Nice - the battery limitations were severe this year weren't they?! No fun chemistry.
I was prepping a bike for it this year, but had a bad accident that stopped me from completing it (and competing). I got around the battery limitations using those 20AH A123's and a DC:DC converter in the home-made controller to get maximum energy density out of them - it just fit the price and weight limit. But I never got to try it out
Couldn't even take the Vectrix VX1 for display either this year (sulk).
Yea as soon as we saw this years restrictions we knew it was likely because of us hahahaha. We had 26kg of batteries on the old bike, it's a shocker to move around and the weight was definitely our losing factor
Does using a DC:DC cause an increase in current the same way you would by changing voltage? Plus a bit for efficiency I guess. I honestly didnt know DC:DC's existed til the other day and now i'm continuously checking them out in the jaycar catalogue lol. Will you be there this weekend to watch the race, I'm sure they wouldnt mind you bringing what you did get done to show off part of the construction stage of bikes?
John in CR wrote:Jman,
It looks when you stretched the wheelbase that it may have decreased the trail a bit on a bike with not a lot of trail to begin with. I had exactly the same problem with my cargo bike, and it got worse as I tucked down for better aerodynamics. You need to increase the trail to get more stability at speed. From you pic, I looks to me like you have only about 1-1.5" of trail. How to change that at this late stage is the problem. I hacked my headset off and welded it back with more slack head tube angle. If yours is AL, that's not an option, so you have to get the tire's contact patch to trail the straight line looking down the head tube by more than it does now by some other method. It's a smaller wheel on the back that would help, though I don't think that's really enough without going too small due to the fairly long wheelbase.
To verify that more trail would make a difference, loosen the headset and turn that front wheel backward if there's clearance with the frame. That will give you more trail than you need, but taking it for a spin that way would demonstrate the difference in stablitiy at speed. It would just be very sluggish at slow speed with that much trail. You could easily find another fork in time that has less offset, which will give you more trail. If the one you have is steel, you may even be able to bend it straighter.
You definitely want stability at speed, so then you can shorten the handlebars for better aerodynamics, and wobbling will hurt efficiency. Are you allowed to pedal? If not then get rid of anything you can, chain derailleur, etc.
I think you might have missed what I said haha, this years bike is the frame in the background, the complete bike is last years: now it was one of the most stable bikes I have ever ridden, weighed a ton but you just couldnt tip the thing, I crashed it once by leaning it too far and scraping the foot tray, all it did was bounce back up and keep going hahaha
But you are right about the headset angle, it needs more angle on the fork to take out some wobble, however as you said, its pretty much too late. I have another fork I'm going to try out with it incase its different but I'm pretty sure theyre the same. I will look into bending it though but I'd really prefer not to unless I added some extra strengthening. One upside though is that it starts getting wobbly over our minimum required speed of 30kph, so it should be manageable for the race
But yea, no pedalling whatsoever, we dont even have a bottom bracket haha, but we do need the derailleur to let us shift for more oomph up the hills.
Heres a couple more pics I found floating around on my phone, nothing too recent though sadly