Tuesday, February 26, 2008

My Own Trainer Project

I've decided to have my own indoor cycling trainer built up. I'm not doing it myself but have a mate who does this sort of stuff for fun. He's done a prototype which I've looked at and it's pretty cool.

Normally I wouldn't bother but with my rehab it's likely when I do start training properly, I'll need to do quite a bit more indoors than I used to (which was bugger all). So if I'm going to have a trainer - I want one that I'll want to get on, rather than dread.

So here are the rough specs:

  • free wheel
  • 7 speed hub gearing (a Shimano of some sort - heavy but bullet proof)
  • double reduction gearing (chainring to cog - hub gearing - to chainring to flywheel cog)
  • 35kg flywheel with high quality industrial bearings (have to remove some mass from the 40kg flywheel we have available as it seems to make it too easy). Need to decide on the weight (moment of inertia I suppose).
  • foils attached to flywheel for air resistance (possibly adjustable for variable resistance - but only adjustable when not moving)
  • a stainless steel or alu frame that's fully adjustable in all directions (think of those specialised cycle fitter frames with square tubing) and solid as all hell but with a real bike feel
  • SRM power meter with their adjustable length cranks would be ideal (ergomo is out for various reasons - but mainly due to power measured by left leg only - half of which I don't have anymore!) - the prototype unit has an ergomo
  • I have considered putting a Powertap power meter in centre of the flywheel but concerned about longevity vs industrial grade bearings.
  • able to be moved (infrequently) by picking up at one end and rolling along. It'll be heavy!
  • covers for safety (esp. flywheel) and protection from sweat
  • fine tune resistance using either a felt padded brake on flywheel or some form of electromagnetic braking
  • The electromagnetic braking being considered are two types: eddy current braking by placing powerful magnets close to the flywheel or the addition of a hysteresis brake controller unit.
The large flywheel/gearing will enable full on acceleration work as well as standard aerobic and anaerobic development workouts.

A programmable ergo brake would be great but I have no idea if such a thing exists that meets my criteria:
  • Needs to be solid, reliable and readily available and not that expensive. The SRM will cost significantly more than the rest of this item together! One suggestion was to use the controller from a Cateye trainer, if one could be located.
Another clever mate of mine (Peter) built a unit which was the inspiration for this project. This one has a 33kg flywheel and double reduction gearing. I had a short ride of this unit a couple of years back and it was awesome. Pete's a sprinter - note the sprinter's pedals with the toe clips and straps.

Progress so far:
  • I have the SRM Pro power meter on the way. Picked one up for a really good price on ebay :)
  • Just need to finalise some construction details for the trainer itself.
  • Also on their way are some high power rare earth magnets from Frenergy Magnets, which I'm going to hook up a rig on the prototype to see how good they are at fine tuning resistance. These are very cheap at only a handful of dollars each.
  • The manufacturer of the hysterisis brakes are investigating the right type of brake and control unit. Cost might be a problem though, expectations are around A$1,500.
Here is a pic of another trainer unit which uses these high power magnets to control resistance. The small round discs are the magnets, which are able to be moved closer to (or away from) the flywheel, enabling the resistance caused by the eddy current braking effect to be modified.

Here are some photos of the prototype with an ergomo installed on which I had a client conduct a MAP Test on last night:

The trainer frame is adjustable in all dimesions imaginable and uses standard saddle, cranks and any handlebar arrangement you want.

The double reduction gearing, with the hub gear shown, placed in the drivechain between the cranks and the flywheel. The hub gear can be moved up/down and fore/aft so the chain tension for both chains can be adjusted. The chain could use a bit of lube!

The prototype has an ergomo power meter. Not a good choice for me as it only measures left leg power. Any sort of handlebar arrangement can be fitted. The gear controller for the 7-speed hub gearing is shown on the drops at bottom right of picture.

The flywheel I will have will be a solid disc. I'll have the diameter reduced instead of cutting out sections like in this one. It'll weigh something like 35kg when finished.
I also sought comments and discussion at the Cycling Forums site which can be found here.

Finally - why the hell don't I just buy one?

