Race Tire/Tube Recommendations

ezellrh

Gearing up for Louisville, I just want to make sure I'm going with the conventional Haus wisdom (after using my search fu in the forums).  Is the party line on tire/tube combo still the Vittora Open Corsa EVO and latex tubes?  If it matters, I'm riding MOP, 185lbs, and have a disc cover for my back wheel.  I had planned to get 23's unless there is a compelling reason not to.  Thanks

ezellrh

Anyone??? Bueller, Bueller? I can hear you breathing... lol

GMAN 19030

Yes on the tires and tubes. What wheel you use would be the determining factor as to the width of the tire. I run a Hed H3 front wheel which is a thin wheel. I use a 20mm tire on it. I use a 23mm tire on the rear disc.

harrast

Like Bob says, the tire should match the wheel width (approximately) or you are likely to produce drag in the area behind the tire. My dangerous lack of knowledge about aerodynamics leads me to conjecture that the aero drag from a wide tire cutting through the air is more significant that the reduction in rolling resistance due to the wider tire on the road. So, if you have a narrower rim, you'll want to look for a narrower tire. Many of the older rims are about 19 mm in width (love my digital calipers). I have found that Conti gp 4000s inflated to about 115 is actually 24mm wide on my training hoops. So, I'm not going to be using these on the front of my bike. On the other hand, my rear disk wheel is about 23mm wide--fine for any normal 23mm tire including vittoria or conti, plus, much of the leading edge is hidden from the air.

Now, here's my question for other ENers: I have a 19mm wide race wheel, okay it's one of those SRAM s80 deals. So, I'm looking for a narrow front tire with generally low rolling resistance, and some flat protection, enough for an IM. My current candidates are the Velo Flex Record 20mm, the Bontrager R4 22mm, and the Conti gp Supersonic. The fastest, and probably the most delicate is the velo flex, the bontrager R4 is probably the slowest (though not a slouch) but it is built to have a profile conducive to air flow, and middle ground is the fairly delicate conti gp supersonic. I suppose I could include the vittoria open corsa cx 21mm, but I haven't seen it tested in its narrower width, so I don't know about how it rolls (the 23mm rolls well, though in a 2007 test the gp4000s rolled better). The guy on one of my shoulders says to throw caution to the wind and ride on paper tires that go like crazy and forget about flats. The guy on my other shoulder says get some flat protection for peace of mind. Any thoughts about riding on paper tires and carrying a bottle of Vittoria Pit Stop? What would you do?

GMAN 19030

Steven,
They make a 20mm Vittoria: http://www.trisports.com/vittoria-open-corsa-evo-cx-clincher-tire.html

I run the 20mm Conti Supersonic on my H3 for shorter distance races (or HIM with nice roads) because they're thin and delicate. I use the 20mm Vittoria for longer distance races because it's more durable.

MattAaronson

I use a Bontrager Aero R4 in the front
Vittoria Open Corsa EVO in the back

harrast

@Matt, I also like the Vittoria Open Corsa EVO on the back with a latex tube; I can't describe the the ride, except smoooooth. Obviously you like the R4 since you're using it. How does it hold up? Any flat troubles? Do the "shoulders" work with your race wheels? My front wheel is 19mm wide, so the 22mm R4 would overlap 1.5mm on both sides. This worries me a little. I'm the kind of guy who installs ceramic bearing in my derailleur.

matthewbward

Steven, what did you decide to do? This thread made me take note I'm running a Corso 23 in the front on my 19mm American Classic 420. I'm going to switch to a 20. Would normally just buy the 20 in the Corso but interested in what you're doing as you seem to be better informed than me...

harrast

Matthew, I like Bob's suggestion of going with a Conti GP Supersonic for HIMs and a Vittoria Open Corsa Evo CX for IM races. However, until I get my third job, I'll probably just go with the Vittoria for HIMs and IMs; I have ridden the Vittoria rear tire and am cautiously optimistic that it would hold up under normal IM conditions (rode mine 65 miles and didn't see any cuts or other wear issues). I'm still interested in the Bontrager R4, but I would have to see one before I could believe that the 1.5mm x 2 overlap on the leading edge of my bike isn't going to cost me 8 - 12 watts. I would really love to ride the Conti GP Supersonic in an IM, but I would be worried about hitting a piece of road debris and holing the tire.

matthewbward

FWIW, I emailed Am Classic to ask about running a 20 on my 420 (19mm) wheel. They said:

20 is a very narrow tire. 21 is usually used for racing and 23 for training or racing. 23s are great if there are a lot of turns, reaccelerations or wet conditions. 20 or 21 is best for straight roads. The fronatl drag may be a bit less on 20-21 but sometimes it's not the best choice. We recommend you choose your tire based on the race day conditions. If you know it's going to rain on a twisty course with fast down hills, go with 23s and a bit less pressure 100-110 psi. Hope this makes sense.

