Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 06-17-08, 06:23 PM   #1
dit
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Middle TN
Bikes: 2 Centurian Ironman, Rossin Genisis, Greenspeed GT3, Stowaway (wife)
Posts: 653
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Triple chain wheels

I am looking to install a triple chain wheel on my old road bike. The frame is a custom 531 db sport tourer built around 1980 and I think it has an english bottom bracket. My thoughts are to rob a crankset off of a mtb to install on my road bike. Will any of the mtb cranksets interchange with my current crankset? I have been away from cycling too long so the technology has passed me by.

Thanks for your help.
dit is offline   Reply With Quote
Old 06-17-08, 06:37 PM   #2
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If you got a double crankset on your bike, chances are you'll need a longer bb as well. Select the crankset, and it'll tell you what length bb goes with it for the correct chainline.

THen you can measure your current one and determine if you need a new one or not.
operator is offline   Reply With Quote
Old 06-17-08, 10:05 PM   #3
dit
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Middle TN
Bikes: 2 Centurian Ironman, Rossin Genisis, Greenspeed GT3, Stowaway (wife)
Posts: 653
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks much

Now that seems to be a fair enough offer and I appreciate it. Thanks

ditz:thumb:
dit is offline   Reply With Quote
Old 06-18-08, 03:52 AM   #4
jim p
Senior Member
 
Join Date: Apr 2006
Bikes:
Posts: 1,024
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I am going to do the same thing. I put the triple on one old road bike and when tightening the cranks onto the spindle it had a wierd feeling like the spindle had a different taper than the crank arms. Today I plan on taking the triple and transfering it to the road bike that fits me and that I ride most of the time. It only takes a few minutes to make the transfer and then you know if the chain line is acceptable. If everything looks good I may even rob the long deraileur off the mountain bike.
jim p is offline   Reply With Quote
Old 06-18-08, 09:05 AM   #5
dobber
Perineal Pressurized
 
dobber's Avatar
 
Join Date: Oct 2003
Location: In Ebritated
Bikes:
Posts: 6,557
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
You may, or may not, have trouble with the front derailleur. To many unknowns to say definitively at this point.
__________________
This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.
dobber is offline   Reply With Quote
Old 06-18-08, 10:11 AM   #6
DMF 
Elitist Troglodyte
 
DMF's Avatar
 
Join Date: Jun 2006
Location: Dallas
Bikes: 03 Raleigh Professional (steel)
Posts: 6,924
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
MTBs and road bikes have different length hanger tubes (where the BB screws in). MTB is 73mm and road is 68mm. Yours is almost certainly 68mm. MTB cranks often have to clear much wider chain stays as well.

Look for your new crank among road cranks.
__________________
Stupidity got us into this mess - why can't it get us out?

- Will Rogers
DMF is offline   Reply With Quote
Old 06-18-08, 11:57 AM   #7
jim p
Senior Member
 
Join Date: Apr 2006
Bikes:
Posts: 1,024
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I got the triple installed. The chain line looks ok but the front deraileur will have to be swapped as well. The road deraileur can't be setup so that it wont rub the chain when either in the small ring or in the large ring. I got it setup to work in the small and middle ring so that I can go out and give it a test this afternoon.
jim p is offline   Reply With Quote
Old 06-18-08, 12:50 PM   #8
onbike 1939
Senior Member
 
onbike 1939's Avatar
 
Join Date: Dec 2004
Location: Fife Scotland
Bikes: Airnimal Chameleon; Ellis Briggs; Moulton TSR27 Moulton Esprit
Posts: 2,026
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 249 Post(s)
The curve of the cage on your road derr will likely be to suit a larger outer ring. This may give you problems when mated with a MB triple which has a smaller outer ring.
onbike 1939 is offline   Reply With Quote
Old 06-19-08, 10:48 AM   #9
jim p
Senior Member
 
Join Date: Apr 2006
Bikes:
Posts: 1,024
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The curve on the road FD did not fit the smaller chainwheel very well and the distance between the deraileur plates was close together compared to the FD on the mountain bike. This causes more chain rub than I like and causes more trimming of the FD than I like. So I put the FD and RD from the mountain bike on the road bike and now things are much better. The mountain bike FD cage is much longer than the road bike FD cage. When I set the heigth of the FD I got it as low as it would go without hitting the chainstay. Now my final test will be riding for a few weeks to see if I am going to have any chain drop problems.

I am very pleased with the new lower gears that I now have. I now have a 1:1 ratio as the lowest gear and I can now maintain 5.5 mph on some of the hills that previously slowed me down to 3.5 mph. Also my heart rate stays in a much narrower range now since I am not having to push so hard.
jim p is offline   Reply With Quote
Old 06-19-08, 03:56 PM   #10
Bill Kapaun
Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Bikes: 86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
Posts: 9,494
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
"When I set the heigth of the FD I got it as low as it would go without hitting the chainstay"
I assume you meant ring?

If it shifts fine, you're good to go. If it doesn't, don't be afraid to try moving it up a few MM.
My brothers 10 speed simply won't "digest" the "correct" setting. I wondered why it came from the factory set too high! Because it works!
Bill Kapaun is offline   Reply With Quote
Old 06-20-08, 10:45 AM   #11
jim p
Senior Member
 
Join Date: Apr 2006
Bikes:
Posts: 1,024
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
No Bill the FD could not be moved down low enough to touch the chainring. The bottom of the deraileur cage hit the chainstay before it would hit the chainring. So I set it up with the bottom of the cage about 1/8" above the chain stay which leaves it about 1/4" above the chainring. If I have the chain dropping off of the large ring when shifting I will have to do some more adjusting. Everything is working great on the work stand so unless the road test shows problems I am good to go.
jim p is offline   Reply With Quote
Old 06-23-08, 10:10 PM   #12
dit
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Middle TN
Bikes: 2 Centurian Ironman, Rossin Genisis, Greenspeed GT3, Stowaway (wife)
Posts: 653
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I want to thank all responders to this thread. I cheesed out and took the bike to "The Wheel" LBS and asked him to do the triple deed. Considering the current chain rings, he asked me if it would be OK to use a mtb crankset which would allow some smaller rings than the typical road triple so I said sure. He is also going to put a sealed bb to replace my old non-sealed one. I should be able to climb these hills now even with these old, out of shape legs.

ditz
dit is offline   Reply With Quote
Old 06-24-08, 03:44 AM   #13
mike
Senior Member
 
mike's Avatar
 
Join Date: Jul 2000
Location: Snowy midwest
Bikes:
Posts: 5,392
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I just did the conversion you described. It worked fine for me crossing parts with different era, different brands, etc. The derailure was a challenge, of course.

Your LBS should have fun with it. Glad to see you are getting the hardware put on. Of course, it would have given you great satisfaction if you could have done it yourself, but hats off to you for giving it a try and following through with your LBS.
mike is offline   Reply With Quote
Old 06-24-08, 06:26 PM   #14
dit
Senior Member
Thread Starter
 
Join Date: Jun 2008
Location: Middle TN
Bikes: 2 Centurian Ironman, Rossin Genisis, Greenspeed GT3, Stowaway (wife)
Posts: 653
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I did the original frame up build including building the wheels. Many changes have taken place in the technology since I last rode so I just was not sure what parts might work together and for the few dollars that lbs is going to charge it just didn't make sense to do it myself. It even seems that there are some different tools required in this modern day. The LBS even thinks that he can make my old neuvo record rear gear changer work. I hope so since it works so well but I am guessing that it will need to be changed out along with the front gear changer. Just for my information, what bb did you use?
dit is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -6. The time now is 08:34 AM.