and whats the confidence interval ... On Wednesday, September 24, 2014 6:54:30 AM UTC-7, Peter M wrote: > > But that's only true 75% of the time... :) > > On Wed, Sep 24, 2014 at 9:51 AM, Tim Gavin <tim....@littlevillagemag.com > <javascript:>> wrote: > >> Johan- >> >> I rode a super low-Q Stronglight 99 triple on my Riv Road for several >> months. It's a very lovely, very narrow crank set. I got it (from a list >> member) with standard extractor and pedal threading. >> >> However, these old French cranks have very little distance between the >> big ring and the crank arm (that's how they have such low Q factor), which >> makes them difficult to shift properly. I couldn't use any modern FD with >> a sculpted outer plate or it would hit the crank arm. I had decent luck >> with a vintage Suntour Cyclone double FD, shifted friction with Silver >> levers. But with that setup it was still very reluctant to shift from the >> small cog to the middle without going to the big ring first. >> >> A triple FD would have a sculpted inner plate to lift the chain better >> than the double FD, but I couldn't find any triple FDs, vintage or >> otherwise, that don't also have a scuplted outer plate. >> >> I recently swapped my Riv to drop bars and index shifting (8 speed Campy >> Ergos) and I couldn't get any FD to work with that Stronglight crank. I >> ended up swapping the Campy Racing Triple crank back on, which shifts >> perfectly with the IRD Alpina FD. >> >> I'm just pointing out that low-Q cranks with little space between the big >> ring and the crank arm do have some complications. Whether those >> complications become drawbacks depends on your priorities. :) >> >> With drops and Ergo shifters, my Riv is at least 17% faster. >> >> And 47% of all statistics are fictional. :) >> >> >> >>>> On Sep 23, 2014 7:20 PM, "Johan Larsson" <seven....@gmail.com> wrote: >>>> >>>>> If I were to design a crankset I'd make it with chain ring bolts only >>>>> from the inside, like old SunTour XCM cranks but with a quite narrow gap >>>>> between the outer chain ring and crank arm. That way it's easy to run it >>>>> as >>>>> a wide double (48/28 for example) with 110/74 or any choice of available >>>>> chain rings and still having a narrow Q-factor. >>>>> >>>>> It's too bad Grant seems to have given up on striving to keep the >>>>> Q-factor low. (?) As far as I can tell, you wouldn't lose anything with >>>>> such a crank, there would only be advantages. If you'd need a wider >>>>> ring-crank arm gap for some mtb style bike with wide tires and a wide >>>>> cage >>>>> front shifter you can add spacers and run it with three rings. Or one. Or >>>>> four. If you have an old road bike you can keep it lean and narrow and >>>>> run >>>>> it as a double with almost an unlimited choice of chain ring combinations >>>>> and a Q-factor in the 130 mm range, still using standard chain rings. >>>>> This >>>>> winter I'm hoping to be able to make such a crank for myself, since I >>>>> finally have access to a lathe and having collected many old cranks I can >>>>> modify and take parts from. >>>>> >>>>> Johan Larsson, >>>>> Sweden >>>>> >>>>> -- >>>> >>>> -- >> You received this message because you are subscribed to the Google Groups >> "RBW Owners Bunch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to rbw-owners-bun...@googlegroups.com <javascript:>. >> To post to this group, send email to rbw-owne...@googlegroups.com >> <javascript:>. >> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/d/optout. >> > >
-- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
