Tapered Axle Length

[Pearson]

Re: Tapered Axle Length

It may be that you have the wrong wheels. The wheels on my 46 BC12D are 6C 4HB. I have attached two pictures. One is a close up of the writing on the wheel, the other is after I polished it up.

The fact that your bearings are 0.175" farther apart than mine also indicates a difference in the wheels. One other difference is that I don't recall there being any individual tubes for the bolts that hold the two halves together to go through.

You may have a pair of wheels for an Ercoupe or something else. Bottom line is if they aren't the model called for in your type certificate data sheet, you are not legal.

Your question about the extra holes in your wheel halves needing to be lined up, I cannot answer. I just don't recall that level of detail since the last time I had my wheels apart. It has been too long.

Regarding the wheel torque, I am sure there is a torque setting, but I don't know what it is. Maybe someone else here on the forum can answer that. But you are going to have to tighten it up really tight to squeeze those wheel halves together 0.175". :-)

If it were ME in this situation, I would take the entire brake assembly off the axle. Then, with the tire removed so I could verify that both wheel halves are mated properly, I would double check VERY closely that both wheel bearing races are fully seated. After all that, I would put the wheel, with bearings in place, up onto the axle and check to make sure the inner bearing goes all the way up onto the axle to within a hair of the flange that the brakes attach to.

If MY wheel went all the way up onto the axle, I would mark the outer end of the axle where the wheel bearing came to. Then I would install the brakes and the wheel to see if the outer bearing still came to the marked spot on the axle.

If all of that checked out, I would just assume I had the wrong wheels and work from there. If the wheel bearing was at a point on the axle where there is no play and you can get the cotter pin in, there should be no problem. But if your outer wheel bearing is not well up onto the 1/2" wide shoulder, it is going to have too much play and you will have to fix it.

You might be able to have those wheels machined so that the bearing sit 0.175" closer together, but I would be extremely careful to ensure that ALL other possibilities had been explored before doing that.

[blakecarl]

Re: Tapered Axle Length

Wow, nice job on the wheel!

I looked in the TCDS (A-696, May 21, 2008) but could not find where a hub model number is specified. Is there another document where this might be found?

From the description of the procedure you would do, “...mark the outer end of the axle where the wheel bearing came to. Then I would install the brakes and the wheel to see if the outer bearing still came to the marked spot on the axle”. The brake assembly we have goes between the dust cover and the wheel bearing. With it in place the bearing would be aprox. 1/8” further out on the axle. Sounds like we may also have a different brake assembly?

We’ve talked about ways that machining could address the problem, but I agree this should be the least desirable alternative.

[Pearson]

Re: Tapered Axle Length

The main part of the brake assembly that screws onto the axle flange, is about 1/8" thick. By removing it and everything else, you are eliminating possible sources that may be putting your wheels too far out on the axle. I wouldn't think 0.175" would be enough to make a huge difference. But I suppose it is possible.

By marking where the outer bearing comes to with the brake assembly off, and then checking it again with the brake assembly on, you are eliminating it as a cause for keeping the wheel too far out.

You might want to go so far as driving the bearing races out of the wheel and reinstalling them to make absolutely positive that they are seated all the way in. It seems strange, to me at least, that they would make two different models of wheels with the only change being the bearings 0.175" farther apart. I am very suspect of that. Obviously you want to be careful so you don't ruin the races or the wheel. Maybe you could just clean the grease off with some solvent and use a tiny mirror to get a really good close up look at how well the races are seated. Maybe by some fluke someone installed the wrong bearings. I would check everything before I machined the wheels.

[Howard Wilson]

Re: Tapered Axle Length

Carl, Check your PM's. h

[Ragwing nut]

Re: Tapered Axle Length

If you can get the cotter pin in, then what is the problem? When preloading the bearings I tighten nut until wheel quits spinning (not locked down) and back off one castelation. If you can get the cotter pin in at that point, I think you are being over concerned about uneeded threads beyond the nut.

there are a few different models of wheels, but there is one one style that will bolt on. Originals are Schinn as everyone know, but there are also some made by Firestone that are identical

[blakecarl]

Re: Tapered Axle Length

...If you can get the cotter pin in at that point, I think you are being over concerned about uneeded threads beyond the nut. ...

What is significantly more of concern to me than the “threads beyond the nut” is that with the right wheel on as far as it will go, the inside diameter of the outside bearing is slightly larger than the axle outside diameter. There is enough difference in the diameters that if you hold the wheel with one hand on each side, you can wobble it to the left and right significantly (as if the wheel is being turned to steer the plane to the left or right). If the bearing were onto the axle somewhere between 1/8 to ¼ inch further, it would fit snugly and you would not be able to wobble the wheel.

I appreciate everyone’s attempts to help. I may not be able to do any follow up checking or to reply to posts for a few days. Don’t let that stop you from posting thoughts you might come up with in the mean time! As soon as I have a chance (hopefully by the middle of next week), I plan to take booth wheels off, take the hubs apart, etc, to see if I can identify any reason for my hubs being wider than they should be. As soon as I discover anything or have had a chance to check I’ll post an update.

[Ragwing nut]

Re: Tapered Axle Length

If you can wobble the wheel, then you have the wrong bearings and also possibly the wrong races if you bought them as a pair. That is definitely not right, I am assuming the inner bearing is seated up against the braking mounting plate with thin protective shim in place?