Advertise on Bikeforums.net



User Tag List

Page 1 of 3 123 LastLast
Results 1 to 25 of 52
  1. #1
    The Duke of Furl
    Join Date
    Jul 2002
    Location
    Lake Limerick, near Shelton, WA
    My Bikes
    Cannondale T800
    Posts
    98
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Granny Gear question

    I have a 2006 Cannondale T-800 with a stock drivetrain that consists of Shimano 105 9-speed shifters, Tiagra FD and Truvativ Blaze triple (26-36-48). All I want is a lower granny gear than the 26-34 that I currently have but have never been able to get a definitive answer as to whether that is a simple job or not. Can someone answer that question in layman's terms please?

    Thanks, in advance, for the replies.
    http://www.geocities.com/salmn8r/northwestcountryflies.html

  2. #2
    Senior Member m_yates's Avatar
    Join Date
    Feb 2008
    Location
    Rochester, NY
    Posts
    609
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Are you sure what you have on the rear cassette? 34 teeth is usually the largest on a rear cassette. If you already have something like 12-26 cassette with a triple, I think all you need to do is buy and install an 11-34 cassette. The derailleurs you have should work. Most people recommend installing a new chain with the new cassette, especially if you have a lot of miles on it.

  3. #3
    Professional Fuss-Budget Bacciagalupe's Avatar
    Join Date
    Aug 2005
    Posts
    6,384
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    With that 26-34 combo, your lowest gear is already close to walking speed -- 3.7mph at 60rpm.

    I don't think you will really benefit much from going any lower. Plus, let's face it, the lower your gearing, the more likely you are to dive for the granniest of your granny gears once you hit a hill.

    You may just be better off doing a lot of hill repeats in a higher gear in order to build up those muscles. As long as you're still spinning rather than mashing, your knees should be fine.

  4. #4
    The Duke of Furl
    Join Date
    Jul 2002
    Location
    Lake Limerick, near Shelton, WA
    My Bikes
    Cannondale T800
    Posts
    98
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for the responses!

    To respond to some of the points: I've got a cassette that has 34 as the biggest cog. Speed is less of a concern to me. What is a concern is a 4% to 6% grade (or more sometimes) for 16 to 18 miles and me blowing up trying to tote my fat ass and 45 pounds of stuff over a couple of mountain passes on a self-supported tour. Knowing my body and what hasn't worked in the past, the low I've got isn't low enough and I'm just trying to figure out the most cost-effective way to go about rectifying that dilemma.
    http://www.geocities.com/salmn8r/northwestcountryflies.html

  5. #5
    Slow Rider bwgride's Avatar
    Join Date
    Aug 2004
    Location
    Georgia, USA
    Posts
    811
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I had a small front of 26 and rear of 34 and found I wanted something even lower, so I install a 24. Since you currently have 26-36-48 crank the FD can handle the 22 difference (48-26=22). You can install a 24 and see it if shifts appropriately, and if not, you may need to drop your 48 to 46. My current setting is 24-36-46 with a rear mega cassette with 34 as the largest. Also, you rear derailleur needs to be able to handle the large cassette. If it is a long cage (SGS in Shimano language), then it should be fine.

  6. #6
    Galveston County Texas 10 Wheels's Avatar
    Join Date
    Nov 2007
    Location
    In The Wind
    My Bikes
    GTO
    Posts
    25,871
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Go with the 24T granny.
    [SIZE=1][B]What I like about Texas[/B]
    http://www.youtube.com/watch?v=PGukLuXzH1E

    Set F1re To The Ra1n ( NY Night Rain Ride)
    http://www.youtube.com/watch?v=W7jfcWEkSrI

  7. #7
    The Duke of Furl
    Join Date
    Jul 2002
    Location
    Lake Limerick, near Shelton, WA
    My Bikes
    Cannondale T800
    Posts
    98
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    So I can get a 24T sprocket, pop the crankarm off, install the new sprocket and ride over the hills and through the woods? It's that easy huh?
    http://www.geocities.com/salmn8r/northwestcountryflies.html

  8. #8
    Senior Member
    Join Date
    Jan 2010
    Location
    Philly
    My Bikes
    IF SCJ SE, Surly LHT, BikeFriday NWT, Cannondale M300, Raleigh 700
    Posts
    4,368
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Don Johnson View Post
    So I can get a 24T sprocket, pop the crankarm off, install the new sprocket and ride over the hills and through the woods? It's that easy huh?
    Perhaps you would have to shorten the chain a bit? I am not too mechanical so I won't say for sure.

