Friday, October 21, 2011

Bearing Some Resemblance to a TerraTrike Rover

I've had a recumbent trike or two over the past couple years, and some months back I convinced my better half of the benefits of 3 wheeled transportation.  She didn't like the ultra-low seating position some of the tadpole-style (two front wheels, one back wheel) trikes were sporting, so we settled on the design of the relatively new TerraTrike Rover.  Its seating position is higher than most of its class brethren while still remaining stable enough for cornering at our regular cruising speeds (without lifting the inside wheel off the ground).  My initial issue with the model was its lack of wide range gearing.  It was available only in a 3-speed or 8-speed internally geared hub configuration which didn't give quite the desired range our hilly area requires.  After some searching I ran across a custom build being done by Utah Trikes: the Rover 8 DL.  Basically they pull the internally geared rear wheel and replace it with a standard rear wheel with 8-speed cassette and rear derailleur.  What's the benefit of that, you ask?  This allows the single front crankset to be replaced with a triple crankset giving more gearing options than you could ever need.  Utah Trikes will even install the triple crankset option complete with bolt-on front derailleur post for a modest $150.  Convinced we now had a winner, I placed the order and waited with baited breath until the day of the huge box delivery arrived.  The trike shipped almost completely assembled and it was up and running in very short order.  The Rover is a great recreational riding trike - very maneuverable, easy to get in and out of, and above all very fun to zip around the neighborhood on.

The great build configuration by Utah Trikes left me wonderfully content... for about a week.  It was about that time that the economy-level drivetrain components and tires left me yearning for better ride quality and crisper shifting (the trike came configured with very modest level SRAM X-3 components which shift a bit imprecisely).  With a few flicks of an allen wrench (and turns of a cassette lockring tool, chain whip, channel lock, wire cutter, and even a few squirts of hairspray to slide grips on and off), the Rover was now sporting a 9-speed rear cassette, Deore rear derailleur and SLX trigger shifters. 
Soon after, the cheap no-name low-pressure tires were replaced with a trio of beastly Maxxis Hookworm tires better capable of handing the suburban jungle in which we reside.  Better shifting?  Check.  Better ride?  Check.  Ahh, content again... sort of.

A few minor tweaks ensued.  Bolted on a rear rack for the pannier bags, added a bike computer and added a chainring guard (the ICE Trice Chainring Guard fit wonderfully).  As I mentioned in previous posts, I'm a big fan of shorter cranks on recumbent bikes, so I swapped the front crankset for a Sugino XD600 152mm triple crankset.

Amid the modifications, I had noticed there was a great deal of room ahead of the 20" rear wheel.  Poking around online I also found other Rover builds that were sporting rear wheels up to 26".  This was just too much of a temptation not to be attempted.  As there is no rear brake needed on a tadpole trike (the left and right brake levers typically work the left and right wheel brakes rather than front and rear), the swap was an easy one.  There isn't much clearance for a large volume tire, but a 26 x 1.5" fit in the frame spacing without any trouble.
Riding was surprisingly unaffected with the exception of a bit higher top end due to the larger wheel circumference and a bit of a forward tilt that could be generally negated by adjusting the seat recline angle.  The only detriment to this configuration was that I lost the advantages of my higher volume tires.  In the end, ride quality trumped top speed and the 20" rear wheel returned home.

It wasn't long after that an interesting piece of hardware found its way to my local craigslist: an Xtracycle FreeRadical.  Xtracycle (www.xtracycle.com) makes a spectacular longtail conversion system allowing a bike to become a very cool and utilitarian device - even allowing the transport of passengers on the back!  I had some experience with the Xtracycle system (will post more on that later), and instantly visions of an Xtracycle-equipped trike began dancing in my head.

The FreeRadical installation was really quite simple on the Rover and the only truly invasive part of the project was drilling a mounting hole in the Rover's frame just ahead of the rear wheel.
The system attaches in three locations - the two rear wheel dropouts and one point where the chainstays typically attach to the bottom bracket (and where a kickstand typically would be mounted) on a traditional diamond frame bike.  The location of the anchor point on the FreeRadical lined up almost perfectly with the point the chain stays attach to the main square tube frame of the Rover and simply had to be anchored to the frame in some way.  I decided the most secure (yet still reversible) mounting method would be using a bolt passed through the FreeRadical and both sides of the square frame tube.
To maximally distribute the load the Xtracycle system would exert on the frame, I used one of the brackets that came with the FreeRadical kit.  Two of these brackets can be used to sandwich the chainstays on a diamond frame, but one of them did a spectacular job of distributing the load forces and protecting the Rover's frame.

