I drove this car for the first time last weekend at a race meeting and on the first outing, it had more vibration than what i would expect so i put a new set of boots on and the vibration improved to an acceptable level but was still there. I was going over the car today and decided to pull the wheels off to check and noticed that the wheel spacers are not exactly round- you can feel it against the hub and then found that the wheel has the wrong size hole for the hub. Now this is not that much of a concern as when you add spacers the wheel no longer centres on the hub but as i always do when making spacers, you machine them with a hub centre. This leeds me to the question, without the hub centreing the wheel, is it possible that the wheel gets fixed to the hub off centre as only the studs are used to locate it. Could this be an issue or do most racers use a standard flat spacer without vibration issues?
Alfa duk
You are correct, you need to locate the wheel on the hub centre in order to avoid the vibration. So the spacers will need to be, as you say, machined with a hub centre.
Awhile back when doing a basic modification to front brakes with different calipers and discs, my Simmons wheels would rub the calipers, so spacers were used to clear it, the wheel was off the hub centre, and vibration appeared, careful tightening of wheel bolts only eliminated vibration slightly. So concluded the wheel was not sitting 100% centred, ie not on hub.
So hub centres are needed. Then again, I could be wrong and this is nothing new. In fact I think there was a discussion on hub centricity already.
Neil
Spigots locate, bolts and nuts clamps, bolts and nuts don't locate, remember this when your car is sitting on its roof, Colin.
Never had any success on Alfas without centering on hubs. A communicative suspension like Alfas have will convey centering errors (and balance) more readily so accuracy is paramount.
There is about '05mm to '00mm clearance between the hub spigot and the bore of the wheel, this will locate the wheel good, when you put the bolts or nuts on, there will be some movement to allow the fasteners to tighten / loosen, if the wheel is not located on a spigot, the bolts will loosen off and you will end up on your roof, the taper on the nut / wheel is not to locate the wheel, it is to add friction between the fastener and the wheel, to stop the fastener loosening off, Colin.
If the wheel is not located on a spigot, then the wheel will move up and down, because it hasn't got anyway of holding it central, thats why all car manufacturers use central locating spigots, to locate the wheel accurately, the fasteners 'clamp' the wheel to the hub, thats why important things like flywheels, clutches, cylinder heads, etc have dowells to locate the part accurately, and fasteners to clamp the parts together, Colin.
Thanks guys, you confirmed my suspicions. Bet this got some people thinking about their own set up
Definitely good to have a spigot to locate the wheel so it does not run out and cause vibration. The wheel won't fall off because you don't have a spigot.
Minis don't have a spigot at all, just the wheel nuts in the tapers in the wheel, and you hardly ever see Minis on their roofs.
No, when a Mini has a wheel fall off, it understeers into the nearest tree, seriously, whatever setup you have, make sure its safe, as it can all go wrong in a split second, car makers put spigots there for a good reason, Mini's have a 10 inch wheel?, so there would be less mechanical advantage in trying to loosen the wheel off, Colin.
Yeah, I will also say that these rules also apply to initial gear shift of drifting. Alfa suspension never worked for me, still in confusion to figure out the technical glitch.
Only ever use 'hub centric ' spacers (spacers that have locating spigots)!
Locating the wheel is obviously important from a vibration perspective, but the central spigot is the part that transfers the bump force from the wheel to the wheel hub. I've seen a few cars loose their wheels from the shock loading of bumps eventually snapping the wheel studs.
Car manufacturers and heavy industry do it for a reason.
If you suggest otherwise, sorry, but you are just plain wrong. And just 'cause Mini's didn't use them certainly doesn't make it right.
Quote from: Duk on October 04, 2012, 05:48:52 PM
Only ever use 'hub centric ' spacers (spacers that have locating spigots)!
Locating the wheel is obviously important from a vibration perspective, but the central spigot is the part that transfers the bump force from the wheel to the wheel hub. I've seen a few cars loose their wheels from the shock loading of bumps eventually snapping the wheel studs.
Car manufacturers and heavy industry do it for a reason.
If you suggest otherwise, sorry, but you are just plain wrong. And just 'cause Mini's didn't use them certainly doesn't make it right.
NO DUK! The spigot locates only. It does not transfer any load. The hub and wheel, once the bolts / nuts are properly tightened, act as one unit and carry all the loads. Once I thought the same as you......
