BMW E85 E86 Z4M 4.10 Diff
4.10 Crown Wheel & Pinion Gear Set for the Large Case Type 210/215 LSD Diff
In late 2020 BMW caused a stir when they discontinued the BMW Motorsport 4.10 Gearset.
188.8.131.521.899 - Gearset 4.10 = NLA (No Longer Available).
Fast forward to summer 2021 and BMW have put the 4.10 Crown Wheel & Pinion's into production again.
The BMW Motorsport 4.10 Gearset is now under a new part number which is:
23.00.8.437.087 - 23008437087 - Gearset 4.10 = £1225 including VAT.
Redish Motorsport have secured 5x Genuine BMW 4.10 CWP Gearsets direct from BMW Germany.
We are offering these at an introductory offer of £895 (including VAT) each.
5x items currently in stock ready for despatch.
What are the Postage options?
P&P within the UK will be £25 due to the weight and size.
(We can only supply within the UK currently).
How long will this special price offer last?
We are offering the 4.10 Crown Wheel & Pinion Gearsets on a first come first served basis as we cannot guarantee we can get any more at this lower-than-retail price.
How can I place an order?
Due to recent card fraud on telephone orders, we are only able to accept Bank Transfer for the 4.10 CWP's.
If you would like to place an order please call us on 01179 781889, or email us on email@example.com, and we will send you a ProForma Invoice with our BACS details for you to make a payment.
How will my 4.10 CWP Gearset arrive?
Your 4.10 Gearset (2 pieces) will be in their Genuine BMW Box labelled with Genuine BMW Stickers to show their authenticity.
These are then packaged inside a Redish Motorsport branded transport box.
What is my original Diff Ratio?
The E8x Z4M uses a 3.62 ratio CWP Gearset.
Why would I want a 4.10 Crown Wheel & Pinion Gearset?
If original, your Large Case (210/215) Diff Ratio will be a neutral middle-ground ratio which BMW had to set to please all world markets.
Doing this pleases a large group of countries & markets but doesn't help us enthusiasts who want the very best driving experiences from our BMW M-power vehicles.
Changing to a 'shorter' final drive (diff) ratio increases the acceleration in every gear without stressing any components (after all this is a Genuine BMW Part).
This allows your vehicle to become faster in every aspect whether it be from a standing start or whilst in motion.
This is achieved without adding or requesting any additional power from the engine.
It's just a simple mathematical equation and happens in Gearboxes, Differentials, and even Bicycle gearing to fine tune a more practical gear set for your desired usage.
In this case, BMW Motorsport developed the 4.10 gear set for their Motorsport vehicles competing on the race track as they wanted them to be faster.
The only downside (if you can call it a downside) is that your top speed is reduced slightly.
For example, an OEM 3.62 E46 M3 Diff ratio's hypothetical top speed (on paper) is 206mph which is reduced to 182mph when using a 4.10.
Here is a table to show the speed differences:
|MPH speed at 8,000 rpm.|
|3.62 ratio||4.10 ratio|
Any videos to help me understand the benefit?
Here's a useful video on YouTube which helps visualise the acceleration difference (albeit with E46 M3's).
3.62 ratio = Left Car (OEM ratio).
4.10 ratio = Middle Car.
3.91 ratio = Right Car.
Is the 4.10 ideal for my vehicle or is there something in between?
The 4.10 gearset is perfect for the E8x Z4M whether it be a road or track vehicle.
Will I need to carry out any coding work?
No, only SMG or DCT vehicles need coding.
As the Z4M was only available in a Manual, you won't need to worry.
However, you can contact the excellent ECU WORX software provider to double check.
You can either buy a licence, download, and then use this useful software yourself.
Or you can buy their remote-coding service as found here:
Is there anything else you recommend changing at the same time?
Yes, if the rest of your Diff is original, we strongly recommend having the original GKN LSD
(currently inside your Diff) rebuilt and upgraded with new Clutch Plates and the Modification Shim. We offer this as a fully built Diff service which you can read about here.
We also advise that you consider replacing your Driveshafts (if yours are still original).
You can read about our Driveshafts here.
Will this cure my driveline slop and 'M Clunk'?
No, this part is purely a ratio change gearset to use with your original Diff LSD.
If you have an issue that you're chasing, consider checking the following items:
Don't forget another common area to wear is the Differential. Rebuild details here.
If you Diff is original you'll still have play within the driveline.
If you Diff has been overhauled but not with the GKN LSD modification you'll still have play.
If you Propshaft is original (regardless if CVJ is new) you'll still have play on the splined end.
If you Subframe Bushes are original you'll still have slop in the driveline.
If your Diff Bushes are original you'll still have slop in the driveline.
If you Diff Bushes have been changed for Polyurethane you'll certainly have more NVH issues.
If you RACP Internal Spot Welds & MIG Welds haven't been repaired this will also contribute.
The moral of the story is: check the entire condition of your E46 M3 due to age, mileage & wear.