DangerousDanR

I just started bringing my winter MTB back to life, and I discovered that the Hope E4 rear caliper was sticking. When I went to remove the pads, the pad retaining screw hole dissolved. Jus a crumbly bit of aluminum crap. There are other spots of corroded metal visible on the caliper.

Has anyone else had issues with Hope or other calipers being damaged by road salt?

cyccommute 

Sorry to say but salt will do that to aluminum. The salt make aluminum chloride which exchanges with oxygen to make aluminum oxide and release the chloride to go back and make more aluminum chloride which...well, you can guess. If you live where the humidity is high, the process is faster and more aggressive since the salt pulls water out of the air and speeds up the process.

I know the horse is out of the barn but you really need to stay on top of removing road salt even during the winter. Take it to the car wash on warm days and do a real good clean at the end of winter.

Looking at the brake on the Hope website, it looks like you’ll have to replace the brake. The body appears to be one piece so there no easy solution

Bob the Mech

Aluminium alloys as a general group hate salt...4000 and 5000 series alloys are more resistance to corrosion but not immune from it. Take a set of alloy 700c rims (say 6061 T6 alloy pretty common) ...expose then to a few hours of salted winter roads, put them away for a few days with out giving them a damn good clean and you will have innumerable pits in the alloy. Leave them coated in enough salt for long enough and they will turn into a 'crumbly bit of aluminum crap'. Salt kills alloy components. The Dutch philosopher Desiderius Erasmus puts it like this, 'Prevention is better than a cure...'

Clean it more often...

cyccommute 

I agree. One thing I forgot to say above is that magnesium chloride is even worse on aluminum because it’s more hygroscopic (sucks water out of the air) and it has 2 chlorides per unit.

DangerousDanR

Thanks for the thoughts. I am aware of corrosion as an issue. My thought was that the anodized coating would protect the caliper, and for the most part the caliper is just fine. The only really bad spot is where the pad retaining pin is threaded into the caliper body. The rest is just minor and cosmetic. My guess is that the hole is threaded after anodizing, leaving it exposed to the road salt.

The bike is ridden in Fargo ND, so there are no warm days from November to March. My garage is not heated, so washing the bike off will mean bringing a pail of warm water out from the house. That may be the best option, but the water might just freeze on the calipers and make them an icy mess.

If I rode to a car wash, if I found a self service car wash open in the winter, then it will just get covered with crap on the ride home. The front is 100% fine. Just the rear.

I may try putting a grease coat on the pin on the front caliper and on the rear as well if I decide to replace it with another Hope caliper. Or maybe clean them thoroughly and put a drop of lacquer on the pin to keep the crap out of that hole.

The frame is Ti and it is not pitted at all, the Olins fork doesn't have any pitting or signs of corrosion. The hubs (Hope) are OK, The crank set and bottom bracket (also Hope) are just fine. The WTB alloy rims are good.

I was wondering if anyone had experience with a different design from a different manufacturer might not have a hole in the anodizing. Hope probably didn't expect some fool to ride in that salt, beet juice, who knows what slop. The American Engineer Dangerous Dan says "durability starts with the design phase", but he may need to adjust his thinking.

dsbrantjr

Anodizing is not an impregnable barrier. Besides gaps in the anodizing, there may be issues with dissimilar metals causing electrolytic corrosion. Your lacquer idea may help keep out brine coming from the outside, but will do nothing about it coming from the inside of the caliper and may impede cleaning efforts. If you start greasing things I would suggest using Tef-Gel, it is specifically designed to impede electrolytic corrosion: https://www.tefgel.com/contain.php?param=tefgel_infor They specifically mention bolt into tapped aluminum as a use case. Winter riding is tough on bikes no matter how hard you try.

79pmooney

The technology to make aluminum stuff that is reliable in salt environments has been around most of my lifetime. Screws and parts dissolving says poor design and/or poorly spec'd materials. Yes, making the item salt resistant drives up cost and limits the use of some of the strongest aluminum alloys but the very common 6061 does very well in salt environments as long as electrolysis is addressed.

A bicycle brake that cannot be serviced in a road salt environment probably should carry a warning. That said, when I started running my bike in Boston's winter, I had to do a lot of the learning on my own.

OP, I don't know disc brakes but I do know that marine boat trailer grease (available in any auto parts store) is completely unaffected by road salt. Bed your screws in lots of it. Use it on all threads. Bearings that could see road water. (I stuff so much in my bearings that it oozes out the next few miles.) The stuff is messy, hard to work with, hard to clean up and your friend on winter road. (Also cheap.)

cyccommute 

[That’s probably what happened.

I hear ya. But cold usually slows down the process. When March comes around, do a thorough washing. Leaving it over the summer doesn’t help. Since this isn’t a structural part , it might not hurt to pull the pin and spray hot water into the threads just to clean it out. You might do a 50/50 mixture of isopropyl alcohol if it is too cold. The freezing point of that mixture is -9°F. It would help and wouldn’t freeze as quickly. More alcohol than that might not dissolve the salt.

Again, I fully understand. Perhaps you should look into making a bit of a brake caliper fender. A bit of old fender might be all that is needed. Just zip tie it to caliper to deflect most of the salt water.

Grease would probably help. Add in a fender and an occasional spritz with alcohol/water solution and you could solve the problem

There ain’t much that touches titanium.

There’s some brakes out there that don’t use a retaining bolt of any kind

79pmooney

I used to ride Super Champion and the like 400 gm tubular rims all winter, commuting 24 miles/workday into Boston. Rims always made it to spring without ever being washed except by puddles and rain. Bike lived in the basement. No running water and I didn't wash it all winter. Now, by March, the rims were trash but that was because they were roughly irregular polygons, not remotely round. All spoke nipples would be frozen solid. (At least 3 different metals and that was long before I discovered marine grease. Spokes were zinc plated steel, not stainless.)

I never noticed much change in stiffness or strength in my rims of those days at winter end from corrosion. The damage was from riding into deep potholes riding under inflated tires. Granted, I paid zero attention to appearance. Filthy bike, square wheels, beat up fenders. Simply a bike to ride and get me there, not to look at.