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Serviced a rear hub where the end caps are retained via a 14.5x1mm o-ring.
Every time I refit the end caps, the o-ring shears.
I'm a quarter way through a bag of 50 o-rings. First 3ver service and the end caps came off sheared. Any advice on how the get them back on in one piece?
Or is it just that a 1mm cross section o-ring is a poor design choice?
Do you lube them sufficiently so they slide rather than grip/tear?
Yep, using Maxima blue grease. Very similar to RG2 or Mobile XP222.
Wondering if I lighter lube, or an oil might do the trick.
I'd try chamfering the ends of the axle to give the cap & o-ring a smoother lead in.
Petroleum based grease isn't good for some types of oring. Use silicone grease,molycote 111 or at a push gt85 or silicone spray. Not WD-40.
Thanks, I don't think the grease is there long enough to damage an o-ring. Also have the same trouble if they're dry.
I could try some Hunters silicone lube, or slick honey
I now have about a dozen split o-rings on the worktop and almost as many different lubricants.
I'm rapidly forming the optioning that I was told the wrong size by the manufacturer.
Okay, a bit of feedback incase anyone was following this.
I was told to get a harder o-ring by the manufacturer so I chose 90 Shore over 70 as to my mind, 70 Shore is standard/normal/typical.
The 14.5x1 90 Shore always split until I cut them. This made them fit but didn't grip the axle particularly well. When I did this, I noticed a gap of about 1.5mm in the seal groove so next I tried 15x1 70 Shore. Fitted no problem at all but still has a low grip strength.
Today, a bag of 14.5x1 70 Shore arrived and I just fitted those. Fitted fine but grip strength is still low.
Is there a good way to temporarily soften an o-ring? Seems like the 90 Shore would grip the best, if I could get them in.
Are you fitting the oring over something or inside something? A picture might help. Do you have calipers to measure the grove dimensions?
If you have the size the manufacturer specifies something is wrong somewhere. Got an intact old one?
Soften it whilst you fit? Maybe sit it in a cup of boiling water or microwave it in a cup of water. I use 90 shore for sealing high pressure hydraulics.
Unlikely for a bike hub, but there is a massive range of oddball o-ring sizes that have BS numbers - there might be one of those inbetween the metric ones you've found.
I'm fitting the o-rung inside a groove in the hub end cap and then sliding that over the axle. The 14.5x1 90 Shore takes a lot of force and always cuts the ring as it's not a tight fit in the end cap. The 15x1 fill the end cap and the 14.5 70 Shore will stretch enough to fit over the axle but none of them hold the end cap on well enough to stop the cassette falling off.
I did wonder about loading a 90 Shore into the end cap and then heating them both with a heat gun before fitting. Figure if I just heat the o-ring, the end cap will act as a heat sink before I can fit it to the axle.