Measuring ERD for new rims

Hi everyone,
I just got my rims today, and do not have any hubs, nor spokes.

I have done a search on the internet about how to measure ERD, and they involve making use of an existing spoke and nipple.

However, I dont have any on hand, are there alternative ways to measure the ERD.

thomas_cho said:

Hi everyone,
I just got my rims today, and do not have any hubs, nor spokes.

I have done a search on the internet about how to measure ERD, and they involve making use of an existing spoke and nipple.

However, I dont have any on hand, are there alternative ways to measure the ERD.

It's not easy to do (accurately) other wise. However, it's very likely that someone else has already measured ERD for your specific rims. You can either post the specifics of your rims or download SpoCalc, from Damon Rinard, from this page:

http://www.sheldonbrown.com/rinard/spocalc.htm

Once you get this downloaded and launched, just click on the "Rims" tab at the bottom of the first page of the spreadsheet. When the "Rims" page comes up, just scroll down until you find your specific rim. Most, but not all, currently available rims can be found in this spreadsheet. Good luck.

thomas_cho said:

Hi everyone,
I just got my rims today, and do not have any hubs, nor spokes.

I have done a search on the internet about how to measure ERD, and they involve making use of an existing spoke and nipple.

However, I dont have any on hand, are there alternative ways to measure the ERD.

It's not easy to do (accurately) other wise. However, it's very likely that someone else has already measured ERD for your specific rims. You can either post the specifics of your rims or download SpoCalc, from Damon Rinard, from this page:

http://www.sheldonbrown.com/rinard/spocalc.htm

Once you get this downloaded and launched, just click on the "Rims" tab at the bottom of the first page of the spreadsheet. When the "Rims" page comes up, just scroll down until you find your specific rim. Most, but not all, currently available rims can be found in this spreadsheet. Good luck.

thomas_cho said:

Hi everyone,
I just got my rims today, and do not have any hubs, nor spokes.

I have done a search on the internet about how to measure ERD, and they involve making use of an existing spoke and nipple.

However, I dont have any on hand, are there alternative ways to measure the ERD.

The ERD (effective rim diameter) is essentially the distance between the eyelets at opposite spoke holes -- on the 700c Ambrosio clincher rims, I think it is ABOUT 604mm... but, you will want to actually measure your rims.

There are several ways to make the measurement -- the easiest is probably to measure across the inside of the rim with a METRIC tape measure & ADD the additional depth between the rim's inside circumference and the "eyelet" face (not all rims have eyelets) against which the nipple rests (x2).

ROUND DOWN the calculated number that you get with the spoke calculator -- a spoke that is a millimeter shorter than the calculation is better than one that is a millimeter longer.

thomas_cho said:

Hi everyone,
I just got my rims today, and do not have any hubs, nor spokes.

I have done a search on the internet about how to measure ERD, and they involve making use of an existing spoke and nipple.

However, I dont have any on hand, are there alternative ways to measure the ERD.

The ERD (effective rim diameter) is essentially the distance between the eyelets at opposite spoke holes -- on the 700c Ambrosio clincher rims, I think it is ABOUT 604mm... but, you will want to actually measure your rims.

There are several ways to make the measurement -- the easiest is probably to measure across the inside of the rim with a METRIC tape measure & ADD the additional depth between the rim's inside circumference and the "eyelet" face (not all rims have eyelets) against which the nipple rests (x2).

ROUND DOWN the calculated number that you get with the spoke calculator -- a spoke that is a millimeter shorter than the calculation is better than one that is a millimeter longer.