About Bob Jones

Entrepreneur, B2B marketer, trainer, cyclist

New Year’s resolution – and a quick tip for retouching your bicycle’s paintwork

Having had an 8 month rest from blogging – at least about bikes – I’ve made a New Year’s resolution to write at least one cycling post per week. Like most such resolutions, it may well fail – but here goes with the first one!

It won’t be a surprise to anyone whose worked on bikes for a while that nail varnish is great for retouching small paint chips on frames and forks. It’s often better than paint because it will go straight onto bare metal (or carbon fibre) and stick, it’s cheap, comes with its own brush and, perhaps most important, is very readily available in a dazzling array of colours – many more than you’ll find in standard paint ranges. The only downside is having to carry your bike around with you until you find the colour that you want. Here’s an easier way to find a match.

A print-your-own Pantone chart provides a cheap and simple way to match touch up paint or nail varnish to your bike

A print-your-own Pantone chart provides a cheap and simple way to match touch up paint or nail varnish to your bike

The Pantone colour chart is primarily intended for use by graphic designers and printers. You can buy one at great expense, or simply download this 18-page version. When you’ve done that, sit your bike next to your computer and print out the page containing the colour that most closely matches your frame. I like to print onto glossy photo paper because the paint on my bikes tends to be shiny, but it’s not critical. In fact, if the printer doesn’t print in accurate Pantone colours it doesn’t really matter. That’s because we’re going to be using comparative rather than absolute colour references.

 

Hold your freshly-printed colour chart up to the frame, ideally in daylight so that you can see the nearest match accurately. Mark the nearest Pantone colour then take your chart to the nail varnish shop and repeat the exercise – matching the nail varnish to the colour marked on the chart. If you can’t achieve an exact match, I find it’s generally better to err on the slight darker side for the nail varnish.

Bike fitting: valuable service or fit up?

Last weekend I went along to the fabulous ‘Bespoked Bristol‘, the UK hand built bicycle show. The beauty and quality of many of the bikes on show was amazing and UK custom bike building enterprises seem to be growing well alongside the general increase in cycling. Even the BBC website now features this piece on the trend so the show’s PR team is doing a good job.

On a couple of the stands, I encountered the issue of bike fitting. One renowned custom frame builder insisted that I really did need a detailed fitting session before they could possibly consider building a bike for me. Another stand offered a 2-hour fitting session for £120 (about $180 US).

This got me thinking, not least because within my modest collection I have bikes of varying geometries with nominal frame sizes of 21 inches to 24 inches, measured from the centre of the bottom bracket to centre of the top tube. With a little experimentation with stems, seat posts and saddles, and the relative positions of each, I have yet to come across a bike that I can’t adapt to be comfortable, even for long rides.

When I started to get sore knees on one trip, I did consult the oracle – YouTube – and quickly resolved the issue by shifting the saddle a little. A search this evening on YouTube turned up this video from Performance Cycling, which has had nearly 1 million views:

It’s very comprehensive but just six minutes and ten seconds long. There are plenty of similar ones and a whole stack of online advice about bike fitting in the forums.

Of course, the right fit is a very individual thing and depends on a number of factors, not least the kind of bike you want to ride and the kind of cycling you’re going to do. Head down on the drops is not ideal if you’re a commuter that needs to attempt 180 degree vision at all times! But whatever shape and size we are, some basic judgements on the frame and a little experimentation should be sufficient to ensure that cycling is a pleasure rather than a pain.

So next time someone tries to sell me a £120, 2-hour bike fitting session, I think I should politely suggest they “take a ride” – don’t you?

The Morgan Two…a brand extension too far?

Iconic English sports car company, Morgan Motors, has jumped on the popular cycling bandwagon by announcing a limited edition bicycle of its own – the Morgan Two. The two-speed bike weighs a bulky 15kg or so, has a Brooks saddle, handlebars and saddlebag, and uses a Shimano Tiagra front caliper brake to complement the Sturmey duo-matic hub with pedal brake on the back. According to the web site, “The special edition revolves around cromoly 4130 double butted steel frame manufactured by Foffa of London, which makes it sturdy on the roads and at the same time light as steel can get.” Clearly, they don’t know about Reynolds 953, and wouldn’t it be nice if they could spell ‘chromoloy’ correctly?

Morgan Two

The Morgan Two is being produced in a limited edition of 50.

Looking the spec, this is a totally unremarkable bike which, at £1196.40 is expensive. In fact, the only remarkable thing about this bicycle is the over-inflated price.  This is just one example of a far better machine at half the price. Alright, the Morgan Two is being produced as a limited edition of 50, but you’d need a very limited knowledge of what makes a worthwhile bike to spend your hard-earned cash on this one.

