WARNING carbon rim profiles

[jonny jeez]

I was a naughty boy and allowed my brake pads to wear right down last week.

Their was still rubber to go and no direct contact with the metal brake shoe and my carbon rim.

But

My brake pad shoes have a sort of shark fin shape on the bottom edge, no idea what for.

It seems that, whilst I perceive my rims to be a v shape, they have a slight bulge to them, with which this shark fin has contacted, causing a distinct gouge all around my rim.

The shark fin has clear wear on it to identify the contact point.

Upon browsing I see a number of carbon rims with very distinct bulging designs, so a word of warning, if you invest the cash in these and the correct type of brake pads, make sure you don't fit shimano shoes with these little shark fins.

Luckily I caught it before critical damage was done.

 

[HLaB]

I let mine wear down a bit much too a couple of year's; never done anything to the carbon fairing but I've got a nice line where I scraped the decal

 

[midlife]

The shark fins are wheel guides and help guide the wheel in without fouling the brake blocks...

Some were just simple wire jobbies

Gratuitous shot of my fave brakes.....

Shaun

 

[raleighnut]

The shark fins are wheel guides and help guide the wheel in without fouling the brake blocks...

Some were just simple wire jobbies

View attachment 340501

Gratuitous shot of my fave brakes.....

Shaun

I always thought the 'shark fins' were to guide water scoured from the brake pads away from the rim.

 

[amasidlover]

Out of curiosity how did you determine there was no 'critical damage' - I've got a wheel with a carbon fibre brake surface where the lacquer/top surface has worn through and the weave texture is no very near the surface and have elected to not use it 'just in case'; am I being over-cautious?

 

[midlife]

I always thought the 'shark fins' were to guide water scoured from the brake pads away from the rim.

Here is a velobase page which half way down describes the brake shoe wheel guides dipped in plastic.

http://velobase.com/ViewComponent.aspx?ID=2E83607D-E755-4D41-8FC9-8532C7C25B90&Enum=117&AbsPos=17

Shaun

 

[fossyant]

And you didn't hear it making a mess of your rims....? The fins aid wheel replacement in a hurry.

Most road shoes are like this - you let the pads wear far too much ! It will do the same on most alloy aero rims too.

This is for you your poor bike

 

[jonny jeez]

Out of curiosity how did you determine there was no 'critical damage' - I've got a wheel with a carbon fibre brake surface where the lacquer/top surface has worn through and the weave texture is no very near the surface and have elected to not use it 'just in case'; am I being over-cautious?

Good question, its a gouge, more through the decal than the surface properties of the wheel, so not deep what I really meant by critical, was that the wheel didn't fail as I was riding. Its a full carbon wheel not a fairing. In truth I have no idea if its critical.or not but it shows no signs of weakness...no flexing under load, no saggyness, seems as sharp (and rigid) as ever.

I am taking it to VO2 ( just sat in the rather lovely teal cafe up the road) for jimmy to check it over) this morning.

If he tells me.its dead ill buy another (hope he's not reading this!)

Personally of the weave was showing on my brake surface,id call it a day too

 

[jonny jeez]

And you didn't hear it making a mess of your rims....? The fins aid wheel replacement in a hurry.

Most road shoes are like this - you let the pads wear far too much ! It will do the same on most alloy aero rims too.

This is for you your poor bike

I am ashamed!

I didn't hear a thing. The wheels are noisey under braking any how, with traffic and stupidity added in...i just didn't notice.

 

[Foghat]

Some were just simple wire jobbies

Gratuitous shot of my fave brakes.....

Indeed, and moreover......:

 

[jonny jeez]

And you didn't hear it making a mess of your rims....? The fins aid wheel replacement in a hurry.

Most road shoes are like this - you let the pads wear far too much ! It will do the same on most alloy aero rims too.

This is for you your poor bike

I let mine wear down a bit much too a couple of year's; never done anything to the carbon fairing but I've got a nice line where I scraped the decal

Out of curiosity how did you determine there was no 'critical damage' - I've got a wheel with a carbon fibre brake surface where the lacquer/top surface has worn through and the weave texture is no very near the surface and have elected to not use it 'just in case'; am I being over-cautious?

Small, semi update.

This week in the way to work, I lost a spoke on the offended wheel.
Coincidence?
The wheels are two years old this summer and I have not dobe a thing to them in all that time, nonfetrlibg, no spoke tightening.

I've ridden thousands of miles over wet, rough London roads and even finished the 150k Flanders ride with all the cobbles....no even a whiff of complaint from the wheels.

Off to see Jimmy for his verdict...this could get costly!

 

[crazyjoe101]

This reminds me of when I failed to notice the horrific grinding noise of a huge stone in my pad until 40 miles into a soaked winter ride and had a trench in the braking surface by the time I noticed the noise - it's shamefully easy to do.

 

[jonny jeez]

This reminds me of when I failed to notice the horrific grinding noise of a huge stone in my pad until 40 miles into a soaked winter ride and had a trench in the braking surface by the time I noticed the noise - it's shamefully easy to do.

Thanks, I don't feel so ashamed now.

After some scrutiny, Jimmy at VO2 thinks its nothing worse than lacquer removal and decal scuff but is going to leave the final verdict to his tekky on Monday.

I'm confident the spoke loss is just a coincidence.

My shame mostly comes from the relationship that I have with the wheels. They have never complained, never creaked, flexed or needed any attention, for miles and miles....and then I go and hurt them as a reward.

 

[amasidlover]

Your post prompted me to do some research and have a closer inspection of mine and I think I'll carry on using them for a while yet so thank you!

 

[jonny jeez]

The shark fins are wheel guides and help guide the wheel in without fouling the brake blocks...

Some were just simple wire jobbies

View attachment 340501

Gratuitous shot of my fave brakes.....

Shaun

What does that mean. I don't really understand how a wheel.needs guiding or how a brake can foul.

Are they "supposed" to make contact with the rim then.