RRSPORT.CO.UK

    Forum   Gallery   Shop   Sponsors
Home > Technical > GAP changes to IPC after fitting bigger wheels
Post Reply  Down to end
Page 1 of 1
 
RallyeSport



Member Since: 20 Jun 2024
Location: Gloucester
Posts: 67

United Kingdom 2010 Range Rover Sport TDV8 Autobiography Stornoway Grey
GAP changes to IPC after fitting bigger wheels

I wonder if anyone has changed the the CCF files to accomodate larger wheels aka 22 inch with 285/35/22?

I currently run the standard 275/40/20 tyres with the relevant settings in the CCF files on GAP iid tool.

Has anyone adjusted them, as the rolling circumference will be out by a decent amount.

Can anyone help.

Cheers

Dean

Post #647059 Mon Feb 24 2025 10:31pm
View user's profile Send private message View poster's gallery Reply with quote
Col



Member Since: 02 Sep 2012
Location: Hawkes Bay NZ
Posts: 5062

New Zealand 2013 Range Rover Sport Supercharged Autobiography Santorini Black

Don't bother, it will not make a blind bit of difference that you will notice.

Cheers
Col

Post #647060 Mon Feb 24 2025 10:50pm
View user's profile Send private message View poster's gallery Reply with quote
RallyeSport



Member Since: 20 Jun 2024
Location: Gloucester
Posts: 67

United Kingdom 2010 Range Rover Sport TDV8 Autobiography Stornoway Grey

Well I hoped it would Col.

As it’ll rotate 28x less per mile.

I run 275/45/20 now, which throws the Speedo out and underreads.

I’d rather it read accurate especially in this day and age with the rozzers constantly hanging about!

Post #647061 Tue Feb 25 2025 12:32am
View user's profile Send private message View poster's gallery Reply with quote
Col



Member Since: 02 Sep 2012
Location: Hawkes Bay NZ
Posts: 5062

New Zealand 2013 Range Rover Sport Supercharged Autobiography Santorini Black

I have run 275/45 x 21 wheels/tyres for years on my L320 and I did comparisons using GPS, Measured distances and the smiley face roadside cameras and the speedo at 30mph is spot on showing 30mph, at 50mph on the speedo I'm actually doing appx. 51/52 and at 70mph actual speed is 73/74 mph.
As the 285/35 x 22 is a slightly smaller diam. than the 275/45 x 21" I would think the speedo would be pretty near spot on.

I played about with nearly every setting in the CCF and as I said none made the slightest difference to the speedo reading and returned it to the original setting and left it at that.

The only thing I didn't try it against was with Mr Plod at the side of the road with his little camera. Rolling with laughter

What you will get is probably even bigger lies from the dash fuel "Lie-O-Meter" and a bit of a harsh ride on the 35 profile tyre.

Cheers
Col

Post #647062 Tue Feb 25 2025 1:03am
View user's profile Send private message View poster's gallery Reply with quote
naks



Member Since: 15 Jul 2016
Location: Stellenbosch
Posts: 1190

South Africa 2013 Range Rover Sport Supercharged Siberian Silver

As Col says, don't bother.

Fit the wheels, drive around with Google Maps to see that the speed difference is, and adjust accordingly. --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport Supercharged V8 HSE Dynamic



Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ

Post #647063 Tue Feb 25 2025 7:23am
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 1 of 1
All times are GMT + 1 Hour

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2005-2025 Futuranet Ltd & Martin Lewis
RRSPORT.CO.UK RSS Feed - All Forums

Switch to Mobile site