The amazing unimportance of chainline and chain lubrication

There are a lot of myths circulating in various forums about the importance of chainline. Chainline refers to how straight the chain runs between front and rear sprockets. In single speed set-ups and where an internal hub gear is used, it’s often possible to get a near perfect chainline. Sheldon Brown explains chainline in three articles, the lead one of which is here. With derailleur gears, the general guidance is to set up a straight chainline based on the position of the middle sprocket on both back and front, where there are 3 on the front, or in the middle on the back and between the 2 front chainrings in the case of a double, or aligned with a single front chainring. The problems with running the chain at an angle include lower efficiency, greater chain wear and noise. But just how big an issue is it?

Chainline

This 2001 paper shows just how little difference chainline and lubrication make to pedalling efficiency

This paper, written in 1999 by members of the American Society of Mechanical Engineers (ASME) throws up some interesting conclusions. The reason that a ‘poor’ chainline is cited as reducing pedalling efficiency is that there is increased friction causing energy to be wasted as heat. The paper doesn’t argue with this point but the conclusion is that these losses are negligible compared with non-thermal losses. The paper describes how an experiment was set up to measure efficiency relating to 3 characteristics of a chain drive: the ratio of sprockets and their relative alignment (chainline), variations in input power and rotation rate (cadence) and lubrication, or lack of it. The detailed results make very interesting reading. The authors concluded that chainline offset and lubrication have a negligible affect on efficiency, at least under laboratory conditions and no significant efficiency differences could be detected between a lubricated and dry chain. (I wonder if a dry chain might actually last longer because grit and grime would not adhere to it and cause greater wear?) The major factors affecting efficiency are spocket size, larger sprockets providing better power transfer, and chain tension. Most importantly, there is a reciprocal linear relationship between chain tension and efficiency, the higher the tension the higher the efficiency. The latter makes a huge difference. With a chain tension of 305N the experiment revealed a drive efficiency of 98.6%. When the tension was reduced to 76.2N, efficiency fell by nearly 18% to 80.9%. Don’t worry about getting your chainline accurate to within mm, don’t worry about lubrication, but do keep the chain well tensioned. I don’t know how the  figures above relate exactly to chain slack but 305N is pretty taught!

A successful improvement to the Kinetics Brompton 8 speed conversion

I’ve now fitted an FSA Vero crankset to the Brompton, removing the outer ring and adding a 3.2mm of washer spacing (2mm + 1.2mm from SJS Cycles) between the spider and the inner 34-tooth chainring to move the latter a little closer in. I used the original chainring bolts and now have a front chainline of about 43mm.

The original Sturmey Archer crankset with 33-tooth fixed chainring

The original Sturmey Archer crankset with 33-tooth fixed chainring

At first, I tried the FSA crankset, that has a JIS square taper, on the original Brompton bottom bracket, which uses an ISO square taper axle. The chainline was out at 50mm or so. I decided that for the modest cost involved it would be better to change the 119mm Brompton bottom bracket (not sure who makes it) for a 118mm Shimano one with JIS taper. It was easy to change and the Shimano BB allows a much greater choice of  cranksets, including those designed for single speed set-ups.

The FSA chainring clears the rear triangle by about 2 – 3mm when folding the bike, so I could probably move it in another mm or two to improve the chainline marginally. The original 100-link chain for the 6-speed Brompton, which I retained intact to use with the 33-tooth Sturmey crankset supplied by Kinetics, works fine with the new 34-tooth FSA one too. 

The new FSA Vero crankset, using the inner ring only from a compact double and mounted on a new Shimano 118mm BB

The new FSA Vero crankset, using just the inner ring from a compact double and mounted on a new Shimano 118mm BB

Despite around 4mm difference between the front and back chainlines, there is no noticeable chain noise and everything feels very smooth. The crankset looks much smarter, the chainring is replaceable, the chainline is adjustable by adding or removing washers under the chainring bolts (either side), and I have a great choice of chainrings if I want to adjust the gearing in future. You can buy chainrings with anything from 33 to 50 teeth that will work with this 110mm BCD crankset. In fact, I think I discovered a chainring with just 30 teeth while researching what to fit to my Brompton, but I haven’t been able to find it again, so maybe I was imagining it! Onto the handlebars…my next target for customisation.

 

More on the Brompton 8-speed conversion….room for improvement?

