Gearing for Touring

Discussion in 'Touring and recreational cycling' started by GTWilliams, Sep 29, 2007.

  1. GTWilliams

    GTWilliams New Member

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    Yes, I'm posting a gearing under touring on purpose because I don't need roadies opinion on this one. So chill out Forum Freaks. :p

    I'm looking at the Trek 520 and most everyone says great bike but change gearing because 30 is not easy enough for a loaded bike uphills.

    Here are my questions from a non-mechanic:

    1) Is it risky to have your smallest and largest chainring too far apart in size? Can I go with a triple 26/__/52?

    2) Any general rules of thumb on gearing. I thought one guy said the rear should be no less than 75% of the front? (smallest to smallest).

    3) What is your front chainring setup. Why? (Tourers only please)

    4) Anything I'm not asking I should?

    Thanks!
     
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  2. alfeng

    alfeng Well-Known Member

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    I think the suggestion regarding NOT using such a wide gearing (26/__/52) is because the chain MAY drag on the rear of the front derailleur cage in SOME combinations when you are using the granny ... AND/OR, because of the amount of chain the rear derailleur can/(may-or-may-not) handle.

    Over time, the gearing on my wife's ROAD bike got wider & wider [we ride on mountain roads] so that the rear cassette is an 11-32 & the front has a 28/36/52 combination (see attachment) ...

    ... the rear derailleur is a normal-pull XTR. The front derailleur is an Ultegra 6503. And, the XTR crankset is mounted on a DA BB (109.5).

    The shifters are Campagnolo Chorus -- this is a critical aspect with regard to smooth, reliable downshifting ... Campagnolo shifters can downshift without hesitation when under load. PLUS, the derailleur cables do not preclude using a handlebar bag (try to keep the weight carried within a handle bar bag at-or-under ~3 lbs. -- wind shell, sun glasses, lotion, light fleece/vest).

    Essentially, all of the pre-2007 Campagnolo shifters (except the XENON) are functionally equivalent, and the primary reason to spend more is for added bling. I recently tested the 2007 Campagnolo QS shifters, and the LEFT shifter handled a triple crankset with a Shimano 6503 front derailleur + 9-speed Shimano chain ... nonetheless, if I had my druthers I would prefer/recommend pre-2007 shifters unless I were ponying up for a pair of Record, or Chorus, shifters.

    Get the BEST hubs you can afford ... I recommend the older Hugi 240 as I'm not fully convinced about any true advantages to having the slightly inboard non-driveside flange on their 240s hubs.

    Of course, almost ALL Shimano hubs are good, but if you can afford some XT/XTR, you'll be slightly (but, only slightly) better off than with LX, or lesser.

    I wanted a 36h rear hub & picked up an ACERA hub ... and, it's fine. Yes, it is heavier than an XTR rear hub, but probably not that much heavier than an XT rear hub.

    Depending on the weight you are planning on carrying, you may also want a 36h rear wheel. The ONLY reason not to spec a 40h rear wheel is because if you were to damage the rim, you would probably have a hard time finding a ready replacement.

    FWIW. I recommend straight 14g spokes ... and, there is an ongoing controversy in this matter where I am on one side & almost everyone else seems to adhere to the belief that double-butted 14/15 are better because they read it in a "book" (i.e., their bible, of sorts). I won't go into depth on this other than to say that it is a matter of whether-or-not lateral stiffness matters AND how much of a difference one spoke type might make over another, or not.

    36x4 on the driveside & 36x3 on the non-driveside will result in a slightly stronger wheel build ... or, 36x3 & 36x2, respectively.

    If you can get the frame, separately, and build it up to YOUR specs, that would probably be better.

    BTW. I'm NOT sure about that 75% rule, or what you mean by it. I had a 26t granny mounted on a SunTour XC LTD crankset (26/38/52 -- a temporary combination) and if the chain was on the largest cog (28t) & I dumped onto the granny, I would sometimes drop the chain. This is partly a consequence of the components [I think a different/narrower front derailleur might have solved the problem] & probably a consequence of the BB "drop" relative to the rear dropout + the chainline/whatever. If dropping the chain when shifting onto the granny is the reason for some people recommending against using a 26t, then consider installing a REDLINE Chain Watcher (or, whatever it's called) or, equivalent (e.g., DEDA Dog Fang).
     
