FD doesn't reach outer chain ring
05-23-07 | 01:32 PM
#1
Thread Starter
Jasper
Joined: Mar 2005
Posts: 505
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From: Zeist, Netherlands
Bikes: '90 Peugeot Ventoux, Cornelo, '89 Gazelle Field Cruiser MTB, '83 Peugeot PFN10, '96 Gary Fisher Aquila
FD doesn't reach outer chain ring
The situation:
- I've got an older type Shimano 600 front derailleur (FD-6207) getting it's cable from the bottom.
- I've got 3/7 STI shifters (RSX).
- I've got an older Shimano crankset (dont have the number here), a double
- I don't know exactly about the bottom bracket but it is a Shimano MH BC137 (aug '88) 1.37x68mm with a square tappered axle
At first, with an old Koga branded SR Sakea crankset it worked perfect. Than i replaced the crankset with the above one and now the FD can't reach the outer chainring. I did try loosen the limiter screws but i think the FD just can't reach that far, thus:
- the crankset isn't far enough at the axle due to incompatibility or
- the FD is not suitabel or
- i do something wrong
Any clues?
05-23-07 | 02:41 PM
#3
Sir Fallalot
Joined: Jul 2006
Posts: 5,288
Likes: 17
Originally Posted by leunkstar
At first, with an old Koga branded SR Sakea crankset it worked perfect. Than i replaced the crankset with the above one and now the FD can't reach the outer chainring.
Originally Posted by leunkstar
- the crankset isn't far enough at the axle due to incompatibility
As the poster above said, you need a BB with shorter axle to adjust the chainline to what it was originally.
05-23-07 | 03:03 PM
#4
Thread Starter
Jasper
Joined: Mar 2005
Posts: 505
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From: Zeist, Netherlands
Bikes: '90 Peugeot Ventoux, Cornelo, '89 Gazelle Field Cruiser MTB, '83 Peugeot PFN10, '96 Gary Fisher Aquila
I have some other BB's in my gear box of the same 68mm diameter.
Is there a way to measure which axle lenght i need?
Is there a way to measure which axle lenght i need?
05-23-07 | 03:43 PM
#5
Sir Fallalot
Joined: Jul 2006
Posts: 5,288
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Originally Posted by leunkstar
Is there a way to measure which axle lenght i need?
EDIT: I found this nice little explanation on the intarnetz:
Originally Posted by https://www.pricepoint.com/helpDesk/ProductHelp/Cranksets&BB.htm
To find the length of the spindle, first remove the crank arms. Then measure the length of the spindle in millimeters from end to end. If your cranks are attached with nuts as opposed to bolts, do not measure the extended threaded portions of the spindle.
If you are replacing a BB and are using your old crank, you'll want a replacement BB with the same spindle length. If you are installing a new crank, you will want to use the spindle length recommended by the crank manufacturer.
If you are replacing a BB and are using your old crank, you'll want a replacement BB with the same spindle length. If you are installing a new crank, you will want to use the spindle length recommended by the crank manufacturer.
This article is excellent. I highly recommend it:
https://www.sheldonbrown.com/bbsize.html
Last edited by wroomwroomoops; 05-23-07 at 04:02 PM.
05-23-07 | 04:37 PM
#7
Thread Starter
Jasper
Joined: Mar 2005
Posts: 505
Likes: 0
From: Zeist, Netherlands
Bikes: '90 Peugeot Ventoux, Cornelo, '89 Gazelle Field Cruiser MTB, '83 Peugeot PFN10, '96 Gary Fisher Aquila
ah thx for the compliment and thx for the add ons.
i know how to measure the spine but i want the opposite
Know how long it need to be
Ah the Sheldon "who else" brown article shows what i want but.. both cranksets arent in the table
well i'll try to guess than i am afraid (trial and error)
i know how to measure the spine but i want the opposite
Know how long it need to be
Ah the Sheldon "who else" brown article shows what i want but.. both cranksets arent in the table
well i'll try to guess than i am afraid (trial and error)
05-23-07 | 06:09 PM
#8
*
Joined: Jan 2007
Posts: 3,458
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Measure your chainline as it sits. For ease of measurement, measure from the center of the seattube to the inner chainring. Lets assume you measure 45mm. The measurement you need is 41mm (giving you a 43.5mm chainline). Measure your spindle, lets assume it's 120mm and symmetrical. You'll need a symmetrical 112mm spindle [120-(2*(45-41))] or as close as you can get. (113 is common)
Just as a guess, your older double Shimano crankset will need a 113/5mm spindle. (Colnago really threaded BSC, not Italian?)
Just as a guess, your older double Shimano crankset will need a 113/5mm spindle. (Colnago really threaded BSC, not Italian?)
Last edited by vpiuva; 05-23-07 at 06:23 PM.
05-23-07 | 07:02 PM
#9
Sir Fallalot
Joined: Jul 2006
Posts: 5,288
Likes: 17
Originally Posted by vpiuva
Measure your chainline as it sits. For ease of measurement, measure from the center of the seattube to the inner chainring. Lets assume you measure 45mm. The measurement you need is 41mm (giving you a 43.5mm chainline). Measure your spindle, lets assume it's 120mm and symmetrical. You'll need a symmetrical 112mm spindle [120-(2*(45-41))] or as close as you can get. (113 is common)
Just as a guess, your older double Shimano crankset will need a 113/5mm spindle. (Colnago really threaded BSC, not Italian?)
Just as a guess, your older double Shimano crankset will need a 113/5mm spindle. (Colnago really threaded BSC, not Italian?)
Just one comment: it's really difficult to measure "from the center of the seat-tube", because you can't reach it with a caliper. Better measure the seat-tube diameter (say, D) and then from the opposite side of the seat-tube to the middle part of the inner chainring (which can be reached with a caliper - just aim for the tip of the teeth), say D1. Then the chainline is, if my math is not fuxored, Chainline = D1 - D/2
