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Messages - DaveB

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1051
Gear Talk / Advice re Trek 520 frame size
« on: February 20, 2007, 09:58:08 am »
One rough but quite effective method for choosing frame size is "stand over height", i.e. the distance from the ground to the top of the top tube.  For the 560 Trek gives 31.7" (80.6 cm) for the 23" frame and 33.5" (85.2 cm) for the 25" frame.  

Measure your "bike inseam" (not your pants inseam) by standing with your back against a wall in your stocking feet with your feet about 10" or so apart.  Push a moderately thick book, spine up, between your legs until it meets firm resistance.  Measure the disstance from the floor to where the top of the book hits the wall.  That's your bike inseam.  Compare that distance to the standover height.  The stand over height should be at least 1" less than your inseam measurements.

Unless your legs are abnormally long or short for your overall height, this is a good starting point.        

If the inseam of 34.5" you gave was measured this way, the 25" frame just makes it and will allow you to get the bars relatively high which is desirable for touring.  

I hope your dealer will work with you to get the stem length and bar position that are comfortable.  It sounds like they aren't familiar with Touring bikes at all and tried to size you based on sports or race bike fit.        




1052
Gear Talk / Most durable Crankset
« on: January 28, 2007, 03:44:15 pm »
Absolutely ANYTHING should last 1000 miles unless you ride exclusively through wet sand.  Road cranks last tens of thousands of miles and I've easily gotten 30,000 miles on the same chainrings.

 


1053
Gear Talk / Building a Thorn Nomad
« on: January 20, 2007, 07:14:51 pm »
I've been to the South Rim three times over the past 40 years all on family vacations.  The last time we were there was three years ago and I had my bike with me.

I rode from our motel just outside the park entrance to the Grand Canyon Village and several points on the rim.  From the hotel to the rim was a real slog and I was wondering why I was so slow.  The way back to the hotel was REAL fast so I had been going up a slight grade all the way in without it being obvious from the landscape. The altitude does have a noticable effect on us low-landers too so be ready to go a lot slower than you normally expect.

BTW, the entire area is staggeringly beautiful.  The Grand Canyon is impressive beyond belief and no amount of seeing photos or films of it can prepare you for the real thing.  I envy you.    


1054
Gear Talk / Building a Thorn Nomad
« on: January 20, 2007, 05:12:14 pm »
XTR should make a great touring group if the expense isn't an issue.  

Using a 44T big chainring and an 11xXX cassette will give you a 108 gear-inch high gear which is identical to a 52x13 so that should be more than adequate unless you insist on pedaling down big hills.  

You will also have a very low low gear either 22x32 (18.5 gear-inches) or 22x34 (17.4 gear-inches)depending on the cassette you choose which should get you up anything!

Summary, XTR will cover about any conditions you are likely to face.

The Grand Canyon area is at 7500' at the South Rim and about 8500' at the North rim so the altitude makes it feel harder.  And, while the climbs aren't real steep, they can be very long.  


1055
Gear Talk / Building a Thorn Nomad
« on: January 20, 2007, 03:00:38 pm »
What kind of terrain do you expect top ride on and how heavy will your loads be on tour?  

If you are only going to ride in moderate hills and carry a modest load, a road triple such as Shimano Ultegra or what ever Campy now calls their top Triple group with a 12x27 or 13x29 cassette should do fine.  

If you are going to carry massive loads up big mountains than an MTB group such as Shimano XT with a MTB crank and something like a 11x32 or 11x34 cassette will likely work better. You will need a road front derailleur if you mate the MTB stuff with STI shifters.  Barcons will shift anything in front.


1056
Gear Talk / Advice-buying a Cannondale'Touring Classic' ?
« on: January 11, 2007, 10:52:33 pm »
I believe Cannondale doesn't sell any model called the Touring Classic in the US and it may be a name used for a European and/or UK/Irish model.  If you can get the specifications for the Touring Classic from your bike dealer you could compare them with the Cannondale US web site's description of the T2000.



 


1057
Gear Talk / does anyone use a rolhoff speedhub on their tourer
« on: January 06, 2007, 01:15:56 pm »
Looks like an incredible bit of engineering. Super expensive, I would guess.

