Bob Dopolina 

Well, for all those opposed to disc brake road bikes on aero grounds here is some wind tunnel data.

Bob Dopolina 

Here are the problems I see with this test:

1. They only went to 10 degrees yaw.

2. They only tested the side with the disc.

For #1 I think it would have been more useful to go to 20 degrees yaw and give a fuller picture. Maybe that will come later.

For #2 what happens if the wind is coming from the side of the bike without the disc? Is there any difference? I think we then need to SPLIT those numbers as wind can come from both sides of the bike, non?

The take away, for me, is that disc brakes matter far, far less than even my most optimistic expectations and it will only improve. I would also like to see the actual numbers.

hairnet

If he had the caliper's QR closed the difference would then be a whopping 10 seconds.

Bob Dopolina 

Yeah, I saw that. Weird, non?

bt

It looks like the test with rim brakes the riders legs were unshaven....

chaadster

I wonder what aero-optimized rim brakes look like in comparison, those integrated/shrouded type as on the Cervelo P5, or rear fork mounted type like on Argon18 Nitrogen. I'd think those are where the aero magic happens.

Bob Dopolina 

Those would be far preferable on a proper TT bike where discs would just be dumbarsed. It's always about the right tool for the job.

Bob Dopolina 

Where are all those who blather about how horrible discs are now?

The weight penalty is evaporating and now the first real data on aero is in and this objection is withering, too.

PUNY MORTALS! Where are you now!?!

BigJeff

Don't worry, soon someone will start doing aero tests without "people" on the bikes to magnify the differences.

The person pedaling is far too real world.

Fred Smedley

My question is , is their a notable difference in ride/compliance comparing a optimally designed fork for each braking system. I would assume the disk fork has to be stiffer and possibly heavier?

Lazyass

You're too worked up about discs. If you like them, get them. Those of us who you consider to be closed minded won't. Pretty simple.

Bob Dopolina 

That's actually a really, really good question.

Certainly you have to strengthen the fork to address braking forces which, I think, would involve strengthening the back of the fork as well as the bridge, whereas the flex you want for compliance would be on the front of the fork (again, I think).

I do think this would be possible but it's early days and I think it would require a bit of experimentation to find the right balance. That may take a generation or two.

Thanks for this question. I'm going to file this away for any future development I hope to be involved in.

Bob Dopolina 

Oh come on. It's 2 for 1 margarita night at buddies pub and I have time to kill.

Worked up might be too strong a word but I am excited about this development. Other than the broader introduction of carbon as a material there hasn't been a significant product area open to real innovation in quite some time. Instead we've seen what amounts to incremental improvements for a decade or more.

Road discs have the potential to be an area of innovation so I am excited by the prospect.

If it ain't your cup o tea that's fine but I'm tired of people peeing in my cornflakes.

Lazyass

I hope discs on road bikes evolve nicely, but there is nothing wrong with pointing out the disadvantages as well as the advantages. And there are disadvantages. I know all about disc brakes, I've had them on mountain bikes. For me and many others, they're a solution to a problem we do not have on the road.

TassR700

This months Velo has a comparison of disc vs rim on two Tarmacs also. I believe they found about 8 watts difference at 20 degree yaw on the disc side with smaller differences everywhere else. Tried to find the article on the VeloNews website to link to it, but it may not be posted yet.

Bob Dopolina 

That could be true for a lot of people. I hope it remains as a choice and not as a default spec as I think there are many situations where they aren't needed.

For me it does boil down to choice. I like choices (options). Depending on where you live and how you ride I think it would be great if this option was both available and evolved to maximized the benefits and eliminate the negatives for those for whom this choice made sense.

In all honestly (the margarita 2 for 1 is over so I'm on to draft...) for smaller players like us it's these niche areas where we can innovate and contend. If we can be first we have a shot. If we simply follow the big players we end up making equal or lesser "me too" products. Where's the fun in that?

I've embraced this OPTION because I see potential and because we have both ideas and manufacturing partners who are willing to work with us in this area.

Remember Gary Klein? How do you think he made his mark on the industry?

Bob Dopolina 

Please post it when you do. It really could move this conversation along.

RJM

This maybe the reason I thought the Trek Domane 4 series with disks was dead feeling compared to the 4 series with caliper brakes when I test rode them.

RPK79

I'm glad to see you making good choices.

Bob Dopolina 

Yeah, and then they will TARE this and TARE that until it has no basis in reality at all...

Bob Dopolina 

It's all about choices, baby.

Bob Dopolina 

So the hottest topic in road cycling is about to fall off the first page? Sad.

What if we talked about asploding carbon disc brake wheel riders that waved or not?

chaadster

I'll go full in with discs when I can get carbon ceramic rotors. Just because they'd look dope.

Psimet2001 

You can. There's a guy near me who is doing some. Been meaning to work with him on some setups...next season.

Bob Dopolina 

Oh man, how I would love to get edjumacted enough to go there. That might be about 100 levels of overkill but it would be uber kewl.