Shimano road disc brake caliper pad retainer bolt - hex-head replacements for cack slotted cheese head original..

[13 rider]

3.5 grams at least you got an excuse for being slower .
They do look at lot more substantial than the orginals

 

[SpokeyDokey]

I now need to see if mine come undone ok BR-RS505 - silver slotted heads.

Might get Robbie Williams to help me if they are stuck...

 

[13 rider]

I now need to see if mine come undone ok BR-RS505 - silver slotted heads.

Might get Robbie Williams to help me if they are stuck...

Get a screwdriver with a really snug fit it the slot

 

[wafter]

Get a screwdriver with a really snug fit it the slot

They appear to be (at least near) parallel slots; so you'll want a hollow ground screwdriver rather than one with a tapered blade that will concentrate all the load on the edges of the screw and try to cam-out when turned).

1/4" hex interchangeable bit screwdrivers are nearly always hollow-ground..

 

[cheys03]

There was a double-take when I weighed each offering as the originals are only around 30% the mass of the replacements; meaning they must be made of something lighter. They're non-magnetic and the obvious material is aluminum; which would explain their reputation for being Dairylea-soft..

I believe the originals are stainless steel - which explains why they are not attracted by a magnet, why I was able to carefully MIG-weld to one without it evaporating and possibly why they get stuck..... could galvanic corrosion be the culprit?
The replacement looks longer and with a larger head, maybe explains the weight difference despite stainless being a heavier material.

 

[wafter]

I believe the originals are stainless steel - which explains why they are not attracted by a magnet, why I was able to carefully MIG-weld to one without it evaporating and possibly why they get stuck..... could galvanic corrosion be the culprit?
The replacement looks longer and with a larger head, maybe explains the weight difference despite stainless being a heavier material.

That's bizarre; perhaps they've changed the material over time. If you managed to MIG weld to it, it's certainly not ally; but likely not stainless either.

I happen to have one of the originals modelled after considering getting some replacements made a while ago.. Rendered in stainless the mass is calculated to be 2.05g while in ally it's 0.70g - exactly what I found my example to be. I assumed it was steel of some sort too before weighing it; but obviously not!

 

[cheys03]

I happen to have one of the originals modelled after considering getting some replacements made a while ago.. Rendered in stainless the mass is calculated to be 2.05g, while in ally it's 0.70g - exactly what I found my example to be. I assumed it was steel of some sort too before weighing it; but obviously not!

Impressive! I'm beginning to doubt my memory, or the earlier RS785 callipers I have did use a different pin. The front still has the original I think, so could test it. Seems incredible they'd use aluminium even in this relatively low-load (just retaining) use case - it's so tiny and soft

 

[wafter]

Impressive! I'm beginning to doubt my memory, or the earlier RS785 callipers I have did use a different pin. The front still has the original I think, so could test it. Seems incredible they'd use aluminium even in this relatively low-load (just retaining) use case - it's so tiny and soft

Ta

The pins look the same, but that's not to say that they're not a different material. If you still have one original left it would be interesting to weight in.

I agree about the choice of material. On the one hand as you say it's not supposed to take a lot of load; on the other it's going to get messy if there's a problem getting it out. While it should be less prone to galvanic corrosion being (presumably) the same material as the caliper, ally does like to corrode and I suspect the caliper can see a lot of water if the bike's used in the wet.

I'm also a little intrigued by the pin's finish - I'd assumed it was zinc plated, but I'm not sure you can plate ally in this way..

 

[cheys03]

Sadly my digital kitchen scales are appalling at reporting on added weight that’s less than about 8g - I couldn’t get a good read unfortunately.

This is the front pin. Looks plated to me - I’m guessing but maybe nickel? The plating has worn through where the pads rest on the shank and the pitting does look more aluminium than steel based on being blue/grey in colour and no brown - but am far from an expert.

I am doubting my memory on the welding. I did definitely need to break out the welder to remove something stuck at the back of the bike, it could have been this or one of the bolts for the aluminium gear hanger which needed replacing after a fall. Sincere apologies for misleading if so

 

[Regular.Cyclist]

I have the RS505 callipers on my 2014 Fuji which has primarily been used for commuting in most weather, I avoid the icy days. The heads on the pad retaining screws still look like new. I have always only nipped them up, as they have the retaining clip on the other side, and not yet had any problems.

 

[wafter]

Sadly my digital kitchen scales are appalling at reporting on added weight that’s less than about 8g - I couldn’t get a good read unfortunately.

This is the front pin. Looks plated to me - I’m guessing but maybe nickel? The plating has worn through where the pads rest on the shank and the pitting does look more aluminium than steel based on being blue/grey in colour and no brown - but am far from an expert.

View attachment 702460

I am doubting my memory on the welding. I did definitely need to break out the welder to remove something stuck at the back of the bike, it could have been this or one of the bolts for the aluminium gear hanger which needed replacing after a fall. Sincere apologies for misleading if so

Thanks and yup; that definitely looks like ally from the colour and form of the pitting. Does looks plated (and Nickel would be as good-a-guess as any) - certainly doesn't look anodised. Regardless of the finish, it's certainly a sh*te choice of material for something that's likely to see abrasion and moisture..

I have the RS505 callipers on my 2014 Fuji which has primarily been used for commuting in most weather, I avoid the icy days. The heads on the pad retaining screws still look like new. I have always only nipped them up, as they have the retaining clip on the other side, and not yet had any problems.

Good for you - have you had them out to check the state of their shanks? I suspect this is the area that will get the hardest time; as attested to in @cheys03's image above..

 

[Regular.Cyclist]

Thanks and yup; that definitely looks like ally from the colour and form of the pitting. Definitely looks plated (and Nickel would be as good-a-guess as any) - certainly doesn't look anodised. Regardless of the finish, it's certainly a sh*te choice of material for something that's likely to see abrasion and moisture..


Good for you - have you had them out to check the state of their shanks? I suspect this is the area that will get the hardest time; as attested to in @cheys03's image above..

Yes. They were out about a month ago when I last changed pads.

 

[SpokeyDokey]

I have the RS505 callipers on my 2014 Fuji which has primarily been used for commuting in most weather, I avoid the icy days. The heads on the pad retaining screws still look like new. I have always only nipped them up, as they have the retaining clip on the other side, and not yet had any problems.

Same brakes here.

Checked mine (silver, slotted) today, never touched them since the bike was new.

They came undone with just a gentle finger twist of the screwdriver.

Both clips in-situ so just gently tightened them back up as they were.

 

[cheys03]

I’m amazed that some of these retaining pins unscrew no issue and last well, but some are a real nightmare.

 

[wafter]

I’m amazed that some of these retaining pins unscrew no issue and last well, but some are a real nightmare.

I think it probably depends on the bike's use - I've had zero issues with mine, however it's barely ever been out in the rain and gets stored indoors.

Conversely if it regularly gets saturated in gritty water I'd wager you're going to see abrasion and subsequent corrosion pretty quickly.