Spoke choice

The correct spoke choice

There are a confusing amount of different spokes currently available on the market. These differ not only by their length and diameter, but also more importantly by the differences in the spoke bend at the head. To accomplish the optimal longevity of both the hub flange, the spoke itself and the entire wheel, the spoke bend dimensions must be harmonized with both the hub flange and the spoke holes. It is not sufficient enough to simply choose a spoke according to its length and diameter (eg. 2.0-256mm), the spoke bend itself must additionally be harmonized with the spoke hole so that the spoke can find its optimal sit within the spoke holes of the hub flange.

Pointer

Because retrofit spokes for the Rohloff SPEEDHUB 500/14 with the required head length of 2.9mm are only available in 2.0mm diameter, we generally recommend the use of DD 2.0/1.8/2.0mm spokes for lacing SPEEDHUB wheels.

Problem 1

If the spoke bend is too long and/or the diameter of the spoke at this bend be too small, then this will result in the spoke having an amount of axial play after the wheel has been trued. The spoke bend can now be bent open, resulting in a possible spoke failure.

Problem 2

If the spoke bend is too short and/or the diameter of the spoke at the bend be too large, then the hub flange could become slightly deformed as the spokes are threaded into the hub shell or as the spokes are tensioned. The damage caused here could possibly lead to a flange breakage.

Checking the correct sit for the Rohloff SPEEDHUB

The hub flange and the spoke hole diameter on the SPEEDHUB 500/14 are designed so that an optimal sit can be achieved with the following spoke dimensions:

Attention

As the required spoke head length of 2.9mm is currently only available on 2.0/1.8/2.0mm spokes, we generally advise the use of DD spokes of this size. Bicycle manufacturers who utilise thick spokes with an oversized head diameter when lacing SPEEDHUB wheels, must guarantee the correct length of each spoke head (3.7mm). The spokes should then be tensioned to a minimum of 1000N measured with an inflated tire or 1300N without tire.

The correct spoke geometry can be easily identified as follows:

Thread a spoke from outside through the hub flange of the hub cap side so that the spoke head finds its seat within the countersink of the spoke hole. This should be possible without requiring any noticeable force. Hold the hub so that the flanges are horizontal and the sprocket side faces upwards. The spoke should be facing radially outwards. The threaded end of the spoke should now find itself within the shaded area shown on the diagram below. Fig. b.

a) Spoke bend is too short and/or the spoke bend diameter is too large.
b) Spoke bend and spoke bend diameter are correct.
c) Spoke bend is too long and/or the spoke bend diameter is too small.

 

Repeat this process. This time thread the spoke from the inside, outwards  through the spoke flange on the sprocket side of the hub. Again, the spoke head should be seated within the countersink of the spoke hole and this without requiring a noticeable amount of force. Hold the hub so that the flanges are horizontal with the spoke facing radially outwards. The threaded end of the spoke should now find itself within the shaded area shown on the diagram below. Fig. e.

d) Spoke bend is too short and/or the spoke bend diameter is too large.
e) Spoke bend and spoke bend diameter are correct.
f) Spoke bend is too long and/or the spoke bend diameter is too small.

 

Determing the Rims Internal Diameter

Determing the effective rim diameter (ERD)

Should the effective rim diameter need to be measured because the rim was not listed in the previous table, the following steps can be used to determine this:

- Measure the head height K of the spoke nipples that ar e intended for use.
- Measure the spoke length S from beginning of the thread to the inside of the 90° bend.
- Thread a spoke through the rim and screw the nipple onto this so that the end of the spoke is level with the head of the spoke nipple.
- Place a second spoke through the spoke hole of the opposing side of the rim and screw the nipple onto this spokein the same way.
- Pull these two spokes together and measure the distance X.

The effective rim diameter can now be determined using the formula: d = 2 x S + X - 2 x K

Spoke Lengths

Spoke lengths for 32/36 hole rims

The Rohloff SPEEDHUB 500/14 uses a spoke hole circle diameter of 100mm with 2.7mm diameter spoke holes (2.5mm up until Serial No.44321). When lacing the Rohloff SPEEDHUB 500/14 into a 26” wheel, the spoke sizes required will usually prove fairly difficult to find in the average bike shop. For this reason silver ‘Sapim Race’ spokes 2.0/1.8/2.0mm with 14mm Secure nipples are available from Rohloff in lengths of 228mm to 244mm. The most commonly used spoke length (for 26" wheels) of 238mm is also available in black. Below is a table showing the required spoke lengths for 32/36 spoke rims. Due to the symmetrical hub flanges of the SPEEDHUB 500/14, the spokes are the same length on both sides of the Wheel:

On wheel sizes 26" and 28" the wheel must always be laced in a two cross pattern. Therefore, the table above shows the spoke lengths for a two cross lacing pattern. On wheel sizes 24" and under, the spokes must only be laced in a one cross lacing pattern. For this reason, the table above shows the spoke lengths for a one cross lacing pattern.  

A constantly updated list of spoke lengths can be found on the internet under  www.rohloff.de. A spoke length calculator can also be found on our homepage to help work out other correct lengths of spokes that may be required (www.rohloff.de/en/technical/speedhub/spoke_lengths/index.html).

