Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

Playing with gearing for the Mercian

Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

Playing with gearing for the Mercian

Old 03-23-22, 07:52 PM
  #1  
noobinsf 
Senior Member
Thread Starter
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 3,286

Bikes: '82 Univega Competizione, '72 Motobecane Grand Record, '83 Mercian KOM Touring, '85 Univega Alpina Uno, '76 Eisentraut Limited

Mentioned: 56 Post(s)
Tagged: 0 Thread(s)
Quoted: 1085 Post(s)
Liked 1,191 Times in 693 Posts
Playing with gearing for the Mercian

I have been messing around with gear-calculator to decide on initial gearing for the upcoming Mercian build, and I'm curious what folks think now that I've narrowed it down to these two options. I've been collecting cassettes and derailleurs for a while, so the two configurations pictured below are not theoretical -- I have the pieces in hand and can install them.

Here's my main concern -- I like the ultra low gear of the 12-34 cassette because there are lots of steep hills near my house (and I'm out of shape), but there are a lot more direct duplicate gears than with the 11-30 cassette. Would I miss something great by having a 22.2 gear-inch low gear vs a 19.3 gear-inch low? Or would the duplicates of the 12-34 annoy me such that I should avoid it, even if it offers me a lower gear?

Either way, I have a Microshift M55 rear derailleur that will handle a 45-tooth spread, and my front mech is a Suntour XC Pro that can easily handle the 24-tooth chainring difference, so capacity is not a concern with either setup. I am going to mount an IRD Defiant with 48-36-24, so the chainrings are set and will not change. I'm not concerned about having too high a top gear, since it's a single outlier with the 11-30 cassette.

I dunno -- thoughts?


noobinsf is offline  
Old 03-24-22, 11:49 AM
  #2  
jonwvara 
Senior Member
 
jonwvara's Avatar
 
Join Date: Apr 2006
Location: Washington County, Vermont, USA
Posts: 3,681

Bikes: 1966 Dawes Double Blue, 1976 Raleigh Gran Sport, 1975 Raleigh Sprite 27, 1980 Univega Viva Sport, 1971 Gitane Tour de France, 1984 Lotus Classique, 1976 Motobecane Grand Record

Mentioned: 75 Post(s)
Tagged: 0 Thread(s)
Quoted: 700 Post(s)
Liked 527 Times in 284 Posts
I doubt that you would notice much difference between those low gears, so I would not worry too much about that.

As always when I look at the gear-chart output for I setup involving an 11-tooth cog, I find myself wondering who decided that the world needed such a preposterous high;
__________________
www.redclovercomponents.com

"Progress might have been all right once, but it has gone on too long."
--Ogden Nash
jonwvara is offline  
Likes For jonwvara:
Old 03-24-22, 11:57 AM
  #3  
nlerner
Senior Member
 
Join Date: Dec 2005
Posts: 16,387
Mentioned: 441 Post(s)
Tagged: 0 Thread(s)
Quoted: 3372 Post(s)
Liked 5,075 Times in 2,104 Posts
I'll admit to not planning out my gearing very well, but one consideration is the gears/cog combos that I'd be riding on most often, not those extremes on either end. Along those lines, I tend to be on 50-65 gear inches for most of my riding, and the second combo above has fewer overlaps and more steps in that range.
nlerner is offline  
Old 03-24-22, 01:06 PM
  #4  
Dfrost 
Senior Member
 
Dfrost's Avatar
 
Join Date: May 2013
Location: Pacific Northwest
Posts: 1,938

Bikes: 87 Marinoni SLX Sports Tourer, 79 Miyata 912 by Gugificazione

Mentioned: 162 Post(s)
Tagged: 0 Thread(s)
Quoted: 481 Post(s)
Liked 384 Times in 227 Posts
My gearing for our very hilly PNW terrain is similar to your second set, but without the 11T cog: 12-30 8-speed with 46-36-24 rings. I’ve been very happy it with for almost a decade. I used to obsess over gear charts and worry about near duplicates, etc. But in actual riding, what I notice is the progression on a single ring, because that’s how shifts tend to happen. And like @nlerner, closer spacing in the range that I use on flat-ish roads feels great with winds and subtle inclines. So I assemble “custom” 8-speed cassettes with single-tooth steps (when I’m in mid-season “shape”) in the middle, wider steps on the ends: 12-14-15-16-18-21-25-30. Early season when I’m riding more in lower gears: 13-15-17-19-21-23-26-30, same rings.
Dfrost is offline  
Old 03-24-22, 01:40 PM
  #5  
noobinsf 
Senior Member
Thread Starter
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 3,286

