Member Since: 03 Feb 2021
Location: Chester
Posts: 6
Any D4 Owners Downsized Their Brakes to Fit 17" Wheels?
Long time lurker, first time poster...
I drive a D4 HSE MY2009 with stock 19" wheels and I've been toying with the idea of swapping my brakes for those off the 2.7 D4, so that I can fit 17" wheels and 33" tyres so get plenty of sidewall to use when airing down.
I'm currently running 255/55 R19 General Grabber ATs, which I'll keep for the black stuff. But I want to swap them out for a set of steelies with muddies when I go and play in the dirt.
I'm thinking I'd need new wear sensors, calipers, carriers, shields, discs and pads. Is these anything else?
My concerns are that it's a heavy car and fitting smaller brake discs seems like a daft idea. I would be planning on fitting drilled and vented discs and performance pads, to try and offset the drop in brake performance if I was to do this.
My question is then, would this even work? Am I missing something? Has anyone else done this mod?
Thanks in advance,
J
22nd May 2021 6:08 pm
rrhool
Member Since: 28 Aug 2014
Location: Norfolk
Posts: 4522
You'd be totally uninsured. I can't imagine any insurance company allowing a downgrade of brakes Richard
D3 SE 2007. Triumph 2.5Pi 1973. Ferguson TEA20 1948.
Discovery 2 4.0 ES 2001- Gone
Discovery 1 300Tdi ES '95 - Gone
Range Rover Classic '79 - Gone
22nd May 2021 6:12 pm
CongoBoy
Member Since: 05 Mar 2019
Location: Wiltshire
Posts: 529
I have a D3 2008 (MY 2009) and I went down from 19" to 18" and upgraded to the V8 brake kit, so you you should be able to go down to 18* with your MY 2009 D4, unless I stand corrected?
I'm not sure why you would want to go down to 17" rims and down grade braking when you could probably get what you want with 18" rims?2008 D3 HSE Stornoway Grey (UK)
2008 D3 HSE Izmir Blue- South African Spec. (Zimbabwe)
2005 FFRR SC V8- Java Black
1995 D1 300 Tdi Blue - (Sourced from the UK, shipped to Namibia, driven by me to RD Congo, then Zambia, now retired in Zimbabwe)
22nd May 2021 6:24 pm
TheJayJay
Member Since: 03 Feb 2021
Location: Chester
Posts: 6
Cheers for the responses all.
Would the insurance really be that much of an issue given that those size brakes are on the 2.7 and the D3 which the same body? I guess that's a cue for me to give them a call before I start anything. I hadn't even thought about that.
To be fair, it's not something I'm desperate for, I just wanted to maximise the tyre wall available when airing down. My logic went that I could get 200mm of sidewall with a 265/70 R17, compared to 140mm as standard. But that said, a 265/65 R18 is the same diameter with only a slighter lower sidewall.
I think I can put this idea to bed. I clearly hadn't thought it through; far too much messing about for not very much return.
I appreciate the help giving my head a wobble! I'm going to go shopping for some tuffants or similar...
J
22nd May 2021 8:57 pm
J@mes
Member Since: 10 Nov 2008
Location: Bomber County
Posts: 4547
Considering the brakes are a fundamental safety feature of the vehicle, "the last model had smaller brakes" is hardly going to cut it if you fail to brake in time and kill someone.
Your insurance would more than likely have your house off you to recover the costs if you failed to tell them.
Tuffants probably the way forward, but again you really must tell your insurance.2014 D4 XS
2005 D3 SE - Gone
22nd May 2021 9:51 pm
LT
Member Since: 31 Dec 2005
Location: South West
Posts: 23829
Fit an aftermarket 18” rim. I ran Compomotive PD1881’s on my later D4’s.2006 D3 HSE (Original & still the best)-GONE
2010 D4 HSE (A bit bling)-GONE
2014 D4 HSE (Almost too bling)-GONE
2015 D4 HSE (A heated what?)-GONE
2016 D4 Landmark (Written Off)-GONE
2016 D4 Landmark (Surely the last!) PD1881 rims-GONE
2017 FFRR SDV8 Autobiography (now semi-retired)
22nd May 2021 9:57 pm
Moo D3 Decade
Member Since: 13 Aug 2010
Location: UK
Posts: 14409
Stupid idea. It’s nearly 3 tonnes! Get some 18 inch Compomotives. D4 HSE EU6 (Known as Jeeves)
New Defender L663 110 SE (known as Noddy!) Sold
Sold Volvo XC90 R-Design (known as Basil)
Sold - D4 HSE (Known as Gerty)
No longer the Old Buses original owner
231,000 miles and counting
05 S manual owned from March 2005
D4 Face lifted
Still original injectors and turbo
V8 Front brakes
BAS Remap, Allisport Intercooler and deCat
EGRs blanked
T-Max split charge
Hanibal Expeedition rack
Prospeed ladder
Duratrac tyres
IID BT
BAS FBH control
22nd May 2021 10:42 pm
galwaygreen
Member Since: 30 Oct 2011
Location: plymouth
Posts: 6525
where you goin offroad...they go most places on standard tyres..thats part of the challenge
22nd May 2021 11:11 pm
pagoda
Member Since: 13 Aug 2009
Location: Not London Anymore (or the US for that matter)
Posts: 1929
Really bad idea.
There's a lot you can do to simply and cheaply modify the vehicle to take outsize tyres on 18s or 19s easily. Look at some of the US sites to see what people do. Some minor bodywork adjustment at one end of the spectrum, to just johnson rods at the easy side. Never heard of anyone downgrading their brakes though.PAGODA
23rd May 2021 12:28 pm
TheJayJay
Member Since: 03 Feb 2021
Location: Chester
Posts: 6
Fair cop, that idea's firmly in the bin then!
I was never intending to not tell the insurance, just clearly hadn't thought the idea through. I was hoping that the drilled and grooved discs and greenstuff pads would've offset any drop in performance from the smaller diameter discs.
What mods are available if I wanted to avoid johnson rods or x-lifter/GAP tool-type lifts? Are body lifts available for D4s? Like a spacer that sits at the top of the air strut or are they a bad idea too? I don't like the idea of running the air struts extended all the time. I know coils are an option but I like the functionality of the air suspension, so don't want to go down that road either.
Cheers,
J
23rd May 2021 7:51 pm
LT
Member Since: 31 Dec 2005
Location: South West
Posts: 23829
Where are you planning on going off road?
I tackled some pretty extreme terrain in my D3 with nothing more than a bit of underbody protection and 19” rims shod with Pirelli ATR’s. I’m far from being the only one to the same or more extreme. 2006 D3 HSE (Original & still the best)-GONE
2010 D4 HSE (A bit bling)-GONE
2014 D4 HSE (Almost too bling)-GONE
2015 D4 HSE (A heated what?)-GONE
2016 D4 Landmark (Written Off)-GONE
2016 D4 Landmark (Surely the last!) PD1881 rims-GONE
2017 FFRR SDV8 Autobiography (now semi-retired)
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