Butyl or Latex inner tubes?

I thought it would be fun to write short opinions on technical subjects. Here is the first one.

Latex tubes roll better than butyl ones. The improved rolling resistance is measurable, quantitatively, for example here. The improvement is real, but relatively small - you could achieve comparable rolling resistance reduction by pumping up the tyre more, or through changing tyres. The competitive edge of latex will be of use to the really top flight racing types. The rest of us have much more to gain through training and improving aerodynamics. There is no weight penalty between the two types of tube, because lightweight butyl tubes are available that compare well with latex ones in grams. In qualitative terms, I find latex tubes more comfortable. They have a wonderful "squishy, yet fast" feel to them. In contrast, butyl tubes give a "harder, harsher" ride. Another factor is that latex tubes need to be pumped up more regularly - pretty much every day - as they do not retain air as well as butyl tubes. I've also noted an odd wear issue with latex tubes. See the photo below which shows some kind of plastic deformation on the inside of the tube - I never figured out the cause.

I had to chuck this one after just a few months use, despite the fact that I had run butyl tubes in the same wheels and tyres for much longer with no issues.

So, if you want fast, comfy tubes with improved rolling resistance and can put up with the extra maintenance hassle, then go for latex. But if you can't be bothered with the extra maintenance (both in terms of time and expense), then stick to butyl.

Cutting a steerer tube

Before and after photos of the steerer on my Iceni TT bike. It was too long, but I wanted to leave some spacers above the stem, in case the bike ever is converted back to a road bike. Before:

 After. Now that's much safer!

 

After removing the required number of spacers, I scored the steerer tube. Then put the pipe cutter in place, 3mm below the scored line. 

 Had to remove the stem in order to be able to rotate the pipe cutter.

 

Took the fork out (carefully placing the headset parts on a sheet, so as to not lose their order). Then, knock in a new star fangled nut. I use an old screwdriver in the hole, but there are great dies for it. Also, when hammering it, I support the fork in my hand under the crown. That way, you are not risking hammering when the forks are braced against the ground!

 I love this top cap. I had a Ritchey one before, but this looks way cooler. I'll need that when I'm sweating on top of it during my next TT!

Cyclocross wheels from Hewitt

A year on, the folding bike wheels that Hewitt built up for me are still going strong. They are in daily use, straight as they were the day they arrived, with no loose or broken spokes. Filled with that confidence, I decided to get my primary CX racing wheels made by them too. First, I de-spoked my Shimano 105 hubs from their old, worn, Mavic MA3 rims, and serviced them. Front hub:

 Then the rear one. I tend to open the nuts on one side only, and then draw the axle out.

The balls were ok, just needed stripping, cleaning, re-greasing and re-assembly. I tried to work some thick oil into the freewheel too.

 

A few weeks later, beautifully built by Hewitt on Mavic CXP33 rims:

 The spoke lacing and tension is simply excellent.

Hewitt have a reputation for quality wheels for a good reason. I can't wait to ride them and will update this post after I have done so.

Update on Peugeot Lautaret Project

I've decided to build up the Peugeot Lautaret as a single speed. No dangly mechs or levers! Opting for freewheel, not fixed. Here's a photo:

I sprayed frame saver inside the tubing. The HLE tubing material is interesting (those d/t levers will be coming off btw):

It's Peugeot own brand "Haute Limite Elastique". A USA 1987 Peugeot brochure that I found online describes it as follows:

"HLE Tubing: HLE is Peugeot's exclusive alloy tubing. It is a "micro alloyed steel" which is comprised of Manganese, Niobium, Aluminum, Carbon and Titatium[sic], which offers a lighter, yet stronger frame. These elements are commonly used in the production of aeronautical steel. The introduction of these elements results in a steel with dramatically improved mechanical properties when compared with more conventional steel. The strength to weight ratio of HLE tubing is far superior to that of conventoinal tubing. Using this tubing enables Peugeot to save more than 7 ounces in the weight of the frame. The HLE tubing, when used with our patented internal brazing system, gives Peugeot a frame which is at the top of its class in performance and reliability."

SEAT TUBE

As best as I could measure it, the seat tube inner diameter was 24.0mm. An odd size, and I could find no post to fit. So, I obtained a shim with 1.8mm thickness, to narrow the internal diameter to 22.2, the rationale being that this is a more common size for seat posts. Here are some photos (the shim is a black, USE brand):

Since the shim was for a larger diameter, I had to trim it along one edge and squeeze it in:

I have a cheepo 22.2 steel seat pin, and it fits beautifully. I may try to find an alloy one. The seat post clamp is a traditional steel nut and bolt type, which is less likely to damage a steel one when tightened.

STEM
I have a solution for the steering end. I sold the quill stem that came with the frame because modern handlebars didn't fit the clamp. It went on fleabay for £5.99. Since I bought the whole package originally for £13.10, that means the frame cost me £7.11! I got hold of a 11/8-22.2 quill-Ahead adapter. Luckily the adapter tube fitted perfectly inside the steerer, but the expander wedge was a bit too wide (probably 22.2). As the wedge was alloy, I was able to reduce it to fit using AlOx paper. The stem is a modern type from M:part, with a 25.4 clamp, perfect for the handlebars.