Bikes: '82 Univega Competizione, '72 Motobecane Grand Record, '83 Mercian KOM Touring, '85 Univega Alpina Uno, '76 Eisentraut Limited

Mentioned: 56 Post(s)
Tagged: 0 Thread(s)
Quoted: 1085 Post(s)
Liked 1,191 Times in 693 Posts
This is precisely the kind of thoughtful feedback I was looking for and why I love this forum! Thanks to you all.
noobinsf is offline  
Old 03-24-22, 01:52 PM
  #6  
52telecaster
ambulatory senior
 
52telecaster's Avatar
 
Join Date: Dec 2016
Location: Peoria Il
Posts: 5,490

Bikes: Bob Jackson World Tour, Falcon and lots of other bikes.

Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 1694 Post(s)
Liked 2,497 Times in 1,202 Posts
Typically I would want less duplication but I like the top end of the 12-34 cassette a lot better. The 12-13 step will be great on long flats. As for the ultimate low the 34 might make u get off a little later but it's not much better than the 30 tooth cog. I used to insist on sub 20 for my low but in my old age I'm not to proud to walk up a hill. Anybody that has a problem with it can just enjoy their superiority.

Also at some point you might think about a different middle ring and you could half step the 12-34. It would be a mighty narrow half step but some folks like it.
52telecaster is offline  
Likes For 52telecaster:
Old 03-24-22, 02:20 PM
  #7  
SJX426 
Senior Member
 
SJX426's Avatar
 
Join Date: May 2008
Location: Fredericksburg, Va
Posts: 9,135

Bikes: '73 Bottecchia Giro d'Italia, '83 Colnago Superissimo, '84 Trek 610, '84 Trek 760, '88 Pinarello Veneto, '88 De Rosa Pro, '89 Pinarello Montello, '94 Burley Duet, 97 Specialized RockHopper, 2010 Langster, Tern Link D8

Mentioned: 67 Post(s)
Tagged: 0 Thread(s)
Quoted: 1439 Post(s)
Liked 1,781 Times in 902 Posts
I have recently moved from 5/6/7 speed to 8/8/10 speed configurations. I find bigger gaps at the lower gears is more acceptable compared to the middle set. When I climb a hill, I need to be able to get to a usable cadence. When I am cruising with small inclines, I like to have finer resolution to keeping my cadence in the range of 75 -95. Higher gears are used for down hills and even then if I run out of cadence, I am willing to coast. For this reason, I converted from 8x2 to 9x3 with much more comfortable control of my cadence. The smallest sprocket is 13 on the 9 speed with a large chain ring of 52. The bottom is a 26/30, which is plenty low for me. Oh and I do use it upon occasion but typically I can stay in the 42.
I have option of changing rings with 54-50 options for the large and 42/40 for the middle. Playing around with the same site offers little in a good combination to address low and high gearing with good spread in-between.
__________________
Bikes don't stand alone. They are two tired.
SJX426 is offline  
Likes For SJX426:
Old 03-24-22, 06:01 PM
  #8  
droppedandlost 
small ring
 
droppedandlost's Avatar
 
Join Date: Jul 2012
Location: PNW
Posts: 918
Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked 669 Times in 298 Posts
second set definitely. The big gap at 70" in the first set would irritate me every ride.
__________________
droppedandlost is offline  
Likes For droppedandlost:
Old 03-24-22, 06:03 PM
  #9  
droppedandlost 
small ring
 
droppedandlost's Avatar
 
Join Date: Jul 2012
Location: PNW
Posts: 918
Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 382 Post(s)
Liked 669 Times in 298 Posts
Two different tire sizes?
__________________
droppedandlost is offline  
Old 03-24-22, 06:30 PM
  #10  
noobinsf 
Senior Member
Thread Starter
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 3,286

