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Monday, February 27, 2023

The Tale of a Tailbox

 For more about 9 years I have been riding recumbent bikes and trikes which have an aluminium main beam as a frame, and a clamp-on unit combining the bike seat (otherwise known as a lounge chair) with luggage storage and improved aerodynamics. 


Since 2014 I have been riding this style of bike and trike with a more upright seat but aero tailboxes. Photo Melvyn Yap

Maria Parker leaned back for aero on a Cruzbike (Photo courtesy Cruzbike)


Some recumbent bikes like the Cruzbike Vendetta have the rider leaning far back to reduce frontal area, and so become aerodynamic. Instead of this, my aerodynamic method is to have a full aero tailbox behind my back, so that my body is not bluff and there is less friction-causing turbulence behind (this reduces the drag coefficient Cd). As well, I try to make my HPV’s “clean” with as few messy protrusions as possible.

Previous "lightweight" tailbox: Standard plywood tailbox with coreflute side-panels and lid.


The tailbox also carries stuff!  Although I have a car, I don’t use it for regular shopping or commuting, and my recumbents are load carrying workhorses.  Up till recently I had one basic plywood tailbox design for everything. Most of it was developed during study at Monash university. The box has swap out side panels and a lid which can be changed from plywood to corflute to make it lighter.

Like lots of changes, it takes an unexpected event to bring things on, and force changes which were ready and waiting come to the fore.  Winston Churchill summed it up by saying “never waste a good crisis”. I am thinking of covid 19, and the way it accelerated the ability to work from home as an example. But in the context of my tailbox, it was Jamie Friday stacking into my bike and damaging my tailbox which started things moving!

This happened in Ballarat in 2019, when we were on our way to the OzHPV challenge in Geelong.  I had organised 2 days of touring as a nice way to extend the OzHPV challenge holiday, and we took the train to Ballarat, rode on to Aireys Inlet and then to Geelong. Soon after starting out from Ballarat Station, I braked suddenly, and Jamie following close behind stacked into me, damaging the plywood ‘box. We were able to patch it up, both temporarily for the rest of the day, and (a bit better) for the next few days and the Challenge.  When I got home, I was left with a damaged tailbox which was a bit heavier due to the repairs. I thought that a bit later down the track, I could strip away all the damaged rear part of the box and make it lighter and more aero by replacing plywood with corflute and rounding off some corners.

Eventually I did this and results were good, with a 2kg reduction in weight compared to my standard tailbox. This wasn’t really enough for me though, I’m an engineer and if I make something, I want to be able to make the same thing at least as good again without too much effort, so that means doing drawings. The original boxes are based on 4mm CNC routed plywood and I got the same mob who cut the last lot of ply, Sean and Horn to make 2 new boxes. 

The wood for the job needs to end up waterproof, and it’s tempting to ask for marine ply. But 4mm marine ply can mean just about anything from low quality timber to high quality hoop pine 5 ply. Birch ply is reliable and I’ve found quality to be consistent. I bend the ply for the tailboxes, and its nice to have this happen reliably. Dropping the timber off for the routing was done by car, but when the routing was ready I was able to pick it up by bike, its a flat 5k ride each way, mostly on bike tracks.

Now a few months down the track, I have made both tailbox kits up into tailboxes. These days I am quite comfortable with 3d cad and home 3d printing, so I have put a few 3d printed parts into the boxes. These help make accurate curves on the corflute, make drilling into the tailbox stronger and removes some manual processes.

The boxes with extra corflute still carry luggage. Even though they hold less than the full plywood boxes, they still carry vastly more luggage than most standard bicycles and the luggage in the box to doesn’t add to wind resistance.

The great revelation about these new boxes is not that they are lighter and probably more aero than my all-plywood boxes. It is that I can relax and not stress about making the all-plywood boxes lighter or more aero, and just focus on making them better for load carrying. Similarly I don’t need to think about load carrying on the new lightweight boxes.

Trike in load-carrying mode with ......

raisable lid for carrying bulky items

Leaning trike with milk crate bolted to tailbox lid.

So I started improving the heavier box by using a plywood lid instead of corflute. The heavier lid doesn’t blow around in the wind much, so I can skip having to close it with a catch. With the plywood lid its simple to mount a milk crate on top, as it only takes one bolt. And lastly I have leather straps holding the front of the tailbox lid. The length of these straps can be adjusted, so if I want to carry bike wheels or other bulky items, I can raise the lid by up to 100mm without using tools.

I like the idea of the milk crate on top of the box. It adds wind resistance but this just makes it as aerodynamically bad as a standard upright bike! As well, I can pick up a milk crate wherever they are, so I don’t necessarily have to bring my own crate to carry more luggage.

There is a way to go with improving the lightweight tailbox. For now it doesn’t provide a fairing for my head, but I think this can be put in without changing the plywood frame or the lower part of the coreflute. Pictures of fairings at the recent world champs have been an inspiration.

Trike with trailer


The tailboxes seem to fit in with the modular trike and bike designs I am slowly finalising (see  ). The bike I have made is lighter, more aero but slightly more complex, while the trike is simpler, heavier and less aerodynamic. So the new tailbox matches the new bike, and they are parts for an aero speedmachine with luggage space, while the trike and timber tailbox go together for an urban load carrier which is still quite fast. I’ve mounted a trailer on the trike too, and the hitching arrangement ended up quite simple.

After my most recent ride in Cobram with the aero bike.

Tailbox interior with 3d printed shapers in white and water bottle holder.

