Impreza_aL

then i don't know. drop it off at a lbs and have them send into sram/zipp.

yah that's a killer but they are just gigantex hoops anyway. zach could ride square wheels and still ride away from people. he's first in the endurance standings and eighth in sprints for usac

carleton

Ah. I'm not much of a wheel builder.

Who is Gigantex? Should I just pick a rim/hub and have them built myself? How do I get them?

Gonna google now...

Impreza_aL

the only us dealer i know that uses them is bike hub store. i haven't done much research on trying to source them. it's been noted on weight weenies and slow twitch that they are preferred hoop over a "generic china hoop".

Racer Ex 

This factory factory builds a large percentage of the carbon rims and supplies most of the "generic Chinese hoops".

That is correct. You have the board.
-----
For almost all carbon items you either

a) pay for the mold and own it
b) license it for X amount of time,
c) design it and hand over the paperwork knowing there will be knock offs within 1-6 months, or
d) you buy the knock offs and slap your stickers on them.


Correct again.

For the most part with wheels there seems to be no difference in core material, with frames the knock offs might use a lower grade carbon than "c".

Correct!

It's the Daily Double!

This company started out building low end Schwinn bikes in a dirt floor warehouse, and now is the largest bike manufacturer in the world

No, sorry. Any one else?

Correct!

Let's pause for a commercial.

Racer Ex 

FWIW there are some interesting hoops from China in deep section right now...23-25mm stuff to 88mm that's worth looking at if your riding outdoors and eat wind.

carleton

Nice!

Thanks for the explanation!

Any suggestions for something close to 80mm for a front wheel for a big guy?

Racer Ex 

Check out Ebay.

If you wanted more spokes or a track specific hub buy a rim and hub and drop them in the lap of a wheel builder. Or contact the guy in China and see if they will do more spokes and a track hub.

Not a lot more money and you can specify spoke type and pattern (a 20h radial won't be as strong as a 2x lacing...most wheel builders will explain the +/- of the various set ups). A bit more hassle but in the end you have something that's Carleton specific.

The 23 wide stuff paired with a low Crr tubular like the Vittoria's hits a great sweet spot for a big guy riding outdoors on rougher tracks...nice aero + Crr.

If you were at VSC you go 19 and 190 PSI with a disc or 3/5 spoke.

On outdoor stuff you actual do better running 120-150 depending on the track and set up.

Quinn8it

you can keep telling me that- and i still wont ever run my tires that low..

as for the wheels-
i built up 88's with low flange DA hubs.. 32x. they are really great wheels. not light the way they are built- but really really stiff and durable.

carleton

That is a $175 wheel. The comparable Zipp 808 Track front wheel is $1,200.

I guess the $1,025 question is:

How do I know which eBay seller is selling high quality knock-offs and who is selling low quality knock-offs?

Is there one with a better reputation?

Baby Puke

Ow, my eyes...

Jaytron

This is a HUGE question for me, and I've researched it time and time again.

The roadies on roadbikereview seem to think they're fine. Then again, these are smaller roadies, so I've still been kinda iffy on them. I'll keep my eye out on the track for anyone with them and hopefully try them out.

queerpunk

I think the trick is to take the wheel to a good wheelbuilder once you get it.
I've seen a variety of chinabron wheels, though never used them. Never seen serious rim issues, but the build quality varies. If I got a set of them I'd take them to a good wheelbuilder and ask him or her to completely detension and retension the wheels.

Impreza_aL

don't you already run zipps and mavics?

carleton

Thanks.

I'm in it for the info. And if I can build a solid weekly race set for a fraction of the cost of Zipps/Mavics, why not?

BTW, I sold the 404s a while back in order to buy the LOOK 496.

Racer Ex 

There are a lot of folks running the 88's who are bigger. Quite a few of them at the last two Elite Nats I raced.

As was pointed out, the build quality matters. That said I can build my own wheels so if the build quality isn't stellar I just tune it up myself. The hubs and bearings are fine, and bearings are standard cartridge stuff if you need to replace them.

Wheel to wheel some of the proprietary wheels (like Zipp and HED) will slightly outperform the "generic" wheel of the same size at certain yaw angles. But often the differentiation is really small and for sprinters (vs. pursuit folks) it's pretty much one head bob or glance to the side if that.

carleton

Awesome.

I've never built (or commissioned) a race wheel before. I'm excited about the project.

Racer Ex 

Hey, I'm not selling anything and I'm not going to let air out of your tires when you're not looking.

Well, probably not.

Think of it this way:

If you wrapped a rim in some kind of stickum that let you get traction and rode it at San Diego you'd still be a lot faster on a regular tire that had some give.

There's a "sweet spot" in air pressure for optimum rolling resistance that's contingent on the surface you're rolling the tire on. It's why mountain bikers don't run 180 PSI despite having suspension.

queerpunk

The best description I heard of that effect is, tires should absorb some shock. Lower pressures are better at that than higher pressures. If they don't absorb shock, you bounce.

When you bounce, your forward energy is converted into upward energy. That is: you lose speed.

carleton

Are you guys taking into account the differences between steady-state efforts like pursuits or longer race or sprints that involve pulling extra G-forces and their effects on tires?

For me, it's about feel more than optimal rolling resistance. I don't like squishy.

VanceMac

That much is indisputable. And while I've never seen, or even heard of, any Encino-specific data, I'd be very surprised if the optimum there was over 160 (for typical tubulars). Same for San Diego. That said, all the rolling resistance studies I've seen are quite underwhelming in the methodology department. Still, taken as a whole, ithe studies certainly suggest that the old school pressures usually erred on the high side.

Racer Ex 

I pretty much concluded the Crr tests could be variabled to the point that it would take a year to test one tire. One "engineer" who was doing some testing claimed that Crr was the same regardless of the speed of the drum. He never changed the speed of the drum though, and of course this was nonsense.

I raced MotoGP and tire selection might have 10 considerations with 3 tires to choose then you'd ride it and the weather would change and youd start over. Every session we'd chart the pressure rise, wear, and durometer and surface temp the tire. We'd dynamically balance each wheel/tire combo and use a variety of tool to make sure the wheels were in alignment.

While our speeds were higher we also had 100 times or more the power to offset mistakes.

Bikes?

We pump em up and cross our fingers

Weight, G forces, all are going to play into where the optimal PSI is. Like the aero/power graph, you hope to find the point where all the lines intersect.

Baby Puke

Wait, you raced MotoGP**********

carleton

(Seriously...damn. I'm impressed!)

Racer Ex 

Yessir, stateside. 250 GP, and Superbike as well. I once followed this guy through the haybales in the chicane at Daytona. Champion at the state level, top ten guy at Nats, and top 20 at the one FIM level race I did. Second tier equipment and poverty level support, but even with a factory ride I was still a second tier talent compared to the guy above. Like cycling, there are folks that are on another level.

Great seat to watch them in the days before on board cameras though

queerpunk

I knew another former moto GP racer turned track racer. He didn't know his own size and liked to bounce into and off people. When called out on his generally careless riding, he'd say, "Aahh, that's nothin'. I used to do that at 100mph on a motorcycle. It's fine." He even said that as somebody was being loaded into an ambulance.

Probably not a reflection on all former moto GP racers...

...right?