Should I worry about freewheel axle?

[Brucey]

the eyelets are set radially but the holes in which they are set are very slightly staggered, by about 0.5mm.

If you lay a (flexible) straight edge against the side of any two eyelets, you will see that the straight edge won't align with the edge of a third neighbouring eyelet

cheers

[NATURAL ANKLING]

Hi,

the eyelets are set radially but the holes in which they are set are very slightly staggered, by about 0.5mm.

If you lay a (flexible) straight edge against the side of any two eyelets, you will see that the straight edge won't align with the edge of a third neighbouring eyelet

cheers

So 0.5mm, is this all you need....................would you be happy with more......................what would you normally expect?

Th rim is convex, so you would expect at least that one plane of the rivet would favour the spoke angle it makes from the hub laterally.
Even single walled non rivet rims have some, even good orientation which favours the spoke in one plane.

[Bice]

I’d overlooked STX before but these seem to tick all of the boxes for a reliable touring hub. Another cheat (other than removing the right side spacer) to reduce dish that I’ve used to good effect is to add 2mm of spacer to the left side and reduce the exposed axle thread to 4mm at either end. Creating a 137mm OLN. This has resulted in 110 / 120 kgf spoke tension. If I had the kit to shave off the shoulder of the freehub the wheel would likely be near as dammit symmetrical.

I think these SFX are very nice hubs.

I have moved the right spacer to the left on this advice, for which thanks, and will build accordingly. I am not keen on a 137mm OLN as there is no flex in these MTB stays. I think I would prefer to under-dish (and there is not much anyway). So long as it is not noticeable in the frame, I think I can live with it.

Roger Musson the wheelbuilder says you can rely on hub data (well, the manufacturer's anyway) but do your own verification of the Effective Rim Diameter calculation of the wheel rim. Basically, trust no one on this.

I have been unable to find the full Shimano tech measurements for the STX FH-MC32, and was perplexed why my measurement of the rear hub is different to both https://leonard.io/edd/and the Spokecalc spreadsheet on SheldonBrown.

I have the distance between flange to flange at a smidgeon over 55mm (measured to mid-point at the top of the flange). But https://leonard.io/edd/ and SheldonBrown have it at 60.6mm. That's quite a difference: I guess measuring the outside bulge to bulge of the flanges (although even then I am struggling).

Anyway, my centre to left flange is: 32.5mm. My centre to right flange is 22.5mm. Theirs are 35.6mm and 25mm.

The Sputnik rim diameter I am using after various measurements applied to all inputs is 548mm.

So, my spoke lengths after inputting the data into the http://www.wheelpro.co.uk/spokecalc/ are:
left = 263.8 and right = 262.6

SheldonBrown is
left = 264.5 and right = 263.1

And https://leonard.io/edd/

left = 264.9 and right = 263.1

The spoke length differences are minimal, given that there is a 5.6mm variation in the calculation.

And for all of them I would get a 264 and a 263 set of spokes.

[NATURAL ANKLING]

Hi,
Measure everything yourself!
There are many errors in tables including hub dimensions.
I made that mistake once, once is enough.

[nsew]

There are two available hub measurements on the Leonard site due to there being 130 OLN and 135OLN versions of the MC32, yours is the 2nd of the two. As Ankling says measure for confirmation.

Just had a look. Your spoke lengths suggest a 4 Cross pattern. You want the 3 cross pattern giving spoke lengths in the region below. With switching the 1.5mm spacer these differences will tighten. Therefore 258.0 (259.0 with 2mm addition) will cover both sides. The 2mm spacer would increase each stay spread by 1mm. 1mm! Any frame could handle that, never mind a steel 90s MTB frame. Surly built the CrossCheck with 132.5 spacing to accommodate 130 & 135. Maybe Brucey could confirm or amend the above.

Hub Shimano STX FH-MC32, rear
Rim Rigida Sputnik (26 inches)
Spokes 36
Crosses 3
Spoke length left 259.1 mm
Spoke length right 257.9 mm

[Bice]

Just had a look. Your spoke lengths suggest a 4 Cross pattern. You want the 3 cross pattern giving spoke lengths in the region below. With switching the 1.5mm spacer these differences will tighten. Therefore 258.0 (259.0 with 2mm addition) will cover both sides. The 2mm spacer would increase each stay spread by 1mm. 1mm! Any frame could handle that, never mind a steel 90s MTB frame. Surly built the CrossCheck with 132.5 spacing to accommodate 130 & 135. Maybe Brucey could confirm or amend the above.

Hub Shimano STX FH-MC32, rear
Rim Rigida Sputnik (26 inches)
Spokes 36
Crosses 3
Spoke length left 259.1 mm
Spoke length right 257.9 mm

I will ponder adding another 2mm spacer on the non-drive side. Not sure I have one.

I know it is 3 cross and an OLN of 135mm. Roger Musson's https://www.wheelpro.co.uk/spokecalc/ suggests:

[nsew]

The ERD of the 26” Sputnik is 537.

https://www.spacycles.co.uk/m20b0s116p6 ... ik-26-inch

https://leonard.io/edd/howtomeasure

[Bice]

The ERD of the 26” Sputnik is 537. You need to get your figures right otherwise you’re wasting everyone’s time and energy.

https://www.spacycles.co.uk/m20b0s116p6 ... ik-26-inch

https://leonard.io/edd/howtomeasure

I don't wish to waste anyone's time or energy, and I thank you for supplying Spa's estimate of the ERD.

