Monday, 26 July 2010

Dunwich Dynamo done



112 and a bit miles, 125 in total for the night. Chickened out of using the Brompton in the end and took the Hewitt tourer, which turns out not to roll much better but at least doesn't pogo when I stand on the pedals (the "firm" Brompton elastomer turns out to be not very firm at all; the jubilee clips will need to go back on).

Some odd sights, including a bloke carrying his (large) dog all the way and the Dulwich Paragon train with blue and white fairy lights.

Left just after 8pm, arrived just after 5am. First half went right according to plan, with a very fast run through to the feed stop at Sible Hedingham. Second half started fastish but then my riding companion faded a bit. Then the drag from Bildeston up to the Wattisham plateau took it out of me too and although Mike recovered after a bonus feed stop (someone selling coffee, tea and bacon rolls near Gosbeck) I got slower towards the end. However, it was a respectable average speed.

Still got a slight touch of the "never agains" but I suppose I'll be there next year, as I have been for the last six.

Wednesday, 21 July 2010

It's back!

And all assembled.



It weighs 23.2lb like this (3-speed, no mudguards but hub dynamo and lights - the rear light is battery powered). Probably 22lb minimum with no mudguards and lights. When it's running as a 4-speed and has Marathon Plus tyres and lights, probably 25lb.

Saturday, 17 July 2010

Brompton update

It's been a week and the dealer still hasn't put in the new bushes. A pox on him. One day I'll buy the £200 tool and charge other people to do it.

I have assembled the front and rear ends ready for when the frame comes back, so it will just be a case of bolting on the rear triangle (I'd prefer to do this myself to ensure the bushes are really well greased and the threadlock is a bit less permanent than Brompton's), fitting the BB and cranks and then cabling it up. Oh, and I need to glue in the new seatpost bush.

I may get it back on Monday, which is cutting it a bit fine for the Dunwich Dynamo next Saturday.

Sunday, 11 July 2010

Training for the Dunwich Dynamo

One problem of having a family and children is that long bike rides are difficult to fit in without causing resentment - after all, you can't really go and ride at 18mph all day as a family activity. This poses a problem when there are two weeks to go until the 112.7 mile Dunwich Dynamo and, as usual, my distance training has been minimal. Since January:

About 80 commutes of 5.5 miles each way. No.
One night ride of 80 miles in April. OK.
One Sunday morning rumble of about 36 miles in April. Not really.
One night ride of 80 miles in June. OK.
One Sunday morning rumble of 32 miles last weekend. No.

So today we all went over to my parents' house and the family went in the car while I went by bike. Fixed gear to make it harder, and the hilly route (which includes half a mile of 1 in 10 to get over the Marlborough Downs). 60 miles in very hot conditions, on fixed, at an average of about 16mph. That'll help a bit. The Dun Run is easier because it's cooler (less of a problem with salt depletion and cramping), flatter and I'll have a freewheel.

Reassembling the Brompton

The frame and stem are resprayed so I collected them yesterday, but immediately dropped the frame off to have the rear pivot bushes fitted and reamed (a very quick job for the dealer; the worst part is getting the rear triangle off, which of course he doesn't have to do).

I've assembled the front and rear end as far as I can without the main frame, which actually has very little attached to it anyway.

Here's the stem and handlebar with the modified shifter. It hangs just in front of the bars so that the long lever can be pulled down to engage "1", only used with a 4-speed hub like the FW. For 3-speed hubs you just use 2 to 4.

Argos masked off a bit too much of the handlebar catch nipple threads (the black plastic Tic Tac sticking out from the stem) and I'll have to put red nail polish on it. This will look OK over the white primer, since it's only a bit of thread.

You'll see that I now have bottle bosses on the stem. There are also two on the main frame tube, just before the "kink". These are about the only places you can have them and still fold the bike.



Friday, 9 July 2010

Brompton crank FAIL

The standard Brompton crank is made by Stronglight and the chainring is swaged directly to the RH crank arm. This is a cheap way to make it (although a 54T crankset is still about 60 GBP to buy), but the disadvantage is that strong riders can rip the assembly apart under starting torque:



This isn't mine, thank goodness - this is the sort of failure that really leaves you stranded.

So I decided to get a proper forged crank with a bolt-on chainring. The Sugino XD is cheap, gives the correct chainline with a short 103mm bottom bracket and looks neat.

However, there is a problem. Most cranks have too narrow a Q-factor (that's the distance between the pedals). If you put a straight edge on the back of the chainring it will usually be about 15mm behind the pedal eye. The Brompton crank is much more "sticky-out" and this dimension is about 25mm. If you go too narrow, the crank hits the folded rear frame and also reduces the already-perilous heel clearance at the rear rollers.

It looks as if the Brompton crank is going to have to go back on for now. This also means reusing the nasty FAG bottom bracket with possible the worst removal tool known to Man.

Wednesday, 7 July 2010

Weight report

Under 11st 10lb this morning. That's the first time for 8 years. Done by...erm...only eating one chocolate bar a day. It's not supposed to be this easy.

Very funny picture taken by my YACF friend Jonathan last Sunday. We were going for a suggestively camp look, as if it were a Rapha advert. I've just ordered and posted 136 jerseys for YACF from the rather brilliant Owayo. I half designed this "King Of The Mountains" one.