MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Brake Drum to Spoke Hub Clearance

My front spoke wheels (when mounted) "touch"... abut, come very close to the brake drum. When I look at the rear drums I notice that there is a clearance of about 1/8 inch between the hub and drum. Is this correct?
Gordon Harrison

You should be OK as long as the wheel is seating fully against the hub and it isn't putting pressure on the spokes to do that.

Touching = OK.

Bending = no-no. The spokes will eventally break.
Bill Spohn

Thanks Bill
Gordon Harrison

The usual cause of the spokes getting close to the brake drum, or touching it, is that over a long period of time the the spoke wheel knock-on has been overtightened. This causes the inner taper on the wheel to spread, allowing the wheel to move closer to the brake drum.

Mick
M F Anderson

I should clarify. It is not the spokes that are touching, the brake drum, on the front wheels but the spoke hub. The center shub of the spoke wheel abuts against the brake drum. As I think it should. In the back wheel, the hub has a slight gap (1/8 in) between the spoke hub and the brake drum. It is like this on both sides. Gordon

Gordon Harrison

Gordon

The Shop Manual shows it as having as small gap.

John DeWolf

That's the answer I was looking for . Thanks to everyone. gordon
Gordon Harrison

Gordon,

You still have a problem. If the wheel hub is touching the brake drum the wheel is not properly located on the taper. Just clamping the wheel to the side of the brake drum could be quite dangerous.
Again, this has been caused by over-tightening the knock-on which has spread the inner taper of the spoked wheel.

Mick
M F Anderson

Gordon

Remove a front and rear wheel and measure the distance from the face of the brake drum to the shoulder of the hub taper. If there is a difference then the wheels will sit differently. I will check mine tomorrow.

John DeWolf

Differences in the gap at the front and rear wheels will not be of importance. What is important is that there is a gap of any amount. This gap will vary on most cars, depending on how much the inner wheel hub taper has been spread by various owners, by overtightening. It could even be different on opposite sides of the car after 50 years.


Mick
M F Anderson

The wheels in question are a set of A/Healey wheels that I bought just recently. I had them verified with a reputable wheel restoration company on the east coast and their response was that these are a very solid, well tuned and a true set of wheels. What I am going to do this weekend is re-install my origional 48 spoke wheel rims and see if there is a difference in the spacing.

John, I really appreciate the tech advise and I will measure the hubs. I will post the results.

Mick, I understand your approach and I must say that the new wheels do run much truer and smoother than the old ones.

If a straight edge was laid flat accross the back surface of the rim (from outside edge to outside edge)what would one expect to be the normal amount of offset between the outside rim and the center hub edge?

When mounting my knock-offs, I generally use a large rubber mallet,for the initial tightening and then follow thru with my origional copper hammer, for several extra hits. Some people say you "can" overtighten the K-offs while others say they are never tight enough. Gordon
Gordon Harrison

Gord, you mentioned you had a slight front end shimmy. If the wheel is not fully tight on the splines, could this be the cause?
Art
A Pearse

Gordon

I inspected and measured my hubs this morning. A photo is attached. I found that there is approximately 1/8" difference in the distance of the front and rear brake drums to the shoulder of the hub taper(about 1/2" rear and 3/8" front). My wheels sit with a noticable gap for the rear and a very small gap at the front. I have the same 60 spoke Healey wheels as you.

John DeWolf

Did you try swapping the wheels around and did you get the same result?
Mike
Mike Ellsmore (1)

John, that is the same as my wheels. The wheels are tight and run smoothly.

Mr. Pearse, The swishing we spoke of was due to the long lugs bolts in the new hub. Apon returning from stowe I cut off the excess and the wheels no longer make the same noise. Frt shimmy is being tracked down to mechanical suspension parts and not the wheels.

I am inclined to accept the rear gap as normal (see John's image) and let things lie. All is tight secure and running well. I am meeting some MGA's this weekend and will check there cars.
Thanks for the help.

Gordon Harrison

This thread was discussed between 24/09/2008 and 29/09/2008

MG MGA index

This thread is from the archives. Join the live MG MGA BBS now