The front of the FreeRadical is designed to rest on top of the chainstay brackets (or kickstand bracket), but on the Rover this caused the Xtracycle platform to slope as well as raise the overall height of the Rover's rear assembly.  Because of these issues I chose to mount the FreeRadical underneath the frame instead.  To make sure the hardware would be equal to the task, I went down to my local hardware store and bought a nice heavy-duty Grade 8 bolt and thick washer to bear the load.
Hardware in hand, the rest of the assembly was fairly straightforward.  The two aft mounting points on the FreeRadical slid smoothly into the Rover's horizontal dropouts and the new bolt secured the system at its forward third point. 

The rear derailleur (removed prior to assembly) was relocated to the derailleur bracket on the FreeRadical, an extra handful of links was added to the Rover's loooooong chain, and a new longer rear shift cable (tandem cables are long enough) was run to the new rear derailleur position.  The rear wheel slid into the FreeRadical's dropouts and we were ready for the maiden voyage.

The first thing you notice after this type of conversion is how LONG the trike has become.  I could no longer turn the trike around in a single lane width.  It now took a full two lanes to turn this stretch limo 180 degrees.  Once the initial acclimation took hold, the ride really wasn't all that different than stock and stability wasn't affected particularly one way or the other.  One problem that became apparent a few pedal strokes in was that the chain had a tendency to rub against the chainstay when in the smaller cog and against the FreeRadical frame in the largest cog.

I found some resolution to this by adjusting the position of the rear power-side idler wheel to one of its upper mounting positions.  This didn't resolve the chain rub in the largest climbing gear, but did make downhill runs rub-free.  With the front triple crankset and small rear wheel, I found I really never needed the largest gear on the rear cassette so I "fixed" the issue by adjusting the set screw and limiting the rear derailleur's maximum range - effectively changing the rear cassette to a 8-speed configuration.  I would venture a guess that the chain rub would not have been an issue had I been using a closer spaced rear cassette rather than the wide range cluster which included the offending 32 tooth gear.
Strange noises quelled, I returned to the streets for some additional testing.  The new configuration proved very functional and usable with a few caveats.  For one, the rear shifting was not as precise as it had been prior to the conversion.  I attribute this to the many mm of additional shift cable needed to reach the rear derailleur.  A higher grade low-friction cable would most likely improve the shifting performance and return it to its former crisp shifting glory.  The second thing I found a bit unsettling was in the feel under heavy loaded conditions.  I have used the FreeRadical systems on upright bikes as a seating area for my 80-ish pound child.  Xtracycle makes a great seat cushion and foot-shaped floorboards for the FreeRadical which make it a very stable and efficient child carrier.  When my son mounted up on the back of the converted Rover I noticed a distinct amount of torsional frame flex.   As we cornered and he shifted his weight while riding I continued to notice the frame flexion.  As the Rover has a strong square-tube frame, it was not overly concerning from a structural perspective, but definitely added a bit of an odd feel to the ride.  Also, the center of gravity became markedly higher with a rear rider and necessitated greatly reduced cornering speeds.  With this type of behavior, I limited two-rider trips to short jaunts to the park rather than longer commutes in higher speed situations.

Overall the design and versatility of the TerraTrike Rover has proved admirable.  While it will never compete with the likes of its low-slung ultra-reclined brethren (think Catrike 700) from a performance perspective, it is by far the easiest to climb on for a bit of fitness, a ride around the neighborhood or a short commute.  Its seating position make it both more visible to automobile traffic and easier to see "out" of to enjoy the scenery and maintain situational awareness of traffic around you.  It really is the trike most of us SHOULD be riding even though many of us envision ourselves aboard performance trikes rocketing down the road cheating the wind and passing the roadies in their pacelines.  It all goes back to the saying that the best bike/trike is the one you actually USE; and the TerraTrike Rover is definitely in that category.

UPDATE (10/21/2011): While a cargotrike was my idea of the ultimate configuration of a Rover, my better half found she didn't agree.  Her typical trips didn't require the extensive cargo-carrying capacity of the FreeRadical, and thus the longer turning radius and increased weight were unmerited.  As I already had an Xtracycle-equipped bike that I used for errand-running and child-carrying, we had little need of a second similarly-equipped machine.  We have since removed the FreeRadical kit, returning the Rover to its shorter and more maneuverable configuration, while the standard rear rack still affords a wealth of carrying space with trunk bags and panniers.  Once again the old adage applies as the current configuration is the one that will be the most used.

1 comment:

  1. Wished I could find a front boom post... you'd think someone would of made them in China and would be selling them, or something. The demand is out there!

    ReplyDelete