Bike Friday New World Tourist – Part 3

22 01 2009
Shimano Nexus 8 w/ 16T cog & 53T/39T chainrings

Shimano Nexus 8 w/ 16T cog & 53T/39T chainrings

I calculated the gear range for my NWT’s current drivetrain as follows:

53T Chainring & 16T Nexus 8:

  • High = 99″ or 47kph @ 100 RPM
  • Low = 32″ or 11kph @ 70 RPM

39T Chainring & 16T Nexus 8:

  • High = 72.8″ or 35kph @ 100 RPM
  • Low = 24″ or 8kph @ 70RPM

I don’t need super low gears on my touring bikes – even in the mountains and I don’t pedal downhill on steep descents so I don’t really need a super high gear either.  On my 700c LHT I spend 95% of my time in the 38T ring up front and the 12-34T cassette.  I’m also not too worried about maintaining a specific RPM.  I tend to change gears infrequently and just vary my RPM a lot.

I’ve got a new 53T/42T Shimano 105 crank & BB sitting in my parts bin that I could setup with only the 42T ring for a really simple drivetrain on my NWT.  I’d remove the left bar end shifter/cable and the front derailleur.  I’d also swap in a push up Surly Singlenator [assuming it fits with the NWT’s chainstays] which would give me a bunch more clearance from the ground to my drivetrain in back.

I calculated the gear range for this setup as:

42T Chainring & 16T Nexus 8:

  • High = 78.5″ or 37kph @ 100 RPM
  • Low = 25.6″ or 8.5kph @ 70 RPM

I think I’d be satisfied with this gear range and would be stoked to have a simpler cleaner bike.  I don’t expect to use the NWT for exteremely heavily loaded touring and my usual touring loads are quite modest.  I enjoy a light bike on tour so I don’t think the lack of extermely low gears will be an issue and I am certain that a top speed of 37kph is satisfactory.  Beyond that speed I’ll just coast happily.

Of course this is all a paper excercise to this point.  I don’t want to spend anytime changing the NWT until I have validated a single chainring will make me happy.  For a start I’ll load it up with 4 panniers and a simulated touring load then hit some steep climbs to get a feel for the bike’s current gearing.  I’m not in top touring shape at the moment so it will be a reasonable assessment of my performance on an off day on tour.



One response

23 01 2009

That is one beautiful NWT and colour Vik! I’m drooling….

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: