UltraRear SX wheel-building

Here you find all the necessay instructions to realize your dream wheels with pre-calculated spoke lengths.

Follow instruction step by step:

1)Measure your "spoke-end diameter"

2)Find your rear spoke length (left side) on table A

3)Find your rear spoke length and lacing pattern (drive side) on table B

(All measures are expressed in mm)

4)Lace the wheel respecting correct lacing pattern (see below)

Maximum spoke tension:

Drive side 100 kgf +/- 10kgf

Left side 60kgf +/- 10kgf


Warning: spoke lacing and tensioning require skills and experience,refer to an expert professional wheel builder for these operations.

1)"spoke-end diameter"

Rim manufacturers always offer ERD figures however we warmly recommend to precisely measure the rim+nipple combination.

Basically a correct spoke calculation requires exact "spoke-end diameter" and rim drilling.

Spoke-end diameter depends on your rim internal diameter and nipple type.

How to measure "spoke-end diameter"

 

2)UltraRear SX

Left side - Radial lacing - Elbow spokes

Spoke-end Diameter
Spoke Lenght
515
243
520
245
525
248
530
250
535
252
540
255
545
257

550
260
555
262
560
265
565
267
570
270
575
272
580
275
585
277
590
280
595
282
600
285
605
287

610

290

Table A

Note: We list "spoke-end diameters" every 5mm step. If your "spoke-end diameter" measure is in between 2 steps adjust your spoke lenght consequently.
Example 1: your "spoke-end diameter" is 563mm use 266mm spoke.
Example 2: your "spoke-end diameter" is 567mm use 268mm spoke.
Example 3: your "spoke-end diameter" is 569mm use 270mm spoke.

Lacing: radial on interal flange side, use only D/B spokes (central section equivalent to Ø 1.5mm).

 

3)UltraRear SX

Drive side - Straight-pull spokes

Spoke-end Diameter
Spoke Lenght
20H
Spoke Lenght
24H
Spoke Lenght
 28H
515
261
253
261
520
263
256
263
525
266
258
266
530
268
261
268
535
271
263
271
540
273
266
273
545
276
268
276

550
278
271
278
555
281
273
281
560
283
276
283
565
286
278
286
570
288
281
288
575
291
283
291
580
293
286
293
585
296
288
296
590
298
291
298
595
301
293
301
600
303
296
303
605
306
298
306

610

308

301

308

Table B

Note: We list "spoke-end diameters" every 5mm step. If your "spoke-end diameter" measure is in between 2 steps adjust your spoke lenght consequently.

Lacing: correct lacing patterns with straight-pull spokes must be as shown below (and not as the traditional 2 or 3 crossings used for elbow spokes)

 

 

 

Hub dimensions
  
Avaiable drillings
20 - 24 - 28
Spoke hole diameter
2,5mm
Spoke drilling diameter (left side)
35mm
Straight pull spoke drilling diameter (chain side)
50mm
Center to left flange (internal)

38.5mm Shim/Sram
39.25mm Camp.

Center to right flange (external)
19mm Shim/Sram
18.25 Camp.

 

 

 

100% made in Italy