  3. daveornee

    daveornee New Member

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    1) it is a compromise. If you will spin out at you maximum cadence and highest gear, then you can/should look for that wider range. That's what we do on our tandems. However, on our singles, we don't find the 52 ring is really needed, and it makes shifting a bit more challenging.
    2) get the compromises favoring your applications and use the derailers that most closely match your choices.
    3) 48-36-26t on my 26" wheeled tourer, 46-36-24t on my 700C wheeled tourer. I use the 26" wheeled tourer more because it meets more of the compromises in the directions I have gone (especially widers tires with fenders).
    4) I favor 9 speed cassettes and Shimano bar end shifters because of cost/durability/reliability/vesatility/availability. I also favor wide tires around 35 mm to cushion the ride and protect the rims better. 36 spokes is a good compromise. Strong and stiff CroMo tubular racks solidly mounted with quality hardware that has the threads coated with Blue Loctite is a very worthwhile investment. KoolStop Salmon color pads seem to be the best compromise of reliable braking and improved wear in the rim braking surfaces.
    I build wheels as part of my living. I have come to compromise that I think provides good reliability/durability/cost: Sapim Race 14/15 DB spokes with Sapim Polyax nipples built to proper tension, tension balance, stabilized via the Barnette's methods. For touring 36 spokes 3X both sides works best for me. I think that Shimano XT-M760 hubs provide a great value and are up to the taks for loaded touring and serviceability for the future.
    What ever you choose, make sure that you have heel clearance with the rack/pannier/chainstay length/and your feet. Many chainstays are not long enough and/or rack doesn't alloy the pannier to be mounted rearward enough.
    Also make sure that the frame you choose has adequate clearance for the largest tires (and fenders) you may ever use. Many frames don't have adequate space.
     
  4. GTWilliams

    GTWilliams New Member

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    Thanks. I thought this link below was the guy who said the 75% rule but I guess not. But he says some good stuff and had some interesting links under gearing.

    http://www.bicycletouring101.com/TouringBikeUpgrades.htm

    Your comment about shifitng under load intrigues me. On my road bike, Trek Pilot 5.9, if you're out of the saddle and shift...well it's a clunker. I'm glad to hear some have good repuations.
     
  5. GTWilliams

    GTWilliams New Member

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    As I said, I'm not a mechanic but I understand the general concepts of gearing. What I do not understand is the relationship between the gearing and the derailleur. I thought the derailleur just moved the chain up and down. Higher quality ones shift smoother which is very important.

    But why would I need to consider changing the derailleur if I change the gears?

    Type S-L-O-W ;)
     
  6. alfeng

    alfeng Well-Known Member

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    Well, on first blush, the whole process of moving the chain from one cog to another OR from one chainring onto another might not seem to be a significant mechanical endeavor ...

    But, it has taken decades to achieve the precision mechanism which most of us benefit from.

    Without a boring historical recap, let me just note that there was & is a variability in the WIDTH of a chain's outer plates + a variability in the space between the front derailleur's cage plates ... 0.1mm of variance isn't a NASA tolerance, but it is enough to preclude the chain from being moved sufficiently OR too much ... this is often NOT evident in a DOUBLE chainring setup, but becomes very apparent with a TRIPLE crankset (at least, IMO) + Shimano STI shifters (SRAM doesn't have a triple-capable shifter, AFAIK).

    Further, the ANCHOR bolt on the parallelogram on the rear derailleur & the length of the rear derailleur's parallelogram can & does vary.

    Back in the Stone Age, the movement of the derailleur was controlled by a FRICTION shifter ... that is, the lever was moved/pulled a certain amount & that moved the cable which subsequently moved the derailleur AND "friction" held the lever in place. A spring 'returns' the derailleur when the lever was moved in the reverse direction ... at one time, a second cable was used to move 'return' the derailleur.

    I believe that SunTour is generally credited with creating indexed shifting for external derailleurs ... however, I suppose Sturmey-Archer (?) could be credited with creating indexed shifting for its 3-speed internal hubs. THAT was a long, long time ago.

    Shimano is generally credited with "perfecting" the mechanism AND (especially) the marketing of indexed shifting.

    BTW. For reasons that are ineffable to me, MANY bike shop mechanics, et al, hate Shimano & embrace SRAM (this is a MTB thing) ... I love Shimano -- SHIMANO has GREAT Customer Service in North America ... and, they have well engineered components. SRAM (since I mentioned them) has INDIFFERENT Customer Service -- so, good luck to anyone if they need something from them.

    Now, whether or not you need to change the rear derailleur depends on which TYPE of rear derailleur whatever bike you get already has ...

    When Shimano created their 9-speed components, one of their engineers had the "brilliant" notion that they could reduce pulley friction by ~10% by using an 11t pulley wheel instead of a 10t pulley wheel because so-called SERIOUS road riders usually didn't use a cog larger than 26t ... so, a 27t cog was generous in someone's mind.

    Further, the parallelogram's cage was shortened, and apparently this means that the shifting is incrementally faster ...

    Personally, I was miffed when I discovered (while I was reading the spec sheet) that Shimano had spec'd their Ultegra 6503 rear derailleur (as an example) at only 27t. Unfortunately, I mistakenly presumed that the Ultegra 6503 was a "touring" rear derailleur; but, sure enough, it was not capable of handling a cassette with touring cogs!

    Tentatively, I took an XTR rear derailleur, and fortunately (despite suggestions by everyone I knew to the contrary), it indexed just fine with a set of Ultegra 6500 STI shifters.

    The parallelogram on the XTR/XT/LX/etc. MTB rear derailleurs is slightly longer (same as the 8-speed ROAD Shimano rear derailleurs by my reckoning) than the parallelogram 9-speed rear derailleurs and can handle a cog up to 34t.

