Ace 90 rear wheel bearing spacer

[JPark]

I have a 90 rear hub apart and the spacer doesn't look at all like the one that Hodakaparts pictures. It is quite thick wall and you'd expect it to be a wrist pin. When I measure up the distances it comes up being about 1.5mm too long which means the bearings can't seat fully home against the shoulders. The wheel had some end float which was made worse by one of the washers that goes inside being on the outside against the seal.

Given that, I'm wondering if the spacer is an orphan or if they were originally just way overbuilt like that. Due to the float, the bearings are a snug but not firm fit in the hub but I plan to use some loctite retaining compound on them. However, if the races don't bottom on the seat I'm worried that they may just go back to wandering about. Maybe the press fit was supposed to hold them wherever they ended up. ??

If someone has a spacer to measure the official length of I'd like to know. I think it's the same hub for the 100 as well, pre cush chain wheel. I have another 90 wheel I could dissect, but it's currently holding up a bike.

The one in question measures 63mm long, 18mm OD, 13mm ID, and of course 2.5mm wall. Nickel plated. The internal shoulder of the hub is 60mm and the washers are about .8mm thick.

[matt glascock]

If no one chimes in with the data, I will measure mine tomorrow.

[Bert44]

My Ace 100 had a thick spacer from memory. 2.5 mm seems about right. The length should be around about the same as the step in the hub where the bearings seat against plus the thickness of the washers. As I’ve written before, I always file a notch in each end of the spacer so I can rest a drift on the inner race which makes it easier to remove for me or a future owner.

[JPark]

So. The spacer is presumably original. The original press fit seems pretty marginal and the newer style one is more appropriate to trail riding. Axial loads on the setup were not well accounted for. That said, I neglected and beat them pretty hard back in the day and never broke anything, which is why I've never looked inside before. I might have been horrified...

I could just reassemble as is. Or I could grind down the spacer about 1.x mm . I could add a washer, if I had one, or make a spacer shim. But the difference is so minimal that the effect on the hub width in the swing arm is irrelevant. So I think I'll just install the brake side bearing and washer and grind the spacer until it is flush with the other washer.

If I'm feeling frisky I might take the wheel off the other 90 and put a rim on the axle to hold it up and steal one of its washers to minimize the grinding, and just order a few washers in my next parts buy.

Old stuff. Always an adventure.

[ossa95d]

I have made several wheel spacers over the years and as a cautionary note I would say that it's important for the spacer to contact the inner races of the bearings before the outer races bottom out in their recesses when the axle is tightened. If the outer races bottom out first and the axle is tightened it will put a side load on the bearings and they will fail much more quickly. My own personal opinion is that 1.5mm in extra length is just fine. Again it's my own personal opinion and I would love to have someone correct me if I'm off base.

[ossa95d]

Re-reading your post it appears the spacer may be 3mm longer than the inside shoulder measurement. I feel that might be excessive if the inner and outer races of the bearing are flush with each other.

[JPark]

The washers that locate the spacer go against the recess before installing the bearing. Thus you end up with 1.5mm extra, or even more if you put the washers in after like the previous guy did in this case. Too kooky for me.

[JPark]

I ground the spacer and it all fits perfectly now. No endplay, no preload. Ready for another 55 year service in 2075.