sin7

Hey. I tacoed my front wheel quite badly and just understood that I need a new rim. Knee power and spoke adjustment are unable to make it fully straight anymore. I thought it will be an easy process cause it's just a usual 29er but appeared that there are too many nuances and too low amount of information provided for parts so I'm lost, even about hubs.
Bike Cube Attention 2023 (yeah, 2 months old)
Hub Shimano HB-M4050, QR, Centerlock
Current rims are CUBE ZX20, 32H, Disc
Tires Schwalbe Smart Sam, Active, 2.25

As I understood rims currently are installed with 2 crosses of spokes on the both sides.
So I have found "Rim M-WAVE Enduro 29'' black 32 holes" that should fit and have okeyish price. Also it has "enduro" in the name so must be good.
But then I found out in the guides about rims replacement that I may have problems with spokes length cause of different inner diameter of the rims. But there is no information nowhere about this rim's diameter so I assume all 29" rims come with diameter of 622mm if no other info provided, same as mine (I hope). Isn't it?
Another question how to know I should replace spokes too (same size, but new)? They seams to be okay and I would prefer to leave them in place.

Thanks.

CliffordK

Ok, 29er rims are the same as 700c rims with have a 622mm bead seat diameter (where the tire bead sits).

The rims come in various widths, with 29er rims somewhat wider and heavier duty than road racing rims.

The other measurement is "ERD", or "Effective Rim Diameter", where the nipples sit. This is not the same for every rim.

Each rim will have an ERD rating, and it could be different for different 29er rims.

So your Cube rim and the M-Wave rim don't necessarily have the same ERD.

The manufacturer should specify the ERD, although I like to measure my own.

There are several online spoke length calculators. They'll ask for the ERD, as well as the placement of flanges on the hub, as well as the offset, and diameter where the holes are. A disc brake hub may effectively be offset slightly, but you probably will have the same length of spokes on both sides (you should measure or compare).

If you don't have a caliper, get one at Harbor Freight.

Even if you only have the M-Wave ERD, ad not the Cube ERD, you can calculate your spoke lengths, and measure a few spokes that you actually have.

As far are reusing spokes. I've done it from time to time. If the spokes look good, and are the right length, then I'd be tempted to do it. Some people tape the new rim to the old rim and do direct transfers of spokes.

It still may not be bad to purchase a couple of spare spokes and nipples, just in case you need them.

The one consideration is that Sapim or DT spokes may be better spokes than the OEM spokes.

Anyway, building a wheel is more than simply installing spokes. You have to center and true the rim. Not to be taken lightly, but it is a good skill to know.

Post as you get closer to building your wheel.

sin7

Exactly after trying to use the calculator I came to this forum cause wasn't able to find necessary measurements. My biggest questions were about Hub measurements. Actually all of them.
It's stupid from the side of Cube but Cube zx20 has no measurements of ERD anywhere on their website, I tried to google and nothing.
Probably I will go with DT Swiss M 502 - 29 cause this rims have 602mm ERD in specification and it looks similar to mine but need to do full disassembly of the current wheel to measure precisely. Will try asking Cube too maybe they will share the info.

Thanks for the info! It was very helpful. I will update on my findings cause may be helpful for other owners.

andrewclaus

I like the tape the new rim to the old rim method above.

It is possible to properly tension and true a wheel at home, but it takes some skill and some ingenuity. If you haven't done it before, is there a bike co-op in your area where you can get some help? They'll have the right tools, and spare spokes and nipples too.

sin7

No, sadly, my city is 400k people only. We have bike service but usually prices there are insane like in all local bike shops and in addition people mostly go with gravel/road cause Estonia is pretty flat. It's ok to have 300 eur difference for buying bike locally and ordering it from Europe. So that's why I mostly maintain it at home and want to learn how to replace rims too. And among all cyclists I know at the moment I'm the best mechanic sadly I fix other people bikes too if needed. But never did the rims replacement, only taco fixing.

Kontact

Remove one nipple from old wheel. Measure down from the bead to where the spoke nipple rests against the hole. In other words, measure from the "outside diameter" to the point where the "spoking diameter" is measured just on one side of the rim. This distance will be around 10-30mm. Now do the same with the new rim. If they are within 2mm of each other, tape the rims together with the valve holes aligned and transfer the spokes one by one to the new rim. Remove the old rim and bring the new one up to tension 1 nipple turn at a time.

If the difference is much more than 2mm, you probably are going to need new spokes.

SurferRosa

A forum member pointed me to the Park Tool site where they teach ERD measurement in this thread (post 3):

https://www.bikeforums.net/classic-v...-ma40-erd.html

I had never done it before. And using a digital caliper, it's super easy.

Hub measurement is easy as well with a metric ruler and a digital caliper:

https://leonard.io/edd/howtomeasure

sin7

Well, I've got an answer from Cube. A bit late, took them 11 days, but better later than never.

So maybe someone will search for this information about Cube Attention. Maybe it will be useful for someone.

alcjphil

The person who answered your question is an idiot who has no idea what ERD actually is

sin7

Actually, you're right. They provided me just a general standard about 700c wheels. I didn't notice this at first.

Dan Burkhart 

584 is the bead seat diameter of a 27.5 wheel, not the ERD. That number is of no use for spoke length calculation.

Jeff Neese

You could just try it. Tape the two rims together as suggested above, then try one spoke. If it doesn't fit, you were going to buy new spokes anyway, right? If it does fit, lucky you.

If it does fit, there's no reason at all to replace spokes that aren't bent, corroded, or damaged in some way. I'd be tempted to replace the nipples, but assuming the spokes are stainless, those have an infinite lifespan.

fishboat

All the info you're seeking is available..you just haven't researched the topic well enough, yet.

Rather than worry about the Cube wheel(unless they can provide an exact Cube rim replacement), just learn how to build a wheel and your questions will be answered. It isn't difficult. You just need to pay attention to what you're doing and follow a guide. Roger Musson's small booklet will take you through the process, step by step.

https://www.wheelpro.co.uk/wheelbuilding/book.php

From this book, you'll understand how to measure ERD(though guides to do this are available on the web also), you'll know how to measure your current spokes to see if they can be re-used, how to do a two or three-cross spoke pattern, understand which rim to buy, and why.................and understand how to maintain your wheels over the long term.

Currently your on a more difficult path of obtaining bits and pieces of info and trying to make sense of it from the inside out. You're going to be building a wheel anyway, you might as well use a methodical, easy to understand process to a sound, well built wheel.

grumpus

That's just the bead seat diameter where the tyre fits, which is what makes it a 700C/29er. What you need is the "effective rim diameter" ERD which is where the spokes fit - this is always going to be less than the bead seat diameter, and depends on the depth and wall thickness of the rim.if the ERD of the old and new rim are within a couple of mm then it's worth trying the old spokes first. If you swap rims without removing the spokes from the hub you avoid the next step.
When I reuse spokes I always put them back in the same position, so on disassembly I put them in four piles - drive side heads in, drive side heads out, non-drive side heads in, non drive side heads out. This way you won't be changing the elbow bends when you reuse them.
Sheldon has a pretty good summary of the wheelbuilding process here.
If you Google "wheelbuilding shraner pdf" (without the quotes) you'll likely find several sites offering a free download of this book that should demystify wheelbuilding for you (if you can forgive the bad OCR).
A classic that covers more than just building is "The Bicycle Wheel" by Jobst Brandt.