Kingpin progress

[rjb]

Heres the latest update to my Kinpin, I have gone back to 3 speed sturmey having built a dynohub rear wheel. The front B&M lumotec had to be rebuilt due to the failure of the internal components, so was a nice addition to this machine which is my runabout shopper. I built a simple bridge rectifier and used the existing switch and standlight capacitor. When i checked the dynohub generated voltage i was surprised it was only 3.2 volts after rectification to dc and not speed related, this must be a property of led diodes, the exact technology of this is beyond me. Realising that this would be the voltage on a cheap rear led light i wired an old smart 1/2 watt clone into the arrangement by soldering a feed direct to the 2 battery terminals fed from the output of the lumotec. It works very well, the rear light is very bright and the voltage dosent rise above 3.2 volts so its like having new batteries in all the time. The standlight capacitor ensures the rear light stays on for a good 5 minutes when stationary but the front dies after a minute or so.
I have also fitted 150 mm cranks, shortened stronglight escape chainset. Having used chainsets with normally 170 mm cranks but occasionally 165 and 175 and not really noticed a difference i was surprised how odd the short 150mm cranks felt initially. The wiring is not as neat as some but will get tidied up later. Enjoy.

this is how it was with 7 speed derailleur and an ahead stem arrangement.


and this is it now with the original bars and stem but with the 406 wheels and dropbolt brakes.

[fastpedaller]

That looks good. 150mm cranks do seem odd at first. I used to ride a fixed wheel bike for time trials with 150mm cranks - all my 12hr rides were done this way, and I found it worked for me. When I used to get on my regular bike with 170mm cranks it seemed as if I was turning my feet around a huge great circle! Strange how the body adapts. I'm not sure it makes much difference one way of the other, within reason of course, as I'm sure 100mm cranks would just be too short, and 300mm ones would touch the ground! I now (no longer racing) use either 160 or 165 cranks, which I find to be a nice compromise.

[Cyril Haearn]

That looks good. 150mm cranks do seem odd at first. I used to ride a fixed wheel bike for time trials with 150mm cranks - all my 12hr rides were done this way, and I found it worked for me. When I used to get on my regular bike with 170mm cranks it seemed as if I was turning my feet around a huge great circle! Strange how the body adapts. I'm not sure it makes much difference one way of the other, within reason of course, as I'm sure 100mm cranks would just be too short, and 300mm ones would touch the ground! I now (no longer racing) use either 160 or 165 cranks, which I find to be a nice compromise.

Why did you use 150 mm cranks?

[willcee]

Likely because of the lower ground clearance.. 406 wheels instead of 451, never measured the bb drop distance, est about 2 inches...as i have a Raleigh 20 with alloy 406 wheels .. 451 alloy wheels are like hens teeth, like hard to find.. i didn't change my cranks and haven't yet had any pedal strike.. nice practical useable machine , enjoy.. will

[rjb]

On the kingpin, changing from 500a to 406 size wheels has dropped the bottom bracket reducing ground clearance. Hence the change from 165 to 150 cranks
That's a nice Raleigh 20 there Will. Looks like you have drop bolts on your brakes too

[Cyril Haearn]

On the kingpin, changing from 500a to 406 size wheels has dropped the bottom bracket reducing ground clearance. Hence the change from 165 to 150 cranks
That's a nice Raleigh 20 there Will.

+1
I would ride it with a fixed wheel, very practical compact and light, could be good for starting conversations too
I guess fastpedaller used an UpWrong for the 12, that is the reason for the question..

[willcee]

Thx Guys, it was a project some years ago, and believe it or not it rode really well, as good as any of my lightweight steels of that time. This was everything modded, headset , bb threading, dropped a new brake bridge in the stays, welded on a derailleur hanger , and put many brase ons for cables ..its lighter as well..named it Zwanzig.. aka 20 in German..will

[fastpedaller]

That looks good. 150mm cranks do seem odd at first. I used to ride a fixed wheel bike for time trials with 150mm cranks - all my 12hr rides were done this way, and I found it worked for me. When I used to get on my regular bike with 170mm cranks it seemed as if I was turning my feet around a huge great circle! Strange how the body adapts. I'm not sure it makes much difference one way of the other, within reason of course, as I'm sure 100mm cranks would just be too short, and 300mm ones would touch the ground! I now (no longer racing) use either 160 or 165 cranks, which I find to be a nice compromise.

Why did you use 150 mm cranks?

They were available secondhand at the time and I though - Yeah whynot?

[tatanab]

A 1973 model. I wanted a pub/shopper so all I've done is to reduce the gearing to a 65" top gear (I live in a hilly area), fit quality cables and uprate the front brake to a dual pivot -- plus of course fit toeclips and straps. It cost me £30 about 4 years ago plus £30 in new bits.

[Brucey]

that is the first kingpin (in otherwise standard condition) I have seen which has clips and straps!

cheers

[mattsccm]

Excellent. I have a brace of the beasties doing nothing. Have long thought of tuning one into a time trial bike!
Would some one like to summarise the best mods to lighten the thing a bit and improve it generally or point me to some other threads please.
Which is faster, blue or brown?

[Cyril Haearn]

Yellow is fastest

[rjb]

Would some one like to summarise the best mods to lighten the thing a bit and improve it generally or point me to some other threads please.
Which is faster, blue or brown?

Try the search facility using kingpin and browse the results. Don't be tempted to try using a quill stem in the fork column, it led to premature failure of the fork column where it's slitted for the handlebar clamp, posted by Russ Coles if I recall.

[rjb]

Would some one like to summarise the best mods to lighten the thing a bit and improve it generally or point me to some other threads please.
Which is faster, blue or brown?

Try the search facility using kingpin and browse the results. Don't be tempted to try using a quill stem in the fork column, it led to premature failure of the fork column where it's slitted for the handlebar clamp, posted by Russ Coles if I recall.

Here it is viewtopic.php?f=5&t=55637&p=464222&hilit=Kingpin+Quill#p464222

[tatanab]

Would some one like to summarise the best mods to lighten the thing a bit and improve it generally

There is little that will reduce the weight by much. Not a Kingpin but a similar small wheeler I reduced the weight by about 3lbs by changing steel for aluminium rims, bars, cranks, saddle pillar etc. Weight is still about 33lbs. Changing rims etc makes very little difference because they are small. The biggest change that can be made is to try to get a better weight distribution than the sit up and beg; this means changing bars and stem (but changing stem may have consequences noted above). My standard layout Kingpin is fine for a plodder, but climbing hills is awkward because of the riding position - but of course this is not whet they were meant for. Beware pumping tyres hard. My Kingpin rides fine on steel rims and cheap tyres, but my modified small wheeler has aluminium rims and hooked tyres so I automatically inflated them to 100 psi which is ok on absolutely smooth roads, but any break up of the surface or just a slightly rough surface really rattles your fillings and is very tiring as a consequence.

My modified small wheeler was a project "just because I could do it", but it was not entirely sensible - just fun.