Paul92V8

New Member
Hi guy's,you've all probably had this one before so here goes.Does anyone know the correct wheel size for
a 1999 P38 2.5 DSE.When I bought her it had 19 inch wheels on,in the boot there was a 18 inch hurricane style spare wheel.Thanks Paul.
 
If 18" in boot is a P38 wheel and obviously the 19"s will be L322 wheels. To use the spare you will need different wheel nuts than the ones on the 19"s. If you fit the 18" at any time you will also need to remove the spigot if it is stuck on the hub.
 
If 18" in boot is a P38 wheel and obviously the 19"s will be L322 wheels. To use the spare you will need different wheel nuts than the ones on the 19"s. If you fit the 18" at any time you will also need to remove the spigot if it is stuck on the hub.
+1
 
Hi guys, firstly sorry for the late response it's been a bit work, home, work home. Thanks for the replies, it doesn't quite pin point the correct size. I've been having gear change problems as it is an automatic the chap at the gearbox specialist said I have to have the right size wheels on to start with then fix the other couple of issues it has. As it has a 18 inch in the boot I'm going to go with that. Thanks again for the info, Paul.
 
Driven one with 19" wheels on and gearbox was fine.

When was the gearbox fluid last changed? Some people use some Lucas product in it and then change it again shortly afterwards.
 
Mine has 19" wheels on and change is smooth as silk. wheel size has nothing to do with wheel size.I dont understand how these "specialists" gain their certification, must be in the new cereal packets,we used to get plastic submarines (about as much use)
 
If you fit 19" wheels with 255/50/19 tyres they are within a few mm the same rolling radius as the 255/65/16 or 255/55/18 wheels and tyres fitted as standard equipment. Only thing a smaller than normal or larger than normal rolling radius will effect is the speedo reading. Smaller than normal rolling radius will give a reduction in gearbox ratios. Larger than normal rolling radius will give an increase in gearbox ratios. Other than that It will not in any way effect the actual gearbox operation.
 
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My beastie has mud pluggers on which, (I suspect), are not standard as my speedo is reading very low but this has no bearing on engine and/or gearbox performance, (other than the vehicle will may not be running within the designed/ideal rev range if the wheel size is wildly out).

I suspect that serious problems may occur, however, if you have a mismatch of sizes on any of the hubs!

Not wishing to hijack this topic but does anybody know the formula for calculating the speedo offset factor for different wheel sizes I wonder?
 
My beastie has mud pluggers on which, (I suspect), are not standard as my speedo is reading very low but this has no bearing on engine and/or gearbox performance, (other than the vehicle will may not be running within the designed/ideal rev range if the wheel size is wildly out).

I suspect that serious problems may occur, however, if you have a mismatch of sizes on any of the hubs!

Not wishing to hijack this topic but does anybody know the formula for calculating the speedo offset factor for different wheel sizes I wonder?

Might help? http://www.tyresizecalculator.com/tyre-wheel-calculators/speedo-error-calculator
 
I will be putting 255 60 18 tyres on my P38 but the spare will not fit in the boot so i am also making up a swing away spare wheel carrier that will be able to fit on the towbar so easily removable.
the reason i am putting on higher aspect ratio tyres is that im hopeing to get fuel consumption and also beter protection for my rims as i have smashed 2 when travelling in Mongolia and Russia .
Also the spare wheel on the towbar will be easier to access when I am fully loaded and get puncture.
 
I will be putting 255 60 18 tyres on my P38 but the spare will not fit in the boot so i am also making up a swing away spare wheel carrier that will be able to fit on the towbar so easily removable.
the reason i am putting on higher aspect ratio tyres is that im hopeing to get fuel consumption and also beter protection for my rims as i have smashed 2 when travelling in Mongolia and Russia .
Also the spare wheel on the towbar will be easier to access when I am fully loaded and get puncture.

Why do you not use standard 16"s?
 
Yes you can.

Where's that setting? I presumed in the ABS module, but the WABCO 'D' in my Thor model doesn't have any options for speedo adjustment - you can force it on/off to test the output but that's about it. Not sure about the earlier WABCO 'C' models.
Haven't seen anything in the BECM settings either.
I always figured that you might be able to tweak it with one of the trimmer pots on the instrument cluster PCB, but have never had a chance to actually see what any of them do.
 
Where's that setting? I presumed in the ABS module, but the WABCO 'D' in my Thor model doesn't have any options for speedo adjustment - you can force it on/off to test the output but that's about it. Not sure about the earlier WABCO 'C' models.
Haven't seen anything in the BECM settings either.
I always figured that you might be able to tweak it with one of the trimmer pots on the instrument cluster PCB, but have never had a chance to actually see what any of them do.

Nothing to do with Wabco look in instrument. Last screen.
 

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