aero road helmets haven't been out for very long correct? would you expected there to be a good bit of development before it gets optimized? I can only think of the giro air attack, s-works evade, and this other one AEROspeed or something that costs like $300.

wait what do you mean your testing? you have a wind tunnel?

Woo I'm down the rabbit hole.

I have existing SRAM 10sp shifters, cassette, RD. Looking at swapping in the CX1 RD. SRAM specifically says the RD will work with an otherwise 10sp setup, so that's all fine.

What gets weird is whether I can then swap in an 11sp cassette, while keeping the 10sp shifters. This web site specifically says that will work:
Does SRAM CX1 work with 10-speed shifters? - BikeRadar

... though they only talk about the cable pull ratio and not any concept of total cable take-up. Does that mean there is nothing designed into a 10sp SRAM shifter that prevents it from making 11 shifts? Or (as is certainly possible) maybe the web site is incorrect.

GC - I've been running a 1x10 setup on my cross bike for awhile now using just a regular Sram Rival RD. I've had no issues. And I read recently that Wolf Components said you can run any Sram RD with its narrow-wide front ring as the spring is strong enough for the most part. Shimano, however, did not work as well.

As for your second question, my understanding is that Sram's 10- and 11-speed RDs are pretty interchangeable and will work with 10- or 11-speed shifters.

With regards to the cassette, you need to have shifters to match the cassette. I am fairly confident that 10-speed shifters and 11-speed caseette, or vice versa, will not work properly. (That said, I also saw somewhere where someone opened a Sram 10-speed shifter and cut an 11th notch to make it 11 speed. Seemed like a lot of work though.)

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I'd be curious I hear if mixing and matching 10- and 11-speed shifters works with SRAM. Seems like it would not...been a while since I opened up a SRAM shifter but the mech stuff generally works on a series of notches in a cog, so even if the pull ratio is the same (seems unlikely that it would be...unless 11s width is exactly 11/10*the distance between 10s cogs....is it?) the max pull would be determined by the number of notches in that cog/gear.

Electronic stuff from shimano was mix and match with speeds determined by the rd...until shimano disabled it for people who updated the fw of their battery.

New shimano clutch rd has a stronger, redesigned clutch, though I never found any issue with the prior gen in years of trail riding. Clutch adds resistance/friction....a setup without clutch but with outer guard and inner ring can be lighter weight and offer more security. If one is set on 1x without a guard+catcher! I wouldn't run a non-clutch rd.

You talking aero road, then? Some of the best aero road helmets come within 50g of drag of the best tt helmets, in certain conditions. Aero road helmets are a newer category, but they have roots extending far back.

ive done field testing and wind tunnel, but no I don't have a wind tunnel. Supposed to test in Morgan hill in a few weeks but think I'm going to get surgery instead. Joy! :)

Well, I upsold myself... going to be using a raceface narrow-wide 42T, sram cx1 RD and force 22 shifters (dummy shifter on the left).

I love when this happens. My intention was to swap components over to a new frame, now I have essentially bought a whole new bike. All I need is a saddle, and I can build the old bike right back up.

Nice. Spare bike is not bad for racing cross? :)

I figure I'll use it for a dead-of-winter road bike.

Or you can just run two cross bikes. A lot of people around here do that when it's really muddy. They swap bikes each lap - someone hoses the second bike down in the meantime to assure a working bicycle.

it appears to me that the new aero helmets look just like my skateboard helmet, and probably comparable in terms of aerodynamics.

Anyone know of a fan for indoor training that is quiet?

Today I learned:

One of the convenient aspects of disc brakes for cross is that the hub spacing is identical to 29er MTB, so wheels are interchangeable. I have a disc cross bike that I swapped a set of nice MTB wheels onto and have been running that way for a couple of years.

I just looked into upgrading to 1x11 on the cross bike and ran into something I didn't know. MTB wheels can't take road 11sp cassettes. There's not enough dish to accomodate the longer freehub body.

I knew that SRAM MTB 11sp was a completely different system from road, but I thought that was because the freehub needed to be smaller diameter to accomodate a 10T cog. Well that is a difference, but in addition, there's the freehub length issue.

TLDR: cross 11sp disc requires road disc wheels. MTB disc wheels are no longer compatible.

