Trap for young players

[ducatijim]

A correctly used retaining compound with a transition (slip) fit bearing is superior to an interference fit in an aluminium housing.

Doh....I wonder wot that means?......No, hang on a moment.......

......I don't!

[clint640]

Doh....I wonder wot that means?......No, hang on a moment.......

......I don't!

It's engineer speak. Basically having a slightly looser fit of yer bearing in it's hole then gluing the fucker in there is better than having a real tight fit & having to whack the bastard in with a FBH.

Cheers
Clints Engineer-Farmer Translation Services Ltd

[Crisis management]

In addition, it costs no more to manufacture than what they are doing now - maybe less, because the bearing fit becomes less critical.

You need to buy a KTM.









Oooooh look, here's one I have for sale!

[warewolf]

Sorry guys but you are both missing the point. It's not about the bearing fit. It's simply that if the internal spacer was about .003" (say 75 microns) longer than than the shoulder to shoulder distance in the hub, clearances and fit would be all but irrelevant. Just bang it together and everything is self locating (and you can throw the fkn Loctite away). In addition, it costs no more to manufacture than what they are doing now - maybe less, because the bearing fit becomes less critical.

Yep, you've lost me - I'm trying, but I just don't get it.

I don't see how bearing fit is any less critical when the gap to the shoulder on the second side approaches zero. You still need a tight fit to maintain the radial positioning of the wheel on the axle, irrespective of the gap to shoulder.

Even if the gap was only 75um, you'd still need a retaining compound as the hub aged and flogged out.

Radial positioning is far more important than lateral. To that end, I've seen plenty of hubs with radial wear causing problems; can't say I've seen any with much if anything in terms of lateral wear.

[Bass]

Yep, you've lost me - I'm trying, but I just don't get it.

I don't see how bearing fit is any less critical when the gap to the shoulder on the second side approaches zero. You still need a tight fit to maintain the radial positioning of the wheel on the axle, irrespective of the gap to shoulder.
Radial positioning is far more important than lateral. To that end, I've seen plenty of hubs with radial wear causing problems; can't say I've seen any with much if anything in terms of lateral wear.

Everything you said is correct except that the tight fit is necessary for radial positioning. That is just not true. The axle is an easy slip-in fit after all.
There are literally millions of machines out there where the bearings are little more than a drop-in fit and they perform just fine because the bearings are located against shoulders.
Where the bearings turn in the housings, the process is usually started by lateral loads, but once it starts, of course it generates radial wear.

For the case in point, the tight fit is required to locate the bearings laterally. With correct design, the bearing contact area with the housing is large enough so that, to initiate wear, rotation relative to the housing is required. For a bearing in good order, the fit does not need to be tight to prevent that relative rotation.

However, my point in all of this was that the lateral clearances provided are so large that if the hub does decide to move on the bearings, it can move so far that the RHS seal can be completely ejected.
I grant that, because this is a 2-wheel vehicle, the lateral loads relative to the radial loads, are quite low and so with reasonable precautions, lateral movement is unlikely.
Even so, it is just poor engineering practice and as I pointed out earlier, requires a particular assembly order to dodge the trap.
Further, as you have pointed out, the bearing fit is tight as a consequence and despite what others have said, requires heating of the hub for safe assembly/disassembly.
Neither of these measures would be necessary if it was set up as I suggested.
Having said that, Mr Suzuki is a far more talented automotive designer than I and so I am interested in why he has done it this way. There will be a good reason.
The rest of the discussion is largely irrelevant.