Measure Effective Rim Diameter (ERD) With Homemade Tools
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- เผยแพร่เมื่อ 7 ส.ค. 2024
- I show how to make simple tools to measure Effective Rim Diameter (ERD) and how to use them. The are made out of old bike spokes. The ERD is one of the measurements needed to determine spoke length when build a wheel.
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Now that is a smart way to do it! Cheap, accurate, repeatable and simple to make the "thingy" =D
100% Thanks!
You know people that usually have something to sell try to make this as complicated as possible!
Thanks again for making very simple! 😃
Thanks for another great video, I got lost on Sheldon Brown's description, but you've shown me how (again!), you're rapidly becoming my fave youtube channel, many thanks from a budding female mechanic.
Awesome!
Trust RJ to pop up on TH-cam when you need him. Good on ya, sir ;)
Nice one! I have been doing that for years, but you have explained it perfectly.
I will be using your thingy to help me build wheels, thanks RJ! :)
You're a genius! I would never think of that :D
Build a wheel over several videos would be awesome! Nice vid RJ
easy explanation. I like that a lot!
Wish I knew about this a few weeks ago! Thanks!
Thanks for the great idea
Smart and simple!
Genius RJ!
Thanks my dude!
Beautfiul.. :) Thanks!
Interesting, if you make more wheel building videos maybe you could label or group them together so they could be viewed step-by-step.
Does this still work if the spoke holes are not in the center of the rim but staggered/offset to the left and right?
Hi again RJ, I ask you because you have always been very friendly in respoder. How can it be that three different online calculators to measure the length of the spokes give me different measures ?. Which online calculator is reliable? Thanks and regards. J
Hopefully they were all close. I think this is the one I have used: www.bikeschool.com/tools/spoke-length-calculator
RJ The Bike Guy
Thanks again. Regards
What tool did you use to cut the two measuring spokes to length? End-cutter pliers or something else?
I think the cutter part on vice grips, and a bench grinder to fine tune the length.
I have a old road bike that using 6 speeds freewheel and I know that I could use 7 speeds freewheel without adjust the frame, So I want to know is that Shimano Claris set 8 speed Derailleur would work fine on 7 speed or not? also can I use 8 speed shifter?
+Kyle Parker Derailleurs don't really have speeds so much. They just need to reach all the cogs and be compatible. The shifters have to match the freehwheel. 7 speed freewheel, you need 7 speed shifters. th-cam.com/video/rj3bYJ7zyLc/w-d-xo.html
+RJ The Bike Guy Thank you very much:) your vids are very useful
Kyle Parker yes
I tried this method then put the info into a spoke counter program and ordered them. When they came in the spokes were way to long. Not sure if it was the program that gave me the wrong info or if this method is unreliable.
Better use the ERD measuring gauge from Centrimaster. Best tool ever.
LOL! If you have a couple hundred dollars burning a hole in your pocket!
It really ought to be that rim manufacturers mark the ERD, the BSD and the number of spoke holes on every rim. They never fail to get their logos on the rim. Why not something useful as well?
I agree. Tire manufacturers have to put specifics on their
products, so rim companies should follow suit. It's only
fair and would make wheel building easier for the DIY crowd.
Didn't really know what an ERD was, the British Guys were talking in Britain, always seeming to have something to sell and I couldn't understand their language!😒🤕🤔😃
@@mtlnascarfan wouldn't the ERD depend on the nipples being used and whether or not the installer is planning to use washers?
What tool was used to cut the spokes? I assume that they are very hard to cut.
+Toshimi Minoura I used the cutters in vice grips, and then used my bench grinder to smooth the end and fine tune the length.
Just a question, it is the same thing if I put a tape measure inside the rim??
No. You need to measure where the spoke nipples sit in the rim. Rim thickness will vary.
RJ The Bike Guy So, will be the same if I have the rim tickness size
can you make a video on dealing with a bent front fork?I mean, the upper body of the fork is bent.Thanks.
+Jiayang Ruan th-cam.com/video/Ytnk7pXEeY8/w-d-xo.html
well, I need to know if I can straighten the bent fork.
Generally the safest thing to do with a bent fork is to replace it. If a fork breaks, you can DIE! Most bike shops (at least here) won't even attempt to straighten bent fork because of liability issues.
+Jiayang Ruan It's advised that you replace the fork due to the fact that once metal is bent out of shape, it's structural strength is compromised (weakened). If you attempt to bend it back, it's weakened even more. The last thing you want is for your fork to fail since severe injury and even death can occur in the event of an accident.
Better safe than sorry. Your safety and your life is worth more than the price of a pair of forks.
Thank you.
Thanks for a great site. I wanted to clarify my earlier comment. I was wrong. You are measuring ERD as nipple seat to nipple seat. Most online calculators and spoke calc use ERD as "spoke end" meaning the distance across the rim to the end of the spoke- most say bottom of the nipple slot is ideal. You are measuring "nipple seat" which is more accurate but can cause issues depending on the calculator used. All book references I've reviewed say ERD is "spoke end" but that is misleading. The only calculator that uses "nipple seat" is the Sapiam app or online version, I think? Do you agree? Did the old WS calc use that as well based on the rim rods? I really appreciate the conversations here.It is a small detail but can be important. I had incorrectly mentioned that the nipple length made a difference-it does not in your measuring example because you are not using the end of the threads as the starting point. You are using the base of the nipple where it contacts the rim. Again, a small difference in most examples but worth understanding for some of us who build a wide range of wheels.
First comment
mine were too long, but I'm not gonna redo it. Fingers crossed.
Are the ends sticking into the rims? Could cause punctures...
@@RJTheBikeGuy Naw, it's a big rim (fr560). Running tubeless also. At least half the thread is engaged on all of them though. I used spoke prep, so maybe that will help keep them from moving. Trying to get 5% or less tension variance to give it the best chances at a long life.
Iso standards and measure tape rest in peace
Also, it can be helpful to use the exact nipples you plan to build with. A 16mm will give a much different result than a 14 or 12 mm. Generally, most build w/ standard 12mm nipples and that is a safe assumption. Just be aware if you are using another length is will cause error in your final ideal spoke length.
Sorry, but that doesn't affect the ERD at all. The ERD is the diameter of where the nipples seat. That doesn't change. It might affect the spoke length choice, but that is something else.
Actually, it does, depending on the assumptions. If your blank spoke is 200mm the different nipple designs impact the amount spoke it takes to get the thread to the bottom of the slot. The wheel pro book explains this well with a cut-away. I'll see if I can share a clip to give you a visual.
Ex- from Wheelpro book. The picture would help but can't figure how to post that.
Spoke lengths for non standard nipples
If you build with something other than 12mm nipples you will need to modify the rim measuring tools and replace the 12mm nipples with those you intend to use. You will need to do this with internal nipples and may need to do this with 14mm and 16mm conventional nipples as previously discussed on page 59.
Screw the nipple you intend to build with onto each measuring spoke using light finger pressure until it stops, then unscrew the nipple 2mm and that’s your ideal position and since the spoke thread is 56 threads per inch, 2mm equals 4.5 turns.
My lbs said they couldn’t do this. 😒
Apparently they don't build wheels?
talking hands