Yep, you could say so.  Sheldon Brown's web site lists them for $950 to $1200 depending on the model.  Remember, this cost is ONLY for the hub, the rest of the bike isn't included.:)

One downside to the Rohloffs is the twist-type shifter is intended for straight bars only.  I've heard of homemade adapters to allow it to be used on drop bars but they seem crude and awkward.



1058
Gear Talk / Touring computer
« on: December 24, 2006, 08:09:27 pm »
I use and like CatEye wired computers.  Enduro or Mity.  $20-25.

We certainly agree on this.  I have Cat-Eye Mity and Enduro cyclocomputers (same computer but a heavier gauge wire) on six of my own bikes and friends and family have them on a dozen more.  They've been ultra reliable and the batteries last for years.  Very good choice.


1059
Gear Talk / cannondale
« on: December 24, 2006, 08:05:09 pm »
the only thing was a questions was finding bike shops that would service canndondales,...

I don't understand this at all.  Bikes aren't like cars with engines, transmissions, etc. unique to a particular make.  Except for the frames, bikes all use the same components made by one of two or three mamufacturers (with the VAST majority being by Shimano) and every shop has seen them all.  ANY shop can work on almost ANY bike.  


1060
Gear Talk / Suspension seat posts
« on: December 16, 2006, 05:55:00 pm »
I can't recommend a specific post but I do know the saddle isn't included.  All you get is the post.  


1061
Gear Talk / STI shifters with XT crank?
« on: December 07, 2006, 12:48:19 pm »
I was told each front derailleur works best with only the size big chainring it was designed for. An Ultegra designed for a 52 tooth ring will have problems with a smaller mtn 44 big ring and vice versa.

Theoretically this is true but in reality a road fd intended for a 52 or 53T large ring will work OK with a 44/46 big ring.  The shifting won't be the very best but you probably won't notice the minor difference.  

Years ago Shimano had the RSX triple group that came with 46/36/26 chainrings and an RX-100 road fd meant for a 52T chainring.  It shifted fine with that "mismatched" combination.  

You probably can't use an MTB front derailleur satisfactorily with a road crank since the cage radius is too tight and the fd would have to sit too far above the chainring to clear it properly.  


1062
Gear Talk / STI shifters with XT crank?
« on: December 01, 2006, 05:03:38 pm »
No, the XTR front derailleur is not likely to work with road STI shifters,  The geometry and cable pull for MTB derailleurs and shifters are different from those for road derailleurs andn shifters.  You will need a road fd to work with  STI's.  You can use the XTR crank with a road fd.  


1063
Gear Talk / 10 speed cassettes for touring
« on: December 15, 2006, 01:58:04 pm »
Most touring bikes have lower gears than road and sport bikes.

That, in and of itself, is a problem.  Low gears put much higher loads on a chain than tall gears. Look at the lever arms, a 42T chainring puts half the load on a chain that a 21T does at the same pressure on the crank. MTB's break chains as a result of their extremely low gears, 20x34 is common, not just wear from abrasive riding conditions.  

Compounding the problem is the extra luggage weight (20 to 50+ pounds) on the bike and you have tourists putting significantly more demands on their chains than regular road riders.      


1064
Gear Talk / 10 speed cassettes for touring
« on: December 07, 2006, 12:54:18 pm »
One other potential problem with 10-speed is that the chains are even narrower than the already thin 9-speed chains.  The chain could be the (pun unavoidable) "weak link" in the system.  

10-speed has proven adequately strong for road and sport bike use but I wonder if it will tolerate the demands of loaded touring.  I think that is the reason MTB's have never gone to 10-speed.


1065
Gear Talk / 10 speed cassettes for touring
« on: November 24, 2006, 09:13:49 pm »
The only problem will be that "10-speed" rear derailleurs are exclusively road derailleurs and are rated to handle a 27T (Shimano) or 29T (Campy) maximum rear cog.  This max can be exceeded by a little but I don't think any of them will tolerate a 32T cog and certainly not a 34T.

You will have to use an MTB rear derailleur to allow use of these cassettes.  They will be marketed as 9-speed derailleurs but that won't matter.


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