Bicycle Gearing

Discussion in 'Cycling Equipment' started by Houckster, Jul 3, 2003.

  1. Houckster

    Houckster New Member

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    I have often wondered if it's just me or if there are others out there who share my frustration concerning the lack of different chainrings and cassette cogs for the current offerings from Shimano and Campagnolo.

    When I got into riding, you could make up your own gearing and see what worked best and you could change cogs to compensate for different riding conditions. I miss those days. One might think that someone in the aftermarket would see the need for other size chainrings than 53 and 39T. No one has so far.

    With all the attention over the last 10 years or more to making bikes more accommodating to the rider's physical needs, the gearing systems offered now are a glaring step in the wrong direction.

    Frankly, I don't think the current systems shift that much better than a properly set up system from the late 80s to early 90s and the over-engineered systems with shifting ramps etc. make custom gearing almost impossible. I still use normal chainrings on the front and have no reason to feel that I could gain any improvement if I surrendered to the 53-39T standard. On the back, I still use the twist-tooth Dura-Ace cogs that I've been able to scratch up over the last 3-4 years. I'm very happy and to judge from what I'm hearing and seeing when I've ridden with folks using the new gearing systems, they're not shifting any faster or more reliably than I am.

    A properly lubricated chain makes far more difference in positive shifting than all those ramps and differentially cut teeth.

    I also am somewhat underwhelmed with the 10-speed systems. For my touring bike, 9 cogs is about all I need. For my other bikes, 8 cogs is just fine.;)

    With the lack of available replacement cogs, I keep a close eye on my chains and replace them whenever I start seeing any wear. Got to protect those cogs.
     
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  2. rmckeller

    rmckeller New Member

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    You are on the money. I have trouble making sense of it all. I just want to upgrade from the Sora line and there are 15 different variables I have to consider before making the move. I am frustrated that any change that I want to make will result in a total system replacement. Not just the rear derailleur, but the shifters, cassette, and wires have to be changed as well. What gives?
     
  3. Houckster

    Houckster New Member

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    I have had this problem as well. When freewheels became history, I had to build new wheels, purchase new derailleurs and new shifters and other stuff to make the switch to cassettes. With 4 bikes to convert, it cost a bundle.

    I also don't like the splines on the Shimano type cassette hubs, Campy's are much better.

    I'll stay with Shimano because they did introduce the spined BB spindle and in my opinion that was a very positive change. I always hated the tapered spindle.
     
  4. kokopuffs

    kokopuffs Guest

    My $0.02 worth:

    I wanted a replacement front derailleur for my '93/'94 Rockhopper and following a nationwide search, I found original Shimano FD735 in used condition for $25 and new for $60. However, I could have gotten an 2002 XT FD for $40 even though the minimum tooth difference was 12 instead of the 10 that my bike requires: my chainrings are 26/36/46.

    I would have needed a whole new gearing therefore drivetrain had the FD-M735 been impossible to locate. What a pain, all of this gearing nonsense.

    And what's worse, I hear that the 9 and 10 speed drivetrains aren't nearly as durable as the old 7 and 8 speed setups. I'm about ready to give up and get an ol' fashioned Raleigh 3-speed. Very little, if any, math there.
     
  5. prestonjb

    prestonjb New Member

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    I hear that too but only from one shop and only from those guys who ride mountain bikes...

    And actually the story I hear is not that it doesn't last as long but that the smaller tolerences and spacing between gears and chain are prone to get mucked up quicker with the sand/mud of the trails...

    But I don't see the problem on my ATB... But I'm not that much of a huckster.

    As for the road... Its not true. the 9-speed DuraAce lasts as long if not longer than the 8-speed stuff...

    Huh?

    So who says you cannot do that anymore? So why can you not find the right cassette for you?

    Pick one:

    http://aebike.com/site/page.cfm?PageID=30&Category=1708

    Also at AEBike I see 38, 39,40,42,48,50,52,53,54,56 rings and that is just for the 130mm dual ring cranks...

    To each his own cadence. My riding range is so diverse that even 10 speeds does not give me enough range.

    I use a 12x23 here in the flat-lands of South Florida... I use a 12x27 in the rolling hills of the N.C. Pedmont.

