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Messages - DaveB

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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.  

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.  

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.      

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.

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.

Gear Talk / heron frames
« on: November 24, 2006, 09:08:34 pm »
Anyone have other suggestions for a light,sporty touring frame?

Light and  sporty usually don't go together with touring but check out the Co-Motion Nor'Wester or Nor'Wester Tour.  They are reasonably light Reynolds 853 frames set up for light to middle-weight touring.  Very well made too.  

Gear Talk / Child Carrier for Cargo
« on: November 20, 2006, 06:41:26 am »
I've not done it myself but I've seen several tourists using a child trailer as a cargo trailer.  I don't see why not.  The downside is that they are wider and have more wind resistance than a BOB but, otherwise, should be very suitable.  

You could probably improve the aerodynamics a bit by removing the overhead canopy and using a more compact waterproof covering since you won't have to protect a child from the rain or sun.  

Gear Talk / Thermarest pad slipping
« on: November 03, 2006, 07:33:18 pm »
You must have an older Thermarest (like mine). I think the newer ones have a surface treatment to solve just that problem.  

Gear Talk / lightweight chainwhip?
« on: November 07, 2006, 10:43:07 am »
Yes it is interesting .With a Phil Wood hub- Again 2 5mm wrenches are all that is needed to remove cassette and free wheel to replace spokes on the drive side.   No chain whip needed.

I'm even more interested. :) How do they do that, particularly with a freewheel?

Gear Talk / lightweight chainwhip?
« on: November 03, 2006, 07:29:49 pm »
I use a Phil Wood hub it comes apart with 2 5mm alien wrenches. Although it is very expensive it is top quality.

That's all very interesting but the problem at hand is how to remove a cassette (or freewheel) so you can replace a broken drive side spoke. I don't think Phil Wood hubs let you remove the cassette with two 5 mm wrenches.

BTW, Campy hubs also disassemble with two 5 mm wrenches.

Gear Talk / lightweight chainwhip?
« on: November 02, 2006, 10:51:51 am »
There was a tool called a "Hypercracker" available years ago but I don't know if it's still made.

You removed the rear wheel to fit it over the Shimano cassette lockring and reinstalled the wheel.  The other end of the tool rested against the drive side chainstay and you pedaled forward to loosen the lockring.  Basically it was a lockring wrench and the "chainwhip" was the chain on your bike.    

Gear Talk / bike light
« on: November 02, 2006, 10:45:33 am »

Well, the Nashbar bulbs are less expensive than the manufacturer's normal price but only at their sale price.  

However the other two 6V MR-11 sources are real finds and certainly offer bargain prices. I'd just caution buyers to be certain to get the glass-faced versions.

My point was that all of the MR-11 bulbs I've seen at Home Depot, Lowes, etc. were 12V bulbs.

This message was edited by DaveB on 11-2-06 @ 7:45 AM

Gear Talk / bike light
« on: November 01, 2006, 03:58:05 pm »
Takes regular MR11 or something halogen bulbs so you could change the 10 watt to 12 or 15 or 20 or whatever.

Most bike headlights have 6-volt batteries and the matching 6-volt MR-11 bulbs are typically only available from the light's manufacturer.  

Almost all of the MR-11 bulbs you find in home center or hardware stores are 12-volt. There are a few 12-volt bike lights but not many.  

Gear Talk / Mirrors
« on: February 20, 2007, 10:05:27 am »
I've used the 3rd Eye mirror for several years after trying, and giving up on, other styles.  It mounts fine in drop bars with the mirror below the bars themselves.  I usually adjust it so I can see a slight bit of my left leg as a point of reference.

Another vote for the Third Eye mirror.  It's really best suited to drop bars but gives a wide and stable view.  The only real disqualifier is if you use barcon shifters.

I've also tried all the alternatives; helmet mounts, glasses mounts, etc. and the Third Eye is the only one I use.  

Gear Talk / Trek 520 rim cracks -no warranty service
« on: October 23, 2006, 04:12:54 pm »
I bought my son-in-law a '98 Klein (after the Trek acquisition) that came with Matrix rims.  A friend bought the same bike a few months later and both rear wheels cracked around a drive-side spoke hole at about 10,000 miles.  These were road bikes and never carried anything but their riders, both of whom are reasonably light.  I think this was too early to fail.  The front wheels are still in service.

My '92 Trek 1420 also had Matrix rims and the rear lasted 20,000 miles and failed by cracking through the brake track from brake pad abrasion.  This wasn't a premature failure

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