What you can expect to find on this page
This page explains how to choose the right spokes for your wheel.
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.
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.
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:
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.
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.
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 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).
32-hole Hub-shell Spoke lengths
36-hole Hub-shell Spoke lengths
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.
Spoke lengths for 32-hole XL/XXL (Fatbike) Hub-shells (min. 12.5mm nipple offset requried)
32-hole Spoke lengths
12,5 mm Offset
32-hole Spoke lengths
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
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)