Testing – a new chain wheel and the Akatarawa Road

The Folding Goldies’ suggestion of cycling the Akatarawa Road for our next ride, and my misgivings about the hill climbs, got John thinking of how he could modify the gearing on my bike so that it would make it easier for me to bike uphill.

So he had a chat to Francis at Johnsonville Cycles and got the necessary bits. Then he spent a fair few hours in the garage tinkering. In essence, he has replaced the 52-tooth chain wheel with a 39-tooth one, which gives me greater leverage in the lowest gear, i.e. more oomph to get up the hill! But I’ll let John describe the details of what he did at the end of this post (or you can look at his website. You’ll have to scroll down to the last three paragraphs of the Technical Details section).

I had the first try of the modification on the steep dead-end road round the corner from where we live. It seemed reasonably OK to get to the top of the hill, but the bike was making some noises. John doesn’t like it when mechanical things make noises they shouldn’t, so more time was spent in the garage to remedy that. So far, so good.

The next thing to check out was the gradient and condition of the Akatarawa Road.  Since it was fine last Tuesday, we drove to Upper Hutt, and headed up the Akatarawa Road (in the car, not on the bike!). Much of it is very tortuous, with lots of twists and turns, and lots of “blind corners”. On the whole the inclines do not seem too bad, as they are short-ish, and interspersed with dips or flat stretches. And the surface is good. But the road is quite narrow. There is only just enough room for two cars to pass each other, and there is no shoulder for a cyclist to get out of the way in a hurry. I must admit that this aspect of the road worries me. What would be the chances of getting hit by a car coming up behind you around a blind bend? Then again, there is very little traffic. We met only three cars during the whole trip.

But there were dozens of cars at Staglands that got there before us. This is the first week of the school holidays – as we found out when we got to Staglands. We pulled into the carpark and had trouble finding a spot. There were two big buses – one of the drivers informed us that the passengers had been children on a school holiday programme. The valley was ringing with excited children’s voices and the calls of birds of various descriptions (peacocks, geese, tui, chickens). I hoped the kids and their minders would not all be in the café where we were planning to have lunch.

It was after 1pm, so it was relatively quiet in the café. We sat out on the deck, near a tree that was labelled “Native Bird Feeding Station”, and lots of little wax-eyes and a tui or two came to feed from a container that contained a milky-looking liquid.

Waiting for lunch on the deck at Staglands (photo by John)

Wax-eyes at the “Native Bird Feeding Station” (photo by John)

Staglands is about 16 km from Upper Hutt, then it is another 4 km to the highest point – probably the most testing uphill bit. The downhill stretch to Reikorangi is quite steep, and there is a drop on the left side of the road – you can’t afford to lose concentration, lest you tip over the edge. It will require a firm grip on the brakes too, I think, as I’m not game to go hurtling down at full speed.

Once out of the forest cover, the view opens up over a beautiful valley (photo by John)

When we got to Waikanae, we decided to try the bike out some more by cycling the Waikanae River track loop. We parked near the estuary, and headed up the north bank. We had gone only a couple of kilometres, when the chain of my bike fell off. John restored it, but it fell off again after the first couple of pedal strokes. This happened several times, much to John’s frustration. He tried taking off the new chain wheel and turning it around (outside-in), hoping to improve the chain line. That did not solve the problem. In the end he discovered what was going on: one of the chain plates was splayed, which caused the chain to keep falling off.

Trackside bike repairs

Out came the full toolkit, but what he needed – a pair of pliers – was not in it. What to do? Squeezing it by hand did not work, banging it didn’t either, but in the end, with the help of a rock and a spanner, he managed to coerce it into the correct shape, and hooray! the chain stayed put, and we were able to continue on our way.

There were quite a few people on the track, and families having picnics on the little beaches. We saw a trio of cyclists – two by the water’s edge taking their shoes off, and one emerging from the bushes – so I reckoned that they’d gone for “a pedal, a piddle, and a paddle”.

A great school holiday activity – a picnic by the river

Approaching the SH1 bridge, you go though a nice wooded area (photo by John)

We crossed the SH1 bridge, and made our way down the southern bank of the river. We stopped to take off a layer, as it was getting quite warm. In the photo below, you can see the difference in the size of the chain wheels on our bikes (click on the photo to enlarge it).

