23–24 January 2027 · Veliky Novgorod
ЗИМНИЕ ВЫХОДНЫЕ ВЕЛОКРОССА · 3ВВ
Два дня ТИПАЦИКЛОКРОССА: Cyclocross, Gravel, Fixed gear, МТБ и беговой кросс. Один день или оба.
WHEEL AND TYRE
To the calculatorsWorkshop on wheels: counts the length of the spokes separately for the left and right sides, checks the rim-tire pair, shows which tire will fit the clearance, and measures the sealant. You drive in all the numbers — from the rim and sleeve specifications or by measurement.
What we count
Spoke length, left and rightActual tyre widthPermitted rim-tire combinationMaximum tyre clearanceSealant capacity
There is no base of bushings and rims here and there will not be: lying with numbers out of your head is the worst thing such a calculator can do. The ERD is taken from the rim specification or measured, the flange dimensions are taken from the bushing specification.
The link to the page stores everything you entered — you can send it to the importer in the chat or save it for ordering knitting needles.
1. Length of spokes
The left and right sides are considered separately: the flanges almost always stand on different spans, therefore the lengths are different. Order two sizes, do not average.
Left side
On the rear wheel, this is the side without a cassette, on the front — the side without a disc. The flange here is usually further from the center, the spoke is longer.
Spoke length
293 mm
In the store: 292mm
Weave angle
Cross 3→ angle 67.5°
Right side (cassette or rotor)
The side of the cassette or brake rotor. The flange is pressed to the center, the spoke is shorter and tightened more.
Spoke length
291 mm
In the store: 292mm
Weave angle
Cross 3→ angle 67.5°
Spokes are sold in increments 2of mm, so round up the estimated length according to the rules of a particular rim: on a deep profile with a long nipple neck, take the near smaller, on a low one — the near larger. It's not scary to miss by 1 mm, by 3 mm — either the nipple will not assemble the thread, or the spoke will come out and tear the camera.
ERD is taken from the rim specification or measured with two spokes with nipples: this is the diameter at the ends of the nipples, and not at the bottom of the rim. The error in the ERD one-in-one moves to the length of the spoke.
Radial weaving (cross 0) on the leading side of the cassette is unacceptable: the spokes do not hold the torque, the flange tears through the holes, and the bushing loses its warranty. There are at least 2 crosses on the right.
Formula — the cosine theorem on the triangle "center of the wheel — flange — nipple":
a = 720° · X / N; L = √( (ERD/2)² + (FD/2)² + WL² − 2 · (ERD/2) · (FD/2) · cos a ) − SH/2
X is the cross, N is the total number of spokes, FD is the flange diameter, WL is the flange extension from the center of the bushing, SH is the diameter of the hole under the spoke. The calculation is checked with the public spoke length calculator on the disassembled example (rim ERD 599, sleeve with flange 57 mm, 32 spokes, 3 crosses): 289 mm on the left and 290 mm on the right.
2. A pair of rim ↔ tire
The nominal value on the sidewall is the width on the reference rim. On a wide rim, the tire is distributed, on a narrow one it sits down. At the same time, we check whether this pair is allowed at all.
Actual width
40 mm
Permitted denominations
33–55 mm
The couple is normal. The tire falls into the range recommended by ETRTO for this rim: the side will sit flat, the sidewall will stand vertically.
The nominal 40value of mm was measured on the rim 23of mm; on your 23mm of inner width, the tire will stand up as 40mm (0mm to the nominal value).
Measuring standard ETRTO: the nominal value of road tires is removed on a rim with an internal width 19of mm, gravel and MTB — on 23mm. Each millimeter of internal width in excess of the standard distributes the tire by about a 0.4mm and also squeezes into a minus.
The allowed range according to ETRTO and Schwalbe tables: the tire is no narrower 1.4and no wider 2.4than the inner width of the rim. Already — the side is open and the rim is easy to break against a stone; wider — the sidewalls converge with a light bulb and fall in turns.
3. Ground clearance: which tire will fit
We measure the gap from the current tire to the feathers or fork in the narrowest place — on the one hand. The increase in width is divided into two sides, so the free gap gives twice as much at face value.
Maximum denomination
44 mm
Required reserve
6 mm per side
It will fit up 44to the nominal mm. From the current 40mm, this is plus 4mm: free 2mm on the side gives twice the width of the tire.
Measure the gap not only on the sides, but also in height — at the exit of the feathers and under the fork bridge, the tire is usually closest to the frame. The bottleneck is often not where you look first.
A real tire is almost always wider than the nominal value on a wide rim — calculate its actual width in the block about the rim-tire pair and subtract it already, not the figure from the sidewall.
The tire is also distributed in the first weeks after installation, and during the run, dirt is stuffed in it. If it turned out exactly in the lapping — take the size already.
Stock norms: highway — 4 mm (dry asphalt, dirt between the feathers is not stuffed); gravel — 6 mm (crushed stone and dust, stones fly off into the feathers); mud and clay — 8 mm (sticking soil, the wheel can get stuck). The stock is counted on each side.
maximum nominal value = current nominal value + 2 · (gap − required margin)
4. Sealant
How much to pour into the tubeless. Less than normal — punctures do not tighten, more — excess weight and a loose lump of latex in the tire.
On the wheel
75 ml
Total
150 ml
From a 1 L bottle
15%
Tire class: Gravel, the manufacturers45' benchmark75 is ml per tire. Rim 622— 700C / 29", so we take the top of the range.
150 ml goes to 2 wheels — this is a 0.15 liter bottle.
Update every 2-3 months, in the heat and in dry air — more often: latex dries and stops tightening punctures. Check with a plastic spoke through the valve or simply by shaking the wheel at the ear.
Dried clots should be picked out, and not poured over: a lump of latex unbalances the wheel, clogs the valve and prevents the new sealant from spreading. Sort, clean, fill again.
Manufacturer's guidelines for one tire: Highway — 30-45 ml; Gravel — 45-75 ml; MTB up to 2.4" — 60-90 ml; Wider 2.4" — 90-120 ml. For 29" we take the top of the range, for 650B/27.5 — the middle, for 26" and less — the bottom.
Link to this calculation
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