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Conference noted::bicycle

Title: Bicycling
Notice:Bicycling for Fun
Moderator:JAMIN::WASSER
Created:Mon Apr 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3214
Total number of notes:31946

1732.0. "The Batbike is dead" by VERVE::BUCHANAN (Bat) Thu Sep 06 1990 18:26

The old Batbike is history!  A sad story indeed, but to make it short, after
3 1/2 years of hard riding including several crashes the seat tube broke.  The
frame maker, Guerciotti/Alan, and the importer, Ten Speed Drive, said that they
would stand by their frames for 2 years only, so I'm SOL.

So now I have a broken bike but most of the components are still good.  What to
do?  I'm thinking about a few options:
     1) Buy a new frame and a few new components
     2) Buy a used bike (I have a possibility of picking up one of Eric
        Heiden's bikes)
     3) Put together a whole new bike.

Option 3 brings me back to a idea I floated a while back of a "racing triple".
That is a triple crank set with a straight or nearly straight block in back.
The two big chain rings would give you your tight racing bike gears and the
granny ring is the bail out/big hill gears.  The reality is that with the hills
around here and my 175 bulk, I can't have very tight gearing because I need a
low of 39x24 (or often lower).

Which brings me to a few compatibility questions:

    Are any of the Shimano down tube shift levers compatible with a Deore XT
    short cage rear derailluer?  A salesman at one bike shop said that it 
    would work with Dura-Ace shifters but I know that Ultegra and D-A are not
    compatible.

    If you do need to use D-A shift levers then will the Deore work on an 8
    speed hub?

    This same salesman also told me that that D-A and Ultegra clusters had
    different spacing.  I use an Ultegra hub with a D-A derailluer and it seems
    to work OK but he showed me an Ultegra spacer and a D-A spacer and there
    *was* a *little* difference.  Maybe the D-A cogs are just slightly thinner?

    If your rear drop-out width is 126mm I understand that you can still use
    the 130mm wide D-A 8 speed hub.  But does the 8 speed have the same spacing
    as the 7 speed?  In other words could you pop in a 7 speed hub (which I
    currently have 3 of) and go (after maybe making an adjustment so you
    couldn't jump the chain off the inner cog looking for the nonexistent 8th
    gear)?

    If I used a triple crank I would need a wide range front derailluer which
    only seem to come in clamp-on models.  Do they make braze-on mountain bike
    derailluers?  If I get a frame with a braze-on hanger will I have to cut
    it off?
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1732.1The front is just one place where you can add gearsCIMNET::MJOHNSONMatt Johnson, DTN 291-7856Fri Sep 07 1990 09:5434
    With an 8-speed rear, running 39x24 doesn't mean you have to give
    up close ratios.  In Vermont (OK, it's not California, but...) I
    often rode a 12-13-14-15-17-19-21-24 with a 39/53.  That gives 
    you nearly a five-speed straight block in the upper gears.  If
    you switched to a 13-tooth outer cog, things would get even tighter
    (13-14-15-16-17-19-21-24).
    
    The inter-gear spacing on the 8-speed and 7-speeds might be the 
    same -- I haven't checked.  But I think it would be hard to line
    up the indexing, as the outer cog is offset 2mm due to the wider
    axle.  Go with friction mode when you use your 7's, if you go with
    the 8.
    
    Aesthetics aside, I still think you're looking for problems with
    the "granny gear" setup.  You've already seen the difficulty of 
    finding parts (like front derailleurs) that serve your purpose.
    Getting a rear derailleur that 1) accepts lots of chain wrap,
    but 2) is slanted for a tight gear cluster will be next to 
    impossible -- MAYBE Mt. Bike "racing" (short-cage) derailleurs
    will do, but "short" for them is 13-24 vs. 13-34.
    
    A final hot tip:  I talked to Tom Craven, of Team 7-11, about
    his gearing.  He says that the 7-11 team DOES NOT use the new
    "superglide" gears on its indexed 8 freehubs.  Apparently, 
    superglide, while it lets you shift under power, compromises
    shifting responsiveness by limiting the shift point to a single
    position on the cluster.  That means that you need a full wheel
    rotation at times before the shift happens.  At high speeds,
    this is unnoticable, but apparently, during climbs, its annoying.
    (I've never tried this myself, so I don't know....)
    
