Tag: shifters

Categories
Cockpit Shifters and Derailleurs

Top mount thumb shifters

So I had a Bridgestone MB-1 circa 1992, I think….might have been ’93. A poor fellow, down on his luck, or perhaps his brain addled from meth or crack cocaine, determined that he was deserving of such a bike. And so he took it. The Bike Hermit is always happy to help those less fortunate than himself. I hope the buzz that person received via my bike made his efforts worthwhile. That bike had Shimano XT top mount thumb shifters which remain my favorite gear shifting solution for straight or swept back handlebars. The shape was perfect. They could as well be called knuckle shifters because the cable tension releasing motion was just a twist of the hand with the index finger knuckle against the lever. Simple, intuitive and unobtrusive.

Even though the great and powerful Shimano decided to make those shifters obsolete others have stepped in to fill the void. Paul Component Engineering makes the Thumbies which are made to be used with the levers cannibalized from Shimano or Sram bar-end shifters.
These are great as long as you have some bar-end shifters. Otherwise it’s sort of an expensive option.

IRD or Interloc Racing Design (Racing. I know, right? But they make a lot of cool stuff) makes two versions of top-mount shifters- one version is friction only and will work with almost any rear cluster. The other version uses indexing for the rear derailleur shifter and only works with 9 speed cassettes.

The IRD Power Ratchet thumb shifters are friction only…no indexing. So they are compatible with almost any rear cog setup.

I’ve also been fascinated with the idea of mounting these on drop bars. On the tops and near the stem where they will be out of the way but easy to use. I had a Long Haul Trucker to put together last week and decided to try the IRD XC-Pro 9 speed shifters. The fixtures clamped to the 26.0 mm section of the handlebar without using the included shims (made for clamping to a thinner, mountain bike style bar). Offsetting the two levers slightly kept the cable housings from interfering with each other. Even so, the cable routing was a little wonky but I don’t think it looked too bad. With a little judicious trimming the cable housing could be made to fit close enough to the head tube of the bike that even a front rando bag such as a Gilles Berthoud would fit.

A slight offset allows for unusual but effective cable housing routing.

Another view of the IRD XC-Pro top mount shifter set up on drop bars.

I took the bike out for a ride and I have to say I was excited by how well the setup worked. The downtube shifters on my touring bike are the ultimate in simplicity but there have been times when taking one hand off the bars to shift did not seem like the most prudent thing to do. Top mount shifters on drop bars instead of bar end shifters would even preclude the need to move one’s hand to the end of the drops to shift. The more I think about it the more sense it makes. One downside could be the room these take up on the bars. Especially if a person wants to mount a computer and/or a headlight there. But the great thing about being in the bike industry is that this means there is a market thus created for handlebar extensions on which to mount those things. Actually, maybe one of those bar extensions would work for mounting top mount shifters. Hmmmmm…more experimenting and blog posting forthcoming.
Something along these lines perhaps:
Cockpit

Categories
Cockpit Handlebars and Stems Touring Bike Components

A Conversion: Drop Bar to Albatross Handlebar

Switching from drop style handlebars to an upright, swept back handlebar can change the functionality and personality of a bicycle. And sometimes a change can be good, maybe turning an unused bike, or one that may duplicate another bike in one’s stable of bikes, into the go to, everyday machine.
From This:

To This:

oxford handlebarsOne such handlebar, the Nitto Albatross is popular in both the alloy and chrome-moly versions. Soma Fabrications makes the Oxford bar which is almost identical in size and shape to the alloy Albatross Nitto makes. This 6061 polished aluminum handlebar will take bar end shifters, and has a 25.4mm clamp diameter making it versatile for use with most stems.Making the switch takes a little bit of planning and thought:
– First of all, the brake levers that fit on a drop bar will not fit on the new bar so new  “mountain bike” style brake levers with a 22.2mm clamp diameter, like the Shimano BL-R550 – are a requirement. The brake levers come with new cable and housing which will come in handy because the old cable and housing is probably too short.
– If the drop handlebar setup used bar end shifters these can be transferred to the Albatross or Oxford bar. If downtube shifters, then, no worries. If the drop bars had “brifters”, or those brake levers with the shifters built in, then new shift levers are in order. Either the bar end style or a top mount shifter or I suppose even the mountain bike standard trigger shifters could be used.
– The hand grip areas can be wrapped with regular bar tape or a slide on grip can be used with the caveat that the cable and housing for bar end shifters will not clear most standard grips, and the more or less conventional solution is to use cork grips with grooves filed into them for the cable.