My measurements of the ERD did need another go. But I cannot get to Spa's figure using the Roger Musson method. Having another go with two spokes and carefully counting off the holes - and mindful that I should aim to go lower rather than higher - I get measurements of 542, 543, 543, 544 only. I am way off 537. I will do at least ten of these measurements tomorrow. I get closest to Spa's figure just running a tape measure and guessing where the spoke hole ends.

I will attach some photos when light tomorrow: the measurement of the ERD is probably difficult to illustrate, but I will have a go. I am not wrong about the centre to centre measurement on the flange, by the way.

Mr Musson:

"Rim manufacturers often provide the ERD but you should never use it because the ERD is not a
strictly defined term and I’ve seen far too many errors to trust ERD data from any source. You
should always measure the ERD yourself since the ERD has the biggest effect in spoke length
calculations. For example, if you calculate your spoke lengths using an ERD that has a 4mm error
then your spoke lengths will be wrong by 2mm which could mean the wheel is difficult or even
impossible to build."

[nsew]

Roger clearly didn’t have you in mind when he wrote that. Trust Spa. There is only one correct ERD for a rim and for that rim it is 537. SPA have built and sold thousands of Sputnik’s over the years. It’s a touring rim and they’re a long established touring specialist shop. The following are not rim manufacturers

https://www.spacycles.co.uk/m20b0s116p6 ... ik-26-inch

https://leonard.io/edd/ type in Sputnik and select 26”

http://kstoerz.com/freespoke/rim/409. (SJS Cycles data)

https://www.cyclechat.net/threads/rigid ... erd.17315/

[Bice]

Just for those mildly interested ...

My ERD for the Ryde Sputnik ERD is slightly wider than the 537 repeated elsewhere (and, possibly, even measured separately elsewhere).

I am assuming a 3mm margin for error given this DIY effort during a busy day. I always come out slightly wider at 541-543.

Less arguable than all this is the markedly different measurement of the STX FH-MC32 hub where the flange-to-flange measurement is given on wheelbuilding websites as 60.6, not 55.

I doubt going with a wider measurement of the ERD and longer spokes is risky: there is also ample space in these cartwheels for spokes to be a bit long.

These measurements are a tricky and approximate, but a valuable exercise especially on older and less frequently used stuff. In the past, with road bikes I have accepted data of ERD on Mavic Open Pros without trouble and the hub data was uptodate.

Ryde Sputnik Effective Rim Diameter 1



Ryde Sputnik Effective Rim Diameter 2



My measuring spokes, glued nipples, 200mm to the nipple slot



The STX FH-MC32 hub, which is supposed to have a centre to centre flange measurement of 60.6mm:

[slowster]

The two spokes are not in diametrically opposite spoke holes. There are 16 empty spoke holes in the top half of the photograph and 18 in the bottom half.

[Brucey]

even so I agree with Bice more than the figure of 537mm.

Possibly they vary, but the last few sets of Sputniks I have built have been

BSD-17mm = ERD (with spoke ends finishing above the bottom of the slot in a typical 14g nipple)

So for a 700C sputnik rim it is 622-17 = 605mm ERD

and for a 26" (559) sputnik rim it is 559 -17 = 542mm ERD.

IMHO 537mm is way off, if you use that value there is zero chance of the spokes being long enough. IIRC Spa quote 607mm ERD for a 700C sputnik, which will typically leave the spoke just poking out of the nipple top (which is OK) but this would make ERD = BSD -15mm and the 559 rims would be 544mm by the same token.

FWIW Ryde often quote NSD (nipple seat diameter) as if it is ERD. It isn't. 537 sounds like a NSD value to me.

cheers

[nsew]

Twilight zone. Can you insert two standard 14g nipples with 17 spoke holes exposed either side and measure between the tips? That distance + 2x overall nipple length is the ERD. That’s how I calculate, though of course Brucey knows his onions. SJS Cycles used to quote 537 and they built thousands of them. Colin must of built up hundreds at SPA. You would of thought one of those two dedicated touring shops would get the ERD right after 15 + years of selling the rim and fielding all the questions.

[Bice]

even so I agree with Bice more than the figure of 537mm.

Possibly they vary, but the last few sets of Sputniks I have built have been

BSD-17mm = ERD (with spoke ends finishing above the bottom of the slot in a typical 14g nipple)

So for a 700C sputnik rim it is 622-17 = 605mm ERD

and for a 26" (559) sputnik rim it is 559 -17 = 542mm ERD.

IMHO 537mm is way off, if you use that value there is zero chance of the spokes being long enough. IIRC Spa quote 607mm ERD for a 700C sputnik, which will typically leave the spoke just poking out of the nipple top (which is OK) but this would make ERD = BSD -15mm and the 559 rims would be 544mm by the same token.

FWIW Ryde often quote NSD (nipple seat diameter) as if it is ERD. It isn't. 537 sounds like a NSD value to me.

cheers

Thanks for this. I have made one or two quite significant cock-ups on this thread (er ... such as not actually having a freewheel on the original hub at all) so I accept the exasperation expressed elsewhere.

Anyway, for the insomniacs among us here is a better visualisation of the ERD, which would work with nsew 's methodology:



Perhaps better seen on Flickr: https://www.flickr.com/photos/50839762@ ... ed-public/

[nsew]

So SPA are and SJS were, selling a rim claiming an ERD that’s a whopping 9-11mm out (4.5-5.5mm out per spoke length). Not once in 15+ years did their wheel-builders inform them otherwise. That’s risible. I subtract 2mm from standard measurable ERD for tension pull seating and erring on the short side. Looks like that rim is a 546.