Member Since: 18 Mar 2011
Location: Oxfordshire
Posts: 156
Nanocom and Tyres/Wheels CCF data
My CCF, as extracted using my Nanocom and viewed using Genesis, suggests that I’m running on wheels and tyres that are quite different sizes to those actually fitted to the car (e.g. I'm on 19” rims, the interpreted CCF data suggests I'm running on 17”).
BBS have yet to update the Nanocom for full use on 2015/16 D4's and so I don’t know whether this is a case of Genesis struggling with a changed-format CCF data file or whether the CCF data itself is actually wrong. If it is wrong, I don’t know either how significant that particular data (i.e. rim size, tyre size and rolling circumference) is to the functioning of the car.
Has anyone with a 2015/16 D4 and a Nanocom encountered the same issue? Also, does anyone know if a IID can access this same data?
Thanks in advance.
15th Nov 2016 2:40 pm
L319
Member Since: 14 Dec 2013
Location: Herefordshire
Posts: 2080
I am interested how one can determine the wheel size given all the wheel tyre combinations have the same nominal rolling radius.
15th Nov 2016 4:27 pm
al cope
Member Since: 08 Nov 2005
Location: Oldbury, WM
Posts: 10299
thats weird, as you cant fit 17" rims to a 3ltr D4
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15th Nov 2016 5:01 pm
Mog60
Member Since: 27 May 2015
Location: Perth
Posts: 18
L319 wrote:
I am interested how one can determine the wheel size given all the wheel tyre combinations have the same nominal rolling radius.
This link to a spread sheet entitled "Tyre size calculator" may be of some help. It also includes info about potential rubbing in wheel arch linings too. I hope the owner of the website won't mind my pointing you towards it.
Spreadsheet headings....Width, profile, size, Make,Type, Task, did, dia mm, Fit (D3), Offrd ht, circa mm, Load Rated, Sidewall mm.
Member Since: 18 Mar 2011
Location: Oxfordshire
Posts: 156
Thanks for the replies.
There is an update to the tale and I’m now more confused than ever.
The car went in to the dealer yesterday for something unrelated and, as they were connecting diagnostics anyway, I asked them to check the CCF wheel/tyre settings and, if they were incorrect and the error was significant, to correct them.
This is how Genesis interpreted my as-delivered CCF; this was consistent with the settings shown on the dealer’s diagnostics.
Click image to enlarge
This is what they changed it to (i.e. they’ve changed the rim diameter only).
Click image to enlarge
As a standard Graphite, the vehicle has 19” rims and 255/55 R19 tyres. So, I’d have expected to see this reflected in the CCF together with a Tyre Aspect Ratio setting of 55%, a Tyre Width setting of 255mm and a rolling circumference setting of 2365.
So, if anyone with a Graphite and the ability to check these settings can let me know what CCF settings they have, I’d be grateful. I’d also be interested if anyone knows the significance of any of them – surely they must be there for a reason and should correspond to what is actually installed on the vehicle.
Having noticed this anomaly, I’m just curious to know why it is as it is. Also, I do have a weird issue I’m monitoring where, in certain circumstances (e.g. stuck behind slowing traffic on a long hill), the gearbox seems reluctant to change down automatically and the engine labours. It’s not a mega issue but, having seen this wheel size thing, I’m wondering if there could be a connection.
That said, I’m certainly disinclined to change any of these particular settings myself given a warning that Robbie gave in relation to tweaking rolling circumference several months ago.
17th Nov 2016 11:01 am
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
The wheel rim diameter value is not used.
When it comes to the CCF values please do not take them at face value, nor be tempted to alter them 'just because'. Some are not used, some are used but not for the labled purpose, some are used in the opposite sense to that listed, some are for other vehicles (or even different makes!) and some are just legacy code from sloppy procedures at JLR. A few are also used for system integrity checks, so incredibly sensitive.
It's a minefield and is why the IID Tool separates tested and confirmed settings and 'unconfirmed' settings.
Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 18 Mar 2011
Location: Oxfordshire
Posts: 156
Thanks Robbie.
I’d picked up your earlier cautions on this and, although I've changed things like timed/remote heating myself, I’m planning to curb my OCD in respect other things I'm not sure of. I would though still be interested in what the CCF’s for other recent Graphite’s show in this respect so that I'm equipped for discussions with LR should the need arise.
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