GC, so I can put a nice set of 29er disc wheels on my wife's 10-speed cross bike?

That opens a lot of options.

Small, quiet, and high volume. Pick two. I use a 20" 3 speed commercial fan. Not a cheesy box fan.

Yes absolutely (assuming it is a disc cross bike). But not 11-speed.

Quiet usually implies it doesn't move a lot of air. I haven't found a fan that is quiet that moves a lot of air. By definition if it moves a lot of air it'll make noise.

However this makes me wonder, would putting my commercial type fan in a different room with a wide diameter duct to my trainer area quiet it down? I realize now that there's the noise of the fan and the noise of the wind going past my ears.

If I get off the bike and move a bit across the room it's quieter (no wind going past my ears). The fan noise is still there of course.

this isn't always the case so wanted to bring it up for people to verify before making a purchasing decision. more and more, MTBs are moving to wider spacing (142mm) and/or larger axles (up to 12mm). if the MTB uses standard QR/9mm front, QR/10mm/135 rear then it should work.

*most* road and cross bikes i'm seeing use that as standard, but raleigh's update to the RXC pro uses a thru-axle rear.

some hubs like the DT240 offer interchangeable end caps so they are more cross-compatible.

shimano's 11s for MTB fits on a MTB 10s freehub; the cassette is dished (very cool design). the spacing between cogs is the same for shimano 11s MTB, sram 11s MTB as well as all road 11s. if one's deraileur can handle 10-42 or 11-40, the shifting would work just fine. also, sram and shimano 11s RDs will handle smaller road cassettes.

you're totally right about 10s.

it can...often but not always, esp with newer MTB disc wheels. see above.

nothing like new cables/housing to remind you of how light and smooth shifting is supposed to be. mine has been **** for so long.

Rule of thumb, noise is related to higher air velocity. Volumetric flow is velocity times area, and higher volumetric flow will mean more cooling, so...

You're back to what shovel said, if you want a quiet, high volume fan, it's going to be big.

Yes, we went down that road at the LBS as well. As I understand it, the Shimano 11sp MTB cassette is only available in 11-40, which is a design limitation -- the big cogs have to be that large in order to cantilever over the spokes.

Summarizing (correct me if I've got any of this wrong):


Any 10sp road/MTB shifters will work with any 10sp road/MTB cassette.

Any 10sp road/MTB cassette will work with any 10sp road/MTB wheel.

Any 11sp road/MTB shifters will work with any 10sp or 11sp road/MTB cassette, but only shift 10 cogs (useful because it means you can incrementally upgrade).

Any 11sp road/MTB RD will work with any 10sp or or 11sp road/MTB cassette, if the RD has the clearance and chain capacity (the usual limitations for RD/cassette compatibility).

Shimano/SRAM 11sp road cassettes will work only with 11sp compatible road wheels, which is pretty much any wheel manufactured in the past few years. 10sp road wheels may be upgradable. 10sp MTB wheels cannot be upgraded, which is the part I learned yesterday.

SRAM 11sp MTB cassettes will work only with 11sp compatible MTB wheels. 10sp road/MTB wheels cannot be upgraded. The SRAM system is designed around a 10T small cog which is too small in diameter to fit on any other existing freehub.

Shimano 11sp MTB cassettes will work with any 10sp compatible MTB/road wheels, but cassette selection is limited.

MTB disc wheel hub spacing is generally identical to cross disc hub spacing, with exceptions.

Also of note, is that what started out for me as a frame swap, followed by "might as well get a new cassette and chain", led one step at a time to purchasing an essentially entirely new bike. I'm very happy to have a new bike, but with all of these different systems on the market, it's important to carefully think through all of the compatibility issues when upgrading any individual part.

New cassette and chain => might as well upgrade to 11sp cassette => new RD => new shifters => 11sp cassette won't fit on 10sp MTB wheels => new wheels.

As I told my LBS, when I ordered the new frame, I didn't think to myself, "well, at least I've already got a saddle I can put on it."

Big is fine. I have a big floor fan, but the motor is too loud. Specifics on the big quiet one?

CDR - Cool idea, but I'm not installing ducts. Nothing complicated.

I think you should suck it up buttercup....


Sweaty is the new sexy...

I say I want a big one, and that's all you got?