After a 5 year Ironman layoff I’ll be racing IM Boulder this August. My race wheels are a set of Hed trispokes from 2007 or so and based on posts/research I gather using 23mm tires is not optimal.
So my question is how “not optimal” are they? Are we talking a 1% aero hit vs. 21mm tires or 10%? Basically, am I sacrificing a minute or two, or several, over 112miles?
For the record I’ve tried 21mm tires but found them incredibly difficult to mount and I didn’t like the ride quality. I guess I can live with the ride quality issue but I fear having to change a flat in the middle of the IM and spending 15 minutes re-mounting the tire (or pinching the tube, or whatever) would negate any aero advantage.
I have a set of Hed3 (alum rim clinchers) so will be interested in how people respond.
For the record I have 23mm Continental Grand Prix 4000S tires with latex tubes, front and back. Practiced and raced on them without incident or flats.
There is no doubt in my mind the latex tubes have an positive affect on comfort and rolling resistance.
23mm on the rear would be sensible as there is no loss of aero, or rolling resistance and they are slightly (I hope) better than a 21mm for rolling resistance. I have read even 26mm (Slowman?) is fine on the rear.
I have difficulty believing a front with a 21mm tire would have any serious affect unless you are (maybe) above 35kph. And the ride quality may be such that you come out of aero more often which would negate any advantage from the 21mm tire.
I am not sure that Heds on the rear are any quicker than a good wheel with a cover, haven’t compared times or speeds on a set course. So that’s strictly seat of the pants, which funny enough is what I also ride on.
There are various ~20 to 21mm tires in the world out there, and not all of them have the same ride quality or difficulty to mount.
Which ~20 to 21mm tires have you tried exactly?
It is definitely better to use a 23mm tire with great rolling resistance than a ~21mm tire with bad rolling resistance.
But you can get both, depending on your durability needs the Conti SuperSonic 20mm clincher would be amazing. But it isn’t super durable. The Conti Attack 22mm might make a very nice tire too, and is more robust.
After a 5 year Ironman layoff I’ll be racing IM Boulder this August. My race wheels are a set of Hed trispokes from 2007 or so and based on posts/research I gather using 23mm tires is not optimal.
So my question is how “not optimal” are they? Are we talking a 1% aero hit vs. 21mm tires or 10%? Basically, am I sacrificing a minute or two, or several, over 112miles?
For the record I’ve tried 21mm tires but found them incredibly difficult to mount and I didn’t like the ride quality. I guess I can live with the ride quality issue but I fear having to change a flat in the middle of the IM and spending 15 minutes re-mounting the tire (or pinching the tube, or whatever) would negate any aero advantage.
I have the 20mm Supersonic. It’s super-supple and handles well, but there’s no flat belt under the tread, so puncture resistance isn’t the greatest (never flatted one though).
The best example of how much a 23 sucks on a H3 is from the Trek white paper for their new wheels. From HED’s WT tests, the H3 is probably about 20g lower drag in the 0-5 degree yaw range than he Jets and Stingers when used with a narrow tire. Trek ran all their tests with a 23 and the H3 was about 10-20 grams worse. So maybe there is a 30-40g loss running the wrong tire.
Their is really only one tire that works well with the H3 in terms of aero and RR and that is the conti super-something (I always get the name wrong) in the 700x20 size. Check Tom A’s RR chart for the real name.
If I didn’t have a quiver of AW19’s to work through, I’d be on the Conti SS 20. Up front, at least. Run a disc cover on a wider rim in the back, so a more durable 23 makes sense back there.
Not sure if the lower RR of the conti ss 20 makes it a faster tire (presuming the AW19 actually is a more aero tire for the Hed3).
I use an older H3 alum clincher up front and once upon a time Andy at Hed wrote me this when I asked about tires:
If the roads are good I would probably run a 20mm tire, as it is more aero. On questionable roads 23 would be the better choice. If you corner fast, 23 may get you through the corners faster, because it has more grip.
23 is more comfortable, no question.
Either way, I recommend the Bontrager TT tires, they are the most aero tire we have ever tested on an H3. Judging from wind tunnel results, they’re good for 5-15 seconds per wheel depending on wind angle.
I agree. I used a 20 Coni SS on my HED3 last year. When the roads are bad I throw on my C2 Jet 6 up front with a 23 Conti 4000s. The data supports a pretty big hit when going 23 up front on the H3.
The best example of how much a 23 sucks on a H3 is from the Trek white paper for their new wheels. From HED’s WT tests, the H3 is probably about 20g lower drag in the 0-5 degree yaw range than he Jets and Stingers when used with a narrow tire. Trek ran all their tests with a 23 and the H3 was about 10-20 grams worse. So maybe there is a 30-40g loss running the wrong tire.
Their is really only one tire that works well with the H3 in terms of aero and RR and that is the conti super-something (I always get the name wrong) in the 700x20 size. Check Tom A’s RR chart for the real name.
A couple things I always kick myself for not doing when I had the chance to attend the Mavic CXR80 intro “shoot out” in San Diego are:
Not borrowing Ryon Graf’s H3 clincher and putting the AW19 tire on it I had brought along, and…
Not mounting the AW19 on my narrow Jet 90 front wheel instead of the Conti SuperSonic 20C I had on there.
I always wonder how both of those would have fared aero-wise in that test…
i’ve had very good luck with the Veloflex 20 (i think it’s the corsa) very comfortable on the front. hard to put on initially but not bad for a flat change after a few hundred miles of use.