SPEEDHUB O.L.D. - 135mm, 142mm, 148mm

32-hole Hub-shell Spoke lengths

*ERD: Effective Rim Diameter
Wheel Size Number of
Spoke Crosses 		ERD* 32-hole
Spoke lengths
18" 1 341-343 128
    344 130
20" 1 372-373 142
    374-377 144
    378-381 146
    382-385 148
    386-389 150
    390-394 152
24" 1 472-476 192
    477-480 194
    481-484 196
    485-489 198
    490-493 200
    494-497 202
    498-501 204
    502-503 206
26" 2 516-519 226
    520-523 228
    524-527 230
    528-531 232
    532-535 234
    536-539 236
    540-543 238
    544-547 240
    548-551 242
    552-555 244
650B 2X 556-559 246
    560-563 248
    564-567 250
    568-571 252
    572-575 254
    576-579 256
    580-583 258
28" 2 584-587 260
    588-592 262
    593-596 264
    597-600 266
    601-604 268
    605-608 270
29" 2 609-612 272
    613-616 274
    617-620 276
    621-624 278
    625-628 280
    629-632 282
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36-hole Hub-shell Spoke lengths

*ERD: Effective Rim Diameter
Wheel Size Number of
Spoke Crosses 		ERD* 36-hole
Spoke lengths
18" 1 341-342 126
    343-344 128
20" 1 372-375 142
    376-379 144
    380-383 146
    384-387 148
    388-392 150
    393-396 152
24" 1 472-474 190
    475-478 192
    479-482 194
    483-486 196
    487-490 198
    491-494 200
    495-498 202
    499-502 204
    503 206
26" 2 516-517 222
    518-522 224
    523-526 226
    527-530 228
    531-534 230
    535-538 232
    539-542 234
    543-546 236
    547-550 238
    551-554 240
    555-558 242
    559-562 244
650B 2 563-566 246
    567-570 248
    571-574 250
    575-578 252
    579-582 254
28" 2 583-586 256
    587-590 258
    591-594 260
    595-598 262
    599-602 264
    603-607 266
29" 2 608-611 268
    612-615 270
    616-619 272
    620-623 274
    624-627 276
    628-631 278
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It is recommended to lace 26", 27.5"/650B, 28” and 29" diameter wheels in a 2 cross pattern - never 3 cross or more. The spoke lengths listed in the tables above always reflect this 2 cross lacing pattern. Wheels smaller than 26" diameter must be laced in a 1 cross pattern and again, the spoke length tables above will reflect this requirement.

SPEEDHUB O.L.D. - 170mm, 177mm, 190mm, 197mm

Spoke lengths for 32-hole XL/XXL (Fatbike) Hub-shells (min. 12.5mm nipple offset requried)

*ERD: Effective Rim Diameter
Wheel Size Number of
Spoke Chrosses 		ERD* 32-hole Spoke lengths
12,5 mm Offset 		32-hole Spoke lengths
20mm Offset
26" 2 516-519 228 226
    520-523 230 228
    524-527 232 230
    528-531 234 232
    532-535 236 234
    536-539 238 236
    540-544 240 238
    545-548 242 240
    549-552 244 242
    553-556 246 244
650B 2 557-560 248 246
    561-564 248-250 248
    565-568 250-252 250
    569-572 252-254 252
    573-576 254-256 254
    577-580 256-258 256
    581-584 258-260 258
    585-588 ✘ ✘
29" 2 589-592 ✘ ✘
    593-596 ✘ ✘
    597-600 ✘ ✘
    601-604 ✘ ✘
    605-608 ✘ ✘
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Attention

Nipple eyelets are currently being reduced in size to save as much heavy steel as possible in the construction. In cases such as these, the nipple is however hindered from aligning itself correctly for lacing large flange hubs and this results in a small kink in the spoke where it joins the nipple. This will lead to premature  spoke failures at the kink.

For this reason, rims should be used where the rim eyelet has an inner diameter of at least 4.4mm, or if possible, rims should be used which are angularly drilled.

Calculating the spoke length (32 + 36)

The formula below can be used to calculate the correct spoke length should your rim ERD not listed in the table

Spoke length: L=square root of ( 0.25 x d² ) + 3400 - (50 x d x c)

d: effective rim diameter in mm
c = 0.924 with 1 cross pattern (32 hole)
c = 0.707 with 2 cross pattern (32 hole)

c = 0.940 with 1 cross pattern (36 hole)
c = 0.770 with 2 cross pattern (36 hole)

Calculation example with 32 spokes: 

Effective rim diameter: d = 539mm; 2 cross pattern: c = 0,707

Spoke length:

L=square root of ( 0.25 x 539²) + 3400 - (50x539x0.707)

L = 238,69mm (always round up/down to the nearest even number. Here: 238mm)

Attention

It is not permitted to radially lace wheels built with a Rohloff SPEEDHUB 500/14, because the drive force is delivered through this Wheel.

Due to the large spoke hole circle diameter of the Rohloff SPEEDHUB 500/14, the entrance angle between the spokes and the rim is considerably small. All 26" and 28" wheels must not be built in more than a 2x lacing pattern. All wheels smaller than 26” (24” and under) are only permitted to be laced in a 1x pattern.