Bicycle TutorBicycle Tutor

Show off your bike!

Post Reply 

Shimano 105 derailer fit new 7 speed cassette?

Related video tutorials:
How to Adjust Your Front Derailleur How to Adjust Your Front Derailleur
* Now with 3D interactive instructions
Author Message
crashq Offline
New Member


Posts: 2
Joined: Aug 2012
Post: #1
Shimano 105 derailer fit new 7 speed cassette?
I have a 1988 Miyata 712 (12 speed). I recently got hit by a car and had to replace the original Mavic front wheel (with a Mavic Aksium). Surprisingly, it was stiff enough and aerodynamic enough compared to the original wheel, that it has me wanting to replace the rear wheel. too. Not wanting to spend too much on an older (though still nice) bike, I want to do this without spending much beyond the wheel itself. Of course, all of the new factory wheels are equipped with cassettes rather than freewheels.

I was wondering whether if I swap out my current (13-24T) 6-speed freewheel for a 7-speed cassette, if I can get away with my current 1988 Shimano 105 rear derailer and just swap out the current indexed (downtube) shifter for one that fits the new 7 speed cassette. That would limit me to about $50 on top of the wheel.
Aug 13, 2012 10:57 PM
Find all posts by this user Quote this message in a reply
painkiller Offline
Veteran Member

Peoria, IL. USA
Posts: 1,354
Joined: Mar 2011
Post: #2
RE: Shimano 105 derailer fit new 7 speed cassette?
how about a pic of the rear D and the Model number on it


There are two kinds of people in the world, "Those who help themselves to people, and those who help people!"
Aug 14, 2012 06:28 AM
Find all posts by this user Quote this message in a reply
RobAR Offline
Veteran Member

Mountain Home, AR
Posts: 725
Joined: Sep 2010
Post: #3
RE: Shimano 105 derailer fit new 7 speed cassette?
1988 6 spd Miyata!? Wow. We need the 'Way Back Machine'! Smile

Your first concern seems to be the shifter. What is it? Can it change modes between Index and Friction?
If it can do Friction mode, it will pull enough cable to travel 7 cogs. In Index mode, nothing will match up.
Whether or not the 105 RD will work - it will, provided that the cage length allows capacity of largest cog and chainring without binding. As you have described the situation, it should.
Funny thing is - 1988 seems so recent.

Wheelies don't pop themselves. (from a QBP fortune cookie)
Aug 14, 2012 06:35 AM
Visit this user's website Find all posts by this user Quote this message in a reply
1FJEF Online
Veteran Member

Northern Mexico (Central CA)
Posts: 604
Joined: May 2011
Post: #4
RE: Shimano 105 derailer fit new 7 speed cassette?
(Aug 14, 2012 06:35 AM)RobAR Wrote:  Funny thing is - 1988 seems so recent.
Yep.
Aug 14, 2012 07:28 AM
Find all posts by this user Quote this message in a reply
RobAR Offline
Veteran Member

Mountain Home, AR
Posts: 725
Joined: Sep 2010
Post: #5
RE: Shimano 105 derailer fit new 7 speed cassette?
Tonight we're gonna party like it's 1999. Prince.

Wheelies don't pop themselves. (from a QBP fortune cookie)
Aug 14, 2012 08:07 AM
Visit this user's website Find all posts by this user Quote this message in a reply
Joe_W Offline
Veteran Member


Posts: 1,177
Joined: Jul 2009
Post: #6
RE: Shimano 105 derailer fit new 7 speed cassette?
You have to consider the width of the frame / hub. Older road hubs are 124mm wide, newer are 130mm. So keep that in mind. If you have a steel frame you can try cold setting it to the new width. But be careful. I have done that to three of my frames and do not have any problems, but still: be careful!
Aug 14, 2012 11:44 PM
Find all posts by this user Quote this message in a reply
crashq Offline
New Member


Posts: 2
Joined: Aug 2012
Post: #7
RE: Shimano 105 derailer fit new 7 speed cassette?
My shifters are also Shimano 105s. The front is a non-indexed (I assume friction) shifter. The rear shifter is indexed for 6 speeds, but I don't know whether it can convert to an un-indexed friction shofter.

