Category Archives: Hacks

Tandem handlebars from flat to drop

Tandem with straight bars

The original handlebar set up.

In the last couple of years we’ve started using our tandem for longer rides and are looking at ways to make the bike more comfortable. We did some touring on it years ago, but now we’re riding 200k+ audaxes, where comfort is arguably even more important than when touring due to the time limit and limited time off the bike. As the stoker Erica tells me she’s very comfortable since we had a bike fit and she switched to a wide bullhorn bar with thick tape. With no need to steer she can easily change position on the bars or even let go or hold the saddle for a change when we’re going slowly. The tandem typically gives a very nice ride due to the long wheelbase, steel frame and 35mm tyres.

Flat bar issues

However, on my flat bars I’ve been stuck with a single hand position for an all day ride, which has caused some aches, particularly at the back of my neck and shoulders. I’ve never been able to ride no-handed and I don’t think it would be at all safe to do so on a tandem, as the stoker can shift their weight unexpectedly.

I don’t get this pain on my drop bar road bike even on much longer rides, so I wondered what the difference was. My current theory is the space between my hands. On the road bike this is at most 40cm, but on the tandem it’s always 50cm. I think this means my upper back has to work harder to bridge the gap and support my weight when leaning forward on the tandem. The usual advice for this is:-

Handlebars should be shoulder width apart (measured from acromion to acromion across the anterior chest) and comfortable.  Handlebars that are too wide may cause excessive trapezius and rhomboid strain leading to muscle spasm and pain.
roadcycling.com on Neck and Back pain

The other possibility is that the tandem simply takes more arm and shoulder strength to manoeuvre, but I think narrower bars with more hand positions are worth a try.

Drop bar conversion

With that in mind I’ve picked a drop bar that is 42cm wide. This should give me enough leverage for the heavier bike and plenty of narrower hand positions. It has a very shallow drop and short reach as I figured it wouldn’t make a huge difference to aerodynamics on a tandem. If I tuck down lower at the front it means I won’t be shielding the stoker from the wind quite so well. I imagine there are still gains there, but I assume a 20mm lower front position won’t be noticeably faster.

Hubbub adapter partly pushed into the Rohloff

Hubbub adapter partly pushed into the Rohloff

But there’s an additional complication to this set up. The tandem has a rohloff speedhub which normally needs a twist shifter. This is tricky to get onto drop bars. There have been quite a few ideas to make the rohloff work with drop bars, some of them rather expensive and fiddly to set up. I’ve gone for one of the simplest and cheapest options by putting it on an extension to the left-hand end of the drop. The extension is called a hubbub and has an expanding end so you can tighten it up inside the handlebar with an allen key. The shifter then clamps onto this as it would the bar. Having to reach down for this is another reason I wanted a small drop on the bars. I want to make it as easy as possible to change hand positions. I tried out Thorn’s Mercury a few years ago which, if I remember correctly, had a split bar with a twist shifter on the tops, near the stem clamp. The problem for me was that I don’t spend much time in the tops, preferring the hoods or drops. So reaching up for the shifter took some effort and I was putting a lot of weight on one arm to do it. Even on a short test ride this got annoying; on a longer one I guess it could actually become painful.

Putting it all together

Cutting a bit off the end of the bars so it's not so far back.

Cutting a bit off the end of the bars so it’s not so far back.

I spent a little under a hundred pounds on new kit, including Cinelli drop bars, Tektro RL520 Aero V Brake Levers, the hubbub adapter and SRAM bar tape. Luckily I already had a suitable stem leftover from a previous bike fit tweak to my wife’s hybrid. I held these up to the bike before fitting and did some rough calculations which confirmed that the hoods would be no further away from the saddle than on my audax bike. The bars were a little higher with respect to the saddle, but the only downside to this would be a slight aerodynamic loss and I could easily move them down later as there were still two 10mm headset spacers under the stem.

Rusty brake/shifter cables

Rusty brake/shifter cables

While I was doing the work I realised that the brake cables were getting a bit rusty, which is not surprising after at least twelve years use in all weathers. So I replaced the cables and outers, which was a bit fiddly but, even with the longer frame of the tandem, it cost less than five pounds. After I’d done this the rear brake seemed to have a lot of resistance in it compared to the front one. I can’t quite remember whether this was always the case, so I checked to see if anything was sticking.

