Monday, October 22, 2007

Equipment - Power, PowerTap, SRM

So I've been doing my typical "end of season equipment review". This is where I decide that next year I'll try and optimize my equipment in order to utilize my soon-to-be-started training to its utmost.

In other words, how do I buy more speed?

I've been very happy with the Power Tap setup except for one thing - I don't have an aero Power Tap rear wheel, whether clincher or tubular, and I definitely don't have one that is a real race wheel. The 32H Mavic Reflex tubular rim currently on the hub is a sad excuse for a race rim and not an ideal rim for a training wheel.

I realized shortly after learning you have to lace Power Tap hubs equally on each side (precluding me lacing a 24H rim onto a 32H hub) that I should have gotten a 24H hub, and in fact, I should have gotten two 24H hubs. 24H Power Taps are hard to find though and weren't an option for me when I first ordered a hub. Whatever. One theoretical 24H Power Tap would be laced to an aero clincher, the other to an aero tubular.

This is due to two theories (of mine) about aero rear wheels:

Theory 1:
You can ALWAYS train on an aero rear wheel, regardless of wind, and since most (carbon) aero rims weigh the same or a little more than a box section rimmed rim, a carbon, deep section clincher wheel would be the obvious choice for a training wheel.

Theory 2:
You can ALWAYS race on an aero rear wheel. Wind conditions can be ignored (see Theory 1, above). The only other factor - weight. Perhaps on a steep hilltop finish, the extra 50-100 grams might be a detriment, but think of the aero savings sitting in the field leading up to the finish. Okay, so on Mount Washington there's no such opportunity so there a light wheel would be good - and probably one without a Power Tap hub jammed in the middle of it. So, if you have a Power Tap hub for racing, you should have an aero rear rim - a deep section rim.

Deep section rims need, at most, 24 spokes, so you need to get a 24H hub.

Unfortunately, I got myself a 32H hub.

According to my two rules above, the hub is unusable.

There's a corollary too.

Corollary:
For most racers (under, say, 225 lbs), you need, at most, 24 spokes in the rear with a deep section rim.

Since Theory 1 and Theory 2 illustrate why you'd never be without a deep section rim, the corollary illustrates why you'd never need a Power Tap hub with more than 24 spoke holes. As an illustration of this - my Reynolds (carbon 46mm deep) rear wheel has 20 spokes.

Exception:
As usual, there is one exception - and it's for whoever wants to buy my Power Tap. They definitely want a 32H Power Tap!

Anyway, with my two theories and the corollary in mind, I realized that, based on my current financial situation, the Power Tap won't meet my needs.

This is because to satisfy my training and racing requirements, I'll need to buy two hubs - both 24H Campy hubs. 24H - one hurdle. Campy - another hurdle. Based on eBay prices, this will set me back about $2000, and based on an email to Saris, I have to choose either wired or wireless, the latter being more prevalent at this time (and more costly). This two hub purchase will set me up with one race wheel and no training wheels. The race wheel will come courtesy of a surplus (and old) 24H Zipp rim sitting in my wheel collection. I'll have to buy one training rim to build a similar training wheel - deep section rim, $400 or so.

I'm looking at $2400, perhaps another $800-1200 if I decide to buy matching rims (meaning two clinchers and another tubular).

And after all that, I'll have just two power-compatible rear wheels.

For someone who's just started racing, or someone with two or maybe three sets of wheels, this would be an acceptable solution. Train on the deep section clinchers, race on the deep section tubulars (with the clinchers as spares, or you can do with two sets of clinchers), and you have a perfect setup - similar parts, easily switchable wheels, etc.

The problem is that I have a LOT of wheels that I use and like - my favorite Reynolds 46mm carbon tubulars, the three Specialized TriSpokes (two front, one rear), my Campy Eurus wheelset (with a second backup set), and a boatload of less exotic wheels - mainly Spinergys and conventional Campy-hubbed FiR-rimmed wheelsets.

All of which, I should point out, do not have Power Tap hubs. The exotics, by the way, do not even accept Power Tap hubs - the TriSpokes (nope), the Reynolds (20H hub? Not readily available), the Campy wheels (21 spoke with a 14/7 spoke count? You crazy?).

I've been kicking around the idea of racing a rear disc wheel in crits as well, and those are definitely not Power Tap-able.

So...

This means my Power Tap experiment is coming to a close.