Compare the size of the chainwheels on our bikes (photo by John)

A bit further along we saw some ostriches in a paddock. I wanted to take a picture of them, and here I discovered what was wrong with my camera (it had misbehaved during our last ride). It was the zoom that didn’t work. The camera must have been knocked inadvertently, as there were a couple of small dents in the lens surround. Darn!

Four ostriches in a paddock, eating cabbage leaves (photo by John)

The estuary, with Kapiti Island in the background (photo by John)

Apart from the problem with the chain falling off, it was a very pleasant 12 km ride. But John spent more time in the garage that evening to deal to the errant chain. And today (Friday), he removed a link from it. So we had to go and give the bike another try.

We drove out to Plimmerton, from where we biked up the hill to Pukerua – the hill that had defeated me a few weeks ago. That day there had been a slight southerly, which probably helped me up the hill to nearly, but not quite, the top. Today though, there was a near-galeforce northerly, i.e. a fierce headwind as you go uphill. It would be as good a test as any.

I made it to the top without having to step off! Yay! I won’t say it was easy – but it was easier than before. The new chain wheel had definitely made a difference.

I made it! (photo by John)

The downhill, of course, was a blast! Not only did I not have to pedal at all, but we were being pushed along by the tailwind. I did find it a bit disconcerting that once at the bottom of a downhill, and starting to pedal again, in top gear, I had nothing to “push against”. John said that this was the trade-off for having the different gearing. Well, so be it. I think that with this change, I will probably do OK on the Akatarawa Road ride in a few weeks’ time.

* * * * * * * * * * * *

I asked John to write about the technical details of the changes he made to my bike.

Technical details – by John Patterson

In cycling most people have a comfortable gear which they use often. Ideally, this should be in the middle of the available range. With our bikes, that range is limited to a factor of two, when three would be ideal.

With difficulties in hill climbing the simplest way to help is to reduce the size of the chain wheel. The chain needs to be shortened to compensate. The number of inches to remove from the chain should be approximately:

(old chain wheel teeth – new chain wheel teeth)/4

Another inch may be required if smooth running is not obtained.

I replaced the 52-tooth chain wheel on Désirée's bike with a 39-tooth chain wheel. Therefore I needed to remove (52–39)/4 or 3.25 inches from the chain. In order for the chain to join up, only whole inches can be removed. I started with three inches, or six half-inch links.

My old chain tool was not very good as it was hard to get the pin and plate set right when joining up. This caused the chain to come off later, when running in the highest gear. A new Park multi-tool fixed that.

In the lowest gear, the top derailleur wheel also conflicted with the largest cog, which made a rumbling noise. As the chain is shortened, this top wheel moves in an arc upwards and then downwards. Adding an inch to the chain made it too loose in high gear. The final solution was to remove four inches of chain.

Longer term, a 44-tooth chain wheel would be ideal. In that case, two inches of chain would need to be removed.

The gear range is now from 27.2 to 54.5 gear inches, or 2.17 to 4.35 metres development, or a 2.03 to 4.07 gain ratio. The lowest gear is the same as that on my Jamis Allegro road bike. The highest gear is now similar to the set-up found on some single-speed commuter/shopping bikes. (An explanation about gear ratios can be found here.)

I also added a recycled BMX chain guard as shown below. These chain guards don't have the "right look" for BMX cyclists, so they are often removed from new bikes before sale. Enough room was left to allow a larger chain wheel to be fitted.

The new chain wheel and chain guard (photo by John)

About the bikes

I have just done a whole lot of "fiddling" with my blog. I have added a list of Keywords along the left side of the page to facilitate finding topics of interest. I have also shifted a few entries that were in the "Other Stuff" page to the main page, even though they are not about cycling, but about some of my other interests.

On John's suggestion that some technical information might be of interest to some people, I am adding below a pared-down extract from his webpage, about the Giant Expressway 2 Folding Bike. This also allows me to add some useful technical keywords to the list.

Giant Expressway 2 Folding Bike (by John Patterson)

 

Introduction

The Giant Expressway 2, 2013 folding bike is the latest folding bike from Giant. The bike is intended for commuting, where a larger bike might not be permitted on peak hour public transport. The bike is also ideal as a means to explore new places, and to get fit. There are many suitable cycle trails and tracks here in New Zealand.