(Aug 14, 2012 06:35 AM)RobAR Wrote:  1988 6 spd Miyata!? Wow. We need the 'Way Back Machine'! Smile

Your first concern seems to be the shifter. What is it? Can it change modes between Index and Friction?
If it can do Friction mode, it will pull enough cable to travel 7 cogs. In Index mode, nothing will match up.
Whether or not the 105 RD will work - it will, provided that the cage length allows capacity of largest cog and chainring without binding. As you have described the situation, it should.
Funny thing is - 1988 seems so recent.

I measured the inside width of my frame (at the rear hub) with a calibrated scale and got 5 inches exactly, which works out to 127mm. My first thought would be that the frame was bent, but it fits the hub perfectly. The hub is also a Shimano 105, so I think that it is the factory original wheel/hub.

(Aug 14, 2012 11:44 PM)Joe_W Wrote:  You have to consider the width of the frame / hub. Older road hubs are 124mm wide, newer are 130mm. So keep that in mind. If you have a steel frame you can try cold setting it to the new width. But be careful. I have done that to three of my frames and do not have any problems, but still: be careful!

(Aug 14, 2012 06:28 AM)painkiller Wrote:  how about a pic of the rear D and the Model number on it

I took some photos, but they ended up being out-of-focus slightly. I will take more tonight. Besides, I cannot find any part number (other than the 10 label) to distinguish short frame, long frame, etc or other features.
Aug 15, 2012 06:19 AM
Find all posts by this user Quote this message in a reply
Joe_W Offline
Veteran Member


Posts: 1,177
Joined: Jul 2009
Post: #8
RE: Shimano 105 derailer fit new 7 speed cassette?
Ooops, my mistake. So it's just 2.5mm more per side. That usually works out well without respacing the frame, though you might want to realign the dérailleur hanger.

http://sheldonbrown.com/frame-spacing.html
Aug 15, 2012 08:40 AM
Find all posts by this user Quote this message in a reply
Post Reply 


Possibly Related Threads...
Thread: Author Replies: Views: Last Post
  Shimano 105 RD-5700 with Tiagra shifters Mehran 0 480 Jun 15, 2014 04:38 PM
Last Post: Mehran
  Help installing rear derailer Bikin4Life 2 435 Jun 9, 2014 10:47 PM
Last Post: 1FJEF
  Shimano Derailleurs! NuroKnight 7 1,096 May 28, 2014 03:48 PM
Last Post: NuroKnight
  Incomplete shifting with ST 4400 Shimano Tiagra souravdeyone 4 727 May 19, 2014 06:42 PM
Last Post: nfmisso
  Stuck gear shift on Next womens 18 speed robynfla133 1 716 May 11, 2014 08:41 AM
Last Post: nfmisso
  Where to buy derailluer for shimano havoc franksevers 1 729 Apr 6, 2014 01:40 PM
Last Post: nfmisso
  Shimano TX35 Rear Derailleur Ebernal32 5 1,476 Apr 3, 2014 12:11 PM
Last Post: Ebernal32
  Shimano FD-6800 CervĂ©lo Paul 1 2,028 Feb 6, 2014 08:27 PM
Last Post: painkiller
  SRAM X0 trigger shifter with Shimano Front Derailleur? gregw 6 2,785 Jan 28, 2014 07:58 PM
Last Post: gregw
  Shimano 105 - Rear Derailleur Problem RunningBehind 7 2,783 Jan 27, 2014 05:48 PM
Last Post: RunningBehind

Forum Jump:


RSS Forum RSS Feeds / Powered by MyBB

ISSN 1918-3445 © Copyright 2007-2010 Bicycle Tutor / Privacy Policy

feed