My leaning trike designs are already on the internet as free plans in both aluminium and timber frame versions. Recently recumbent bike plans were added, and the new tailbox design has been put up in the last few days. Bike and new tailbox are variations on the aluminium trike design.

Regards Steve Nurse, 27/2/2023


Sunday, February 12, 2023

I Don't Do Hills 150k ride

At Rodney's

The athlete (me) and the machine.

Brevet Card


Steady as she goes, riding.....

with Alex McNee.......

in the "I Don't Do Hills 150"

Cracked it!  Just over 20k average for the 150k.


The I Don't do Hills ride was yesterday and I very sensibly switched from doing the 200k to doing "only" 150k, so joined Alex McNee for the whole of the ride. He was very well equipped with dyno lights, and dyno powered speedo and navigation. I could relax about navigating and just ride, and use my own Garmin GPS as a speedo / ergometer.

So most of the way we were doing just over 25kph, and the k's went by quite quickly. Occasionally, without putting too much effort in we were up to 32kph, helped by small downhills and tailwinds. We left at 6am to beat the heat and had brief stops at Katatamatite (Muffin and Big M Chocolate milk for me) and Yarrawonga (Some form of schnitzel burger and half a litre of coke.)

The last bit of the ride was into a headwind and a bit tougher but we still averaged just over 20kph for the whole ride. Rodney had done the 100k version of the ride and greeted us as we came in. We had a cool drink and a chat with him and then headed off.

Rodney is a very accomplished Audax rider and is closing in on 50,000 Audax km, a huge achievement.

Not Sure what's next for me in Audax, will keep you posted. Regards 

Steve Nurse

Wednesday, February 8, 2023

I don't do Hills Prelude


Dropped some carrot cake off at George and Chris's before training.

My bike fell on my plastic tool box which was sort of the last straw for it. Had the same box in yellow stored in the spare room, so am able to use that now.


After completing Buckley's Ride last month, I am back for more and have signed up for the 200k Audax I Don't Do hills Ride around Cobram.  The ride was a nudge for me to visit my Aunt Mary who lives nearby, and the visit to my Aunt Mary was a nudge to do the Audax ride!  Anyway, I've done 3 training rides sofar and will record all my training rides here. I'm feeling good, and don't think I've completely lost the fitness gained prior to and including Buckleys. Wish me luck, will report more soon.

 Update Feb 9, 2023

Strathmerton Op Shop and some purchases shown below.

Decor lunch box complete!  The same as the tool boxes above but with bonus water / ice bottle thingy. Ah! Thats what the ridgy / ribby things in the side are for. To keep the bottle in place. Hmmmm.

Some Splork (spoon, knife, fork all in one) type things. Good for a laugh when my girlfriend Mary and I have our next carrot cake.

Near Barooga



After a slightly frustrating night on the computer trying to upload ride with GPS (route mapping) data to a Garmin bike navigator, (I got there in the end), I was up and going late this morning (10ish) on my way up to the ride. The drive went well, and it helped to stop in a few shady stops to eat, check navigation, and generally stretch and pee before moving on.

The Srathmerton Op Shop was open when I got there just before 2. I've stopped there a few times and usually find it quite good.  Then on to Cobram where I'm staying at a quite friendly motel where the owners like to hang out outside, and there are a few silo building workers hanging around and splashing in the pool.

Once I'd settled in I did about 20ks on the bike up past Barooga, coming through the golf resort part of town on the way back. Nice quiet ride, I've had a big pub dinner and am settling in for the night.

Update Feb 10

Church oppie in Cobram. The same church is in the background in one of yesterdays pics.

Discarded golf trolley as op shop sign

Mary  Nurse  in Barooga


 My Aunt Mary had rung while I was having dinner at the pub last night, and changed our meeting venue from her place to a caf in Barooga. So this morning I rode the bike from Cobram to Barooga, kept on going to Tocumwal, and then came back to Barooga to meet Mary, and we arrived at the caf at about the same time. We arranged for me to pick up a knitting machine her Dad Eddie had designed, made and invented, which at the moment noone knows how the f*&%*ing thing works. (I had seen it 8 years ago and documented it in my blog post here. Since then, both Mary Nurse's husband Geoff and my wife Christine have passed away. Time marches on!) 

Now its evening and I've just driven out past Barooga to pick up the knitting machine from Mary's, it was on the top of a cupboard in a dusty plastic bag and it itself dusty. Anyway it will make its way back to Melbourne with me tomorrow where I will start to clean it up.

As well I had dinner at the pub with Alex McNee and organizer Rodney Kruz who are both on the Audax ride tomorrow. I've bailed out of doing the 200k ride and am "only" doing the 150. I was going to be the only one doing the 200, and now will be riding with Alex (also recumbent) on a shorter distance - sensible given the 36 degree predicted temps. Signing off now except for adding some pics. I still have to pack the car as I am leaving Cobram straight after the ride tomorrow.

Alex and Rodney "Of course the solution to the whole bike riding thing is quantum time travel and we have just the machine for the job"



The motel has wonderful wifi so I have been youtubing a few faves that have kept me going

Until You, Kerryn Fields

Don't be denied, Neil Young. An oldie but a goodie, I have it on record at home. They sing "don't be denied" about 200 times in the song, and then you play it 1000 times and eventually it sinks in.

Training Rides

Aireys Inlet to Lorne and return 38.2k

36k kew boulevarde

39.5k in 2hours 11 minute kew boulevarde

20k Cobram to Barooga, 5k out towards Tocumwal and return.

About 40k in about 2 hours, Cobram to Tocumwal via Barooga and return.