Twin bikes. Note the higher seat on John's bike in front (photo by John)

I purchased this bicycle as an easy re-introduction to cycling. I got it at Burkes Cycles for $560 which was a standard discount from the retail price of $599. This price to that of a good quality conventional bike so a decision can be made purely on personal needs.

I had not cycled for 13 years because of health issues. The folding bike was perfect as I could put it in the car and take it to somewhere flat to ride. Now that my fitness has improved, I have started using the folding bike for longer rides. It deals well with variable surfaces – I have had no problems with riding it on gravel.

I bought Désirée a bike so she can join me on the rides. Both bikes can easily fit inside our small Nissan Micra car with room to spare for luggage when travelling further afield.

Both bikes easily fit into our Nissan Micra, with room for luggage behind the front seats (photo by John)

 

 Technical details

The components are basic, but sufficient for most applications. So far I have had no problems. The Expressway wheels are quite strong with 36 stainless steel spokes, alloy rims, alloy hubs, and solid axles. Other good points are a Cr-Mo fork, a hydroformed 6061 aluminium alloy frame and a substantial carrying bag. Specifications are available from any Giant web site or dealer.

The bike has a wide range of quick release adjustments for seat height, handlebar height and tilt. Other settings for gears and brakes are finger adjustable. Horizontal seat position, and some other brake adjustments, require a 5 mm allen-key. Wheel removal requires, preferably, a 15 mm ring spanner. Quick releases are not required as the bike fits in a car without removing any wheels. If you have a good local bike shop then none of this will be a worry.

The bike has seven speeds ranging from 70 to 35 Gear-Inches, 5.6 to 2.8 Metres-Development or a 5.24 to 2.62 Gain-Ratio. These terms are defined here. In other words, the lowest gear requires half the effort of the highest gear. Here in Wellington, New Zealand, I can climb most hills with these gear ratios. I can always walk if things get too difficult.

The geometry of the bike has similarities to the classic, and well regarded, Raleigh 20 folding bike. Both bikes have a larger rear triangle than most folding bikes sold today. This strengthens the support for the seat post and the more heavily laden rear of the bike. The seat post is supported, in 4 distinct places, rather than in just the 2 places found on many other folding bikes. The Expressway wheel base is 1013 mm, while the Raleigh 20 wheel base is 1003 mm. The shortest distance from the seat-post axis to the handle-bar axis is the same at about 570 mm. The seat-post and head-tube angles are similar at about 71 degrees. The Expressway chain-stay length is 404 mm while the Raleigh 20 chain-stay length is about 392 mm.

Improvements

I was told that I could not fit a standard carrier on this bike. In fact it was easy to fit, so both bikes now have carriers. They are set back far enough to take my old pannier bags, if needed. I have mounted a small pump under the carrier.

A Cateye bar-end mirror was fitted to each bike. This addition is probably the most important as it contributes to safety. You can see the line that traffic is taking behind you, whether any indicators are flashing, and the approach of other cyclists. I have used a bar-end mirror on my mountain bike since the late 1980s. When riding on busy roads it helps me to assess the space that wide vehicles, such as trucks, would leave me. I filed some plastic off the inside of the end-cap so the mirror tilts out further. This prevents it being knocked by my hand during rides.

A rear-view mirror is added onto the end of the handlebar (photo by John)

On each bike I was able to fit a holder for a 600 ml drink bottle behind the seat, attached to the carrier and its support-stay. The bottle holder tabs were bent slightly to fit and a single 5 mm hole was drilled in the carrier. The triangle thus formed made the carrier-stay more rigid as well. I did not like supporting the bottle horizontally on the frame, in front of the rider as it interferes with stepping over the frame to ride or to dismount.

A bottle holder was added behind the seat (photo by John)

 
I purchased two Cateye Velo 5 bike computers so we can each keep track of the distance travelled. This basic model has trip distance, odometer, maximum speed and a clock. The Velo 8 offers more options, including average speed.

I had some old Lowepro camera bags which were easily mounted on the front handle bars. They can contain items such as locks, sun-glasses, cameras and tire repair kits. These bags have pull-out rain covers.

