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MG MGB Technical - Worn splines - how much?

I've been trawling thru the archives looking for advice on exactly how much spline wear is tolerable, without any luck.
With the wheel on and the spinner on loosely, how much rotation is normal or tolerable? ie how many degrees movement or how much circumferential movement at the rim.
I'm referring to 1967 hubs, wheels.

Thanks
John


John Minchin

When in doubt change them.

It isn't a 'wobble' test, it is a visual test of the sharpness of the splines. If they are worn, change them and take a good look at the wheels.
Bill Spohn

John-
As Bill says, it isn't the amount of free play that is critical. You have to visually inspect the splines in both the wheels and the hubs. Click on the following for a visual aid: http://www.britishwirewheel.com/faq.htm
Steve S.

If you can shim the splines with beer can aluminum sheet, it is probably time to give up on them. I wish I had some photos of some of the hubs I have seen people try to use, they would horrify most of us. Most any spline drive, whether on wheel hubs or driveshafts have a minimum wear before replacement.

Please take a look at Paul Hunt's commentary (about mid-page) at this site: http://www.mgb-stuff.org.uk/wheelstext.htm , it may be of some interest to you on this matter.
Bob Muenchausen

Thanks everyone for the advice - I am going to be very careful to ensure everything is safe. I didn't want to go to a lot of effort measuring and inspecting if there was a simple rule of thumb that would tell me to get new hubs and wheels and toss the old ones.

Cheers
John
John Minchin

John,
Since you are up for hubs and wheels, you might look at getting some Dayton wheels.
These are the best there is and better than standard issue ones in every way. Triple chromed, super true/balanced, you can use tubeless tyres. They are going to be my next set. More expensive, but they last heaps longer. Proportionally many times the additional expenditure. They certainly look better.
My car is a daily driver and last time I replaced my wires (the previous MG) the new splines and wheels were clunking again with in a year.
http://www.daytonwirewheels.com/wirewheels.html
You will need to contact them to find their representative. Worth the trouble.
The only downside is that your old spinners are going to look a bit ordinary next to all that triple chroming!
Peter

John-
This article with pictures may help.
http://mgaguru.com/mgtech/wheels/wl104.htm
David Levy

John, As one of the above web-links points out, there is a portion of the spline on the wheel side - the innermost portion - which doesn't contact the spline on the hub as it overlaps it. This will be the "unworn" original spline - so if you clean the splines with solvent and can detect a ridge, or step, a little way along the spline from the innermost end, there is probably enough wear there to indicate replacement time. Unfortunately, the splines both wear at about the same rate so putting new hubs with old wheels and vice-versa only wears the new item prematurely. Although its one of the more expensive repairs on an MG, its quite cheap compared with suddenly having no brakes! Cheers, Bob.
Bob Elwin

John,

The thing to check before you start throwing out your existing splines and wheels is that the rotation you mention is not in axle/differential wear. If the test you did was on the rear axle, what you have described would more likely be diff wear, a common thing on these cars as they have aged.

Of course, if your test was on the front wheels re-read everything above and act on all of it.

Regards
Roger
Roger T

Some good advice from everyone, Thanks.
David, the website link is very good. It answers my original question; "Anything over 1/8" is a concern to watch. More then 1/4" is serious. More than 3/8" is life threatening. At 1/2" it may shear and allow the wheel to free wheel on the hub the next time you hit the brakes hard at speed"
Now, where did I put that tape measure............

John
John Minchin

You should put the tape measure away and measure the hubs. If you want to really know for sure, buy or borrow a dial caliper and measure the outside diameter of the splined hub. As they wear, they shrink in diameter. One can also feel for wear on the splines, but if someone's fingers were that practiced at detecting levels of wear, would they be asking about such a thing on the internet? They can also look ok, especially to an unpracticed eye, and not be.

Hubs should measure 2.440" or more; new replacements (2.440") are smaller than originals (2.450" when new). Once you get down to 2.435" or less, you should be concerned, less than 2.430" and they need to go. If the hub a particular wheel has been on is worn, It's more than likely that the wheel's hub is worn too. You can measure the inside diameter of the wheel hub with an inside micrometer, or a bore gauge, or any number of other tools but they are far less commonly used than a dial caliper so I wouldn't advise getting one. Look and feel the splines as they meet the portion that does not contact the hub, as well as determine the axle hub's condition to get a handle on how the wheel hub is. "Measuring" the rotation at the tire's edge to determine spline wear is probably the worst way to figure out where, or even if, the problem is.
Wade Keene

I can't remember where I read it but I have seen that worn splines can be *larger* than the 2.440 of new, due to the hammering action on the side of the spline. When they are stripped it will be less than this, but by then it is too late.
Paul Hunt 2

This thread was discussed between 21/08/2007 and 29/08/2007

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