Each part seemed fairly free and I could still get plenty of force through to the rear brake, so I decided it was good enough to try out there road.

I also added a small mirror to the opposite end of the bars though, being further inboard than the previous one, I’m not sure it will be worth it.

Test run

We took the bike out for a twenty km spin with a couple of steep hills. At slow speeds, especially starting off, I didn’t have as much leverage and fine control of the steering with the narrower bars, but once above walking pace they felt natural and I could even climb out of the saddle if I was careful. It was possible to hit my knee on the shifter, but didn’t happen often. What was not so good was that the shifter came loose and started rotating in the bar. The rohloff is quite easy to use, but each change does required a bit of force to get it to click. This soon became impossible without putting two hands on the shifter which was totally impractical and unsafe. So we stopped and found a suitable compromise gear to take us home.

Back in the garage I realised that the hubbub adapter wasn’t gripping the inside of the handlebar properly. I thought I’d got it as tight as possible with the shorter end of the allen key, the long end being required to reach down inside the adapter to the nut. If I had to epoxy the thing in it rather defeats the point of the hubbub adapter over a lump of wood or pipe. Online advice suggested that it just needed more torque, so I hunted around the garage for something to extend the small allen key lever. A bit of metal pipe would’ve done, but I was lucky to find an old suspension seat post. Miraculously, this is adjusted with an allen key in the bottom of the same size as the hubbub – 6mm. With a foot-long lever I could apply much more torque and it now shows no signs of moving. We’ve done a three-hour ride since and I’m confident enough to give it a go on a 220km audax at the weekend, which will be a real test of comfort.

New_bars

Finished and cleaned.

EDIT: After riding a 200 and 300km events (including one 1 in 4 climb) with this set up, I’m mostly pleased with it, but getting out of the saddle on a climb can result in  bashing my knee on the shifter unless I’m really careful. A sharp corner of it actually cut my knee on two occasions, so I may think about putting some tape over it or just stay seated.

Script for Garmin eTrex 30 barometer

If you use Strava and a Garmin eTrex 30 and care about that the climbing figures you get are accurate, then you may be disappointed that Strava is ignoring the barometric data the eTrex 30 gives you and working it out roughly by itself, presumably through the average elevation of large map tiles or similar.

There is a simple fix for this, as pointed out by tubbycyclist of yacf:-

A generic “with barometer” device is provided to force the system to use the elevation data from TCX and GPX file types. One only needs to add “with barometer” to the end of the creator name.

Easy enough with a text editor, but a bit of a faff to do every time you upload.

So I’ve created some scripts to make it easier. My idea is that these scripts will be kept in the root directory of the GPS so that they’re always accessible at the same relative path to the file(s) they are editing. There are different scripts for different operating systems, so they should work even on unfamiliar computers. So when travelling and using other people’s computers, they should still work.

Windows

This Windows Script uses PowerShell 1.0, so should work on  Windows XP SP2 or later. I’ve tested it on Windows 8 and 10. It’s the first bit of PowerShell I’ve written, so any comments are welcome.

Opening up a powershell window and running this script isn’t a lot quicker than editing the file manually, so I’ve also created a clickable shortcut to the script as described here. This avoids having to change the script execution policy on the machine, making an exception for this script only.

  • In Windows Explorer, create a new shortcut in the root folder of the GPS device (this might be E:\ or F:\).
  • Right-click on the new shortcut, and choose “Properties”.
  • Change the shortcut’s Target to the following:
    %SystemRoot%\system32\WindowsPowerShell\v1.0\powershell.exe -ExecutionPolicy Bypass -File "add_barometer.ps1" 
    
  • You may also want to name the shortcut something like “windows_add_barometer.ps1.link”.
  • Click “OK”.

Linux

This Linux script uses generic linux shell commands and has been tested on Ubuntu 14.04 and 16.04. It can be run from the command line with: sh linux_add_barometer.sh or possibly by double-clicking the file if you use one of the methods described here. I’m certainly not a bash expert, so again, your comments are welcome.

Mac

I’m told that it’s possible to run *nix shell scripts under Mac OS, so the Linux solution may work with some tweaking. I’ll update this post when I’ve tried it.

