Thursday, 18 December 2014

Making ends meet.

It's been a week. A quick week. The last ramped up week of long endurance base sessions before a deserved rest. It's also the last week of the 30 day cold shower challenge. That ends Sunday.
Rather than repeat myself, or admit to a few smaller sessions I have slacked off on due to the dark mornings (warm bed) and the dark nights (coal fire) putting a dampener on things I have also delayed blogging on the premise it is better to be quiet than repeat myself or be negative and not motivate people.
It's an expensive time of year too though, and it occurred to me today that that is worth blogging about. Any way you can save some money is worth consideration in my mind.
It's not just busy and expensive because its Christmas, it's also the time of year when all the big events for next year are open and you start carefully watching the entry lists to see how quickly they are filling up. Before you know it you have little choice but to fork out for entries or risk being a spectator, and the bank balance can soon take a serious wallop. Today alone I got 'invites' to 4 events in 2015, and spent the afternoon thinking "I'll pay for that one then, this one there... oh, but I need this replacing, and if I hold off and enter that in Feb there's no council tax to go out and we can also book a hotel..." You know how it goes I'm sure....
Everyone has an annual budget. That budget might be £5000, it might be £500. Whatever it is, that doesn't just have to cover entry fees, it covers travel, accommodation, and more importantly kit that might need replacing or improving. This is a tough ball to juggle - once you get more serious about your sport you need the right kit to be competitive, but you don't want to spend a penny more than you have to. After all its got to be better to spend the money on entry fees and competing than it has on having a load of equipment and no money left to race, right? And that's where I did something last year that saved me around £500 and bought me a good few minutes on the bike.
I'm pretty outspoken about how much of a waste of money most kit is. Overhyped, over branded and mostly not worth anything more than a bit of hard graft can't improve on anyway. Something we can't escape though is physics, and the all important chunk of that we call aerodynamics. The stats are out there clear as day on the benefits of good aerodynamics, and a great place to start is a decent set of wheels.
The problem with wheels is they are expensive, and so I had avoided entertaining them up until the point where I just wasn't getting the improvements in my times that I used to, despite training harder and harder. Then I hit on an idea. Having looked at the various designs, and deciding that the weight of my wheels wasn't an issue, the next thing to consider was a disc wheel to really help cut through the air. 
I quickly concluded buying a budget end heavy lump of a disc had to be false economy. What I gained in aerodynamics I would lose in weight, and a decent carbon one was going to cost me dearly. For a solid back wheel I decided that with a bit of thought and patience I could make a lightweight 'in fill' for a fraction of the cost of going out and buying one. So that's what I did. And that's what I want to share.
I was lucky enough to be able to get sheet plastic through work for free. I knew what specification I wanted. Either ABS or GPPS (the type of plastic sheet I was looking to work with - both much lighter than PVC) and rigid but flexible. Anything used in a process called 'vac forming' would be ideal. I got a few sheets sent to me of varying thicknesses and settled on the thinnest suitable one I dare use, 200 microns thick. That's 0.2 of a mm. This I got free, but if you want to buy some it will cost you about £15 a sheet. At most these wheels are going to cost you £30. Just do a Google search on PS or ABS Sheet suppliers. Be sure that the width of the sheet you order is greater than the diameter of your wheel. 
I have put some images I took below with simple to follow instructions.

                                                                The unrolled Sheet PS.

Remove the back wheel and measure the radius from the skewer entry point to the edge of the dish where the spoke disappears into the outer edge of the wheel. Add 2 cm onto the radius depth.
Next secure the plastic sheet to a board with nails in each corner.  Knock a nail into the centre point of the sheet and tie some string to the nail.
Measure the string out to the radius +2cm distance you just took from the back wheel. Tie a nail into the string at that point.


Keeping the nail straight and upright, carefully and systematically work round scoring the sheet, keeping the string pulled taught. Measure intermittently with a tape measure to ensure you are scoring out the required radius evenly.

Once you are happy you have got the right size marked out, cut the disc out. I tried a few methods, a stanley blade was sharp, but left jagged edges. In the end I settled for my wifes dress making scissors. Sharp and smooth, and adds an unexpected element of danger when she finds out!!
Once you have cut out the disc, cut out the centre hole and then a straight line from the outer edge down to the centre.
Carefully slide the cassette on the wheel between the slit and ease it down and jiggle the centre hole around the inside of the cassette.
By adding the extra 2cm at the start you can now finely trim the sheet down to the perfect size so the rim of the disc sits on the dish about 3to 4mm just outside its inner edge. You need to leave a good bit of dish visible between the disc and the tyre for securing the disc to the wheel.

Once the disc is sized up and you are happy take it off and use it as template for the other side. You now have both sides ready to fix up.

I tried various methods, including bits of tubing and cable ties, but found that the best way to secure the disc was using nothing but a good quality duct tape. The glue in the duct tape bonds with the plastic and fixes very securely. Run it the length of the spokes and press it firmly and snugly around the spokes as I have started doing in the image above. Finally cut a flap in line with the inflator valve.
Once you repeat with the other side take your time. Slide you hand up and curve the sheet gently to get access. There should be enough flexibility in it to let you bend it to gain access.
Once it's stuck down both sides it should look something like this.

Now secure the sheet onto the dish by using good quality flexible electric tape. This will shape smoothly around the wheel, if you take your time you can pull it evenly round without pucker or ridges. Run another strip straight down the centre seam. Press it all down firmly.

Once everything is secure clean it up using white spirit or similar, and wipe over with a cloth.

The finished article below.

Before (complete with Aero Pineapple)

After creating this disc I took it out on a well used 10 mile TT route. I instantly took 40 seconds off my PB for that route. An unbelievable time saving at an incredibly low cost. The additional weight to the wheel is a mere 98 grams. It really is a thin and durable disc. Buying a wheel like this would have cost me knocking on £600. That's the entry fee on another 3 x 140.6's. Result.
I have since used this wheel extensively and am happy to confirm it holds up in all weathers and has not once come loose.

It has been used in anger without issue - pushing me to a 24.3mph bike average in the Club Sprint Relays and my part in our team Silver medals, and also at Olympic distance bagging me an age category win and 5th overall. These results wouldn't have been possible without it.
Bored in the holidays? - Get out in the garage and spend some time now to save money and minutes in racing next season.

If you want any more info on the wheel please get in touch and I'll be happy to help.