As to other trainers, well the only ones I know about with power and a large flywheel are the SRM, PT 300, Velodyne & Velotron. The SRM trainer is probably the closest but hideously expensive. Velotron would be perfect but is 5 times the price. PT 300 looks interesting but I don't like the handlebar set up, the less than fine tune adjustment of power levels and it's a fixed gear. I'd like gearing to allow a greater variety of workouts. And the prices:

300PT US$1,800
Velodyne US$2,600
SRM trainer US$7,250
Velotron basic US$5,700
Velotron Dynafit US$8,000

I'll let you know how I go!

Read More......

Tuesday, February 19, 2008

What about me? / 100 degrees

OK, this is my blog and I'll cry if I want to....

Not really, no blubbing from this duck. So some have asked - how am I going? - I haven't heard? - are you riding yet? and so on....

So a quick update.

I'm doing fine, actually socialising quite a bit lately, which has been great. :) Part of the plan* to return to some "normality", whatever that is. Those that know me from the cycling and training forums know I'm still kicking about and occasionally being useful.

* The shorter term plan includes a return to work and a return to cycle training.

My leg is doing OK although Schooner is on his, er, last legs. Simple fact is Schooner doesn't fit very well now and I am ready for a new leg. I keep having to wear these thick cotton ply socks inside the leg liner to ensure a snug fit. I'm up to six socks now and it doesn't really do the job all that well.

So after a bit of walking I get sore. Sometimes it drags over to the next day. The other annoying thing is the patch of skin that got rubbed off ages ago just doesn't get a chance to heal. Last time I tried a pedalling session on the home trainer, I created and popped a small blister. It's still healing and that was weeks ago. I've been trying all sorts of remedies. Unfortunately, as soon as you cover it with anything, it just increases the pressure on the wound and makes things worse.

I had another 25-min trainer session but it's only very small doses at the moment. So not much pedalling for me I'm afraid. I'll try again soon but it's a risk until I have a prosthetic more suited to the cycling function.

On that front, I had a good session with my prostheticist (George). He has this funky new socket design ready for me when I upgrade to the next leg. It is pretty low cut but very clever and will enable full knee flexion without interference behind the knee. It's a carbon fibre socket and very strong. I will be able to clip on separate walking and cycling legs. Inspector Gadget look out! Only a handful are in use in Australia I’m told and not used elsewhere in the world. Must be for special people like me!!

He was pretty happy with my walking. I’m a little over 3 months in with current leg. I’ll get some photos of the new socket when I get the new leg – probably not 'til later in March I’d say. My next review with the Rehab Doc is at the end of the month.

As for managing the changes in stump volume, I am eyeing off the computer controlled vacuum pump George has on his own prosthetic leg – that looks the bees knees.

I also like the look of George's “ankle” which appears to be a multi-directional joint of some kind – great for walking on – I have most trouble walking on slopes and cambers as my prosthetic ankle is a fixed joint - no flexion at all.

I am having trouble getting motivated to exercise much I have to admit especially with the current set up not being all that comfy. I’m sure hoping the new leg will help in that regard.

I also need to keep working on the knee’s range of flexion. It straightens OK but I’m not bending as well. It has improved – my physio measured 100 degrees last week, it was 85 when I left hospital. Crap for pedalling though. She has given me some exercises/stretches for the knee and I'm having a weekly physio sessions to work on it. I guess I'd need to get to about 135 degrees.

I’m also in the process of designing/building a new home trainer, with a big flywheel and power meter. Should be a cracker. I figure I’ll be doing more indoor workouts once I’m back into the swing of things. I'll be writing a separate post on all that later. Here's a prototype:

No ergomo power meter for me though (like on this bike) - it only measures left leg power!!

A week or so back I also visited the track to watch some of the Australian National Track Championships. I met many of the Athlete with Disabilities crew (nice people) and then watched their Time Trials and Individual Pursuits. Amazing.

On the right is Michael Milton. Have a read about some of his amazing feats, including the world record for downhill speed skiing.

Hello to the girls from the Paralympic Committee ! It was great to say hi.

And I bought a Boule set and had my first game. I got beaten!! They'll keep :)

Enough for today.

Read More......

Thursday, February 07, 2008

An Hour of Power

For a change, I thought I'd write about someone else. It's not all about me you know!