I mentioned in my last post about the Kinetics 8-speed conversion kit for the Brompton that the new crankset looks rather cheap and nasty. It is. I’ve discovered that it’s a Sturmey Archer FCS30 model with 33 teeth (why it’s not called the FCS33 is a mystery), which retails for about £16. So we now have a bike that’s cost the best part of £1000, with a somewhat poorly matched crank that’s ugly.

The Sturmey Archer FCS crank - cheap, ugly and no way to change the chainring

The Sturmey Archer FCS crank – cheap, ugly and no way to change the chainring

Worse still, I found that the chainring fouled intermittently on the rear triangle, preventing the bike folding properly. I started looking around for alternatives. The first thing to note is that the Brompton bottom bracket has a 119mm ISO square taper axle. By far the majority of today’s cranksets are JIS taper, so the choice is more limited. The differences are explained most clearly here by Sheldon Brown. According to Sheldon, “if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length.” More about chainline in a moment.

It seems relatively uncommon to find a single-speed chainring with less than 39 teeth, and the most commonly available versions start at 42 teeth or bigger. I need to stay close to 33 teeth to achieve the gear range of the original, which seems ideal for the rather hilly countryside around here. The hub has a 20 tooth sprocket on the back, so according to the online gear calculator, it produces a range from 27.3 to 88.7 gear inches.

Chainline is the next consideration. According to the Sturmey Archer spec, the 8-speed hub with flat 20-tooth sprocket has a chainline of 39.7mm. I measured it and came up with about 38mm, so that checks out. At the FSC30 chainring, I found the chainline to be around 40mm – not perfect but not too bad either. If I’m going to cure the folding problem, the front chainline will need to be bigger at the front, about 41mm. Again, it won’t be perfect, but 3mm difference between front and back doesn’t seem to likely to be much of a problem.

There is no easy way to correct the chainline at the back. You can buy 25-tooth dished sprocket to fit the 8-speed hub. Reversing it would add about 1.5mm. However, the chain tensioner is so close to the sprocket that it’s not possible to use one with more than 20 teeth.

There's not room to fit a sprocket with more than 20 teeth, and you can only get that one in a flat version

There’s not room to fit a sprocket with more than 20 teeth, and you can only get that one in a flat version

The solution at the front may well be to fit a JIS taper compact double crankset and remove the outer chainring – changing the fixing bolts and using washers to adjust the exact position of the inner ring to get the desired 41mm chainline. This will give me a chainring of 34 teeth, rather than 33, so I’ll need one more link in the chain to take it to 101 links. Fitting a new chain at this point seems like a good idea anyway. The gearing will move up very slightly to a range of 28.1 to 91.4 gear inches.

If it's possible to get a reasonable chainline, the inner ring of this compact double would be a much more attractive and flexible  alternative to the Sturmey crank

If it’s possible to get a reasonable chainline, the inner ring of this compact double would be a much more attractive and flexible alternative to the Sturmey crank

It may even make sense to change the bottom bracket for a JIS taper version at some point – Shimano sells them in 118mm and 122.5mm axle widths, so it’s likely I can achieve a fit one way or the other. The FSA Vero compact crankset looks infinitely better than the Sturmey one, so it’s on order and I’ll know if it’s going to work later this week.

Incidentally, the 6-speed parts taken from my Brompton fetched over £100 on eBay, after deducting the costs and PayPal commission, so the final cost of the upgrade will be £200 plus whatever I end up spending on the crankset and/or bottom bracket.

Kinetics Brompton 8-speed conversion kit

I’ve not done many miles on my 6-speed Brompton, despite owning it for several years. It’s not that I don’t like it; I simply don’t do many of the sort of miles for which it’s designed – short commutes around the city. Nevertheless, I had two niggles with the bike from new – the cheap and grotty handlebar grips and the rather ugly and fiddly gear shifters. If you don’t know the Brompton, the 6-speed version has a Sachs 3 speed hub to which a pair of sprockets is attached. The left hand shifter selects the sprocket and the right hand one the  internal gear. To go up and down the gears one by one, you use the shifters alternately.

The 8-speed Brompton chainset and tensioner installed. Note the much smaller front chainring

The 8-speed Brompton chainset and tensioner installed. Note the much smaller front chainring

While on holiday over Christmas, I found out about the possibility of converting the Brompton to an 8-speed bike with just one twist grip shifter. A kit is offered by Edinburgh-based Kinetics and, in a slightly cheaper form, by Tiller Cylces. Both firms offer other hub options, but I decided on the Sturmey Archer X-RF8(W) 8-speed kit. I ordered it from Kinetics over the Christmas period, paid my £300 plus postage, and waited for the 2-week delivery stated on the web site. By the middle of the 3rd week of January I’d had no acknowledgement of my order and nothing had arrived. I called Ben, the owner of Kinetics, and he explained that he was just building up a batch of wheels with the hubs and my kit would be despatched later in the week. It wasn’t. I emailed and got a quick reply and apology, saying that it would be sent the following week. During the last week of January it arrived.