    Good luck with your new rig,
    
    MATT
1732.2Racing-Triple feedback...DELNI::MARCINKUSFri Sep 07 1990 10:5519
    Hey "Bat",
    
    A "racing triple"???  Well, maybe, but I think you will be disappointed
    with shifting performance.  Even with Dura-Ace quality.  I have
    Dura-Ace on my two road bikes and I can feel a shifting difference
    between the two.  One bike has much longer chain stays and therefore a
    longer chain.  It's noticeable but on a training bike it's acceptable.
    Such shifting performance on a racing bike just won't do it.  I suggest
    it would be too slow.  So consider this; I also weigh in on the heavy
    side, 178 or so.  And I often ride very hilly terrain.  I ride a 39x52
    chainring setup and a 13-15-17-19-21-23-26, 7 speed freewheel.  It 
    works great!  At least for me.  I can climb major hills and still find
    a gear to keep pace with the fastest pack.  In fact, this setup has
    worked so well for me I run it on both my racing bike and sport bike.
    Of course, be prepared to take some kiddin' on the "girly-man" gears
    from your macho friends as I do.  The payback will come when you ride by
    them on a steep hill and have to wait at the top for them to catch up.
    
    John
1732.3still trying to sell myselfVERVE::BUCHANANBatFri Sep 07 1990 20:1074
    I'm still thinking this thing through.  I've run this idea by a couple
    good bike shops and they think it would work just fine.  They've all
    put triples on racing frames but usually with a large rear cluster.

    My original setup was 42-52 x 13-26 7 speed.  This does work OK and
    gives a pretty low gear.  However all the shifts are 2 or 3 teeth
    jumps.  If you've ever ridden a straight block you know how nice it
    feels when each shift is only 1 tooth difference.  You feel like you've
    always got the perfect gear.  I now am using a 39 inner ring with a
    13-24 rear cluster.  The rear is a bit closer but I really don't like
    the jump from 39 to 53, it's just too big.
    
    I should note that even 2 tooth jumps are better than what I've got
    now.  With the road bike out of action I put the TIME pedals and some
    1.5" road times on the Mount Batbike and am trying to do battle with
    the road bikes.  I have a 6 speed 13-17-20-23-26-30.  Pulling a 30 lb
    mountain bike with big wheels up the hills is tough enough but my
    biggest problem is finding the right gear.  The jump from 13 to 17 is
    huge!

    My thinking is with the normal setup you have to make a choice, either
    get close gearing and suffer on the hills or get low gears and live
    with bigger gaps in the gearing.  But why make the choice?  Why not
    have both?  Keep the close rear cluster and get the lows by adding a
    third chain ring.

    As I said in an earlier note to change over an existing setup would
    cost too much, but I'm thinking of building a new bike from scratch so
    it wouldn't cost any more.

    What will the shifting performance be like?  That I'm not sure of.  A
    D-A derailluer can wrap 25 teeth, a short cage Deore XT 27, so all my
    setups have been based on this limitation.  So there will be no long
    cage derailluers or 32 tooth rear cogs.  I might also note that my
    mountain bike setup shifts pretty damned good, the only time you really
    notice it is when you drop from a large to smaller chain ring.

    Just for comparison look at the gearing I was using vs. one possible
    triple combination.  The triple gives a higher high, a lower low and
    more gears in my "sweet spot".  By sweet spot I mean my most used range
    which is from about 65 to 90"


       39         53
13    *****     110.08
14    75.21     102.21
15    70.20      95.40
17    61.94      84.18       needed wrap = 21
19    55.42      75.32
21    50.14      68.14
24    43.88      *****

     40        50        60        70        80        90        100       110
56789012345678901234567890123456789012345678901234567890123456789012345678901234
         |     |    |      |       |    |      
                                 |      |        |          |      |       |


       28         40         50
12    *****      90.00     112.50
13    *****      83.08     103.85
14    54.00      77.14      96.43
15    50.40      72.00      90.00       needed wrap = 26
16    47.25      67.50      84.38
18    42.00      60.00      75.00
20    37.80      54.00      *****

     40        50        60        70        80        90        100       110
56789012345678901234567890123456789012345678901234567890123456789012345678901234
   |   |    |  |   |         
                   |     |      |    |    |     |      |
                                        |        |     |     |       |       |
 

