Wheelbuilding

[CdT85]

Good morning guys and girls,

 

I need a sanity check form the technically inclined again. I am currently lacing up a set of 29"Raceface Arc 27 Offset to Shimano SLX Hubs.

Rim details:

29"Raceface Arc 27 Offset

• ERD: 600
• Offset: 3.8
• Holes: 32

Hubs:

• Front :Shimano SLX HB-M7110-B Front Hub - 15 x 110mm Boost, Center-Lock, Black
• Rear: Shimano SLX FH-M7110-B Rear Hub - 12 x 148mm, Center-Lock, Micro Spline, Black, 32H

 

I s used https://spokecalculator.qbp.com/spokecalculator/ to calculate my spoke lengths and I am using the 3x pattern.

Spoke lengths:

Front: 293mm Left and 283mm Right

Rear: 290mm Left and 289mm Right

 

I oriented the offset with the deeper side towards the freehub body in the rear and the deeper side to the disc rotor in the front. and laced the wheels up with 16mm brass nipples. Yet I can get tension on the spokes. the spokes are starting to stick out on the spoke heads as well.

 

Did I miss something? or was my calculations wrong? First time building rims that I encountered this.

 

Thanks in advance

 

 

 

[droo]

Without actually measuring up your components I can't tell you what your lengths should be, but I can tell you that your rear lengths are out. A 10mm difference in length means 2 different lacing patterns.

If the front is also not tensioning up I'd go with a lacing error. Lacing is far easier to get wrong than it is to get right, especially first time out.

[PregoRoll]

I have stuck all this data into the DT Swiss spoke calculator and it came up with this: 

Front: 

293mm

292mm

 

Rear: 

289mm

290mm

 

This looks closer to what you are needing as the front and rear are very close and only a few mm difference in length but cant be 100% sure the flanges etc are the correct size without measuring myself. 

[CdT85]

32 minutes ago, droo said:

Without actually measuring up your components I can't tell you what your lengths should be, but I can tell you that your rear lengths are out. A 10mm difference in length means 2 different lacing patterns.

If the front is also not tensioning up I'd go with a lacing error. Lacing is far easier to get wrong than it is to get right, especially first time out.

Hi @droo, thanx for the reply.

 

That was a typo on my side, was in a rush to get the tread posted before my morning standup meeting. Correct spoke lengths below.

• Front: 293mm Left and 293mm Right
• Rear: 290mm Left and 289mm Right

I measure the hubs to confirm the calculator's dimensions and everything is spot on.

My issue is that the spokes seems to be about 1mm too long. I will relace them tonight and see if I made a mistake. Did 5 wheels this weekend, and the other 3 worked out perfect.

[David Marshall]

I always measure the components myself, even if I have them in my database.  You can't always trust published data.

Based on "Published data" for your components I get front: Left 291mm, Right 292mm.

rear: Left 290mm, Right 289mm.

As this is close to what you get, as Drew suggests, it is probably a lacing error.

Best advice I can give is to get hold of a copy of "The Bicycle Wheel" by Joobst Brandt and follow his lacing instructions.

[CdT85]

1 minute ago, PregoRoll said:

I have stuck all this data into the DT Swiss spoke calculator and it came up with this: 

Front: 

293mm

292mm

 

Rear: 

289mm

290mm

 

This looks closer to what you are needing as the front and rear are very close and only a few mm difference in length but cant be 100% sure the flanges etc are the correct size without measuring myself. 

Hi @PregoRoll

 

Thanx for the reply. I confirmed the hub dimensions on the calculator with the  hubs, all looks fine. I doublechecked on prowheelbuilder and sapim's spoke length caculators as well, only issue is neither of those have an input for rim offset.

 

my limited experience with offset rims *this is the third set I have built) is that the spoke lengths are usually the same of very close to being the same, so the values looked right.

I will re-lace the rims again tonight as a sanity check. Glad that my calculations weren't that bad

[CdT85]

3 minutes ago, David Marshall said:

I always measure the components myself, even if I have them in my database.  You can't always trust published data.

Based on "Published data" for your components I get front: Left 291mm, Right 292mm.

rear: Left 290mm, Right 289mm.

As this is close to what you get, as Drew suggests, it is probably a lacing error.

Best advice I can give is to get hold of a copy of "The Bicycle Wheel" by Joobst Brandt and follow his lacing instructions.

Thank you @David Marshall.

 

I have originally used Sheldon Brown's resources for my entry onto rim building. I have built about 20 sets of wheels in my life, so I still have loads to learn. Will look into the book you suggested.

 

Much obliged

[Alouette3]

9 minutes ago, CdT85 said:

My issue is that the spokes seems to be about 1mm too long. I will relace them tonight and see if I made a mistake. Did 5 wheels this weekend, and the other 3 worked out perfect.

I'll let the professionals chime in, but 1mm extra length on a double wall rim should not be he end of the world?

[PregoRoll]

5 minutes ago, CdT85 said:

Hi @PregoRoll

 

Thanx for the reply. I confirmed the hub dimensions on the calculator with the  hubs, all looks fine. I doublechecked on prowheelbuilder and sapim's spoke length caculators as well, only issue is neither of those have an input for rim offset.

 

my limited experience with offset rims *this is the third set I have built) is that the spoke lengths are usually the same of very close to being the same, so the values looked right.

I will re-lace the rims again tonight as a sanity check. Glad that my calculations weren't that bad

Lacing can be a biach sometimes, on a few occasions I wondered how the wheel isnt building only to realize I must have been blind while lacing to miss my mistake. Hope you come right! 

[CdT85]

2 minutes ago, PregoRoll said:

Lacing can be a biach sometimes, on a few occasions I wondered how the wheel isnt building only to realize I must have been blind while lacing to miss my mistake. Hope you come right! 

Thanx. Will provide feedback after a rebuild tonight.

[droo]

24 minutes ago, Alouette3 said:

I'll let the professionals chime in, but 1mm extra length on a double wall rim should not be he end of the world?

It isn't until it is. Once the thread bottoms out, you're done.

[Alouette3]

2 minutes ago, droo said:

It isn't until it is. Once the thread bottoms out, you're done.

Yes, provided it doesn't bottom out

[CdT85]

Quick update.

Managed to get the rims sorted sorted. Got some new nipples from Rapide and it sorted my issue.

Thanks for the sanity check with  spoke  lengths

Edited June 13 by CdT85

[Wyatt Earp]

On 6/10/2024 at 11:17 AM, Alouette3 said:

I'll let the professionals chime in, but 1mm extra length on a double wall rim should not be he end of the world?

1 mm extra per spoke adds quite a bit if you are already out by a mm or two.

Also it’s crucial to get the correct length for drive and non drive side, and it’s  not for the dishing, but getting the spokes up to the correct tension.

I often get wheels in ,way under tensioned because incorrect spoke length was used for the drive side. 
Biggest issue I find with some of these “expert” wheelbuilders out there, is that they struggle with roundness, and that throws the spoke tension all over the place, and if your are gonna bottom the threads out, with unequal tension, you are bound to get low tension spokes  with nipples slowly unwinding, making for a floppy and poorly tensioned wheel.

Roundness, correct tension and spoke length is everything.