Bikes: '82 Univega Competizione, '72 Motobecane Grand Record, '83 Mercian KOM Touring, '85 Univega Alpina Uno, '76 Eisentraut Limited

Mentioned: 56 Post(s)
Tagged: 0 Thread(s)
Quoted: 1085 Post(s)
Liked 1,191 Times in 693 Posts
Originally Posted by droppedandlost View Post
Two different tire sizes?
You know, I must have changed them between setups and forgot to match them. In any case, the difference was pretty negligible, and it didn't affect the quantity of duplicates or the distribution of gear inches, even if the individual values were shifted slightly. I mostly wanted to illustrate the "point spread," but yes, that's a good catch.
noobinsf is offline  
Old 03-24-22, 06:45 PM
  #11  
xroadcharlie
Full Member
 
Join Date: Apr 2019
Location: Windsor Ontario, Canada
Posts: 469

Bikes: 2018 Giant Sedona

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 151 Post(s)
Liked 99 Times in 83 Posts
I like the closer spacing of the 11 - 30 cassette. But make no mistake, the 15% jump from 19.3 to 22.2 gear inches can be a game changer for long steep hills if you need them, not so much for a short steep one. Just use you past experience as a guide. If you where OK before with 22+ gear inch, I'd recommend going with the 11 - 30 cassette. I think 22.2 gear inches would get you up most climbs without too much trouble, at least without 30 lbs of groceries.

It's mostly the high gears where I want them closely spaced, And both cassette's seem OK there, The difference between 16/14 and 15/13 is only 1%, But the 20 - 17 jump on the 12 - 34 cassette would be irritating to say the least, That's 18%. For very low gears it's fine, but not in the midrange, especially climbing. I don't like the 20 - 23 jump either, but could live with that.

I wouldn't care about how many gears duplicate, as long as I can keep gear jumps about 10 - 14%, and they cover the range I need.

Last edited by xroadcharlie; 03-24-22 at 07:30 PM.
xroadcharlie is offline  
Likes For xroadcharlie:
Old 03-25-22, 06:54 AM
  #12  
L134 
Senior Member
 
Join Date: Dec 2015
Location: San Diego
Posts: 587

Bikes: 1978 Bruce Gordon, 1977 Lippy, 199? Lippy tandem, Bike Friday NWT, 1982 Trek 720, 2012 Rivendell Atlantis, 1983 Bianchi Specialissima?

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 280 Post(s)
Liked 118 Times in 70 Posts
[QUOTE=noobinsf;22448919 so the chainrings are set and will not change.[/QUOTE]

May I ask why? This seems like an extremely limiting and unnecessary condition unless that crank doesn't have removable chainrings. Slide those chainring numbers around a bit.
L134 is offline  
Likes For L134:
Old 03-25-22, 11:24 AM
  #13  
noobinsf 
Senior Member
Thread Starter
 
noobinsf's Avatar
 
Join Date: Sep 2005
Location: Oakland, CA
Posts: 3,286

Bikes: '82 Univega Competizione, '72 Motobecane Grand Record, '83 Mercian KOM Touring, '85 Univega Alpina Uno, '76 Eisentraut Limited

Mentioned: 56 Post(s)
Tagged: 0 Thread(s)
Quoted: 1085 Post(s)
Liked 1,191 Times in 693 Posts
Originally Posted by L134 View Post
May I ask why? This seems like an extremely limiting and unnecessary condition unless that crank doesn't have removable chainrings. Slide those chainring numbers around a bit.
I have been waffling on this build for a long time, and I just need to make a decision and build so I can try out the frame, so on one level, this is just removing a variable. I wanted to address the paint on the frame (which I tackled last year) and build a wheelset for it, and I've tinkered with several "practice" bikes before finally getting to this one, so I'm eager to get it on the road. Also, I bought the crankset as a shiny new triple, so I want to use it undisturbed, at least initially.

I mess with chainrings all the time, so I certainly could. I just don't wanna this time. Also, I don't really know my optimal gearing enough to know what my preference will be, and hearing folks' feedback above has been really helpful in my thinking about how to set it up and ride different terrain, so this is active research anyway.
noobinsf is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.