In this case it's about my club mate, Jayson Austin, who had the guts to take on a cycling challenge which is not for the faint hearted. You see Jayson wanted to break the world record distance for riding a bicycle around a velodrome in one-hour, for his age category (Mens Masters cat 2 - ages 35-39).

The current record is held by Jason Sprouse at 45.641km. Think about that - go out and ride your bike at 45 km/h. Now do it for an hour. By yourself.

Now these record attempts are done under strictly controlled conditions. They must be done on an officially certified track, so that the track distance is precise. In this case it was performed on Sydney's 250 metre Dunc Gray Velodrome, which hosted the track cycling events of the Sydney Olympic Games in 2000 and many world level events since then.

There must be World level International Cycling Union (UCI - the world governing body for the sport of cycling) officials present to officiate and sign off on the results. Electronic timing must be in place and the tape of the record showing every lap split is to be provided to the UCI for certification. Electronically controlled starting gates must be used. The bicycle must conform to UCI regulations and be checked and passed by relevant UCI official. In this case the bike is similar in set up to those used by riders who ride the Individual Pursuit.

Officals from the Australian Sports Anti-Doping Authority have to be present to conduct drug/dope testing. The velodrome has to be hired. The local cycling administration has to provide its support and so on.

And that's before you even get on a bike and ride!

Jayson was preparing well for the event, had taken on a coach (my club mate and good riding buddy - Peter Montford of mypowercoach.com.au), was using an SRM power meter to guide training and had even done a practice trial at which he unofficially beat the target riding 46.41km.

I had designed a spreadsheet to manage the split timing data and provide his coach valuable feedback on Jay's pacing (relative to target) and with Jay's Mum calling the splits to me as we went - I entered the times in the laptop and could tell Peter what was going on.

Why bother with that? Don't you just go out there and ride it hard, and do what you can do? Well not quite. You see for aerobic endurance events like time trialling, good pacing is critical to attaining the best result (in this case the maximal distance in an hour).

So all was set. What happened?

He didn't make it, that's what. Missed it by 4 laps of the 250m velodrome. Arrgghh!

How come?

1. Well in fairness to Jay - he did get quite sick in the fortnight before the event. That's never good when you're about to lay it all on the line.

2. His gearing and pacing on the day were sub-optimal.

3. A fault in the timing system didn't help but was not, in my view, a primary consideration. His first attempt was aborted after 4 minutes as the electronic timing had not worked correctly. He had to stop and do a restart.

I'll talk through #2.

Here are some charts to show how it panned out. The first one shows his cumulative average speed through the hour. It also shows the distance covered at each 15 minute mark. Click on the chart to show a larger version.

It is pretty clear than Jay started too fast and faded as the hour progressed. His last 10 minutes were particularly painful.

How did that translate in power terms? Well here is a graphic showing his power output (yellow), speed (blue), cadence (green) and heart rate (red). Again,click on the chart to see a larger version.

This one tells the tale even more starkly. It's almost as if, without realling knowing it, Jay paced by Heart Rate (which is never a good guide to pacing a TT). His speed and power in the early stages were simply unsustainable and so began the long slow decay in his power output until it reached such a low level that his pace became very slow, so slow that it more than made up for Jay being over the target until the 53rd minute!

The other remarkable thing to note is Jay's average power for the hour. An amazingly low 242 watts. So despite comments from some that considered him to be less than aerodynamically positioned on the bike, Jay's Coefficient of Drag by Frontal Area (CdA - a measure of how "slippery" through the air you are) is estimated to be less than 0.21, probably close to 0.20. That is very slick for a time triallist and most testers out there would give their eye tooth for a CdA that low.

Could he have broken the record on the day? Absolutely. How? Well the data clearly shows that Jay really should have listened to his coach's pacing instructions. While I was on the laptop collecting the split data - I would yell through to Pete that he was going way too fast. Jay however, simply chose to ignore the sideline pacing instruction to ease back and instead went by feel. Remember it's not a distance Jay hasn't tried before. But I don't think Jay counted on the mental effect of race day and the extra adrenaline it produces.

He didn't want to break the record - he wanted to smash it.

However, since Jay was determined to go faster than he was capable of on the day, had he followed the pacing instructions, started more conservatively, I am pretty darn sure the record would be his.

