With all these threads on rear wheel Disc covers and solid rear wheels, I could not find the answer on the handling aspect of a solid rear wheel. I have always wanted to go with a solid rear wheel cover on my bike but am concerned with crosswinds affecting handling. I currently run Mavic Cosmic Carbones and these have a 50MM dish. Anyone here who has a dished front wheel has certainly felt the “snap” of a cross wind shake the front end up while in an Aero position. It would seem to me that if 50MM of carbon dish catches the wind, wouldn’t a whole solid rear wheel catch a cross wind even more? I am looking to make some improvements this year on my bike times all across the board from my 40K olympic time to my first Ironman split in Arizona(April race). I train and race in Dallas Texas, I have ridden on very windy training rides and races, Texas is one of the more windy states because its flat in DFW and nothing slows the wind down. I always assumed that the rear disc would handle rather poorly but after reading some of the other posts I am now a little perplexed .
With all these threads on rear wheel Disc covers and solid rear wheels, I could not find the answer on the handling aspect of a solid rear wheel. I have always wanted to go with a solid rear wheel cover on my bike but am concerned with crosswinds affecting handling. I currently run Mavic Cosmic Carbones and these have a 50MM dish. Anyone here who has a dished front wheel has certainly felt the “snap” of a cross wind shake the front end up while in an Aero position. It would seem to me that if 50MM of carbon dish catches the wind, wouldn’t a whole solid rear wheel catch a cross wind even more? I am looking to make some improvements this year on my bike times all across the board from my 40K olympic time to my first Ironman split in Arizona(April race). I train and race in Dallas Texas, I have ridden on very windy training rides and races, Texas is one of the more windy states because its flat in DFW and nothing slows the wind down. I always assumed that the rear disc would handle rather poorly but after reading some of the other posts I am now a little perplexed .
Here’s my speculation on the subject:
http://forum.slowtwitch.com/gforum.cgi?post=1642698;search_string=disc;#1642698
In short, IME running a disc with a deep front wheel is MORE stable in crosswinds than with a deep front, shallow rear…or even equivalently deep wheels like you discuss above.
That’s, of course, up until the point that the wind is so strong that it actually blows you off the road 
This has been addressed quite a bit. The answers will range from a disk having no wind issues at all to a disk being so dangerous that you shouldn’t ride it. As with most things, the truth is somewhere in between. A disk obviously has more side area so it is more affected by cross winds. Rear wheels are less sensitive than front wheels because they are not steerable. This is why front disks are not generally used off the track. I have found a rear disk to be manageable. I ride mine in fairly windy conditions and haven’t had a problem. At some point if have to struggle to control your bike, the control issues would negate the aerodynamic benefits.
Here’s my take:
You *will *feel some turbulence through your bike from gusty crosswinds when using a rear disk. You will feel that.
Now, the question is, will it slow you down? Could it cause you to crash?
The real answers aren’t absolute.
A few months ago I started a thread on this forum about busting triathlon myths. One of the myths I wanted to debunk was the “myth” (my words) that a person has been blown over on their bike by cross winds when using a disk wheel. I asked for specific names, dates, events and places and wanted to hear from a real person who had* actually been blown over themselves* when using a disk wheel in gusty winds*.* I don;t recall the specifics of the thread- you may want to use the search option on this forum to find it. Search on “mythbuster” as a key word. I do recall one person in the thread did actually crash as a result of cross winds while using a disk. Based on that it would appear that it is *possible *to crash while using a disk in high crosswinds but highly unlikely and quite rare.
The other concern surrounding disk use is the question of whether turbulence slows you down. That question is largely coningent on the rider themselves. Simply put, if the movement of the bike underneath you freaks you out then you are likely to back off the pedals without even realizing it. That* involuntary* reaction is what is slowing you down- not the wheel itself. If you can develop the confidence to maintain good pedalling form and power output even in gusty conditons then you will go faster with a disk in almost all weather conditions.
Here is a photo of my wife at the Superfrog Triathlon in San Diego:
The weather that day was extremely gusty with a strong storm blowing up the Pacific coast from Mexico. She had no problems with bike handling that day even though she weighs 120 lbs with full kit and is on a lightweight bike equipped with a 60mm deep front wheel and a full disk rear. She had a good bike split day and got on the podium for the race.
The disk only slows you down *if you let it. *If you are a strong, confident bike handler you will still feel the turbulence, but it won;t slow you down. Remember, that turbulence could be the sensation of the wind momentarily accelerating the bike. What we’ve learned from Steve Hed’s research on disk wheels suggests there are very few yaw angles and bike/wind speed combinations where a disk is slower. There are conditions where a nervous rider may be slower, but that isn’t the fualt of the wheel.
I didn’t read it but I liked Tom’s reply.
Great points from all around the table, I consider myself to be a strong rider and certainly even with cross winds will always run a deep front and now will look into the solid rear. I think a strong point really is the confidence of the rider and their own abilities good stuff indeed.
Thanks again everyone.
Joey G.
I followed the advice of our local pro David Thompson on wheel selection. His opinion was its almost always to your advantage to use the disk, windy or hilly conditions included. Only when the wind is violently gusting(think Kona) or the course has walls instead of hills(think St. Croix) have I skipped the disk. I find the disk acts like a sail and actually picks my speed up in all but total crosswinds. My problem has been more with front wheel wobble. Sometimes I need to grab the base bar on the opposite side from the crosswind especially when descending fast. I only weigh 150 with all my cycling gear included and run a Zip 808 on the front. Try out your setup before the racing season to make sure you develop the skills and confidance. End result?
Faster Bike Split !!