Showing posts with label Dolan DF4. Show all posts
Showing posts with label Dolan DF4. Show all posts

Wednesday, March 04, 2020

Plan 2020 - Gathering Supplies


So I've been working on lifting, I've been gathering the materials for the bike/s, and I've been consumed by researching stuff whenever possible.

Dolan Bike

The Dolan is a bit on standby. I have the frame (and fork, seat post, headset), the Zipp disc wheel, an ISM saddle, and a few possible front wheels.

I have, but need to install, a Zipp disc track axle, and (spoiler alert!) also the SRM crankset.

I'm also working on what bars and stem to put on the bike - sprint bar for sure, for other events, but I'm wondering if I can effectively use aero bars to improve my power/speed ratio at the end of the 500m. Each bar will require a proper stem for fit.

Dolan clincher rear wheel

I need to build my rear clincher wheel. I decided on a 24 hole DT rim with graphics on the side, because I'm all about the graphics. I have some Wheelsmith spokes from eons ago, and I'll be lacing those onto my old 32 hole Suntour Superbe track hub.

This is the wheel I'll use on the trainer and on rollers.

Dolan brake

Brake?! On a track bike?!

Yes.

For outdoor tests, standing start practice, and just getting used to the fixed gear, I'll be switching out the fork with my ENVE fork from the red Tsunami. I replaced the ENVE fork with a 3T team fork, as I really liked the 3T team fork on the black Tsunami.

I'll have a brake on the fork and will use a 'cross top-of-bar lever to actuate the brake. This way I can put a brake on the bike and ride it outside. I figure it'll be good for getting better with technique and even with aero testing.

The 'cross type lever will make it possible to mount the lever on pretty much any bar, including some of the swoopy track sprint bars.

Spin Bike, soon to be a CycleOps 300 Pro

Initially I was going to invest in a number of things for the spin bike. Stem adapter, stem, bars, a better BB adapter, a set of cranks, etc. I even contemplated getting yet another SRM for the spin bike.

Then someone suggested a fixed gear CycleOps 300 pro trainer. These came out long enough ago that I was working Interbike when they came out. And although I wasn't impressed with them at that time ("my spin bike does all that just without a powermeter") now I see the value in its massive, 45 lbs flywheel. It perfectly replicates the effort required for a standing start event. Apparently one successful Masters racer uses such a trainer to practice standing starts.

So I looked and lo and behold, a place very close by is selling 15 such trainers. 15! And at $550 asking, it costs way less than just a used SRM powermeter, forget about everything else.

Training Needs

That should situate me for a decent amount of time. I can train the following:

1. Standing Starts - CycleOps 300 Pro, outdoors on Dolan w/brake
2. Speed power - CycleOps 300 Pro, Dolan on trainer, outdoors on Dolan w/brake
3. Top speed - CycleOps 300 Pro, Dolan on trainer, outdoors on Dolan w/brake
4. Pedal fluidity - Dolan on rollers

Sunday, February 16, 2020

Plan 2020 - Dolan DF4 Frame

The first step in the whole process was to get a frame. Track frames are different from road frames, and I'd want the frame to be UCI compliant as well, something my beloved Tsunamis are not.

Here's the big thing with track frames: the bars are really narrow.

Wait. Bars? You were talking about frames. Why the bar comment?

It all comes down to that. Nowadays a regular track bar is 33-35 cm wide. In contrast, on the road it's normal to see 40-42 cm, although that's coming down a bit. I'm running 41 cm bars on my Tsunamis, and they look narrow under me.

The ultra narrow track bars cause a problem though. The reach to the bar is shorter, due to the reduced width. If you're reaching 3 cm to each side that's 3 cm of length. If your bars are 3 cm narrower on each side, you have 3 cm more arm "left over".

You need a longer frame.

Therein lies the problem for me. I'm already pushing it with my odd proportions, short legs, long torso. My frame is basically a 50 cm (high) frame, a size which normally comes with a 52-53 cm long top tube. However my frame has a 56.5 cm top tube, and, additionally, has a steeper seat tube angle. That pushes the top tube forward, effectively making it about a 57-57.5 cm top tube. And my head tube, at 12 cm total height, requires a 3 cm drop stem.

I can't commission another Tsunami because they're not UCI compliant.

So I Googled all the track frames I could find. I looked at their frame geometry charts. I needed to find a UCI compliant 50 cm seat tube frame with a 74.5-75 deg seat tube angle, a 57 cm top tube, and a 12 cm head tube. It had to be aero. It had to be a real track frame, not a fixie bike.

And I needed to get it done for less than $2000 shipped.

Dolan DF4

The only frame I could find was the Dolan DF4. A world class frame, no less, raced professionally. Aero design. 50 cm seat tube. 57 cm top tube. 74.5 deg seat tube angle. 12 cm head tube.

It was exactly what I needed.

And with a pre-season discount, it fell way below my $2000 budget, shipped.

Dolan DF4 - size 57 (!!)
It's their second largest size frame.

First, the frame is UCI certified. That means I can do official events, like Worlds. At the very least I know that the frame is okay for Nationals, which is my focus.

The second most important feature of the frame is the geometry - it almost mirrors the Tsunamis. Very long top tube (0.5 cm longer), steep seat tube (1 deg shallower), and short head tube (same height as Tsunami). Although I'll have to move my saddle up within the seat post clamp, I'm at the UCI limit on the Tsunami for a sprint bike (zero setback to nose of saddle) so I should be fine on the Dolan.

The third most important feature, because without it I'd have eliminated it from consideration, is that it is aero. No vintage round tube stuff - this frame is meant to go fast.

After that it's all gravy.

Aero tubing, aero seat post

The aero isn't obvious until you turn the frame. The frame gets real thin real quick.

Cut out for rear tire, but tire will not be as close as on the Tsunami

In my research I've found evidence that a cut out will save a fraction of time, and help a less than optimal rear wheel. In less scientific findings, I think it looks cool. Either way, this frame has a rear wheel cut out.

Rear dropouts.
I need to order spares.

Carbon fiber isn't very strong - it's just a plastic reinforced by carbon fibers. So contact points under pressure tend to be constructed of metal inserts. The rear dropouts on a track frame see a lot of abuse, so those are metal. I forgot to order spares. I'll want to get some dropout screws while I'm at it.

Potential Weak Points

I saw two potential weak points in the frame when researching online. The first was that the rear dropouts are pretty short. This helps handle a problem the longer dropouts had, where the weight of the rider bend the top part of the dropout up. This caused the opening to widen, making it difficult to secure the wheel. If you look at the geometry picture in the Dolan site, you can see the older DF3, with the super long dropouts.

The problem with a short dropout is that you can't move the wheel very much to take up chain slack. This means getting multiple chains for various gear combinations.

Since I prefer a very, very short chain stay, I'd probably want to keep the rear wheel as forward as possible anyway, so this "weakness" becomes a non-issue for me.

The second weak point is the seat post clamp. It's a wedge clamp with a very small bolt, with a very high torque rating. There are reports that it's virtually impossible to tighten enough to deal with jolts, like when you hit a seam on the track.

The workaround is pretty easy - you put a piece of pipe in the seat tube. Cut to the right length, the seat post will just sit on it. I have ideas for that "pipe" as well, so that critical cutting shouldn't be an issue.

So that's the frame. Next up, the wheels.