Woody Freese

Per an article in the Wiki (I think that's where it was...), if I am reading an entry by William Jenks - he recommends Vittoria with latex tubes - correct? Thinkiing ahead to mid-Octoberalready. Has this entry been updated and I missed it? Note to self - conduct an full-blown analysis of cost of triathlon vs. cost of extreme chess (think X Games) and see what is cheaper...

delesh

 The Evo CX has good rolling resistance but at a certain point the aerodynamics may play a larger part in the drag. Some tires are more aerodynamic on a specific rim than others. Make sure you are using the correct width and type of tires for your wheels. Most tests show the GP 4000s is a very aerodynamic tire whereas the Evo CX usually has less impressive numbers. Here is a chart that shows how much drag different brands of tires can have (50g is about 5 watts):

harrast

Per the chart David posted, the GP 4000s 25mm has greater than 5 watts more drag than the same tire in a 23mm dimension (looks like maybe 6.5 watts of extra drag to me). That's over 3 watts per 1mm of increased width. People may obsess about rolling resistance because there is a lot of data, but IMHO, the aerodynamic properties of the tire are more important, though much more difficult to quantify and often depend on the rim. Still, the general rule seems to be to match the tire width to the rim, at least for a race where turns aren't a big factor, like IMs. I have to say that the Bontrager R4 is looking better and better to me because it seems to be designed with aerodynamics in mind. The GP4000s is a great tire (for years I have ridden then both in training and racing), but the 23mm (nominal dimensions) tire is still 24mm wide on my training hoops, so I probably will look for something narrower, no wider than the 22mm R4, for my race tire. But, in spite of all my obsessing, I should probably be more worried about what I'll eat during my next race. That will have a bigger effect on the outcome.

MattAaronson

Posted By Steven Harrast on 28 Jul 2012 04:40 PM

I'm still interested in the Bontrager R4, but I would have to see one before I could believe that the 1.5mm x 2 overlap on the leading edge of my bike isn't going to cost me 8 - 12 watts.

I don't understand what this means. What is overlapping what? And how does it cost 8-12 watts...that is a crapload of watts. I have my R4 on a Zipp 808 (not firecrest). I sure hope I'm not losing 12 watts!!

harrast

@Matt, my rim is 19mm wide at the brake track, so a 22mm tire overlaps the rim 1.5mm on each side (which is not bad; my gp4000s' are 24mm wide inflated to 120psi overlap 2.5mm). Rim manufacturers are trying to eliminate this overlap by producing wider rims, and tire companies are putting "shoulders" on the tires to reduce this area, but it's clear that it produces drag. And data shows that going from a 23 to a 25 tire on a zipp rim creates around 6.5 watts of drag. It's difficult to get data on the drag produced by wider tires, so most people settle for the tire with the least rolling resistance.

MattAaronson

@ Steven, got it, thanks. I assume the thing you need to be concerned about is 'incremental drag', since you will always have some drag at that wheel/rim interface. The loss of 8-10 watts really is in reference to some alternative. Regarding the R4, I don't know the specific statistics, but I assume because it's a 22 not a 23 and because it's suposedly designed for aerodynamics that it's numbers are not terrible vis-a-vis drag.

harrast

A little update on tire width: I was mounting my race wheels to get ready for a little Oly next weekend. I took a quick measure and found the 23mm nominal width vittoria open corsa evo cx is almost 26mm wide mounted on my 2011 Hed Jet disk rim (the rim is 23mm wide at the brake track). IMHO, there's a reason this vittoria rolls well and produces a very-smooth ride: it's a VERY-WIDE tire in addition to being very supple. In other words, I'll look for something narrower for the front of my ride.

imc1792

Just looking at these tires for next weeks IM (Vittoria Open Corsa Evo CX) says PSI 115/145.

>140 PSI, does anyone do this, why/whynot?

GMAN 19030

http://www.vittoria.com/tech/recom-tyre-pressure/

harrast

@Tim, I would only run the Vittoria 23mm on the back as it is 26mm wide inflated to 120 psi on a Hed Jet wheel. I know they have a 20mm version of the Vittoria also. In my experience, I've never gone to full pressure (145psi) on the tire and don't know why anyone would unless they were riding on a perfect surface. Just my thoughts from riding on one. I'm still searching for the perfect tire;-).

Woody Freese

Doesn't the type of wheel play a role in the PSI rating? As I recall, Zipp recommends 404's and 808's to have a max of 125 PSI. I could be mistaken - and admittedly have not looked at the Zipp website for confirmation.