1732.4Yeah... what he said.GUIDUK::MONINFri Sep 07 1990 20:217
    I concur with the other warnings about poor performance on a triple.
    When riding our tandem w/ Deore XT, I always have to factor in the
    low-speed shifts compared with a Campy drive train on my road single.
    Some of the loss is cable length, etc. but unfortunately, its the
    middle-to-low ring shift (the one you really need when the road goes
    vertical) that always seems unpredictable.  Go w/ the eight instead,
    or the big spread in front.  I think you'll be lots happier
1732.5JUMBLY::MACFADYENSend money now!Mon Sep 10 1990 06:1428
>      <<< Note 1732.1 by CIMNET::MJOHNSON "Matt Johnson, DTN 291-7856" >>>
>    
>                                           Apparently, 
>    superglide, while it lets you shift under power, compromises
>    shifting responsiveness by limiting the shift point to a single
>    position on the cluster.  That means that you need a full wheel
>    rotation at times before the shift happens.  At high speeds,
>    this is unnoticable, but apparently, during climbs, its annoying.
>    (I've never tried this myself, so I don't know....)
    
    I think yer man means Hyperglide (tm, reg) rather than Superglide (�).
    Superglide is what Shimano calls their latest chainring shifting,
    Hyperglide is for the cogs as the back. Anyway, I don't agree with him,
    speaking as a recent convert to Hyperglide. On the bigger sprockets
    there are at least two places on where the chain can be lifted onto the
    sprocket for a downshift. I've never noticed a shifting delay -
    Hyperglide is the fastest and most undramatic shifting I've ever used.
    Then again I don't run a racing team and I'm not a pro.
    
    
    Re chainwrap for the Batbike:
    
    Why worry about the extremes of chainwrap when you can simply avoid
    using them? I bet that adding a third chainring won't be a big deal.
    
    
    Rod
                                                                        
1732.6Racing triple sounds good to me!BCSE::KLASMANALL-IN-1 DESKtop for PCs. dtn 381-0731Mon Sep 10 1990 08:2823
I've thought about doing the same thing, living here in New Hampshire and having
a few steep hills in the area :^)  I'm currently using 39x53, 13-21 7spd and am
pretty happy with it, except for the huge change when shifting the front.  I 
find I usually have to do a triple shift, 1 back, front, 1 back, to get the 
right gear.  Using SIS and Flight Controls on my Scott DH bars helps a lot, but 
its still rather inconvenient.  I'd never do this on a bike with shifters on the
down tube.

Non of the shops or other riders around here seem to thinks a racing triple is a
good idea, but I do.  And I was surprised to read in Hinault's book that he 
thought it might be a good idea, too.

My motivation for my current setup was the realization that although I had a 14-
spd bike, I really only used 6 speeds, with a 13-26, 42x53.  But I just don't 
want to be without bailout gears on the long, hilly rides.

My only suggestion would be to add the device that clamps on the seat tube to 
prevent the chain from slipping off when sbifting to the granny ring.  I put one
on our tandem and it really helps a lot.  Don't remember what its called, but 
its listed in the catalogs.  I wish there was something that made the shift up
from the granny a little smoother.

Kevin
1732.7ALLVAX::JROTHIt&#039;s a bush recording...Mon Sep 10 1990 08:417
    Marie Canins rode (and won) the TdF Femin on a road bike with a triple,
    and she's certainly no wimp.

    I've seen several people on Brevets with road bikes set up that way,
    some of whom were pretty fast riders so the idea has merit.

    - Jim    
1732.8The bat will soon be historyTPWEST::SHROYERWed Sep 12 1990 12:047
	For those of you who didn't know, the bat's group is being
disbanded (they don't offer the package in the silicon valley) and the
bat will soon be gainfully employed in a non-dec environment.  He
resigned Monday.  I hope he will still be available for our lunch
rides all winter. 

	Should we get his digital jersey before he leaves?
1732.9Taking it personally?CIMNET::MJOHNSONMatt Johnson, DTN 291-7856Wed Sep 12 1990 12:304
    Gosh, I didn't mean to be that negative about the racing triple
    idea!
    
    MATT
1732.10still thinkingVERVE::BUCHANANBatWed Sep 12 1990 13:399
>    Gosh, I didn't mean to be that negative about the racing triple
>    idea!
    
>    MATT


When interviewing with companies I made it a point to ask their opinion on the
racing triple idea.  If they laughed, I walked!