The Sturmey Archer 8-speed hub at the centre of the new wheel

The Sturmey Archer 8-speed hub at the centre of the new wheel

The web site stated that the conversion takes about 30 minutes. The Kinetic instructions were reasonably clear so I set about the conversion. I’m not quick, but not that slow either…you might do your 100th conversion in 30 minutes, but I challenge anyone to do their first one in that time. It took me several hours, but I was not too familiar with the peculiarities of the Brompton, having never worked on it before. You take off the existing wheel and tensioner, plus all cables and other parts associated with the drivetrain. Then you remove the chainset and replace it with the new, smaller one.

I followed the Kinetics directions to the letter but the tensioner jockey wheels were about 5mm out of line with the sprocket on the hub, so the chain wouldn’t stay on. I emailed Ben at 10pm on a Saturday evening and got a reply within minutes. One of the changes during the conversion is to replace the tabbed washers on the wheel axles with thicker ones from the kit. Ben suggested I revert to one of the original thinner ones in order to move the tensioner closer to the frame. It was bad advice because it caused the tensioner to press against the edge of the hub, preventing the gears from changing. I went back to the original washers and packed out the jockey wheel fixing bolts with some washers to move them the required 5mm. All was well and the gears change smoothly.

The new gripshift if much neater than the original Brompton shifters - just need to find some new grips to go with it now.

The new gripshift if much neater than the original Brompton shifters – just need to find some new grips to go with it now.

SUMMARY: This is a nice conversion and, if you don’t mind the extra weight (perhaps a kg or so?) it makes for a more rideable bike with a slightly wider range of gears. The bike looks neater, has cleaner lines and is not quite so quirky, although quirkiness is something that few Brompton riders will worry about. I was disappointed in the service, the hassle of having to modify parts to get the conversion to work, and the rather cheap and nasty looking drive side crank and chainring supplied with the kit. In my view the latter is nowhere near as nice as the one shown on the converted bike on the Kinetics web site. At £300 plus postage, enough to buy a reasonable bike, the kit is expensive, but I’m hoping to raise £100 by selling the original parts, so that eases the pain a little.

When you’re stuck in the UK in February, this really looks like a dream ride…

Alex's Cycle

“This has been such a flat day”, I said to Tom as we pedalled out of Turin. We had started just outside of Carmagnola and had managed to make it to Turin early for breakfast. It was an extravagant affair…we pulled up outside an ‘Intermarche’, Europe’s finest small supermarket; sat down next to a bin in front of our bikes and feasted on our fresh tomato flatbread. We had made it. Thinking we had done the worst of the climbing the previous day. Little did we know what was in store for us.

After pedalling sedately around Turin for a short while and having our pictures taken in front of some minis -thinking we were hilarious. Yes Italians drive minis in Turin; it’s not just the English stealing gold bars. We departed, keen to make good miles. The first 30km were almost completely flat “this is the life”, we thought…

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Cold mornings, warm days….a neat solution to the ‘what to wear’ question

You know the problem. You’re setting off for a long day ride at 6am, when it’s going to be cold, but later in the day, it’s going to warm up. What to wear? Is it worth suffering the chilly morning for a couple of hours to be more more comfortable later, or do you end up doing most of the ride carrying a spare jacket, maybe a bulky one, that you don’t need. The solution is a device that works in conjunction with your normal cycling clothes but gives you a continuously variable way to control your levels of insulation. This great innovation was first demonstrated to me by my father when he used it during his winter commutes by motorcycle…it’s called a newspaper…stuffed up the front of your jersey or jacket.

Tabloid is about the right size for most people. Just wear one under your top layer and peel off a few pages at a time as it gets warmer, disposing of them in an environmentally responsible fashion along the way. If you’re really hard up, you could even fold up the pages and keep them for the next trip. Push them up the back of your jersey, rather than the front, and you won’t notice the insulating affect.

City traders favour the FT, school teachers The Guardian, Tories The Telegraph and Liberal Democrats The Independent. Your own choice is  an opportunity to make a little statement about yourself.

Of course if you’ve money to spare, I can provide you with an old newspaper of your choice,  trimmed to your size (S, M, L, XL) and complete with Pedalitis logo sticker on the front page for just £20……plus P&P.