Converting wheel PCD

Post by **picky** » Wed Mar 04, 2009 5:30 pm

Would this work. Its probably easier to make wheel adapters instead, but this looks like a neater solution. Thought I would put this on the forum to see what people think.

Converting 100mm PCD wheel to 4" PCD.

101.6 - 100 = 1.6mm
1.6 / 2 = 0.8mm

4" = 101.6mm, so if each mounting hole was drilled out to 0.8mm greater diameter and centred 0.8mm further away from the wheel centre, then you would end up with a 4" PCD wheel from a 100mm one. The wheel studs will have a gap around them due to increased mounting hole diameter, but its the tension in the wheel stud that is important, the stud doesnt actually have to be touching the wheel itself. Used with angled wheel nuts to centre the stud on the mounting hole as it is tightened, the wheels should centre properly on the hub. Or maybe sleeve nuts.

This is only in the ideas stage at the moment, Im frustrated at the number of alloy wheel designs that are available in 100mm PCD but cant be used on the minor

Picky<br>

<br>

Post by **PSL184** » Wed Mar 04, 2009 6:40 pm

I've done similar before and used sleeved nuts, although, I would suggest you satisfy yourself as to how safe you feel doing this. I haven't done it on a Minor though...

Post by **picky** » Wed Mar 04, 2009 9:33 pm

I think it would have to be done on a big pillar drill, or maybe a milling machine. Im worried that the drill bit would bend and find the original hole instead. Can you remember what you used?

Picky

Post by **bmcecosse** » Wed Mar 04, 2009 10:20 pm

Aye - but how will you form the taper shape in the wheel - on the new centre? If solid centre alloy wheels - easy enough to just drill a new set of holes to the desired PCD at 45 degrees to the original holes.

Post by **PSL184** » Wed Mar 04, 2009 10:42 pm

picky, they were milled out if I remember rightly by a local machine shop - cost was next to nothing.... Taper can be recut to suit the nuts you are using. I'm just not sure if you would find sleeved nuts to fit Minor studs - Might have to change them too ?

Post by **minor_hickup** » Wed Mar 04, 2009 10:43 pm

Wobble bolts can be used to fit wheels of a slighty different PCD, is this what you mean by an angled taper? You must supprt the wheel by the centre bore however.

Post by **Kevin** » Thu Mar 05, 2009 12:11 am

Wobble bolts

Well there's a new one to me, only heard of wobble pins before.

Post by **bmcecosse** » Fri Mar 06, 2009 7:31 pm

Sounds wonderful - please stay well clear of MY car !

You really MUST NOT take chances with wheel security.

Post by **silly** » Sun Oct 04, 2009 8:24 am

i would have thought this would work fine as the wheel nuts are tapered, so they ill center..
however most of the japanese wheels have a smaller diameter hub so the wheel would not likely fit over the hub. i found an interesting chart that says that a mazda mx5 has a 100 pcd with a hub diameter that is similar to morris..
a lot of ford hubs are similar hub diameter as well but dont have the 100 pcd
it is my thoughts to change pattern by changing stubs . or hubs with bearing shims
peuogeot have similar hub size as well but are 108 pcd
i guess if you really want to future proof then a five stud would be the way to go. IMO of a jeweller not an engineer so i could be way off the mark

Post by **LouiseM** » Sun Oct 04, 2009 9:24 am

You really MUST NOT take chances with wheel security.

Agreed. Please do not attempt to alter safety critical parts unless you are suitably experienced / qualified to do so.