This is a terrible answer. The spacers simply should not be sized so that they can contact the bearing seal; if they can, it’s a design flaw. And the problem has nothing to do with fitting the bearings; it has to do with fitting the cranks. And the spec on the cranks is 25 foot-pounds of torque, which is not “gentle” by any means–and you need to put a lot of torque on cranks for them to actually work as designed.
You might be able to get this setup to work, but I don’t think it’s likely to work “very well.” Either your wheel won’t spin freely or your cranks will be too loose.
The answer I gave is correct. To summarise what I said:
The problems are in the minority.
Fitting must be done with more care than with standard bearings (this of cause does include fitting the cranks as it is part of the system).
When fitted with care these bearings do function perfectly, they do run smoothly and the cranks do not fall off in my experience. They are a good solution to fitting an ISIS hub into a 40mm frame. We have many customers (including myself) who have done many miles on them without any problems.
Roger - thanks for the comments.
To add: I think it’s worth clarifying expectations and intent here, with this item.
The simplest solution to fitting a 42 mm hub to a 40 mm frame is to get yourself a new frame. Of course, that’s a silly answer; there are many very good frames out there, particularly hand made frames, that people want to keep using. This bearing merely aims to help out the frustration of owning a perfectly good frame that you want to keep using, even if it doesn’t fit the new bearing size standard for ISIS hubs. That’s about it.
My opinion is that as those bearings are made of 2 bearings fitted in a ring, when you tighten the cranks you push on the bearings and this create stress.
The solution would be to add a spacer exactly between the 2 bearings inner cages (see red mark) in order to press the bearings against the hub when you tighten the cranks without stress itself in the bearings.
In some double bearing sets his is the case. In this design it is not. The two bearings are designed to be in full contact, there is a 0.25 high lip within the ring that holds them in place using the chamfer on the bearings to allow 100% contact between the bearing.
Do you mean that there is a lip between the 2 bearings inner cage or outer cage ?
If there is a lip between inner bearings cages, the design is fine
If the lip is only between the outer bearings cages, the design is totally wrong as when you tighten the cranks with a spacer between crank and bearing, you push the inner bearings cages against the hub and so without inner lip between the 2 bearings you put a lot of stress in the bearings themselves.
as when you tighten the cranks with a spacer between crank and bearing, you push the inner bearings cages against the hub and so without inner lip between the 2 bearings you put a lot of stress in the bearings themselves.