    In the mountains (Blue-Ridge/Black Mountains mostly) I use a XTR rear derailleur with a custom, YES CUSTOM, rear cassette that is a 13x32 to handle those 12% grades... The 9-speed gives me one extra gear, which I chose to be the sweet-16 so I could have a nice 15,16,17 so I could run in the 39x16 and keep my cadence very consistant as I go through the rollers between mountain passes <living in florida gives me abilty to travel very fast if the roads are fairly even>...

    What gives is tolerances... To add the extra gear for the 9-speed without you having to toss your frame and rear wheel, they had to make the pieces that move the cable to move less... This means more precise maching and to ensure it would work for a long time... While I think they did this... Except that for mountain bikes the mud seems may be a problem...

    And that is why you have to replace a lot of parts...

    Now also your SORA is the last of the dying breed of 8-speeds. If you had bought a bike back in the RSX days 3-years ago... You would just now be seeing the 8-speed fade out. For that reason I try to get people buying new bikes to not get Sora but Tiagra... It will take about 5+ years for the new 10-speeds to trickle down to the bottom when you will have to toss all the shifters and change to 10 speed. Well 5+ years plus when replacement parst run out for 9-speed.


    FYI I played the game back in 1998 with my 12-speed (6-speed).. Hey I never need more than 6 gears in the back... and who needs those fancy pedals and shifters... I've seen the changes but that's not for me... SUNTOUR FOREVER!!!

    Man I'm glad I decided to get out of that trap! Now the SUNTOUR is in my collection along with a gaggle of 6-speed SACH replacements, never to be ridden, except around the block, again...

    JBP

    P.S. A little reading about ramps and numbers and you too can make your own custom cassette... Either mix and match mountain and road cassettes, or go to Harris Cycles

    http://www.sheldonbrown.com/harris/hub.html
     
  6. Houckster

    Houckster New Member

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    Was some one referring to me?:confused:

    Anyway, the problem with gearing is not just chainrings (getting a 45T is not easy these days) but the general approach to gearing that Campagnolo and Shimano take which is large gaps between the chainrings and more closely spaced cassette cogs is not for me. I don't like this approach and probably never will because I usually find that with this setup, a chainring change necessitates 1-2 changes on the back which I don't like to do.

    Also, when using the stock Dura-Ace cassettes (none of which I really like), I found a lot more hesitation with the 15T and larger cogs even after making sure that the derailleur tab was properly aligned and all components were installed correctly. With the new systems, the shift has to commence when the chain is near a ramp and if it doesn't the shift isn't very clean. Maybe some people don't mind this but I want my shifts now. Those small hesitations make the rider pay on steep hills. The old Dura-Ace twist-tooth cogs don't have this problem. Therefore I only use the first two modern Dura-Ace cogs, the rest go in the trash or metal recycle.

    Another problem is the front derailleur. Modern ones for touring have a large inner plate to help deal with the large differences between chainrings. I use a 48-42-30T combination on my touring bike and those derailleurs don't work at all. They require at least an 8T difference between the middle and out rings before they'll work properly. Fortunately, the standard Ultegra derailleur works fine.

    Getting the gearing right for my style is the most difficult part of putting a bike together for me.
     
  7. rek

    rek New Member

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    One thing I'd really like to have is a 13-27T cassette -- i.e. a 12-25T cassette with the 12 cog taken off, and a 27 cog put on the other side.. extra hill-climbing range while keeping nice even spacing, and does away with the 12 cog that I never use.

    I know the ramps and stuff on Hyperglide cassettes mean you need to buy a specific cog depending on which cogs are adjacent to it..

    http://www.sheldonbrown.com/k7.html

    Can you buy individual cassette rings for things like this? That site above says my current 12-25T 105 cassette doesn't have any rings joined together, so I'm guessing the only real question is finding a 27 cog that can work properly with a 25 next to it.

    What would happen if the 27 cog was a normal un-ramped one? Would it just mean shifting is a little less smooth into that one, or would it do something nasty like throw the chain into the spoke-guard?
     
  8. Houckster

    Houckster New Member

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    I don't believe you can't do what you propose. The teeth on the second cog are different from those of a cog for the high gear position.

    All the cogs are keyed to work with a specific cog and in the case of Dura-Ace and Ultegra, groups of 2 and 3 cogs are connected further reducing flexibility in gearing. The low gear cogs, for example, are in a group of 3. They cannot be separated.:( Other Shimano lines may not adhere to this but I'm not familiar with them.

    The individual cogs for the middle and larger tooth sizes are almost all gone now too.

    When you talk about space rings, do you mean spacers to keep the cogs separated properly? If so, yes you can.

