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Wonky pistons
 

[Closed] Wonky pistons

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[#5224119]

Just checking the pads in the front caliper. At first glance, they're fine. Still a bit of meat on them, equi distance from the rotor and running drag free. Spotty dog!

Then noticed that the pad material is slightly tapered. This is in line with rotor rotation. Almost like toeing in canti pads.

Anyone else had this?


 
Posted : 06/06/2013 8:01 pm
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Wonky pistons or caliper not aligned properly?

Edit: If you have a slightly bent rotor this could cause the tapered effect?


 
Posted : 06/06/2013 8:04 pm
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Caliper is perfectly aligned. They both taper the same way. Both pads are thicker at the top and thinner at the bottom. Rotor isn't bent, runs drag free and always has done.

I can see the pistons out further at the bottom, only slighly, but it's there.


 
Posted : 06/06/2013 8:11 pm
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Formula brakes?


 
Posted : 06/06/2013 8:15 pm
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Interesting, never had that personally but maybe strip the caliper and lube the pistons with DOT 5 if that is what you use. From what I have read that can help a sticky piston.


 
Posted : 06/06/2013 8:16 pm
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That's the weird thing, there's no stickiness on the piston. They move very freely. I'm wondering if it's just rotational forces.

Not formula by the way but they are big brakes with large pistons and a deep brake track.


 
Posted : 06/06/2013 8:19 pm
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What brakes are they?


 
Posted : 06/06/2013 8:21 pm
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Hope V2. It's only slight and they're working perfectly. Also wonder if it's because I'm using the single skin rotor rather than the vented, so the pistons are further out to accommodate that.


 
Posted : 06/06/2013 8:29 pm
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I get it on my saints, thinner at the front


 
Posted : 06/06/2013 9:26 pm
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I noticed this on the front Hope Moto on our tandem.
It's got a normal rotor on the front and a vented on the rear so you may be on to something there.


 
Posted : 06/06/2013 9:29 pm
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If they're thicker at the top & thinner at the bottom is it due to the pads 'hanging up' ever so slightly on the pin? It wouldn't take much resistance(over time) to produce some degree of taper?


 
Posted : 06/06/2013 9:37 pm
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Well in STW fashion, since it's Hope I'd say it's probably a design feature and worth paying extra for. If it was anyone else I'd say send them back ๐Ÿ˜‰


 
Posted : 06/06/2013 9:39 pm
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Sorry, my use of top and bottom was relative to me viewing the bike. The difference is between leading edge and trailing edge. The rear isn't doing it so I wonder if it's a rotor size/braking force thing.


 
Posted : 07/06/2013 11:20 am
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Don't use DOT 5, use DOT 4 or 5.1, DOT 5 is very different from the other 2.


 
Posted : 07/06/2013 11:50 am
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Cheers, I use finish line stanchion lube actually. Inert and stupidly slippery.


 
Posted : 07/06/2013 12:16 pm
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If I've got this right - (Its the leading edge thats thinner) - I think its because that is the edge that gets the crap (microscopic) on the disc first and hence more abrasive, so will wear faster.


 
Posted : 07/06/2013 12:36 pm
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Sound theory. There is greater wear at the edge that gets presented with the most crap. (the back of the caliper where the rotor "enters")


 
Posted : 07/06/2013 12:42 pm