I’m mostly a road cyclist but am really enjoying the time/training on my TT bike. I’m considering getting a disc but I really know very little about them.
I’ve searched around on this site and I’ve read Zipp’s and HED’s homepages. I also liked the Reynolds Element disc but didn’t see hardly any info about it on
this site. I’m looking for something obviously aero, that’s the main goal. I’m a smaller rider. 5 foot 5 and 150lbs. I do worry about getting blown around but
like anything, I’m sure riding with a disc rear just takes practice. I ride dv46 in the wind without too much trouble.
Any constructive information welcome. Thanks in advance.
Cheers,
Kyle
Those disks seem nice and all but for much much less money and nearly identical aerodynamics you could get one of these:
http://www.wheelbuilder.com/store/product.php?productid=16265&cat=0&page=1
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5’5 147-150lb roadie here as well. Riding a disc takes a few days practice, that’s all, to be comfortable. One of the first times I took a disc out was on a VERY windy day. Tapped the front brakes which lifted the rear off the ground about a millimeter or two, enough for a crosswind to swing the rest of the bike like a rudder. I consistently trained on a disc, which eventually led to greater confidence in handling. It was a Corima Carbone 650 carbon clincher disc, which BTW took quite a beating, surprisingly durable.
I got a chance to use a Sub9 in a TT last year. Very stable handling with a Cadillac feel. You don’t realize how fast you’re really going.
What ever happened to Renn?
Oh yeah, Like R10C says, don’t forget Renn:
http://www.rennmultisport.com/~rennmem/store/commerce.cgi?product=575a
They have a hilariously aero picture on their website too:
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disc covers are a big hassle. Wheelbuilder is a great company, and Rich is an awesome guy as he sent me another cover when one of my cracked at the screws. My new covers have a slight crease through the middle of them…they weren’t sent to me like that, but the crease was “developed” while they sat in the packaging in the fall of 08. I currently have them affixed to my wheel by electrical tape and will race on it in 2 weeks. While coasting on my trainer it is REALLY REALLY loud…perhaps rubbing on the cassette, hub, etc.
I’d just rather buy a disc and get the “whomp whomp” (which is what everyone really wants, lol)
I’m really trying to do my homework on this, so I don’t want to just jump on any disc. I’ve even considered getting an 808 rear.
However, I imagine the the full disc offers quite a bit more aero advantage. I’ll check out the sub9. I do worry about it fitting in my tiny size 48 Cervelo SLC SL.
keep the comments coming!
Thanks much
K.
+2 for the Renn. It’s an amazing wheel for half the price of a Zipp or Hed.
Oh yeah, Like R10C says, don’t forget Renn:
http://www.rennmultisport.com/~rennmem/store/commerce.cgi?product=575a
They have a hilariously aero picture on their website too:
That is hillarious! That might be the least aero I have seen someone in some time. At least when he needs to climb, he won’t need to get out of aero when he stands…
i think that guy had testicular cancer recently and that may be why his position is more upright
I think he also wins like that
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I’m really trying to do my homework on this, so I don’t want to just jump on any disc. I’ve even considered getting an 808 rear.
However, I imagine the the full disc offers quite a bit more aero advantage. I’ll check out the sub9. I do worry about it fitting in my tiny size 48 Cervelo SLC SL.
keep the comments coming!
Thanks much
K.
I think there is only a marginal difference in the aero advantages from one disc to another. Therefore I suggest the Renn. I also think that the disc cover is a very smart move if the budget is a concern.
Also, you should know that the amount of advantage a disc offers over a deep section rim like an 808 or a Hed3 is also fairly minimal.
If you want a wheel that is more versatile yet aero enough that you can feel secure it’s not changing your placing much at all in a race then you can consider one of those options.
I think there is only a marginal difference in the aero advantages from one disc to another. Therefore I suggest the Renn. …
There is a huge difference between discs. For e.g., there is a sizable difference between the Zipp 900 and Sub-9 disc. The Sub-9 will go negative drag at certain wind conditions.
I would bet that a Zipp 1080 is quicker than a Renn disc.
I think there is only a marginal difference in the aero advantages from one disc to another. Therefore I suggest the Renn. …
There is a huge difference between discs. For e.g., there is a sizable difference between the Zipp 900 and Sub-9 disc. The Sub-9 will go negative drag at certain wind conditions.
I would bet that a Zipp 1080 is quicker than a Renn disc.
Check this out:
http://www.analyticcycling.com/WheelsConcept_Disc.html#Coefficeints of Wheel Drag
“The total drag of the wheels is in the range of 10% to 15% of the total drag on a bike. Drag improvements between wheels can reduce this by 25%, or 2% to 3% of the total drag.”
“Deep section aero wheels are better than a conventional 36 spoke wheel and are all about the same within the limits of measurement. Disk wheels are better yet.”
“The drag on the rear wheel is reduced by 25% due to the seat tube.”
Wheel
Cxo Conventional 36-spoke
0.0491 Campagnolo Shamal 16-spoke
0.0377 HED CX 24-spoke
0.0379 Specialized tri-spoke
0.0379 FIR tri-spoke
0.0382 HED disk (lenticular)
0.0361 ZIPP 950 disk (flat sided)
0.0364
(doubt that formatting will stay, so see the link)
What this means is that a HED disc at .0361 is better than a Specialized tri-spoke (Hed3) at .0379. But because the rear wheel is shielded by the seat tube you need to reduce the difference by 25% in calculating the effect of the entire bike with the 2 different wheels.