How to tell when blueberries are ripe

Maybe everyone else knows this, but I recently worked out when to pick blueberries. As with a lot of fruit, they come off the bush easily when they’re ripe. If you have to pull hard to get the fruit off the stalk, it’s a sign you should leave it for a few days.

With blueberries, they are so small and numerous that gently pulling at each one to see if it’s ripe is quite time consuming and you can end up damaging the bush in the process. I think I’ve worked out a way to tell just by looking.

Blueberries on the bush

The berry in the top-left has a darkening stalk where it attaches to the fruit, showing it is nearly ripe.

At first I thought the colour of the berry was important, and it is, up to a point. The berries aren’t ready when they’re green or red in colour, but even the blue ones often have some way to go.

What seems to count is the colour of the stalk where it joins the berry. As you can see in the photo above, the stalk will go very dark blue at the berry end, indicating that it’s ready to come off. I’ve now learnt that there’s little point in trying to wrestle them off the bush until the stalk has gone dark.

Mounting a B&M Toplight on a Carradice Bagman 2 Sport

I recently bought the battery powered Busch & Muller toplight. The idea is to be seen in complete darkness and because of the size and the way it spreads light horizontally, allow drivers to judge my distance from them, without dazzling anyone. It also meets German standards, which are apparently enough to qualify it as a legal light. In the event of an accident this gives inattentive drivers and their insurance companies less room to wriggle.

Normally they attach to a full pannier rack, but the Carradice bagman 2 sport has no suitable attachment holes.

So a bodge was needed…

Ah, this painting tray isn't being used!

Ah, this painting tray isn’t being used!

Hmm, looks like it might work.

Chop, chop. Hmm, looks like it might work.

 

 

 

 

 

 

 

 

 

P1040273

Washers to prevent the plastic bending too much from a point load.

P1040272

More washers on the underside of the rack. Fiddly to fit, but got there.

Top secured with two cable ties.

Top secured with two cable ties. Possibly need one more in the middle.

Yeah, that should get me seen.

Yeah, that should get me seen.

 

No more rattling rack

Aug13_P1030489After trying to put up with the saddlebag slapping the backs of my legs, I soon got a Carradice Bagman 2 Sport  rack. This does a good job of eliminating any movement from the bag and is really easy get the bag on and off.

However, the QR bracket clamps onto the saddle rails with a single, large nut. I always try to be aware of the sounds the bike makes and investigate any unusual rattles. After a 120km ride last year I noticed that the rack was noticeably loose. Reluctantly I stopped to tighten it up, knowing it would only get worse and it would be pretty serious if it fell off and went in the spokes or the shock load damaged the saddle rails. In another 20 bumpy kilometres it was rattling again.

After that ride I covered the nut thread in the recommended blue threadlocker, which is meant to stop things rattling loose. This does help, but it still comes loose from time to time, which is frustrating and slows me down.

Then I thought that maybe I need to damp the rattling to prevent tiny movements from working the nut loose. I’ve heard plenty of cyclists use old inner tubes for just about anything, and as I had a thoroughly-punctured one lying about I chopped a few rings off it and put them over the bagman’s clamps.

Rubber inner tube bits on both parts of the bagman clamp around the saddle rails.

Underside of saddle with rubber inner tube bits on both parts of the bagman clamp (black) around the saddle rails (grey).

I’ve only done a 300k ride with this, but I haven’t noticed any movement so far. I should probably check it regularly for any play – if it did get loose, the rubber may quieten any rattling noise – so I may not notice. As always I’ll update the post if this hack doesn’t work out.

UPDATE: Well the hack mostly works. It has come loose again though, so rather than adding it to a list of things to check, I’ve put two narrow cable ties through the middle of the clamp. Even if it came loose it wouldn’t fall off. I do have to cut and replace them when I move the rack, but it’s no big deal. Still a nice rack, but a shame these things can’t work out of the box.

Admitting defeat

A few months ago I tried to fix an old monitor that had gone, literally, on the blink. As it was an intermittent fault, it seemed to have worked, but it didn’t last. I tried one more trick, replacing the large cylindrical capacitor in the centre of the beige circuit board below, but that didn’t help. I think the larger ones can break more subtly, rather than bulging or popping like the little ones.

ViewsonicCircuitSo it’s been taken to the tip household recycling centre.

ViewsonicScrappedI could’ve carried on replacing components at little cost, but you do have to admit defeat sometime!