SINGLE SPEED CONVERSION OPTIONS 
Here is a summary of what I've been mulling over. Over the last few weeks, it was useful that I spotted some 1980s racing bikes parked in public places that had been converted to s/s. I've seen three different approaches:

1. Replace the multi-speed freewheel with a single speed freewheel, simply screwed on to an old style threaded wheel hub. Predictably, with a single chainset, the chainline is rather angled. It was not a very good solution for one of the bikes I saw. It could be made to work if the freewheel was shimmed out a bit, and at the front, one could use a shorter BB axle length and a different chainring that fits to yield a shorter chainline (that is, closer to the seat tube). One bike I saw achieved a good chainline by using the inner ring of a double chainset up front.

2. Keep the screw-on multi-speed freewheel, and use a single chainring at the front. I guess one selects the sprocket that gives the best chainline, so it may be a lottery to get a useful gear ratio. The one I saw had a super straight chainline. Not bad and a cheap solution. But the 6 speed freewheel is a heavy-ish rotating weight, five other cogs are spinning around unused. Not so elegant!

3. Use a modern cassette hub wheel, shim it up to take a sprocket on the back, with a single chainring up front. This is less dependent on the chainset and BB, as the back end sprocket position may be adjusted with shims.

I've bought my chainset, because it was a total bargain and suited a Shimano UN54 113mm square taper BB that I have in my spares box.  It's a Sturmey Archer single with 44T.  When I fit it I'll measure the chainline first, so that I have a reference to work from. It could be that Option 1 may not be possible. We'll see. I appear to have all the parts needed to try each of the above solutions.

Interesting thing is that standard 130mm rear hubs fit with just a slight hand springing of the rear dropouts. I guess it's only 2mm each side that needs to be sprung! The HLE rear stays are rather more flexible than those on modern frames. I'm guessing the ride will be soft. Anyway, next steps are to service the head set, fit the BB and shine up the frame with car polish...Photos later as I progress.


RECOMMENDED LINK
Velo Solo - A totally brilliant website for riders interested in single speed conversions. The online shop has superb photos, so that you can see exactly what you're ordering. Really worth visiting, even if just for idea-generation.

Graham Weigh Cyclocross Frame - Update

Here's an update on the bike I built up a few months ago.

 

And racing - bit of fun blurring up my face there! 

The steerer has been cut down to my preferred height. I used a Rothenberg pipe cutter for this - great tool - I'd recommend it. Saddle is a ProLogo Kappa, not expensive and fine so far for cyclocross, if a bit narrow for my "a-few-too-many-puddings-hips". Wheels are Mach1 Omega rims on Shimano Tiagra, 32h, shod with Michelin Mud 2 folding tyres - cheap as chips and go ok. There's a seat pack which obviously will be removed for racing. I've enjoyed this bike - three races so far, and all is well.

 That's the end of this 'cross season. I'm really looking forward to the next one!

Commuting bike for £15

Here's a photo of the Concept Excelsior that I bought on eBay for £15, on its first day as a London commuter. 

I fitted mudguards which were lying around unused at home (you can see that they were for 700c wheels, not 26", but they will work fine). Other than the longer seatpost and cheepo saddle, no new parts have been fitted. Since the front shifter was knackered, I removed the gear cable and adjusted the mech to middle ring (38T). After lubrication and cable tension adjustment, the 5 rear gears work reliably now. Basically, very little cost and work to get this roadworthy and working at an acceptable standard. The chain had surface rust, but was not stretched - in fact, it seemed hardly used. So, I wire brushed it and thoroughly oiled it. Gearing is perfectly sufficient for London. First impressions are that it rides well, but is heavy. After winter, I'll fit lighter, narrower, touring type tyres, and that will help a fair amount. 

Heart Rate on a time trial "out and back" course

I think this is a great chart of heart rate data against time. It compares my heart rate during an "out and back" time trial event, but 2 years apart. The red data is from earlier this year. Black is on the same course but 2 years ago in 2009.  This year I was faster by almost 2 minutes and set a personal best for this course. The data tells me at least three things:

1. I could have tried much harder this year. Especially during the second quarter and last quarter of the race.

2. On an out and back course, wind will usually reduce the overall time. (There's plenty of stuff online that explains why). This year there was more wind than in 2009, and it was a tailwind on the way out and head wind on the way back. This is clearly evident in the data, the dip in HR being the turn point. Indeed, in 2009, it seems I was actually quicker on the return leg, but slower overall.

3. Considering the above observations, it's great that I'm faster this year! This must be combination of training and equipment - but I like to think more to do with training than equipment :)

4. Older does not mean slower!

The data is very informative and makes me feel that I can improve further. It was gathered using Garmin FR60 heart rate monitor, which I think samples heart rate every 5s. Yes, I know this blog is about working on bikes, but working out on bikes has got to be included in that!