coilover Kit is aimed at the F2x owner whose turbocharged six-cylinder has outrun its original suspension. The M135i, M140i, and M235i make enough power to ask a lot of a chassis that was set up for comfort first, and on aging factory dampers that shows up as float over crests, a rear end that takes its time to settle, and a car that feels less planted than its output suggests. Nitron’s passive NTR-R1 replaces the front springs and dampers with matching coilovers and swaps the rear damper for its own, with firmer race springs throughout. The rear keeps the divorced layout the car was built with, a separate spring and damper, so nothing about the rear geometry changes. Ride height is adjustable, and adjustable top plates are included. The kit covers the F20 and F21 M135i and M140i and the F22 M235i, and it suits drivers who split their time between spirited roads and the occasional track day.

Unique Technology

A monotube damper keeps the oil and the nitrogen charge in a single bore, separated by a floating piston, and that layout gives a damping curve that stays consistent through a long run of hard use. Nitron’s valving for the NTR-R1 is built on motorsport experience and sized for the weight and spring rates of the F2x cars. Compression and rebound are tied together in one 2-way adjustment at each corner, so a change of setting is a single turn rather than a balancing act between two knobs. The reservoir sits inside the damper, which keeps the installation free of hoses and remote canisters.
- Basic Damper Design:
  1. End Eye / Top Mount
  2. Damper Piston & Shim Stack
  3. Shaft / Rod
  4. Floating / Separator Piston
  5. Suspension Oil
  6. Compressed Nitrogen Gas

Bespoke Engineering

This kit is built by hand in the UK to the order, and that is why spring rate is a decision you can influence instead of a fixed number. Owners with a specific use in mind, such as a track-focused car or one that stays mostly on the road, can request custom rates to suit.

Features

Divorced rear suspension type
Internal reservoir type
2-way combined adjustment
Full alloy body
Preload adjuster
Combined 24 clicks of adjustment
Nitrogen gas charged
Precision bearing spacers supplied as required
Consists of 4 coilovers, and top mounts
Hand made to order

Specifications

Coilover Type: NTR-R1
Adjustment Type: 2-way combined
Adjustment: 24 clicks combined
Rear Suspension Types: Divorced
Droplinks Included: No
Recommended Spring Rates:
- FRS – Fast Road Spec:
  - Front: 514lbs/inch (90N/mm)
  - Rear: 570lbs/inch (100N/mm)
- TDS – Track Day Spec:
  - Front: 685lbs/inch (120N/mm)
  - Rear: 685lbs/inch (120N/mm)

Applications

BMW M135i: F20, F21 | 2012-2016
BMW M140i: F20, F21 | 2016-2019
BMW M235i: F22 | 2014-2016

Other Suspension Kits for F2x BMW M135i, M140i, and M235i

NTR-R3 Coilover Kit

Notes

Fitment not confirmed for F23 M235i models
Custom spring rates also available
Please feel free to contact us directly here for more information or for a consultation on custom rates
Images used for illustration purposes only. Specific details, finishes and end fittings may differ from that shown.
Precision bearing spacers supplied as required

Frequently Asked Questions

Which BMW models does Nitron’s F20 NTR-R1 Coilover Kit fit? This Nitron F20 NTR-R1 fits the F20 and F21 BMW M135i and M140i and the F22 BMW M235i.
Does the Nitron NTR-R1 kit fit the M235i? Yes. The F22 M235i is covered alongside the F20 and F21 M135i and M140i.
What does a divorced rear suspension mean on the Nitron NTR-R1? It means the rear spring and damper stay as separate parts, the way the car came from the factory. The Nitron rear damper takes the place of the original, and the rear geometry is not changed.
How is the Nitron NTR-R1 adjusted? Compression and rebound are adjusted together through a single control at each corner, and the damper uses an internal reservoir with nothing remote to mount.
Are top plates included with the Nitron NTR-R1? Yes. Adjustable top plates are part of the kit.
Can I order different spring rates for the Nitron NTR-R1? Yes. Every kit is made to order, and custom rates outside the standard range are available by contacting us directly.

