rim brake vs disk in wet/misty conditions

Discuss light weight issues concerning road bikes & parts.
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Boshk
Posts: 187
Joined: Wed Jul 19, 2017 2:59 am

by Boshk

Not a flame, just 1st experience.

I've always been a fair weather rider, if its raining outside, I don't ride or I ride on Zwift but today I went out with a bunch of RCC guys up to the highest point in Hong Kong which is only around 3500' high. Hard for me....easy for some of you I know.

Near the top, it was cold, windy and misty with light rain. naturally my standard Zonda rim wheels were wet.
I always thought I setup my campy Chorus rim brakes pretty well....for a novice. This morning was an eye opener......I've never used that much braking ever, I had doubts on the descent, admittedly I was using them more than the other guys since it was a new route for me, didn't want to fly off the edge.
I was on the campy hood ,holding both front and rear (rear less) brakes pretty hard and my speed was just ok.
Braking when the rims and pads are dry vs wet is like night and day....to me anyway.

I know there's a lot of debate still, especially from more advanced riders about rim vs disc, but I actually wished I had disc today. One guy blew out his tube....not sure whether it was from the heat or from a spike on the ground.

-I have no idea how you guys with full carbon wheels on rim brakes race or ride in pouring rain.....how do you even control your speed on steep descents?
-I found the braking portion of my rims are not clean, there's a small amount of black grease-like residue on it....I air dry my drivetrain after cleaning, lube my chain with RnR Dry then wipe off any excess with dry cloth....so I'm wondering how both front and rear rims have some...not a lot of this residue. I'm sure it affects the braking in wet conditions.
Any suggestions to cleaning it?
Last edited by Boshk on Sat Feb 17, 2018 7:56 am, edited 2 times in total.
Oltre XR3, Diverge DSW

by Weenie


AJS914
Posts: 1753
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

Just scrub it off with soap and water. Scrub your brake pads too.

There are scenarios where discs can be better. It sounds like you found one.

alcatraz
Posts: 568
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

If you are a heavier rider you generally can't expect to keep the same speeds descending as lighter riders in the bunch without taking greater risk.

They might furthermore have better calipers/brake pads/rims.

Whats the grade on those slopes? Even 7-10% can get scary to descend when cold and in some moisture.

I had a phase when I started dreaming about disc brakes but it passed. It did make me look over the brake system a bit. Check which pads are good in allround conditions. For alloy rims I get amazing bite with swisstop black for example.

Descend in the drops and hang your ass off the back to get better weight balance and less hand pain. Be crazy light on the rear brake in corners. It's easy to forget that it can lose traction easily while descending if you havent tasted the tarmac in tight corners before. You can brake on the wheel you have weight on.

/a

Boshk
Posts: 187
Joined: Wed Jul 19, 2017 2:59 am

by Boshk

AJS914 wrote:
Sat Feb 17, 2018 6:58 am
Just scrub it off with soap and water. Scrub your brake pads too.

There are scenarios where discs can be better. It sounds like you found one.
Will do, I'll take the wheels off and give the rim part a good wash and scrub the pads. Thanks
alcatraz wrote:
Sat Feb 17, 2018 8:27 am
If you are a heavier rider you generally can't expect to keep the same speeds descending as lighter riders in the bunch without taking greater risk.

They might furthermore have better calipers/brake pads/rims.

Whats the grade on those slopes? Even 7-10% can get scary to descend when cold and in some moisture.

I had a phase when I started dreaming about disc brakes but it passed. It did make me look over the brake system a bit. Check which pads are good in allround conditions. For alloy rims I get amazing bite with swisstop black for example.

Descend in the drops and hang your ass off the back to get better weight balance and less hand pain. Be crazy light on the rear brake in corners. It's easy to forget that it can lose traction easily while descending if you havent tasted the tarmac in tight corners before. You can brake on the wheel you have weight on.

/a
I'm not that heavy, 68kg. I was doing what you suggest, my butt was off/just on the rear portion of my saddle, lucky I didn't loose traction on the rear, I was quite hard on it thinking my butt is over/close to rear wheel.

It probably did help my rims weren't super clean....good experience.

Gradient from mousing over my Strava graph, ranges from 6-19% but they weren't crazy long consistent steep descents, still had me on edge.
more practise and more riding!
Oltre XR3, Diverge DSW

alcatraz
Posts: 568
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

I ride in asia as well. Some other riders here get crazy skinny. A friend is 183cm and 55kg. :lol:

68kg is not a lot. I wouldn't go disc brake in your case and I like to climb. However that's not to say you can't benefit from them. If you are more concerned with feel/safety/consistency and less with weight/speed you might be more inclined than me to make the shift to disc brakes. It almost never rains where I live, unlike HK.

There is also the option of n+1. A dry and a wet weather climber. :lol:

/a

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corky
Posts: 1145
Joined: Thu Jul 06, 2006 5:53 pm
Location: Expat in Washington DC

by corky

Experience counts for a lot......knowing how your bike reacts to changes in conditions enables you to know how to handle it.

Also IME if you run discs in damp conditions you need to develop a deaf ear to the banshee wail.....

fromtrektocolnago
Posts: 980
Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

not going to suggets that disc wheels do not hold advantages in wet weather, but disc are no panacea either. tire tread, size and grip matter a great deal too. if the roads don't have grip, braking on them will not be optimal.
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Trek 5200(ultegra)

liam7020
Posts: 754
Joined: Tue Jul 27, 2010 10:04 am

by liam7020

Perhaps you need to ride more in the rain - it's an essential skill every biker should master. For wet braking on alloy rims I've found Kool Stop Salmon pads to be the best.
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"Sometimes you don't need a plan. You just need big balls." Tom Boonen

Boshk
Posts: 187
Joined: Wed Jul 19, 2017 2:59 am

by Boshk

liam7020 wrote:
Sat Feb 17, 2018 10:42 am
Perhaps you need to ride more in the rain - it's an essential skill every biker should master. For wet braking on alloy rims I've found Kool Stop Salmon pads to be the best.
completely agree, something I need to do.
Oltre XR3, Diverge DSW

by Weenie


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