Now it’s a simple matter of disconnecting all the brake and shift cables, un-wrapping the handlebars and taking off the brake and shift levers. The old handlebar comes off and the new one goes on. New shift levers (or the old bar end shifters), brake levers and grips go on, the new cable and housing is fit and tightened and adjusted and that’s it except for possibly adjusting the height or angle of the handlebars to the rider’s preference. A threadless stem with a removable face plate makes removing and installing handlebars pretty simple.

bare oxford handlebars installed
The new bars clamped into place
Sun Race shift lever
This top mount shifter is inexpensive but it works great. It is a single lever meant to be used with a rear derailleur, single chainring and no front derailleur. Who needs more than 5 or 8 gears anyway?
silver bar end shifter
Bar end shift levers work too. See how close to the bar the cable is? This calls for a grooved grip….or just a tape wrap.
IRD brand top mount shifters
Another option might be the IRD brand top mount shifters, indexed for use with a 9 speed rear cassette.
Categories
Drivetrain Touring Bike Components

Fears of Gears,Gear Inches, Gear Development

Photo of Shimano 10 speed cassette
This is a "10 speed" cassette

“ Hey baby, what kind of gearing you got on that thing?”

What kind indeed.  I guess I got gears in the front and gears in the back. But how do I know what my “gearing” is?  One way to measure mechanical advantage on a bicycle is to use a concept called “gear inches”. Gear Inches? Huh? Gears have inches? What about gear development? What? Are gears reaching puberty? What’s a gear? On a bicycle we use toothed wheels (the front chainring and the rear cogs) to give us mechanical advantage. That means we can make our legs go around really fast compared to how fast the rear wheel is going around…..like when we are climbing a hill. Or we can make the wheel go around really fast with relatively little motion from our legs…..like when we’re going downhill with a tailwind, just by changing the combination of front and rear chainrings/cogs.

Photo of a double crankset ie,one with two chainrings
A double crankset.
Photo of a triple crankset, one with 3 chainrings
The triple crankset

Really, “gear inches” are just a way to quantify the mechanical advantage offered when the chain is engaged on a particular size of front chainring and a particular size of rear cog. A gear inch is not a real unit of measure –                   “Why are women bad at estimating lengths? Because they have always been told “this is 8 gear inches.””

But it is a useful way to compare different combinations of gears to achieve the riders goal. If I know how many teeth are on each of my front chainrings and on each of my rear cogs I can figure out the gear inches for every combination and plot them on a chart.

Snapshot of a chart showing gear inches for 46,36,26 crankset and 12-27 rear cassette
Chief's current gear range in "gear inches"

The late Sheldon Brown has an online gear calculator that makes figuring gear inches snap like. This chart shows the gearing setup on Chief, my touring bike. I’m using a crankset with chainrings of 46, 36 and 26 teeth and a rear cassette which ranges from a small cog of 12 teeth to a large cog of 27 teeth. Giving me a top gear of 103.5 gear inches when the chain is on the big ring in the front and the small cog in the back…. for those high speed descents, and a climbing gear of 26. If I had a larger big cog in the back and/or a smaller small chainring I would have a lower number for my climbing gear and hence a little more mechanical advantage. Some touring bikes, for example, the Surly Long Haul Trucker come stock with a low gear of 21 -22. The 103.5 top gear has been adequate for my purposes.

Comparing the values on the chart, it becomes apparent that their is some overlap, some redundant gears. Noticeably, the 46/27 (46 tooth cog in the front and 27 tooth cog in the back) and the 36/21. It’s entertaining to play with different gear combinations to try to get the best range with little redundancy. The most important thing though for the touring cyclist is to have a low gear that provides enough mechanical advantage to get them over the hills on their planned route. Knowing that  number will only come from experience but  21 to 22 gear inches should work for most people on most routes. For mountainous, off road touring a low gear of 18 to 19 might be more suitable.