    BTW...Assuming 700c wheels with 35c tires and a 172.5 crank arm length, Sheldon Brown's web site says the change from a 26 to a 24 will drop your low gear inch from 20.8 to 19.2.

  9. #9
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,219
    Mentioned
    47 Post(s)
    Tagged
    0 Thread(s)
    Perhaps you would have to shorten the chain a bit? I am not too mechanical so I won't say for sure.
    if you are not changing the 2 big cogs, don't shorten the chain,
    though It's often a good idea to replace the chain , preemptive maintenance.
    if its a 74 BCD 3rd cog , 24 is all you have,
    a Mountain bike compact crank with a 94/58 BCD lets the gear size drop to a 20t

  10. #10
    Because I thought I could ks1g's Avatar
    Join Date
    Dec 2004
    Location
    Wash DC Metro
    My Bikes
    November, Trek OCLV, Bianchi Castro Valley commuter
    Posts
    969
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    indyfabz - no (on shortening the chain). The chain length is set by his big-big combination (48+34). The OP doesn't need a longer chain. If he needs to shorten it to accomodate small-small combos with 2 fewer teeth (26 to 24T chainring), I'd try to avoid the small-small combos first as it's easier to recover from a dropped chain (greasy fingers) than a locked-up drive train (greasy fingers, some dissassembly may be required, broken derailluer, damaged chain!).

    Is a 7% plus change lower gear worth the cost and effort to the OP - it's up to him. The same "expense" reducing weight of gear carried (or as I suspect many of us including myself - carried by the 'motor'!) would pay off throughout a hilly ride, but he knows his terrain and abilities better than we do.

  11. #11
    Senior Member
    Join Date
    May 2011
    Location
    Northern Minnesota
    My Bikes
    1985 Trek 720, 2010 CAAD9-6, mid-90s Trek 750 hybrid (winter bike)
    Posts
    294
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    As an alternative, how about using a 12-36 cassette, either with the current 26 tooth front chainring, or switching to a 24.

    Another alternative -- put on a standard 22-32-44 front crankset to replace the 26-36-46 -- should be less than $100, and that would make a big difference in your low and you could keep your current cassette. And you'd have plenty of high end if you wanted that.

    I too have heard people tell me "you're just going at walking speed in "X" low gear". I've had people tell me that anything less than a 1:1 ratio is pointless (e.g. 27 gear inches). OK, maybe it is for them, but I like low gearing, especially with a load. And if we're talking "walking speed", it's a lot more efficient to spin fast and pedal a bike up a hill than walk it, even if your low is 21 gear inches. And as you say, speed isn't the issue anyway.

    In my opinion most bikes are geared far higher than they should be for the average rider.

  12. #12
    The Duke of Furl
    Join Date
    Jul 2002
    Location
    Lake Limerick, near Shelton, WA
    My Bikes
    Cannondale T800
    Posts
    98
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I have thought about the 22-32-44 front end but have been told that with the 105 shifters and Tiagra FD, I'd have a lot of tinkering I'd have to do to make it work and I'd have to buy a different FD. I am not a hardware expert...yet but can one just swap out the crank arms without changing those shifters and the FD?
    http://www.geocities.com/salmn8r/northwestcountryflies.html

  13. #13
    Bike addict, dreamer AdamDZ's Avatar
    Join Date
    Nov 2009
    Location
    Queens, New York
    My Bikes
    Surly Disc trucker (DIY), Fuji Reveal 1.0 (DIY MTB), Specialized Roubaix
    Posts
    5,161
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Going from a 26T chainring to a 24T chainring won't make much difference, not worth the effort IMHO. 22T may make more difference. You might try shorter crankarms too. Although, your legs may not like that.

    The lowest you can go is 22T chainring and 36T cassette. I'm just not sure how that works with road bikes. All my bikes use MTB drivetrain.

    Quote Originally Posted by OldZephyr View Post
    As an alternative, how about using a 12-36 cassette, either with the current 26 tooth front chainring, or switching to a 24.