A camera bag is fitted onto the handlebar. Note also the bell, the bike computer (top right of photo), and the quick-release lever to adjust the tilt of the handlebar (photo by John)

On my bike I replaced the saddle with one with longer mounting rails and better comfort. This allowed me to set the saddle back further so that the set-up was similar to my mountain bike. On Désireé's bike I also replaced the saddle with a more comfortable one.

I have a basic LED lighting set-up for emergencies. I don't anticipate cycling at night.

Tyres

For reference, the Kenda Kwest 20x1.25 inch tyre, fitted on the Giant Expressway 2, is actually 480 mm or 18.9 inches in diameter. The circumference is therefore 1508 mm or 151 cm. The last value should be entered when the bike computers are set up. The measured tyre width is actually 1.39 inches or 35 mm, when inflated. In the front, the tyre clearance is an average of 13.5 mm on each side. In the rear, it is about 6.3 mm on each side.

There appears to be little relationship between the specified and the actual tyre dimensions on many bikes. This means that any upgrading is essentially an experiment. The frame clearance from the tyre wall should not be much less than 3 mm. This maximum measured width of a substitute tyre should therefore be no more than 56 mm in the front and 42 mm in the rear. The particular internal width of the rim can affect the measured tyre width and place limits on the maximum tyre width that can be safely fitted.

After experiencing a few punctures I upgraded to Kenda 912 20x1.75 inch tyres. They ride better on rough surfaces and they also have a good tread pattern for the road. The new tyres are 3.3% larger in diameter so a tyre circumference of 156 cm needs to be used with the bike computer. The chain-stay clearance is about 2.5 mm. Note that the Giant tyre specification is wrong in New Zealand. Here, Kenda 20x1.25 inch tyres are supplied instead of the specified 20x1.75 inch tyres.

Maintenance

The maintenance required on this bike is similar to any other. Keeping the chain clean and lubricated is important. I first use some light oil to penetrate inside the chain. I wipe off the outside of the chain and then I apply some dry lubricant.

On Désirée's bike I removed one shim from the freewheel cassette, as it was a little loose and noisy when ridden. This is a low cost item so replacement is an alternative. The shim removal stopped the noise by reducing the bearing clearance. The cover recently worked loose because I did not tighten it up enough when I refitted it. Using a punch I have tightened it up more firmly. I also used blue loctite 243 threadlocker to assist.

Learning to adjust the derailleur will help to keep the bike running smoothly. It is a simple twist adjustment on the derailleur end of the cable housing. The cable can stretch slightly with time or the cable housing may shorten. To compensate, the adjustment is turned while pedalling the bike by hand, in a middle gear. You may need help to support the rear of the bike off the ground, or you could turn the bike upside down. Adjust for minimum chain noise. Excessive noise means that the derailleur is trying to move the chain out of alignment. Your local bike shop can help.

The brakes may also need adjusting as the brake-pads wear. In this case the adjustment is on the brake lever.

I carry some spares and safety equipment on our trips. This includes a spare tube, a tyre repair kit (including patches and tyre levers), a 15 mm ring spanner, a bike multi-tool, light rainwear, a sun hat, a basic first aid kit, a torch, a lock, a small tripod and a tiny folding kite. We always take water, a sliced apple and some small chocolate bars. I usually have a locality map on my iPod Touch. We both carry cell phones. I keep a larger tool-kit and lubricants in the car.

Conclusion

The bikes are performing well. As I have gained fitness, the urge to upgrade the gearing has dissipated. Much of the recreational cycling, in the first half of last century, including round the World trips, was done by people using 1 or 3 speed gearing. The 3 speed bikes also had less than half the gearing range I have now. I see no need to substitute higher grade bike components for our application.

I have found that off-road loose surface riding is a good way to gain bike handling skills.

When cycling recently in New Plymouth we discovered that the bikes are good in the rain. The carrier, added at the rear, provides spray protection from the rear wheel. The small wheel size at the front means the feet don't get as wet as they do on a standard bike.

The folding bike has provided me with a pleasant way to improve my health. The gains have been significant. In addition, I have been able to explore many areas in my own city that are new to me.