spigot

Red Estate · Post by **Red Estate** » Sun Jun 21, 2009 11:37 pm

Hi, i have a set of MOMO arrow wheels with 195/50/15. it fit fine on estate but it seems that bore hole on the wheels is 73.1 mm and spigot on the car hub is 65.1 mm. as i understand that wheel bore hole must sit perfactly on hub's spigot, it is the one that take the weight of the car not wheels bolt. there is some spigot adepter on sell on internet but most of them are made from plastic. their main job is to stop a vibration. so,i wonder would it stand the load without deform sir?

Kitch · Post by **Kitch** » Sun Jun 21, 2009 11:47 pm

I had a mate who had the placcy spiggots fitted an never had a problem. Seems a bit of a bodge when you fit them, but remember most of the weight is taken by the bolts.

Vanny · Post by **Vanny** » Mon Jun 22, 2009 2:55 am

Your a smarter man than me Kitch, i couldn't make head nor tale of the original post.

Red Estate · Post by **Red Estate** » Mon Jun 22, 2009 12:29 pm

Sorry about unclear on original post. Can plastic spigot in alloy wheel center bore take the weight of the car without quickly deforming or should i look for metal one sir?

Way2go · Post by **Way2go** » Mon Jun 22, 2009 2:14 pm

Red Estate wrote:Sorry about unclear on original post. Can plastic spigot in alloy wheel center bore take the weight of the car without quickly deforming or should i look for metal one sir?

Surely the "plastic spigot" is for ease of wheelbolt insertion/alignment and is not in anyway structural with regard to the weight of the car? The wheel held by the bolts and against its mating surfaces on the hub is what supports the car in this regard.

Brian · Post by **Brian** » Mon Jun 22, 2009 2:38 pm

I agree, virtualy no weight is taken on the wheel centre as that is a clearance hole. The bolts engage in a countersunk recess.
So car weight is transferred to the hub via the bolts and the interface between the wheel and hub face.

Post by **mat_fenwick** » Mon Jun 22, 2009 2:58 pm

Thirded(!) My 3.5 ton van only relies on the wheel studs/bolts to locate the wheel and take the weight. Which makes it a pain when changing the wheels on the front, as the front wheels use bolts rather than studs for fixing.

Kitch · Post by **Kitch** » Mon Jun 22, 2009 5:17 pm

Yeah thats it, it's not a load bearing part. Only issue I've ever found is that if the hub isn't a tight fit to the wheel centre, there's enough float in the bolts to allow the wheel out of balance slightly as you tighten it. Car would drive fine, until you braked! Then it'd shake itself to pieces!

Way2go · Post by **Way2go** » Mon Jun 22, 2009 6:20 pm

Kitch wrote:Only issue I've ever found is that if the hub isn't a tight fit to the wheel centre, there's enough float in the bolts to allow the wheel out of balance slightly as you tighten it. Car would drive fine, until you braked! Then it'd shake itself to pieces!

That's an area that the Steelies are better than the alloys then as the cones on the bolts micro-align the wheels as you tighten.

Red Estate · Post by **Red Estate** » Tue Jun 23, 2009 10:56 am

From this www.nice-wheels.co.uk/pcdandoffset.html. they said" If you don't have the spigot taking all the weight of the car, chances are you'll break one or more studs when you drive the car hard or have to brake hard. Remember the wheel nuts are simply there to hold the wheel on, NOT support the weight of the car.

RxBX · Post by **RxBX** » Tue Jun 23, 2009 1:03 pm

Brian wrote:I agree, virtualy no weight is taken on the wheel centre as that is a clearance hole. The bolts engage in a countersunk recess.
So car weight is transferred to the hub via the bolts and the interface between the wheel and hub face.

Incorrect , therefore I disagree

Red Estate wrote:From this www.nice-wheels.co.uk/pcdandoffset.html. they said" If you don't have the spigot taking all the weight of the car, chances are you'll break one or more studs when you drive the car hard or have to brake hard. Remember the wheel nuts are simply there to hold the wheel on, NOT support the weight of the car.

Correct

But (Red Estate) The link quoted fail's to open up

But does open with this LINK and then select 'PCD and Offset Explained'

Post by **docchevron** » Tue Jun 23, 2009 1:06 pm

Red Estate wrote:From this www.nice-wheels.co.uk/pcdandoffset.html. they said" If you don't have the spigot taking all the weight of the car, chances are you'll break one or more studs when you drive the car hard or have to brake hard. Remember the wheel nuts are simply there to hold the wheel on, NOT support the weight of the car.

What utter crap.

Post by **mat_fenwick** » Tue Jun 23, 2009 1:42 pm

How does that explain the situation on vehicles that have no locating 'spigot'? On the van there is nothing to locate the (original) wheels onto, and that has a maximum rear axle weight of 2 tons, all taken by 5 studs each side...

DavidRutherford · Post by **DavidRutherford** » Tue Jun 23, 2009 1:44 pm

docchevron1472 wrote:
Red Estate wrote:From this www.nice-wheels.co.uk/pcdandoffset.html. they said" If you don't have the spigot taking all the weight of the car, chances are you'll break one or more studs when you drive the car hard or have to brake hard. Remember the wheel nuts are simply there to hold the wheel on, NOT support the weight of the car.
What utter crap.

Indeed. The hub of the wheel is not load bearing in any way. The wheel bolts are.

After all, how on earth can the hub of the wheel transmit the torque they are referring to from acceleration or braking? Answer is that it can't.

In actual fact, when the wheel bolts are torqued up correctly, they don't carry any of the braking or acceleration forces either, that's done entirely by the friction between the wheel and the brake disc and hub. This friction is of course only available as the wheel is being clamped to the disc and hub by the tension in the bolts.

Brian wrote:I agree, virtualy no weight is taken on the wheel centre as that is a clearance hole. The bolts engage in a countersunk recess.
So car weight is transferred to the hub via the bolts and the interface between the wheel and hub face.

This is correct.

Having read a couple of pages of that web site, there's a fair amount of utter bollocks on it...

Post by **mat_fenwick** » Tue Jun 23, 2009 2:19 pm

DavidRutherford wrote:there's a fair amount of utter bollocks on it...

What, like this?

It is, of course, extremely important that the clearance Pitch Circle Diameterof both the vehicle body work and steering/suspension components are maintained.

Just to clarify what I was saying earlier, if there is no spigot then the wheel bolts/nuts must be domed, in order to centralise the wheel…not like a Mondeo I saw recently that had the domes towards the outside "Because they look better".