    Another alternative -- put on a standard 22-32-44 front crankset to replace the 26-36-46 -- should be less than $100, and that would make a big difference in your low and you could keep your current cassette. And you'd have plenty of high end if you wanted that.

    I too have heard people tell me "you're just going at walking speed in "X" low gear". I've had people tell me that anything less than a 1:1 ratio is pointless (e.g. 27 gear inches). OK, maybe it is for them, but I like low gearing, especially with a load. And if we're talking "walking speed", it's a lot more efficient to spin fast and pedal a bike up a hill than walk it, even if your low is 21 gear inches. And as you say, speed isn't the issue anyway.

    In my opinion most bikes are geared far higher than they should be for the average rider.
    Yup. I found that pushing a loaded bike uphill is much harder than actually riding it at the same speed.

  14. #14
    Slow Rider bwgride's Avatar
    Join Date
    Aug 2004
    Location
    Georgia, USA
    Posts
    811
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You won't need to shorten the chain. As noted above, my crank is 46-36-24 and cassette is 11-34. The chains I use are 116 links and I put them on without shortening them on my Surly LHT. In most cases a long chain is not an issue unless you run in the 24 crank and 11 cassette combination then you will get sage and perhaps the rear derailleur touching the cassette if not properly adjusted. The real issue is when one runs a chain that is too short -- that could lead to a broken rear derailleur.

  15. #15
    Senior Member
    Join Date
    Aug 2010
    Location
    Madison, WI
    My Bikes
    2004 LHT, 2009 Thorn Sherpa, 2013 Thorn Nomad, 1961 Ideor, 1972 Raleigh Gran Prix, 1994 Bridgestone MB-6, 2006 Airnimal Joey, Perfekt 3 Speed of unknown age.
    Posts
    1,323
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Don Johnson View Post
    So I can get a 24T sprocket, pop the crankarm off, install the new sprocket and ride over the hills and through the woods? It's that easy huh?
    Yeah. But, changing a 24t for a 26t is a tiny difference you might not even notice. But, this is a very simple low cost option to get a lower gear. Anything else is much more effort and pricey.

    Regarding shortening the chain, don't. I am running a 52/42/24 front and 11/32 eight speed rear. If I am using the 24t front, my derailleur cage won't take up all slack if I am on the 11 or 12 rear sprockets, but that is pretty far cross chained so I do not use those gears anyway. You want to make sure you have enough chain so if you accidently went into your largest front and rear gears, you would not bind anything up.

    Option B. If you really are serious about this, you can try a mountain tamer. It is a spider that goes on instead of the 26t chainring, that spider holds a smaller chainring that would normally be installed on a Suntour rear cluster. You can go as low as 18t on the front with that.
    http://abundantadventures.com/mt_triple.html

    I tried one with a 20t and did not like it so I went back to a conventional 24t front chainring. I found that the 20t had me going so slow that I had trouble staying upright. Photo is with a 20t front with the mountain tamer.

    IMG_2055.jpg

    One problem I had is that the instructions say to hacksaw off some of the crankset bosses to shorten them. I did not do that. It is a bit hard to see in the photo, but I cut a piece of sheet metal and put that on each arm of the spider with a little ramp to force the chain over and onto the sprocket. Otherwise the chain lands on the spider and not on the sprocket when I downshift.

    Avid also made an adapter but I do not recall what the exact name of it was.

    If you try the Avid or the Mountain Tamer, you likely would need a friction front shifter.

  16. #16
    Slow Rider bwgride's Avatar
    Join Date
    Aug 2004
    Location
    Georgia, USA
    Posts
    811
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Don Johnson View Post
    I have thought about the 22-32-44 front end but have been told that with the 105 shifters and Tiagra FD, I'd have a lot of tinkering I'd have to do to make it work and I'd have to buy a different FD. I am not a hardware expert...yet but can one just swap out the crank arms without changing those shifters and the FD?
    Tiagra seems to work with many triple cranks. Here are a few threads with folks who use Tiagra with differing combinations of triples:

