spare wheel size, HELP??

[john_374325148]

Hi al, my van has four stud,s to the wheel centre, and has 155, 13 inch tyre,s on them, now iv measured from nut to nut centre and it measures, 3 inch and 7, eights, in old money, but in new money 97mm , now the whell centres i,v seen so far that has come close to this is 100mm, now i might sound a little thick, but seeing as this so far is the nearest to my size, i ,m thinking it wont fit or will it, im realy struggling to find a spare wheel centre to fit my van,..

This pcd working out, looks like you neen to be on mastermind to work it out, which im not, is there anyone who no,s any good van wheel web sites or could recormend something, PLEASE as i m realy stumpped on this one, thanks john..

 

[antrimboy]

Most caravan dealers keep a supply of 'van rims. If they don't have a new rim to suit, they may have one lying around that will do your job.

It would be best if you could take one of your wheels along for comparison.

 

[ProfJohnL]

Hello John,

I am not wheel expert, but I do know that there is more to specifying a wheel rim than just the PCD of the studs.

Usually somewhere on the rim is a stamped reference number which defines the rim. You must ensure that any replacement is an exact match, - being close is not good enough or legal.

Eddies advice is sound. Either take a sample wheel with you or if you can find the reference number on the rim (not the tyre) that should suffice.

 

[Brum1]

John

When you do get a wheel rim for your van be very careful to get the correct tyre fitted to it.

Don't be mis-led by the 155.13 size that you quoted but also look at the weight and speed rating that will be also marked along with the tyre size.

The PCD is measured from centre to centre of diaganol holes so should be no more difficult to measure than what you have done when measuring side to side holes.

Can the caravan maker or one of its dealers offer any advice?

Brum

 

[gary]

PCD is not mastermind if you only have 4 holes, this is simply centre to centre across any two diagonally opposite holes.

Where it gets slightly complicated is when there are five holes so no two are directly opposite on a line through the centre point of the wheel.

In this case you measure from any bolt hole centre to the edge of the big hole in the middle with the rules edge still running more or less through the centre point of the wheel. Now by doubling this measurement you are simply imagining another hole diagonally opposite and then by adding the diameter of the hole in the middle you arrive at the PCD as if one was actually there....yes..no?

Working it backward, 97mm from hole to hole on a 4 stud rim gives a PCD of 137mm, the closest to this is 139.7mm or in old money exactly 5.1/2 inches

 

[john_374325148]

PCD is not mastermind if you only have 4 holes, this is simply centre to centre across any two diagonally opposite holes.

Where it gets slightly complicated is when there are five holes so no two are directly opposite on a line through the centre point of the wheel.

In this case you measure from any bolt hole centre to the edge of the big hole in the middle with the rules edge still running more or less through the centre point of the wheel. Now by doubling this measurement you are simply imagining another hole diagonally opposite and then by adding the diameter of the hole in the middle you arrive at the PCD as if one was actually there....yes..no?

Working it backward, 97mm from hole to hole on a 4 stud rim gives a PCD of 137mm, the closest to this is 139.7mm or in old money exactly 5.1/2 inches

Thanks all for the help, and gary for working the correct pcd, again thanks all and hope to get sorted. john