Spoke length calculation
03-16-13, 04:28 AM
#1
Newbie
Thread Starter
Join Date: Mar 2013
Location: Amsterdam
Posts: 3
Bikes: Gazelle Pista, Benotto Pista, Concorde Stelvio
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Spoke length calculation
Hi!
As i am planning to build my own wheels (for a track bike) i have a question about my calculated spoke length. The outcome of the calculation states that the length difference for the rear wheel left side is only .6mm? I've used Sheldon Brown's excel sheet for all the data. I've attached screenshots of the calculation. The hubs I will be using are Campagnolo Record Pista high flange.
Thanks in advance!
As i am planning to build my own wheels (for a track bike) i have a question about my calculated spoke length. The outcome of the calculation states that the length difference for the rear wheel left side is only .6mm? I've used Sheldon Brown's excel sheet for all the data. I've attached screenshots of the calculation. The hubs I will be using are Campagnolo Record Pista high flange.
Thanks in advance!
03-16-13, 07:11 AM
#2
Mechanic/Tourist
All spoke calculators use basic geometry and math to calculate spoke length, and don't really care about anything but the numbers you put in. If you measured or entered the data correctly then the results are correct. If you don't trust the results there are other calculators and spreadsheets. It's even possible to do all the measurements yourself and plug them into the spoke length formula from Sutherlands. In the end a mm is not likely to make a difference in any case.
Last edited by cny-bikeman; 03-16-13 at 07:15 AM.
03-16-13, 07:48 AM
#3
Senior Member
Join Date: Sep 2004
Location: boston, ma
Posts: 2,896
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
looks right fora rear track hub. what is your question? track hubs are pretty symmetrical or have a similar center to flange
03-16-13, 08:09 AM
#4
Senior Member
Join Date: Mar 2010
Posts: 919
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 3 Times
in
3 Posts
If the difference between the left rear and right rear is less than 1 mm, then go with the shorter dimension on both sides. If the difference between the left rear and right rear is between 1 mm and 2 mm, then you can add 1 mm and use the same spoke length on both sides (drive side with be a little longer, and non-drive side will be a little shorter). In this case, adjust the spoke 0.5 mm below the end of the nipple when measuring for the ERD.
This strategy avoids the need to purchase two different spoke lengths for the rear wheel.
This strategy avoids the need to purchase two different spoke lengths for the rear wheel.
03-16-13, 09:05 AM
#5
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,779
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3583 Post(s)
Liked 3,395 Times
in
1,929 Posts
03-16-13, 09:54 AM
#6
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,671
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5767 Post(s)
Liked 2,541 Times
in
1,407 Posts
If you want a quick, approximate confirmation of your calculation, consider that every 10mm in difference in center to flange (CTF) distance results in 1mm difference in spoke length. So working back from your answer, I'd expect that your CTF distances would be different by about 6mm or so. If the CTF distances differ by more than 10mm, you made an error someplace along the line.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
03-16-13, 06:31 PM
#7
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
03-17-13, 02:05 PM
#8
Newbie
Thread Starter
Join Date: Mar 2013
Location: Amsterdam
Posts: 3
Bikes: Gazelle Pista, Benotto Pista, Concorde Stelvio
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
If you want a quick, approximate confirmation of your calculation, consider that every 10mm in difference in center to flange (CTF) distance results in 1mm difference in spoke length. So working back from your answer, I'd expect that your CTF distances would be different by about 6mm or so. If the CTF distances differ by more than 10mm, you made an error someplace along the line.
I just decided to go for it, ordered 80 spokes and nippels and see where this goes
Thanks a lot guys!
03-17-13, 02:12 PM
#9
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,671
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5767 Post(s)
Liked 2,541 Times
in
1,407 Posts
...c my calculation states such a small difference in spoke length, whilst the difference between center to left / right flange is 5mm. I thought it would be more.
Thanks, there was an error somewhere along the line.. I've calculated it again and now the difference around 1,6 mm, so i guess that is more realistic. In my noobieness I didn't realise that a substantial increment in CTF, doesn't have "much" inpact in spoke length (only 1mm for every 10mm) ....
Thanks, there was an error somewhere along the line.. I've calculated it again and now the difference around 1,6 mm, so i guess that is more realistic. In my noobieness I didn't realise that a substantial increment in CTF, doesn't have "much" inpact in spoke length (only 1mm for every 10mm) ....
Check your entries a third time, because there's no way the 1.6mm spoke length difference can be right (assuming, of course, that the 5mm difference is right).
This seems to be a case of GIGO. The computer doesn't make mistakes, but it's accuracy is 100% dependent on the accuracy of the data you feed it.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Thread
Thread Starter
Forum
Replies
Last Post
speedevil
Bicycle Mechanics
9
09-23-13 11:46 PM
lukasz
Bicycle Mechanics
4
10-26-10 10:26 AM