I've decided to sell my Power Tap, the wheel around it (Mavic Reflex, 32H, DT 2.0 Revolution spokes, alloy nipples on the left side, brass on the right), as well as the original wheel around it (DT 1.1 double eyelet rim, 32 2.0 straight DT spokes, brass nipples, but all currently not on the hub). No tires but there's a rim strip on the DT rim I'll leave. $850 or best offer, by the way, unless I have to eBay it, in which case I'll let the market decide. That's for both rims if you know how to build wheels (you choose which one is actually built around the hub), and I even have a set of 32H FiR tubular rims that I bought sort of by accident (not realizing when the Reflex was coming in, I order other rims "just in case"). And a couple new batteries for the head.

And at some point I'll be buying an SRM crank - 175 mm, 53x39, not sure what other specs.

The big decision on the SRM will be based on Q-factor (the crankset's width, measured by the distance between the left and right pedal's vertical path). The Campy cranks have always been low - as low as 112mm, currently in the 120s. A DA SRM crank is about 139 mm - I'd feel like I'm riding a horse, not a bike. I'd need to stick with the standard SRM setup or go to the System Integration model, i.e. specific for the Cannondale frameset.

That's another thing.

Ever since someone told me their Giant felt a bit flexy, I've been obsessing over that, even if I've denied it in public. A good friend of mine works for a company that makes frames and commented on "flexy is as flexy does" as well. As a clincher, on my pre-wedding training ride, one of the guys had a 6-13, the aluminum lugged, carbon tubed Cannondale - and he loves it. Incidentally he also rode on deep section clinchers, front and rear - the perfect training setup.

So, if Cannondale's frame measures okay (I'm obsessive about fit) and I get to test ride one in some reasonable time, I'll probably be getting a Cannondale frameset, 52 cm. I'm thinking either the 6-13 (unlikely), the System Six (carbon front triangle, aluminum rear, probable), or the new Super Six (all carbon, unlikely).

This would mean getting the SI version of the SRM crankset - the best of the versions, apparently (stiffest anyway).

Then I'd be able to use my beloved Reynolds wheelset and still get power readings. Build my 24H Zipp rim around a Campy 32H hub. Use a disk wheel. All that kind of stuff.

For now though I guess that means I need to dismount my PT stuff and start training on, gasp, "normal" wheels. I suppose that'll be okay - it's how I trained until April of this year, after all.

4 comments:

suitcaseofcourage said...

Wow - really appreciate your sharing your thought processes/analysis.

And I thought *I* was OCD!!

But your reasoning is sound. AAMOF, I've been following your PT experiment closely and, with my recent (first!) purchase of wheels was wondering what to do when you wanna use a different set for your trainer (or in a race). So I too started thinking the PT crankset would be the way to go.

That is, if I could afford to get to that level!

Thanks for letting us live a little through your experience - Looking forward to reading more!

suitcaseofcourage said...

BTW, also must mention you're making a GREAT decision to go Cannondale.

'course, I'm biased...

Be sure to let us know what you get - or as important, your decision-making process in getting it!

hobgoblin said...

Super Six, Team Si--All Campy with that SRM crankset. About 15 pounds. I want it! You're going to make me go into insane fits of bike jealousy. Unfortunately, we don't ride the same size, so I can't ride off on it while you're dragging that blower around the course, getting rid of the salt and sand.

Aki said...

SuperSix is a bit high for me - but there's a sweet SystemSix which is doable - esp if I sell off the PT, a pair of wheels (or two), and perhaps one of my bikes. If it's really nice then I'll sell my other bike and buy a second frame/crankset (SI).

15.9 lbs according to the Cannondale site for the SystemSix with SRM.

I measured the Campy (aluminum Record) crank's Q Factor - high 140s, so not as narrow as I thought. This means the SRM version of the SI, which is about the same, would be a good thing.

If I do this it'll be my first complete bike since I bought my first race bike in 1982. I realized I never bought complete bikes because they inevitably came with Shimano - and being a Campy guy for most of my life (a few Suntour years in there), Shimano bikes only meant selling off a group.

One final hurdle - I may have to go to a 170mm crank (at $2k per crankset for SRM it's not a quick decision to make) - which sort of goes along the lines of returning to my core strength, my sprint. If I can trade some leverage for some speed, it might be worth it, but we'll see. My absolute best sprints were on a 167.5 mm crank but I was fit enough to turn it over.