I was looking at these spacers: http://www.serpentautosport.com/HTML/Hub%20Adapters%20and%20Spacers.html
Specifically the adapter-style that you fix to the hub (see picture).
Any other recommendations for suppliers? Probably need to be made to order, and exact spigot size, PCD, and spacer width.
(http://www.serpentautosport.com/images/Spacers/38mm-63.5mm_spacer_adapters_GTAM.jpg)
OMG I just posted in the "Racing > Rear Wheel Drive" section. Blasphemy. Washing my mouth out!
Evan
Remember, you have crossed to the darkside, you are a racer now and there is no turning back.
Neil
Its OK Evan, we read your restoration posts as well... :)
aggie57
QuoteNO DUK! The spigot locates only.
Mate, I usually agree with your posts but I gotta say I am not buying that. A good interference fit of a wheel centre onto a hub machined down to provide a location is both a locator AND a point of load bearing in conjunction with the bolt fixings. It has a two fold purpose. Load bearing and centering.
I'll second Evan's question, does anyone know where these can be made in Australia? ... Those ones look really good ...
whilst i concur with the spigoting of the wheels, is there any mechanical disadvantage by running a spacer ... say on a sud using about a 4-6mm spacer and longer wheel bolts than standard?
Southern75,
A small track change of 4-6mm is not likely to make any noticable handling change. The important thing to remember is to keep the front to back track change the same. Alfas generally have a wider front track than the rear**. This all has to do with the way they handle which is one of the things we love about these cars.
A careful look at the spacers in this topic will show that they are of two thicknesses. The application of these units is obvioulsy intended not only to create a wider track, clear wheel interference etc but also to alter one track width to the other. (for whatever reason ?)
** For the sake of perspective I will make this generalisation. European cars cater for enthusiasts that love cornering and this is best achieved with a wider front track than the rear. The Yanks love to do drags and straight line speed and are looking for maximum rear traction from wide rear tyres. Due to fouling reasons, the front tyres are usually smaller than the rear set and this inevitably resullts in a wider rear track than the front..
The effect of this is that the front axle set is working to a shorter radius than the rear and therefor turning in sooner that the rear. Result, automatic oversteer Starsky and Hutch style. ;D
Horses for courses..
MD - I stick to my earlier assertion that the spigots DO NOT take load. Well, if they do then sooner or later you will have a failure. That's why they can be made out of plastic.
http://www.spigotrings.com
Quote from: aggie57 on December 15, 2012, 09:21:10 AM
MD - I stick to my earlier assertion that the spigots DO NOT take load. Well, if they do then sooner or later you will have a failure. That's why they can be made out of plastic.
I read once, somewhere, that plastic spigot rings aren't allowed in Australia.
And I maintain that the large central spigot is much more resilient to impact than the bolt/studs are and that is the whole idea of the central spigot, correct location and support.
Here in heavy industry I've seen plenty of sheared bolts when they are subjected to (duh :P) shear stresses. Locating blocks, additional dowels or significantly larger bolt diameter is the answer, even if the clamping requirements of the original bolts were sufficient.
Seen a few cars with 'non hub-centric' wheel spacers that have sheared their wheel studs, too.
Well alfa duk, I suppose by now you have well and truly been informed by all arguments so there is no excuse for lack of action. Now go out there and slap some black doughnuts on, (with or without location) and burn some rubber.- you do know that REAL MEN burn rubber don't you ?? !! ;D
Quote from: Duk on December 15, 2012, 12:46:57 PM
Quote from: aggie57 on December 15, 2012, 09:21:10 AM
MD - I stick to my earlier assertion that the spigots DO NOT take load. Well, if they do then sooner or later you will have a failure. That's why they can be made out of plastic.
I read once, somewhere, that plastic spigot rings aren't allowed in Australia.
And I maintain that the large central spigot is much more resilient to impact than the bolt/studs are and that is the whole idea of the central spigot, correct location and support.
Here in heavy industry I've seen plenty of sheared bolts when they are subjected to (duh :P) shear stresses. Locating blocks, additional dowels or significantly larger bolt diameter is the answer, even if the clamping requirements of the original bolts were sufficient.
