Mountain Gear

Tech FAQ: Derailleur compatability and an unyielding debate on yielding

Dear Lennard, I started messing around with a newish XTR rear derailleur with the intention of converting it to a short cage

Dear Lennard,

You may have answered this question previously, but I cannot seem to find the right archive, so here I go again: Shimano has recently come out with a 10-speed off-road group. Previous generations of rear derailleurs used to be backwards compatible with 9- and even 8-speed and worked with STI shifters too, for ‘cross use. Is that still the situation or have they changed the cable pull ratio?

To pass the wintertime blues, I started messing around with a newish XTR rear derailleur with the intention of converting it to a short cage. I made the rounds to a couple of knowledgeable shops in my town and they could not give me a firm answer as to whether I can do so or not.


Dear Ray,

With the advent of its 10-speed MTB drivetrain, Shimano has changed the cable pull ratio, and it is no longer cross compatible with previous generations of Shimano MTB or road drivetrains. I actually have discussed this here: http://singletrack./tech-faq-what-about-1×9-or-10.


Regarding Momentum Wins: Scrap the Downhill Rider Yields to Uphill Rider Rule

Dear Lennard,

Can I respectfully disagree on that one? I find going downhill, I can easily use the more technical lines on the trail the uphill rider can’t, since I’ve got the speed and momentum. The uphill rider has much more limited options. I would rather see them just stay in the groove, albeit as far to the right as possible. But as in recreational sailing, a right of way is not carte blanche to be a jerk. Rather, it means maintaining your line, letting the downhill rider make the pass. If done right, rarely does anyone need to stop, even on seemingly quite narrow trails.


Dear Steve,

Maybe we are interpreting it differently. My interpretation is that to yield the right of way means to actually stop or at least reduce speed to a crawl until the other rider has passed.

Otherwise, I agree with you that when both riders continue rolling on a narrow trail, the downhill rider often has more directional options, due to higher momentum. But I guess I viewed the situation you presented as one in which nobody really yielded; both riders recognized that they could keep moving and each picked a line that both allowed them to proceed and allowed the opposing rider to proceed as well.

This tends to be the normal situation in most passes of riders going opposite directions, and I guess I saw your scenario as an instance where neither rider felt the need to apply the IMBA rule. But I have certainly run into instances where the uphill rider faulted me for continuing to roll past rather than stopping completely, even though I had picked a downhill line that didn’t impede him.

When doing this, you of course have to make allowances for the apparent skill or lack thereof on the part of the opposing rider; you don’t need to allow as much room for a skilled rider as for one who is obviously less confident.

Of course, on multi-use trails where horses, dogs and pedestrians can be present, the bike rider, whether going up or down, should be sure to yield or pass in such a way as not to surprise them.


Dear Lennard,

In regards to your “Momentum Wins” article, I agree with you completely. Altering the rule would lead to safer more enjoyable trails. Negative responses to your article seem to be based on:

“unhelmeted idiots on dirt jump bikes”


“after all you did spend good money buying that truck to get you to the top of the mountain without breaking a sweat”


“I shouldn’t have to yield to morons who are purposely ruining trails with idiot braking habits.”

It sure seems to me that the riders that are displaying the behavior above have not received the appropriate education in regards to respecting fellow riders and the trails they ride on. Clearly the current writing of rule #4 is not alleviating this problem, indicating to me that rule #4’s implementation and reckless downhillers are mutually exclusive issues.

What we need is an education system that works. A list of rules that only some people are aware of is insufficient. I think that IMBA should develop an education program that all riders should have to go through to ride their local trails (take a course, pay a fee, get a tag). This tag system implemented in major cities and towns would go a long way towards educating most mountain bikers about respecting other users and respecting their trails.

What do you think?

Enjoy the Descent!


Dear Chris,

I think it’s a good idea in theory, but I’m doubtful that it would work in practice, primarily because I think that there would be overwhelming pushback to a tag system. How better to educate riders, though, I don’t know…


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Technical writer Lennard Zinn is a frame builder (,
a former U.S. national team rider and author of numerous books on bikes and
bike maintenance including the pair of successful maintenance guides
Zinn and the Art of Mountain Bike Maintenance” – available
also on DVD, and “Zinn
and the Art of Road Bike Maintenance
,” as well as “Zinn
and the Art of Triathlon Bikes
” and “Zinn’s
Cycling Primer: Maintenance Tips and Skill Building for

Zinn’s regular column is devoted to addressing
readers’ technical questions about bikes, their care and feeding and how we
as riders can use them as comfortably and efficiently as possible. Readers
can send brief technical questions directly to Zinn. Zinn’s column
appears here each Tuesday.