Time Trial / Time Trialling / TT

damn, affects, got to admit the last one was pretty bad ha

:)

"Ayone" too, if your being picky is to be accompanied by thoroughness.

Ayone know if an untrue disc effects, aerodynamics/ride or just breaking?

How much runout does it have? More than 1mm radial or 2mm axial will probably be noticeable to the pilot, you'd really want it to be less than half that. Your aeros won't be measurably affected by anything that's ridable, but a lot of runout will cause energy loss in the tyre as it flexes to damp the attempts of the wheel to throw the rest of the bike about.

I assume there radially true, just laterally out by 2mm.

Probably somewhat but it's one of the bits shielded behind the bike, etc so not likely to make too much difference.

I assume there radially true, just laterally out by 2mm.

Personally, I wouldn't touch a monolithic wheel (disc, trispoke etc.) with 2mm of axial runout, it wasn't like that when it left the factory so something must have happened to make it like that.

British roads.

Anyone familiar with the Cole disc wheels? Any thoughts? http://www.220triathlon.com/gear/bike/wheels/cole-disc-wheel/5584.html

A clubamte has one. It's a disc, they're all pretty similar tbh.

While we're on wheels...
My current stock of 'race wheels' looks like this (all tubular):
FFWD disc
Hed 3 front
PlanetX 50mm front and rear (rarely used now)

I'm going back to IM racing next year and I'm so shit at changing my tubs that I'm petrified I'll get stuck on the roadside grunting and swearing at a tub that I can't fit back on a rim.

I'm therefore thinking of a change of setup... If I keep the H3 (just because it's awesome) but sell the rest and buy a Flo 60 front and a Flo 90 rear + Raltech cover then I figure I've got most of my bases covered...

IM races/100mile TT : Flo90+cover / Flo60
shorter TTs: Flo90+cover / H3
Road races/ stupidly windy days/Very hilly TTs: Flo90 /Flo60

Does that sound like a vaguely sensible plan? I love my current disc so I'm a bit anxious about taking the perceived step backwards to covers but I the Flo disc is basically a 90 with integrated cover anyway so the only thing I'd be loosing is the flexibility of being able to use it on my road bike.

are the px not clincher?

I can do sub-4hr 100s on my 24hr TT setup (fat clinchers, wheel covers). Makes more sense to me than running a wheelset that might end your race.

Nah, I don't know if modern PX 50mm come in clincher form but mine are a few years old and are tubs.

@hippy that's my logic too. I guess I was just wondering whether there were any more economical/sensible ways of achieving a good balance of flexibility/reliability and speed.

The FFWD has a claimed weight of 1195g, Flo90 has claimed weight of 1199g so there would definitely be a slight weight penalty. I don't know how much the Raltach cover would weigh, but Flo Disc weighs 1260g so probably slightly more than that.

A minor secondary consideration is that all the wheels in the new setup would have alu braking surfaces which would mean I don't have to faff with brake pads when swapping between race and training wheels.

Claimed 4g? That's not a weight penalty, it'll be less than their measuring error. Weight on TT bikes unless you're riding up the side of a mountain is far less concern than aeroz.

I'd be inclined to get something cheap and strong to go under the Raltech covers, then you have a spare wheel for not much extra money, and you don't have to keep swapping the covers on and off.

Hippy, yeah I didn't mean to trust the claimed weights that completely. Rather, I meant that given that the claimed weights of the Flo90 and the FFWD disc are essentially the same, I am bound to incur a weight penalty by adding a wheel cover. I know aero trumps weight, but with over 1500m of climbing in IM Wales I don't want any unnecessary extra weight.

Tester, I thought about that too. I can't find the test right now but I'm sure I saw a wind tunnel test where both the FFWD disc and the Flo Disc were compared and the flo was significantly better. I know eyeballing aeros is wrong, but the primary difference between the two appeared to be the (?)toroidal shape of the the Flo Vs the lenticular shape of the FFWD. Adding covers to the Flo90 is basically identical to the design of the Flo Disc, so I hoped that that would be faster than adding covers to a box section rim which would give a more lenticular shape. The category of races where I would want to use the Flo 90 without the cover is by far the rarest, so hopefully the faff would be minimal.

I can't find the test right now but I'm sure I saw a wind tunnel test where both the FFWD disc and the Flo Disc were compared and the flo was significantly better.

Comparative tests between discs are meaningless unless they were at least on the same frame as you use. I expect @xavierdisley will be along with solid data at some point, but I thought Cervelos were best with flat discs anyway. The idea that any disc is significantly better than another is more indicative of poor test protocol than any actual difference.

Yep rear wheels will depend on the frame. Most Cervelos do just fine with Zipp 900s and a narrow tub but finding the tubs is a pain these days.

I'd sell everything and buy a pair of 2nd hand clincher trispokes if you don't want to run a disc (not sure why you wouldn't). You can train on them as much as you like too to get used to the front handling wise. If you want you can get some <50mm front clincher for the silly days or just man up and get the mega benefit from the trispoke in the wind.

if you don't want to run a disc (not sure why you wouldn't)

Discs are not allowed in IM

Discs are only banned in at the IM world Championships in Kona. I'd plan on using a disc at IM Wales, but I don't want to use my tubular disc for fear of punctures.

Probably my best options are
a) Flo90+cover
b) Flo disc
c) box rim + covers

Option A would be basically the same as option B but just gives me some added flexibility to use the wheels in the VERY occasional road race that I might do. Option C would be the cheapest for a clincher disc but would mean I don't get a bonus road wheel.

VERY occasional road race

There's an app for that :-)

Dat tub with tape install is a 5 minute job - 10 tops

Organisers occasionally ban discs in triathlons for no apparent reason, but I've only heard of a handful of cases worldwide.

In that case how about box rim + RALTech, pair of cheapo 50mms, and Flo 60 front (or 2nd hand clincher trispoke/the most aero front you can afford). Then you have RR wheels as well as everything else. Focus on the target race wheels first rather than compromising on wheels now for potential convenience later. So get the cover and hunt for a nice front or get the Flo.

Sell me tub H3 pls