    Eventually, I just needed to know how Shimano managed to cripple the capacity of their ROAD rear derailleurs -- so, I looked & looked at it until I deduced (this seems obvious in retrospect) that the 11t pulley wheel was the reason for the largest cog limitation. AND, by trial-and-error, I determined that simply changing the upper pulley wheel to a 10t will easily allow a 30t, and sometimes a 32t cog.

    Does that matter? Well, yes, sometimes it does for some riders, particularly if they are using a 10-speed STI setup & want a larger rear cog (e.g., when using an IRD 10-speed cassette OR if one were to restack their 10-speed cassette with a larger cog cannibalized from another cassette).

    MOST of the time, simply installing a cassette with a 32t cog will provide low enough gearing for MOST people on MOST inclined roadways ... for the DEATH VALLEY CENTURY ... or, other occasional ride!

    To use cassette stacked with a 34t cog, you will need a MTB rear derailleur.

    Now, with regard to the various Shimano rear/front derailleurs ... MY impression is that ALL but the cheapest are as functional as the most expensive ... the actual difference between an ACERA-grade & a Dura Ace (beyond the difference in parallelogram geometry) is in the finish, materials & weight ... and, BLING.

    If the Dura Ace shifts better than the Acera it is because it is closer to being "blue printed" to the engineers specs than the Acera ... AND, the Acera (which is burdened with barely-finished steel bits) probably was not attached (i.e., the cables & housing were probably NOT lubed) nor adjusted with the same care. Installed & adjusted with the SAME level care & cables/housing and the Acera/Tiagra/whatever will be almost as good (most probably won't notice the difference) as the DA if it were atttached to DA shifters.

    The bottom line is that Shimano, for the most part, makes GREAT components ... so if you do need to buy a MTB rear derailleur, you can opt for a lesser, DEORE (vs. DEORE XT) rear derailleur and anticipate the same level of shifting quality IF you ensure that the cables are lubed, etc.

    BETTER components are generally slightly-or-signficantly easier for the mechanic to work with ... and, since I do my own wrenching, sometimes it's worth it to me to pay a little more ... let your budget be your guide.
     
  7. alfeng

    alfeng Well-Known Member

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    BTW. If you get a stock TREK 520, you won't have to change the rear derailleur (I looked at the specs ... it appears that the bike comes with 36h wheels, too).

    Try a smaller granny and/or large chainring, first ...

    If a 26t isn't small enough, then opt for what James Noble chose and install a MTB crank with a 104BCD + chainrings of your choice -- I would probably opt for a 48/32/22 + 12-34 cassette ...

    While a 48t is actually LARGE for touring when mated with an 11t smallest cog ... and, a 42t large ring is "okay" for trails, it seems really small for riding on the road unless you've got an 11-32/(or, 34) cassette ...

    Anyway, presuming you will be using the bike for non-expeditionary riding, too, then the 48t 104BCD chainring makes more sense (to me) for the large chainring.
     
  8. geoffs

    geoffs New Member

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    Touring gears for me when I was young and fit involved unscrewing the 13-18 freewheel on the rear wheel and installing a 13-25. working fine for me then.

    I found using a 48/38/26 with a 12/28 used to give me the range that was fine for me when riding around europe. The only hill that I really struggled on was the Grossglockner which I rode up the day after a bad case of food poisoning. We use a 53/39/26 and an 11/34 on the tandem which uses 26" wheels and the short hill we couldn't ride up was nearly 30%. on a 10% we would be able to do about 8-9kmhr.

    Cheers

    Geoff
     
  9. rcrampton

    rcrampton New Member

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    I have used a few gearing ranges on fully loaded tours (w/ tent, sleeping bag, etc., no hotels).

    REI Safari, Trek 4900, 26/36/48 & 11/32, 26" wheels: I like the low end, pretty much never use the 48 chain ring. If I'm going that fast I'm taking the opportunity for a rest! Works fine on- and off-road fully loaded.

    REI Randonee, 30/42/50 & 11/28 (I think), 700c wheels: Low end was not low enough, never used the 50 ring. I swapped out the cassette for an 11/32 and it's definitely usable but I'd prefer a little lower gearing.

    Bottom line is I want a 26 in the front to get a good granny gear, and I don't need anything as high as 48 because I don't pedal at those speeds.

    While experimenting with deraileurs and gears I found that Shimano's specs were good guidelines but I could generally exceed them and be happy. On my REI Randonee (~2005 vintage) the frame geometry limited my choices. I ended up experimenting with various combinations to find out what worked best.
     
  10. joeyc87

    joeyc87 New Member

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    most important is....it doesnt get easier you just go slower. I have been going 7 mph and passed people like they were standing still with the gearing some of these people are advocating.
     
  11. psiclist

    psiclist New Member

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    I think it's MUCH easier with lower gears. I've toured all over Colorado and France (among many others) and IMHO not being macho about gearing is better for your knees. Get the lowest gears you can, you'll be happy you did halfway up Mt. Evans. I use a 24/36/48 with a 12/32 rear. BTW, STI is great, I wouldn't use anything else on my road, mtn, & tandem. But on a tour when i am out in the middle of nowhere, I want to be able to fix it. I use bar-ends on my touring bike. ( I know).
     
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