Folks

I have been offered through my work a set of All weather 255/55/20 tyres from a much newer RR.

I currently have 275/40/20’s on the TDV8 with Brembos on the front.

Will they fit without causing any rubbing and or clearance issues?

Clearly they will effect the speedo reading, but I wouldn’t have thought it would be by much. Previously owned 1999 Disco 2 TD5
Disco 3 HSE TDV6 2007
Gone 2007 TDV8 RRS1 in Buckingham Blue.

How do know if the knocking at the front has been sorted?

You can hear the knocking at the rear better

Cant see why not, same size as a Disco 4 runs on 20” wheels I believe 2003 BMW M5 - 5 Litres of V8 Optimax Slurping Goodness in Carbon Black

2013 SDV6 HSE Black Edition- Orkney Grey with Ebony & Ivory. LR Facelift RAI, Genuine G4 Expedition Rack, 4x Warn SBD-160 Spotlights, Warn 9.5XPS Winch, Mantec Underbody Protection and Sump Guard, Full Easy Lift Suspension Module, LR Light Guards, Light Force HTX230 Hybrid spotlights, 18” Compomotive PD1881 on 265/65/18 BF Goodrich KO2, ARB fridge, TuffTrek awning 😎

If this site is correct, there’s a big difference.
 2012 5.0 SC AB
Mods:
TPMS
Genuine LR DRLs
Remote Boot close from key fob
2016 Discovery 4 Mirrors AKA RRS2
2014 L405 Surround Camera retro fit (WIP)
2013 RRS Dual View Screen fit (Complete)
2016 LR4 RSE
2014 LR4 Homelink
2016 FFRR Electrochromatic Wing Mirror Glass

70 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Just a guess but it does look to me that they would be very tight. The extra height from Brit Plumber's post does seem quite a difference. I have a TDV8 with Brembos and 275x40x20s, and just looking at the gap between the tyre and the wheel arch makes me think you may get some problems. How about selecting Access height on the suspension then turning your wheels to full lock. It might then give you an idea of the space you've got to play with.
Alternatively, and of course the best answer, is to get one fitted in order to check before you part with any money. After my experience with wheels and tyres (documented elsewhere on here) I'd be very cautious. Robin
2008 Range Rover Sport TDV8
Gone:
Jaguar S-Type V8 4.2 Sport
MGZTT 190 2.5

The 255/55R20 have a diameter of 775mm. My car has 265/60R18 and they also have a diameter of 775mm - I have no clearance issues at all from access height to super extended and with tyres 10mm wider I have no touching so there will not be an issue.

Garry 07MY RRS TDV6
Arctic Frost
Aspen Interior

According to that website 225/55r20 have a diameter of 787mm not 775 which is 13mm difference. Not much in it compared to 58mm in the OPs question. They may fit but what speed difference will it create on the speedo? 2012 5.0 SC AB
Mods:
TPMS
Genuine LR DRLs
Remote Boot close from key fob
2016 Discovery 4 Mirrors AKA RRS2
2014 L405 Surround Camera retro fit (WIP)
2013 RRS Dual View Screen fit (Complete)
2016 LR4 RSE
2014 LR4 Homelink
2016 FFRR Electrochromatic Wing Mirror Glass

70 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Thanks folks but without trying one on and having it fitted, I just cant tell. They do look massive compared to my current tyres, so I will give them a miss.

Bit of a mute point as the is currently sat in the works car park refusing to statrt  Previously owned 1999 Disco 2 TD5
Disco 3 HSE TDV6 2007
Gone 2007 TDV8 RRS1 in Buckingham Blue.

How do know if the knocking at the front has been sorted?

You can hear the knocking at the rear better

Brit Plumber wrote:

225/55r20 have a diameter of 787mm not 775 which is 13mm difference.

https://www.disco3.co.uk/forum/swap-rrs-d4...35d4a75170

Seems this Sport member runs the size you asking about  2003 BMW M5 - 5 Litres of V8 Optimax Slurping Goodness in Carbon Black

2013 SDV6 HSE Black Edition- Orkney Grey with Ebony & Ivory. LR Facelift RAI, Genuine G4 Expedition Rack, 4x Warn SBD-160 Spotlights, Warn 9.5XPS Winch, Mantec Underbody Protection and Sump Guard, Full Easy Lift Suspension Module, LR Light Guards, Light Force HTX230 Hybrid spotlights, 18” Compomotive PD1881 on 265/65/18 BF Goodrich KO2, ARB fridge, TuffTrek awning 😎