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 12-17-07, 07:25 PM   #1
Sir Lunch-a-lot
Senior Member
Thread Starter
 
Sir Lunch-a-lot's Avatar
 
Join Date: Jun 2005
Location: Saskatchewan
Bikes: Customized Sekine
Posts: 377
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Wheel build turned out loose wheel

Good day. I am building up a new franken road bike, and I found that I needed a new rear wheel since:
a.) the rear cassette on this one was nearly toast (and I don't currently have the tools to swap it, nor am I likely to have the needed tools any time soon).
b.) too many spokes were missing for my liking, and could not be replaced without removing the cassette.

I had out back a hub with intact spokes and cassette that I had taken out of a rim a number of years back (I can't figure out why I did that), but since these both come from the same size wheel (an old 27" steel wheel) I figured I ought to be able to swap them around and build up a whole new wheel.

Well, after trying and retrying, I finally get it put together right (as best as I can figure) according to the instructions on sheldon browns website. However, it is way too loose. In order to get it taught, I need to tighten it to the point where the spoke ends would rip through the inner tube. I can not figure out what I am doing wrong here. I compared the spokes and they seem to be of identical length.

What am I doing wrong here?
Sir Lunch-a-lot is offline   Reply With Quote
Old 12-17-07, 07:47 PM   #2
Joshua A.C. New
Senior Member
 
Joshua A.C. New's Avatar
 
Join Date: Aug 2007
Location: Northampton, MA
Bikes: Iron Monkey: a junkyard steel 26" slick-tired city bike. Grey Fox: A Trek 7x00 frame, painted, with everything built, from spokes up. Jet Jaguar: A 92 Cannondale R900 frame, powder coated matte black with red and aluminum highlights.
Posts: 956
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
The dimensions on the hubs are different, which means that the spokes you have are too long. Which sucks, cuz you're going to have to buy a whole new set of spokes, which will cost some $36, and all you'll have is a 27" steel wheel.

The relevant dimensions are the distance to the wheel center from the flanges and the distance to the center of the flange holes from the axle center.

I'd suggest downloading the full version of Spocalc and seeing if your hubs and rims are in there. Then you'll know how long your spokes should be.

The tool to get apart a freewheel or freehub is usually like $3.50, by the way.
Joshua A.C. New is offline   Reply With Quote
Old 12-17-07, 07:50 PM   #3
Scooper
Decrepit Member
 
Scooper's Avatar
 
Join Date: Aug 2005
Location: San Francisco California
Bikes: Waterford 953 RS-22
Posts: 10,230
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 123 Post(s)
There are several things that could account for the spokes being too long:

1) The hub flanges on the hub you had out back have a larger flange diameter (distance between centers of opposite spoke holes) than the old hub, resulting in a shorter distance from the hub spoke holes to the rim spoke holes.

2) You may have laced the wheel 2-cross instead of 3-cross,

3) The ERD of the old 27" rim may not be the same as the ERD of the replacement 27" rim.

There are critical dimensions you need to measure on the hubs and rims in order to determine the correct spoke length for the lacing pattern you want to use. Once you have these dimensions you can plug them into spocalc.
__________________
- Stan
I'm with her.
Scooper is offline   Reply With Quote
Old 12-17-07, 07:51 PM   #4
dcb
THAT GO
 
dcb's Avatar
 
Join Date: Oct 2007
Bikes:
Posts: 58
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Are the old and new hub holes the same distance from the center?

Are the old and new spokes the same length?

Are you sure you laced it correctly?

Do you have a hand grinder of some sort?
dcb is offline   Reply With Quote
Old 12-18-07, 07:21 AM   #5
San Rensho 
Senior Member
 
Join Date: Oct 2005
Bikes:
Posts: 5,548
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
I believe sheldon's instructions are for a 3X wheel, the wheel you had may have been 4X, which would definitely account for the long spokes. You can try relacing it 4X and see what happens, lots of hassle for a franken wheel, however.
__________________
Il faut de l'audace, encore de l'audace, toujours de l'audace

1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1
San Rensho is offline   Reply With Quote
Old 12-18-07, 10:05 AM   #6
tellyho
Your mom
 
Join Date: Aug 2006
Bikes:
Posts: 2,541
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
You figured wrong, as you have discovered. Each rim has its own diameter. one 27" wheel is not the same dimensions as another. Easiest solution is to buy a cheapo 27" wheel. More difficult: measure the parts you have and get the correct length spokes.
tellyho is offline   Reply With Quote
Old 12-18-07, 02:06 PM   #7
Sir Lunch-a-lot
Senior Member
Thread Starter
 
Sir Lunch-a-lot's Avatar
 
Join Date: Jun 2005
Location: Saskatchewan
Bikes: Customized Sekine
Posts: 377
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks guys. As it turns out, lacing it 4x instead of 3x made all the difference in the world. I think I tried 4x before to no avail, but I think I was screwing up and putting the wrong spoke in the wrong hole the first couple of times (very likely, since I kept making stupid mistakes even with the 3x method the first number of times). But it worked this time, so thank you for suggesting it. Now I just have to finish tensioning and truing that bad boy.

Thanks once again.
Sir Lunch-a-lot 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 07:09 PM.