Seen a few cars with 'non hub-centric' wheel spacers that have sheared their wheel studs, too.
It's very simple. Spigots locate. Bolts / studs clamp the wheel to the hub which then becomes one unit and carries the load.
Neither spigots or bolts support the car. The bolts will break if they become loose as the clamping force releases and the bolts then become part of the load bearing system. I've lost two wheels on Alfettas because of this. One on the track and one on the road.
Quote from: aggie57 on December 15, 2012, 08:35:17 PM
It's very simple. Spigots locate. Bolts / studs clamp the wheel to the hub which then becomes one unit and carries the load.
Neither spigots or bolts support the car. The bolts will break if they become loose as the clamping force releases and the bolts then become part of the load bearing system. I've lost two wheels on Alfettas because of this. One on the track and one on the road.
Well, that's your opinion, you are entitled to it.
I'll stick with what I've seen and learned from heavy industry and automotively.
Quote from: Duk on December 15, 2012, 08:45:47 PM
Quote from: aggie57 on December 15, 2012, 08:35:17 PM
It's very simple. Spigots locate. Bolts / studs clamp the wheel to the hub which then becomes one unit and carries the load.
Neither spigots or bolts support the car. The bolts will break if they become loose as the clamping force releases and the bolts then become part of the load bearing system. I've lost two wheels on Alfettas because of this. One on the track and one on the road.
Well, that's your opinion, you are entitled to it.
I'll stick with what I've seen and learned from heavy industry and automotively.
It's not an opinion. Normally I don't bother with these types of exchanges except this is a real safety issue with many many examples of people getting into trouble because its not understood properly.
Here is quite a good article on the question:
http://www.crashforensics.com/wheelandhubfailures.cfm
MD,
wasn't concerned about the handling thing just the safety thing.
Handling can be affected by wheel offset but again the changes i want to make are fairly minor it's more a clearing interference thing.
I may not have to anyway as the wider rims i have the tyres will be stretched ...
I just though a tyre may rub on a suspension linkage ... but it's pretty close anyway...
I'll read that foresics article ... that will be interesting ...
Ok, now read,
does a double joint result in s ofter joint. It must do, mustn't it?
If done properly no reason it should.
I've just measured a hub spigot and wheel and there is .008"/ 0.2mm clearance on the diameters.
If friction from tightening up the wheel nuts wasn't enough to stop the wheel moving across the hub face, then the wheel would move this 0.2mm each wheel revolution and the wheel nuts would eventually work loose.
Friction is enough.
Well after all that, i am in the process of getting these hub centering spacers. I note what you say scott and got the spacers machined to fit tight or at least closer than the standard hub to wheel arrangement. I will report on the vibration issue after testing in the new year. It was an interesting observation from MD about the wheel track being wider at the front being better for handling. My opinion is that the gtv6 is a natural understeerer, by increasing the rear track and introducing oversteer it balances the car. Do we need to create a new post? Duk
This is what i had made up. 15mm front 25mm rear to suit 6inch wheel with a 18mm offset. Rear spacer has a step in the hub hole to add some strength as the spacer wall is 4 to 5mm thick on the section that centres the wheel. Front is not thick enough to do the same. Makes the car look like its been on steroids.
Do you have a photo of the car with the spacers fitted?
Will do when it comes back from some surgery.
Finally got her back and dry weather to take the shots
Some more
Hi Duk, just saw this post, I have been laying low for some months.. do you have any wheel clearance issues with the rear under squat? and I guess depending on the castor angle, you'd have turn in clearance issues with such a wheel offset? certainly a broad stance.. I noticed no one piped up about the front to rear track discussion on oversteer/understeer.. I personally would have thought a wider front and narrower rear will induce oversteer..
sorry to restart an old post..
Hi Midda, Rear guards need to have the lips rolled and not sure about turn in clearance with group s cars as they are restricted to 2 degrees camber. I run another alfetta with the same wheels but with 4.5 degrees camber and it just touches the firewall. I never ran that car in the pictures with the spacers as it was sold before i could test. If you are not familiar with group s rules, the wheels are a 14x6 and use 60 series rubber. Different types of rubber albeit the same specification are different in dimension. My findings are using the Bridgestone re55s. In regard to the front to rear track, check out MDs comments within this topic, He has a better explanation of the science than i am able to give.