About Nitron Suspension

Nitron Suspension has been at the forefront of precision suspension engineering since 1998, founded by Guy Evans with the goal of building high-performance shocks for enthusiasts and professionals alike. Over 200 dealers now carry Nitron products across Europe, Asia, the US, Australasia, and Africa. In 2008, the company moved into a dedicated facility in the UK’s Motorsport Valley, adding dynamometers, 5-axis CNC machines, and 3D CAD capabilities to support both growing demand and continued product development. A second expansion came in 2023 with a new office in Murrieta, California. The team behind every Nitron product draws from deep backgrounds in machining, materials technology, hydraulics, bike engineering, and F1 racing, with many engineers bringing firsthand experience as competitive drivers and riders. That depth of knowledge across both the technical and competitive sides of motorsport shapes every product Nitron develops.

Additional Information

The Bulletproof Automotive website contains many thousands of products purchased in multiple different currencies. All of the prices are entered manually and accurately at the time of entry. Due to the consistently fluctuating international exchange rates, at times prices may not be able to be honored at their original intended rate. We apologize for any inconvenience this may cause, unfortunately our website is unable to compensate dynamically for what can at times be volatile changes in the cost of items due to currency values fluctuating, changes in prices from suppliers, changes in shipping and import duties, and other factors. Rest assured that any order you place on line will be at zero risk to you in this area. If in the event your order cannot be fulfilled at the original intended website price we will offer you a 100% refund, no questions asked. We will continue to do our best to maintain updated prices and we will always continue to offer our price match guarantees as well to ensure our prices are always the best for you. In short, prices may change without notice. It is always advised to give us a call prior to placing your order online to confirm availability and to confirm current pricing.

Shipping Policy

Items that are in stock in the US, either at Bulletproof’s warehouse or at a supplier’s warehouse, are generally delivered within 7-10 days. Special order items from overseas take considerably longer. As a courtesy Bulletproof offers delivery estimates to our customers which take into consideration manufacturer availability and shipping schedule. These estimates represent our best guess based on previous orders from the manufacturer and do not in any way imply a guaranteed delivery window. Many manufacturers work in a “just in time” inventory system and often take 2-20+ weeks to produce an item once an order is submitted. All deliverable items are then sent to our Japanese warehouse. Bulletproof ships a minimum of one full ocean freight container every month from Japan, oftentimes more than one a month. Ocean freight takes an average of 4 weeks. Typically it breaks down to one week in Japan for paperwork and customs, two weeks by boat and one week in US customs/clearance. Due to the wide number of variables between manufacturer and shipping schedules, delivery estimates are simply just that – estimates. We attempt to estimate conservatively and we usually deliver faster than our estimates suggest. It is not Bulletproof’s policy to guarantee delivery time of any special order item, this is impossible for us to do. By ordering you acknowledge that there is no required delivery ETA and an order may not be canceled or altered due to manufacturing or shipping delays, all ETA’s are provided as a best guess only. Please review the full Terms & Conditions here.

BP Pricing Difference

We do pricing a little differently on our JDM brands and we believe in making things simple and clear. No hidden fees or surcharges. Every price you see includes the shipping cost to our office in Los Angeles, California and all the associated taxes/duties/fees for bringing the products into the US. The only shipping you ever pay is from our facility in the US to your location. Be wary of resellers that don’t include the cost of international shipping in their pricing on JDM parts. While we believe we’ll always have the lowest all-in price on JDM products, we offer a price match guarantee for all authentic parts purchased from authorized dealers as well. For many international customers, it’s much more affordable to ship from the USA than from Japan directly, as the air freight and ocean freight costs are typically much less. However, for customers looking to ship directly from Japan outside of North America, or domestically in Japan, we can provide pricing specifically for that scenario. Please do not hesitate to contact us with any pricing questions or concerns. Please email us at sales@bulletproofautomotive.com with any inquiries.

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Nitron NTR-R1 Coilover Kit for F2x BMW M135i, M140i, and M235i [NTCBM035R1_D]

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Nitron NTR-R1 Coilover Kit for F2x BMW M135i, M140i, and M235i

Unique Technology

Bespoke Engineering

Features

Specifications

Applications

Other Suspension Kits for F2x BMW M135i, M140i, and M235i

Notes

Frequently Asked Questions

About Nitron Suspension

Reviews