The the difference between those two wheels on your bike is 5% for the wheels alone, then we reduce the difference by 25% and we get 3.75%.
The total drag of the wheels in the entire rider/bike package is about 3.2%. 3.2% of 3.75% = 1/10 of 1%. So over a 1 hour race that comes out to: 3.6 seconds!!!
Not the huge difference you were led to believe.
I think there is only a marginal difference in the aero advantages from one disc to another. Therefore I suggest the Renn. …
There is a huge difference between discs. For e.g., there is a sizable difference between the Zipp 900 and Sub-9 disc. The Sub-9 will go negative drag at certain wind conditions.
I would bet that a Zipp 1080 is quicker than a Renn disc.
But is the price differential really worth any time savings you might get.
Is it 10 minutes quicker for an IM? That might be worth the money. Is it 2-3 minutes quicker in an IM? Not worth it imo.
that’s a significant difference in a one-hour time trial.
to the op, i ran an 808 w/wheelbuilder cover for the first time at a tt last week. it took about 10 minutes to put on, tape, and install the cassette. and i have zero bike tech skills.
I think there is only a marginal difference in the aero advantages from one disc to another. Therefore I suggest the Renn. …
There is a huge difference between discs. For e.g., there is a sizable difference between the Zipp 900 and Sub-9 disc. The Sub-9 will go negative drag at certain wind conditions.
I would bet that a Zipp 1080 is quicker than a Renn disc.
Check this out:
http://www.analyticcycling.com/WheelsConcept_Disc.html#Coefficeints of Wheel Drag
“The total drag of the wheels is in the range of 10% to 15% of the total drag on a bike. Drag improvements between wheels can reduce this by 25%, or 2% to 3% of the total drag.”
“Deep section aero wheels are better than a conventional 36 spoke wheel and are all about the same within the limits of measurement. Disk wheels are better yet.”
“The drag on the rear wheel is reduced by 25% due to the seat tube.”
Wheel
Cxo Conventional 36-spoke
0.0491 Campagnolo Shamal 16-spoke
0.0377 HED CX 24-spoke
0.0379 Specialized tri-spoke
0.0379 FIR tri-spoke
0.0382 HED disk (lenticular)
0.0361 ZIPP 950 disk (flat sided)
0.0364
(doubt that formatting will stay, so see the link)
What this means is that a HED disc at .0361 is better than a Specialized tri-spoke (Hed3) at .0379. But because the rear wheel is shielded by the seat tube you need to reduce the difference by 25% in calculating the effect of the entire bike with the 2 different wheels.
The the difference between those two wheels on your bike is 5% for the wheels alone, then we reduce the difference by 25% and we get 3.75%.
The total drag of the wheels in the entire rider/bike package is about 3.2%. 3.2% of 3.75% = 1/10 of 1%. So over a 1 hour race that comes out to: 3.6 seconds!!!
Not the huge difference you were led to believe.
lotta fuzzy math there. Did you realize that dataset is over 10yrs old?
i cant believe that i only save 3 or 4 secs over 1 hr tt .any times i have used i have come in considerably quicker with disc
now on a windy day … the more wind the faster for disc i am only 147 lbs and have had no problem hanlding a disc on windy days
i honestly believe the more wind the more time you save on the course to me it is when a disc comes into its own
i cant believe that i only save 3 or 4 secs over 1 hr tt .any times i have used i have come in considerably quicker with disc
now on a windy day … the more wind the faster for disc i am only 147 lbs and have had no problem hanlding a disc on windy days
i honestly believe the more wind the more time you save on the course to me it is when a disc comes into its own
Those numbers on coefficient of drag were at zero yaw. discs do relatively better in cross winds, so you are right.
And what is your alternative to a disc? And how much faster do you guesstimate your disc is over that alternative wheel? I was comparing something good (H3) to a disc, not a box rim wheel.
+1. This is absolutely correct. Ceteris paribus, a windy day is a reason for (not against) using a disc wheel. The front wheel is a different matter, although not aerodynamically, but principally from the standpoint of bike stability/handling (at speed deeper-section rims will require you to “lean” into wind gusts etc.).
To the OP (from a Zipp disc user): If you do decide to get a disc wheel instead of a wheel cover or something else, my recommendation is the Corima Carbone C+. The thing is bombproof, light, with awesome bearings, and as aero as any other disc. (I do think that discs are measurably more aero than non-disc wheels, but beyond this, i.e. within the category of disc wheels, I don’t believe there are any significant performance differences–just a lot of marketing departments trying to mess with our heads.)
my alternative is mavic cosmic
i have always been faster with disc on all of the courses i train on ,i dont have a power meter but on my 25k course guestimate would be 25-30secs obviously based on wind on another 75k course i consistanly come in 3 minutes or faster apx 2hrs with disc all i can only go with pulse avg but as i say consistantly (not once or twice always)faster with disc, i would reccomend a disc as i say may not be much faster when calm but in wind;-) by the way it is rarely calm in ireland
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