The number of teeth on a chainring are marked.
Most chainrings will have the number of teeth marked on either the front or back of the ring.
The number of teeth on each cog in the cassette is marked on the back
The number of teeth on each cog of the cassette is usually marked on the front. Not always easy to see, especially on dirty cogs.
Categories
Cockpit Drivetrain Touring Bike Components

Bar End Shifters a.k.a. Sneaky Petes

I’ve talked about my preference for down tube shifters, now I thought I would give equal time to probably the most popular method of shifting gears on a modern touring bike. That would be bar end shifters. Being inserted into the ends of the handlebars and held secure by means of an expanding wedge these shifters make it possible to shift gears without taking the hands off the handlebars.

Shimano Bar End shift levers

Ergo (Campagnolo) or STI (Shimano) accomplish the same thing by incorporating the shifters with the brake levers, but these only work on drop style handlebars and they are significantly more complex and prone to failure and/or wearing out. Some really old guys remember the days before STI type shifters when bike racers with bar end shifters could shift into a higher gear in preparation for opening a can of whoop-ass on the group without being too obvious…hence the moniker “sneaky petes”.

Bar end shifters will fit in most drop or road style handlebars and the Nitto Moustache bar as well as some in upright bars such as the Nitto North Road aka the Albatross. The limiting factor being the inside diameter of the bar tube where the expanding wedge fits. The simple design and absence of numerous moving parts makes for reliable shifting even on the most demanding and lengthy tours. The Shimano version is made to work with either 9 or 8 rear cogs in index mode. The index mode can be disabled allowing the shifter to be used with any number of rear cogs and even when the derailleur or derailleur hanger gets bent. A nice feature for the bicycle traveler. There is a friction only (no index mode) bar end shifter designed by Rivendell too.

The shifters go on like this:

Oh yeah, and the Rivendell shifters, even though they come with their own pods (the part that goes inside the handlebar), will mount on the Shimano pods. To be safe, if using either one of these use a Shimano rear derailleur too.

Categories
Cockpit Drivetrain Touring Bike Components

What I Like About Down-Tube Shifters

Downtube shifters are shift levers mounted on the downtube of the bicycle.  Not everybody will feel comfortable taking their hand completely off the handlebar in order to shift but for those of us who don’t mind doing so, downtube shifters offer the most minimalistic of gear shifting solutions.

Shifters on the downtube means taking one hand off the handlebar in order to shift.
Shimano Dura-Ace Downtube Shifters

These Shimano shifters have an “index” option on the right lever which means there are eight detentes or pauses signaled by audible clicks for each gear as the lever is moved back or forth. The left lever works the front derailleur and doesn’t have an index option. Rivendell is producing downtube levers without the index option for the real caveman in us all. The right lever can be used to change one, two or more gears up through all nine at one stroke. Kind of a nice feature. And the transfer of movement to the derailleur is super positive, mostly because there is only one short piece of housing at the rear derailleur and no housing on the cable to the front derailleur. Housing compresses and adds friction to the system.

Shorter runs of cable and no housing make down tube shifters more positive.
Only one short piece of housing on the rear shift cable.

I didn’t even realize it until I started reading a thread in Bike Forums about using downtube shifters, but to use these I actually reach across the downtube through the frame with my right hand in order to shift the front changer, the lever for which is on the left side of the bicycle.

Reaching through the frame to shift

One bike tourist I know uses Campy ergo shifters which means the shifters are incorporated with the brake levers. He carries a downtube shift lever and a piece of cable with him in case the ergo shifters fail. Keep in mind that in order to use downtube shifters, the bike must have brazed on attachments on the downtube. Those look like this:

Brazed on fittings to accept downtube shifters.

For those who appreciate a stripped down approach to touring and the peace of mind in having bike parts which are not failure prone, downtube shifters might be a consideration.