    http://www.bikeforums.net/showthread...ight=Tiagra+46

    http://www.bikeforums.net/showthread...ight=Tiagra+46

  17. #17
    Member
    Join Date
    May 2007
    Posts
    48
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I dropped from 26t to 24t on my LHT. I would have gone to 22t if my equipment allowed it for a reasonable cost. I found a significant difference between the two. The 8% drop in my lowest gear was quite noticable on really steep grades, on which I often (always?) ride slower than 3.6 MPH. The lower grade allows a noticably higher cadence up these steep grades, reducing stress on my knees. My ride has 26" wheels, so I estimate my lowest gear at 18.4 gear inches now. This is about as low as I can handle with my current bike-handling skills. I need to keep enough speed to steer while spinning up those hills. I've read on this forum that other more skilled riders have gone lower with good success as well.

    Front shifting is not as crisp, between small and middle chainrings. I only make this shift in bail-out mode anyway.

    I find that it's much easier to spin up hills at walking speed than to actually walk.

    That's been my experience. I am not a performance-oriented cyclist, so your experience may differ.

    Jim

  18. #18
    Senior Member staehpj1's Avatar
    Join Date
    Aug 2006
    Location
    Parkville, Md
    Posts
    7,758
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    The difference between 26T to 24T is noticeable but not huge. Since you can do that for $10-12 and going to a 22T is probably going to require a different crank, I figure that a 24 is a no brainer.

  19. #19
    Mad bike riding scientist cyccommute's Avatar
    Join Date
    Nov 2004
    Location
    Denver, CO
    My Bikes
    Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
    Posts
    15,968
    Mentioned
    24 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Don Johnson View Post
    I have thought about the 22-32-44 front end but have been told that with the 105 shifters and Tiagra FD, I'd have a lot of tinkering I'd have to do to make it work and I'd have to buy a different FD. I am not a hardware expert...yet but can one just swap out the crank arms without changing those shifters and the FD?
    No you won't have to do a lot of tinkering. You could even just change the inner ring to a 22 (better than only a 2 tooth change) and leave everything else the same. I am currently using a 46/34/20 crank on my T800 with 105 STI and a Tiagra front derailer. It works just fine and didn't take a whole lot of extra effort to make it work properly. In fact, it too nothing special at all.

    The change isn't all that hard either. You just need the proper bolt center diameter and bolt number for your crank. I believe that yours is a 64mm inner. Get a steel ring for durability.

    OldZephyr has it right on gearing too. I regularly pedal up steep crap in my 20/34 combination. You aren't going to fall over and, to be honest, 60 rpm in that gear is a bit slow to be spinning the pedals.
    Last edited by cyccommute; 05-31-11 at 06:06 PM.
    Stuart Black
    Solo Without Pie. The search for pie in the Midwest.
    Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
    Days of Wineless Roads. Bed and Breakfasting along the KATY
    Twisting Down the Alley. Misadventures in tornado alley.
    An Good Ol' Fashion Appalachian Butt Whoopin'.

  20. #20
    The Duke of Furl
    Join Date
    Jul 2002
    Location
    Lake Limerick, near Shelton, WA
    My Bikes
    Cannondale T800
    Posts
    98
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    A big Thank You to All who have responded. I greatly appreciate the time and effort taken to share your knowledge and experience with me, and the Forum at large, in this endeavor of mine. I'll contact my LBS tomorrow and get the ball rolling on the parts. If this doesn't work I may trade the bike in on one with a V-Twin motor.

    We'll see.

    Best regards,
    Don Johnson

  21. #21
    Senior Member
    Join Date
    Jun 2010
    Location
    Pearland, Texas
    My Bikes
    Cannondale, Trek, Raleigh, Santana
    Posts
    5,721
    Mentioned
    7 Post(s)
    Tagged
    0 Thread(s)
    "If this doesn't work I may trade the bike in on one with a V-Twin motor." --Don Johnson

    I don't have a face palm pic serious enough! (Yes, I ride motorcycles also.)

    Some numbers assuming 700X35 and a bit of rounding off:
    26/34=21.03 GI (now)
    24/34=19.41 GI (proposed)
    24/36=18.33 GI (proposed + 36T in cassette)
    22/34-17.8 GI ($$ swap to mtn crankset plus required items $$)

    A 20 GI granny is the most often recommended (lower doesn't hurt, of course) granny gear I've read. My T700 has a 20.8 GI granny that so far has stood me well. I'm also sure that there are some hills that I'd need to walk whether I went to a lower granny, or not. The change from the 26T to the 24T isn't much, but maybe enough.

