Tuesday, 22 May 2012

Quibell Park Velodrome

Quest, Quattro & Wobbly Bob
Firstly a big thanks to Jeff (blogwat) for all the photographs, I have not used any of the ones I took, as his are so good.
We arrived at a cold and overcast Quibell Park Velodrome at about 10am on Sunday morning after a three hour drive from High Wycombe. Having said our hellos and signed on for the race, I did a few test laps. The handling was still horrible, just like it was at Reading and my low slung spats were catching the timing loop wires that were taped across the track. I stopped to check the wires and they seemed OK, so I carried on for a while.
We then all lined up for a three lap standing start time trial, which is not my favorite event, in a hefty Quattro but I gave it my best. The first bend on the track feels horrible from a standing start because the speed is low and you feel like you are going to tip up on the relatively steep banking. By the time the second bend comes along, the speed is high enough to make it more comfortable. I rode the whole event in my middle chainring to give me better acceleration, but it did mean that I was spinning rather fast on the final lap.
Main Race
After the time trial, Martin the race organizer asked me if I could do anything with my spats to stop them hitting the timing wires. The wires are probably only about 5mm diameter, which shows how little ground clearance I was running. He was quite reasonably worried that I could un-stick the wires and drag them down the track, potentially damaging them and causing an accident. As my time trial performance was not very good and the handling was poor, I was quite happy to take them off completely. This also gave me a chance to look at the steering to see if there was anything obviously loose causing the bad handling, which there wasn’t.
Lee Wakefield's High Speed Crash
The main race was due to be a 40 minutes mass start but was stopped after 10 minutes because of the 42mph (67kph) puncture and crash of Lee Wakefield’s Beano. The Beano lost a lot of paint but Lee was fine and the race was re-started with him in his Quest.

Although it was my fastest race yet (about 28mph-no official results yet), I found it a little depressing as the handling was rubbish and Lee and Ian Fardoe both beat me easily in their Quests. Ian Perry was the fastest multi-track with his exposed knee Wobbly Bob. The bad handling of Quattro seems to have appeared since I locked the suspension. Ian Perry had a go after the racing and was amazed at the way Quattro kept changing direction and didn’t dare try and go fast.

Watching Ian Fardoe’s video of the event clearly shows me struggling to hold a line around the velodrome.
Ian Perry Flashing His Knees
I was talking to Jim at work the other evening about the efficiency of the drive chain in Quattro and it occurred to me that what I had assumed about the Sprags being locked is not actually the case. Because of the slight speed variation in my UJs, unless they are lined up, the drive shaft will drive one wheel and then the other, depending on the relative position of the UJs. I think the speed variation is only about 1.2% but it could create quite a bit of drag as each Sprag locks and unlocks under torsional and side loads. A cure would be to have the aligned UJs fixed to the drive shaft and the Sprags on the outside. Having said all that, on a velodrome, I am probably driving the inside wheel for 80% of the lap.
After the 30min race I did stop quickly and turn Quattro over to see if there was any heat in the bearings etc. The only thing I could detect was a warm disk but that was probably from stopping quickly.
Steve in his Beano
I suppose I should mention that (subject to publication of the race results) Steve won the time trial and the main two races despite his chain falling off in the 30 minute race. He had to stop to put it back on but still managed to beat a newly spatted Howard Yeomans in his Great White.
Howard Yeomans in his Great White
I am beginning to think these spats are over-rated....!
I had a useful chat with Geoff Bird after the weekend and he mentioned my long connecting rods from front to back maybe vibrating on the rough track. I think he is probably right about the rods. When I looked at them yesterday, the rear ones which are thin and kinked seemed to be working in compression, which is not good. He also reminded me that I had similar problems on bumpy roads around High Wycombe. Hillingdon and Castle Combe circuits are smooth enough not to be a problem. Back to two wheel steering for a while I think.
UJ Outer & Bearings
While putting Quattro back into two wheel steering mode, I decided to check all the front bearings as well. I stripped down the front axle and found that my UJ bearings were knackered, one side slightly rough and the other side very bad. I know one of the bearings failed completely on the last day of ROAM but I can't remember how many bearings I changed when I got back to the UK. I have got 8 new ones here so I am going to change the whole lot. Definitely need to go up a size on the re-design, at the moment they only seem to manage about 1500miles.
After getting back from the frozen North on Sunday evening feeling a little depressed about Quattro and my performance, I have again got reasons to be optimistic. I will replace the bearings, sort out the steering and then it’s off to Reading again for another testing session........

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