    This is what I've been talking about, we can customize just about every part of the bike but customizing the gearing is becoming almost impossible and that's a very critical part of the bike's performance.:rolleyes:
     
  9. rek

    rek New Member

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    Sheldon Brown's site shows that the only stuck-together rings in an Ultegra 12-25T is the 17/19/21/23/25 (and the 105 has no such problem) .. could one remove the 12 and 13 cogs it has, replace the 13 with one that has the thread, and stick a 27 at the end?

    Some of the talk on that page says that this shouldn't be impossible.. unless of course you can't find a blank 27 cog :(
     
  10. Houckster

    Houckster New Member

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    These 5 cogs are all attached?
     
  11. prestonjb

    prestonjb New Member

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    Nope... Sheldon's site may say that but actually the gears are stuck together into two groups...

    The 17 and 19 are stuck together...

    The 21,23, and 25 are stuck together...


    AND... The 21, 23 and 25 are on a carrier so they cannot be seperated and used seperatly...

    HOWEVER the 17 and 19 (ultegra only Dura-ace are on a carrier) are just two gears pinned together...

    A dremel tool with a grinding stone can remove the heads of the rivits holding the 17 & 19 together and now you can treat them like individual gears.

    Here is what I learned when building my own cassettes:

    ATB CASSETTES:
    XTR: 7 gears are pinned to a carrier ... Bottom 3 are Ti. A VERY VERY light cassette cosidering how big the gears are (12x34)
    XT: 7 gears are pinned to a carrier... Steel gears. 11x32 but I think they now offer 12x34
    LX: if you get a very small allen key you can simply unbolt the gears. The gears are full size and the spacers are aluminium. 11x32 cassette.

    NexAve: (well not atb but not road either) size 12x34. Gears are pinned with rivets. Grinding off the rivet will seperate the gears. Spacers are plastic and may crack during dissassembly...

    ROAD CASSETTES:

    Dura-Ace:
    Typically bottom 5 gears are pinned to carriers in two groups. The bottom 3 gears grouped and all Ti. Middle 2 gears are pinned to carrier and are steel. Spacers are aluminum.

    Ultegra:
    Bottom 5 gears pinned... But only bottom 3 gears are pinned to a carrier. Middle 2 can be seperated using a grinding stone. All gears are steel. Spacers are aluminium

    105. Bottom 7 gears are pinned. Grinding out rivet will seperate them. Spacers are plastic and may break or warp when seperating the gears.

    The comment about MTB was not directly to anyone ;-) but was just to say my experience with poor shifting seems to be related to the fact that the smaller toleraces of the 9-speed tends to be affected by dirt and mud... Perhaps 9-speed is not ready for ATB. On my road bike however I see no such problems.



    John

    P.S. Now for some comments... Also from experimentation and to address/counter the downshift comment above... I've mixed the ramps around this way and that and I've not noticed a big change in the shifting or chain lag...

    Some of my friends have problems with their STOCK setups... Perhaps I'm more of a maintanace and cleanliness and mechanical freak then they are so I seem to keep the setup right... Though all I typically do is keep it very clean. Taking the cassette off of the wheel once a month and scrubbing it... Changing chains every 4 months... I never see chain spins or slips during shifting or even on ring-shifts.

    I was concerned a bit on this because my custom 13x32 had one gear that was out of place but I hammered on it before my trip and it got hammered a lot during the trip and it shifted flawlessly.

    JBP
     
  12. prestonjb

    prestonjb New Member

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    Oh, hey REK,

    I'm not sure you can find an individual 27 gear that doesn't require a carrier...

    You can get a 28 from a mountain bike cassette such as an LX cassette.

    I'll look to see if there is such a thing as an individual 27 gear.

    Sheldon Brown may carry a 27 gear individually ($10) but AEBIKE is where I would get the 13 top gear $8. I think Sheldon wants $20 for them.
     
  13. rek

    rek New Member

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    I just noticed today at the LBS, one of the staff there has got himself a gleaming new Trek 5500, and with it a 38 tooth chainring.. I think this is a more likely, less "pain in the arse" option. Now to calculate the gear-inches of all the various options..
     
  14. Houckster

    Houckster New Member

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    It seems to me that there is a custom cog business opportunity for someone with the necessary skills. In my opinion the best shifting cogs were the twist tooth Dura-Ace cogs. I'd buy up a bunch of them if they came in the right sizes and could be attached to a carrier.
     
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