Sunday 11 March 2012

Peugeot Lautaret Single Speed project - build log

Following on from my earlier update, here is how I built the bike. First of all, I took apart the headset (I've explained in previous posts about the quill-Ahead stem adapter, and funny French sizes):
I want to ditch the ball race cages and use loose balls. With loose balls, the pressure is spread out more within the cups because you can pack more balls in. So, using calipers, I measured the ball diameters:
Definitely 5/32", which is great, because I have some. Reassembled headset with loose balls (this is a view of the bottom cup - the frame is upside down):
Although with a cartridge bottom bracket, a plastic sleeve is not strictly necessary, I cut one out anyway from the Boss's old oregano spice packet:
Trimmed it down to size, making sure that the overlap is at the bottom so that water can drain out through the somewhat massive cable guide hole. Fitted square taper Shimano UN54 113mm cartridge bottom bracket:
Once that was in, I enjoyed some time gleaming up the frame with Simoniz car polish:
Tyres on, wheels on - Tiagra 32h on Omega Mach 1. Fitted the chainset, a Sturmey Archer 44T ally job with steel teeth. This was cheap yet good quality and also had a right side chain guard. Utilitarian, as I intend to use this for commuting. Pedals are MKS resin types for now, again chosen for practical reasons - I could ride this in flip flops - (later I may stick some single-sided SPD touring pedals on):
Using a steel ruler, I measured front chainline, which is from centre of seat tube to plane of chain ring teeth. It was a pretty lengthy 49mm. So, that means the rear cog position would be 16mm from right OLN ((130/2)-49mm). I'm using a Shimino 18T sprocket on a standard cassette type hub to give a gear of around 65 inches. The Velo Solo shims are great, because you can use different thicknesses to set the rear chainline. This is how I measured the rear cog position using two rulers:
After doing that, I did a secondary check on the chainline with a long steel ruler:
Much to my surprise, it was spot on, so the calculation had worked! Then I put the handlebars on. The front brake was a cheepo steel side pull unit off eBay. Rear was an alloy side pull unit (from my box of old unused bits). I also needed some bolt spare parts, again sourced cheaply from eBay. I fitted the brake levers in a position that suited braking from the hoods, as that is mostly how I will ride this bike. I don't want flat bars because I like the greater number of hand positions of drop bars. Fitted the cables, the only interesting thing here is that the rear cable runs into the top tube. I used a hook to pull top tube cable out of interior cable run. You can just about see the rear cable entering the top tube in the photo below [I'll need to get a better photo of that]:
I hooked up a SRAM 8sp chain, estimating length by running it around with the wheel in a forward position in the dropouts, taking account of the length of the Powerlink joining link. I decided to keep the rear hub QR skewer, because when I lock the bike I always run it through the back wheel:
On the front, I fitted a bolted skewer from Halo. Fitted saddle - I'm still umming and ahing over black or green (Charge Bucket, which is a cheepo one that looks a bit like a Turbo). Steel chromed 22.2 seat post. Handlebar wrap with Trek red light bar end plugs - once again, a practical thing for late evening commuting.
The only hitch along the way, was a problem with the seat post slipping (it went down about 1cm during a 1h ride). As a temporary solution, I did the "good old coke can shim thing". First, drink some coke, then rinsed the can and cut it:
Trimmed to fit and inserted inside the existing seat tube shim. Shoved the post in, taking care not to let the shim slide in fully. I did that by cutting slits in the top of the foil, to make tabs that I hooked over the edge of the shim. After tightening the bolt, I then unfolded the tabs:
So that I could trim off the excess carefully with a serrated knife:
Lovely jubbly! So far, the temporary solution has worked well. I've ordered a slightly thicker seat tube shim anyway, but hopefully, I'll never have to use it. I'm guessing that the original seat post would have been around 24.2mm. What a weird size. Let's see how it goes. To continue with the practical theme, I will probably fit some mudguards, but will keep them low profile!

Hope you enjoyed this build - click on single speed conversion project on the right for all the posts on it. It's very satisfying to get an old frame running again. It feels light and comfy and has cheered up my commute a great deal. So far I've got up to about 44km/h on it and at that speed it seemed sure footed enough, although not rock solid like a modern bike. I've surprised myself at the versatility of the 65 inch gear is - I've ground up some decent grades with it now. But most of all, I'm impressed by how efficient and quiet it is to pedal. So silent, that on one ride I was bothered by the noise of a crease in my jersey fluttering in the wind! Never thought that would ever happen!

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