    Brad
    Last edited by bradtx; 06-01-11 at 07:45 AM. Reason: 24-36

  22. #22
    Professional Fuss-Budget Bacciagalupe's Avatar
    Join Date
    Aug 2005
    Posts
    6,384
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    An argument in favor of granny gears that aren't super-low

    Since I'm in the minority...

    At a certain point, I'd say that lowering your gears not only hits diminishing returns, it's actually counter-productive.

    Let's say you are on a hill that is 1 mile long. If you're pedaling at 4mph, that hill will take you about 15 minutes. At 3mph, it will take you 20 minutes. I'd say for many people that's a good trade-off, although you're working 25% longer.

    What about a longer hill, say 5 miles? At 4mph, it takes you 75 minutes; at 3mph it takes you 100 minutes. Now, you're fighting gravity for an extra 20 minutes. Is it still worth it? (Before you answer, try to recall how you felt when you recently got to the end of a 5-mile climb in your lowest gearing. )

    How about over 10 miles worth of climbing? 4mph is 150 minutes, 3mph is 200 minutes. Even if that's spread out over a 50 mile ride, a slower pace will mean you have to climb for an extra hour.

    20 miles? 4mph, that's 300 minutes of climbing; at 3mph, it's 400 minutes. I'd say that adding over an hour and a half to your day's efforts is quite significant.

    How about comparing a 4mph pace to 3.5mph -- can't be that much, right? At the 20 mile amount, it's an extra 45 minutes of climbing. So lowering from that 26 to a 24 up front, which is a very small change, is going to mean you work longer on every climb.


    Keep in mind I'm not characterizing this in terms of performance or presuming that saving time is of primary importance. Rather, I'm pointing out that almost any mechanical decision involves a compromise. If you choose to work less on the climbs, then you'll need to work longer -- even when you happen to be cycling at slower speeds.

    Thus at some point, it's better to get stronger than to lower your gears.

  23. #23
    Member
    Join Date
    Jul 2008
    Location
    Port Angeles
    Posts
    35
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    "An argument in favor of granny gears that aren't super-low"

    Around here the hills are not a constant gradient and a goody granny combination can keep the whole deal moving through the steepest 100 yards.

    That is why I have a 48-36-22t crankset and an 12/36 cassette.

    With that big of a tooth differential use a chain guide. When downshifting the chain may tend to overshoot the small chainring and jamb between it and the frame, leading to sudden stops and pain. N-gear jump stop works well for me. http://www.gvtc.com/~ngear/

  24. #24
    imi
    imi is offline
    aka Timi imi's Avatar
    Join Date
    Feb 2009
    Location
    Gothenburg, Sweden
    My Bikes
    Bob Jackson World Tour (touring) and a Miyata 100 (commuting)
    Posts
    2,108
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm sure Bacciagalupe's math is spot on

    When climbing a steep hill for hours on end - that dang hill up Death Valley to Towne's Pass came to mind - I start off in a higher gear, then shift down the tireder I get, shift up one gear and stand on the pedals for a while, shift down and sit down again :repeat: As the day wears on the gears get smaller and smaller... At last I take micro breaks and start off refreshed with a higher gear - for a while :repeat:
    My speed (and cadence) is probably very erratic, a bit faster standing up (higher cadence sitting down?)... but all the time I'm shifting gears, adjusting my position, resting, to an inner voice that is telling me how best (for MY legs) to get to the top of the dang hill fwiw my granny is 22/28 and very very occasionally I'm so knackered that I wish it was even lower... Rambling point being, I'm not considering the math involved, just trying to get up the hill

    IMG_0942..jpg
    Last edited by imi; 06-01-11 at 12:16 PM.

  25. #25
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,219
    Mentioned
    47 Post(s)
    Tagged
    0 Thread(s)
    All else, i use the 24 inch gear... two feet .. and walk the bike up the slope.

    One memorable climb, the south side of Loch Ness
    [B862 on my map, Ft Augustus towards Foyers]

    It was push, grab brake, rest, push, repeat, etc.

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •