Did what I had time to do, sorry.

Can these riders you mention produce data? I know JeffP has data, but his is w/ a Zipp firecrest rim.

I know one used a Jet9. That wasn't WT though, that was field testing, which he does a lot.

How wide are those tires compared to your brake track?

James is that a 20mm? Looks wide like a 23mm, but I know the data Jack linked to listed it as a 20mm.

thanks for chiming in.

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

The SS is a 20 and the GP4k is a 23

okay guys - can someone explain to me the "magic" attack - sorry missed it somewhere

i am in a bit of a quandary because I am doing South Africa - they changed the course so all of the bike is on the coastal road which means
- significant wind and very possible high yaw
- road surface is gnarly

- for the back it will be either TC 26 or GPTT 23/25 but for the front at those wind conditions and bouncy surface it is a problem - SS23 i feel may succumb to the road surface; i thought GP TT wd be it with its fat 23 but the aero data is damning at high yaw, then attack - the 22 seems its too narrow

that is why looking for best tire that would still provide some puncture protection and some comfort (i still remember the chipseal of IMNZ!)

If yaw and durability are of concern, IMO, the Attack is a pretty tough choice to beat.

Puncture protection won't help you with chipseal and roughness. The vectran belt is for thorns, wires, glass, etc. If you stay in the traffic lane and off the shoulder, the need for puncture protection is greatly reduced.

Some Attacks have tested very well. Nearly as good as SS23. Others not so good.

wdnt 22mm be of an issue of a chipseal road?

I took some measurements of a 20ss and a 23 ss on a jet+ wheel. values in mm

Wheel Tire Width Height
6+ 20 23.1 18.1 90psi
6+ 23 24.9 20.0 90psi
6+ 23 26.6 22.5 4000s 90psi
H3 20 19.7 16.8 110psi

Thanks, Jeff. Wow. I guess the inner width must be wide, and the tubeless shape sticks the tire beads right on the outer edge. Doesn't seem ideal, but the Jets (+) test well, I guess.

21mm per HED with 25mm track

edit: not positive 20mm tire is a good idea on these rims

The two I've had have measured a bit wide at right around 23mm. IMO it's tough enough. Certainly tougher than a supersonic. If you want something a bit tougher and cushier the 23mm GP4000s II is a good choice. That's a tire that seems to perform well consistently at yaw.

it's probably not. James Haycraft found that the 23mm GP4000s was *better* than the 20mm SS at zero yaw and Tom A. found that the SS 23mm was very good, better than a 22mm Attack or 22mm Turbo on a Flo 9, so with the Crr differences I'm going with the 23mm SS

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

my thought was more along the lines of will the tire stay on under stress, not crr and aero.

I have seen vastly different results with certain tires in different bikes wrt aero such that I would never trust wheel alone data(which James' data was not) but it was on a different bike

Damn, how bad are these roads? Maybe the course calls for one of these?

I'd be concerned with amount of bead under hook on the 20SS, ie is it sufficient

I've seen loose tires fall off a rim before

it is probably fine, but I don't like being my own guinea pig

when has the tipping point been reached...http://www.slowtwitch.com/..._Rim_Width_2803.html

I tried the 20mm supersonic on a fc808 and never got comfortable that is was a solid fit. Probablu all in my head, but I was always nervous cornering on that setup.

I was never concerned with that set up, have ridden 20ss on both 808fc and super9 in past.

20ss snapped into place on jet+ rims just as 23ss and 4000s did. just not sure when it is too much

Can anybody explain this 'MAGIC" tire that keeps coming up in these discussions? I'm curious what they are, where you get them, and how to validate it is indeed magical.

---

------
"Train so you have no regrets @ the finish line"

22mm Attack (and its inherent aero goodness) w/ 24mm Force or TC or 23mm SS Crr

Roller test

---

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”

oki i found out what the magic means .. Tom A usually tested attack and force gave him around 33 watts at 40kph; however couple of attack tires actually tested at 27 watts; means whole 6 watts faster - thus if you have this selected aka magic attack this is the grail as it is good aero and this crr is one of the best

Thanks for that R2!

---

------
"Train so you have no regrets @ the finish line"

Soooo, question.

I have a set of HED Ardennes SL + (25mm wide rim) and am planning on ordering 2 pairs. Is it faster to run 24/24, 24/26, or 26/26?

seems to me the fastest set up wd be

SS 23 + TC 26 - assuming it's an aero frame for TT purposes