Anyway - a few of us are having a beer this weekend to conduct the post mortem.

So that it's clear there's nothing in what I say that Jay doesn't already recognise, here is his own summary - in his own words:

“Just An Hour”-the Day

Oh so close but not to be. What happened-I blew up big time- more than anytime on the road when I had gone out as an attack rider for my team in races or when I bonked from hunger flats. This was harder than an ironman but I gave 110% & had nothing left. I experienced blurry vision and hit the pads in the last 10 mins of the event & fought hard to lift the pace when I knew it was over. I was determined I would finish but it sure was hard BIG time.

What went wrong -easy in hindsight? Being sick with a strep throat & asthma since 21 January & on antibiotics did not help especially the final track workouts which we would have used to determine the gearing. I have ridden when sick before but nothing of this intensity and relentlessness. I overruled Coach Peter on the gear-stuck with 59 x 16 believing that another gear may have been harder on my respiratory & overruled him again on the pace. I had been on target before the sickness to go, we thought in the 47kms + for the hour. & I wanted to really break the record by a big margin. Pace would be as per training I said. (On June 17, 2007 I had ridden 46.41 km in an hour with no problems or any predetermined pace.)

Saturday morning felt better than I had for a fortnight although I was already starting to feel nervous. Bike was ready and it was pouring rain but warm OK. Had an easy 20 mins on rollers & some coughing but not too badly. Started hydrating with First Endurance EFS & water & watched DVD of Chris Boardman .That got me choked up but I was feeling up to it.

At the Dunc Gray Velodrome all was ready-Kevin Young had worked hard to get me an area with access for a fan & away from some of the crowds. All was good. Warmed up well and took to the track & felt great. The new TWE chain ring was so smooth & the bike moved so nicely.

The gun goes & I felt good- cadence was a bit high 109 but would slow over the next couple of laps. Don’t look down-affect aero dynamics-helmet great-concentrate & focus-laps are coming up quickly –trying to slow as too fast –feeling very good. Coach Peter calling me to back off-found out later was hitting 51.5kph/111 cadence for over 3 mins but trying to slow was difficult, it was just rolling & the adrenaline was up.

At 4 mins Peter is waving me down & yelling to stop-what’s going on-Oh no the electronic timing didn’t start. Regroup-stay calm-heart is racing-breathing affected-asthma spray-go again –bit slower.

50 mins-Really hurting and I knew the record was gone- just had to finish-don’t fall off bike. It is over & I missed the record. Congratulation to Jason Sprouse who holds the current record it is yours for the time being. I will try again & be wiser the next time.

Went to the Handlebar Tavern for a beer and a talk with some of the team and then drove back to Terrey Hills. Had beers & pizza at Terrey Hills Tavern with my parents & then home.

Sunday- feel OK a bit upset but body, legs, back are very good. My neck is sore from holding the position. No saddle sores-the chamois in the Hot Design skin suit was fantastic-even has a saddle imprint in it.

Some Facts from the Race—restart

1 km 1.21.58___10 km 12.30.15___35 km 44.57.12

2 km 2.33.94___15 km 18.50.38___40 km 52.23.71

3 km 3.47.14___20 km 25.11.48___44.628 km 60.00.00

4 km 5.00.57___25 km 31.39.40

5 km 6.14.90___30 km 38.13.26


1 Should have cancelled attempt when I got sick-result definitely affected

2. Should have cancelled attempt after completing over 12 laps when electronic time keeping failed- result definitely affected

3. Should have not set the pace so high- result might have been different.


I would like to thank my sponsors: Peter Montford-mypowercoach.com.au, Steve Hogg-cyclefitcentre.com, Austin’s Timber Flooring, First Endurance Aust/NZ and my club Bicisport Cycling. Other supporters whose help & encouragement has been invaluable were, Jim Tzakos-Proline Technology P/L, Lindsay Harvey, Warwick McAlpine, Vic Davidson from LactAway, Greg Ryan-Twe Wheels, Mike O’Reilly and training partner, Peter Verhoeven.

Cycling Australia, Cycling NSW, Bill Clinch, Kevin Young, Brian Crawford, Paul Craft, Cycle SportNews and the officials and people in attendance at the Dunc all encouraged me and I am truly grateful for your support.


Read More......