SHimano Nexus WH 8R25 spoke hole angle

[NeilP]

I have not stripped it to measure accurately but from a general viewing of this 8 speed hub, with its odd lacing pattern it appears that the holes that are drilled on this hub seem to be spaced 10 degrees apart.

12 holes each side, one side offset by one hole to the other side.

Shimano tech docs do not have info on this.

Just wondered if any one had done any work on lacing this hub to different rims and if anyone had measured the spoke hole angle accurately...unlikely I know, but worth asking

Neil

 

[Martin@e-bikeshop]

I have not stripped it to measure accurately but from a general viewing of this 8 speed hub, with its odd lacing pattern it appears that the holes that are drilled on this hub seem to be spaced 10 degrees apart.

12 holes each side, one side offset by one hole to the other side.

Shimano tech docs do not have info on this.

Just wondered if any one had done any work on lacing this hub to different rims and if anyone had measured the spoke hole angle accurately...unlikely I know, but worth asking

Neil

HI Neil,

Just curious to what the spoke hole is relative to?
What are you aiming to achieve? Are you re-lacing the hub onto a different rim?
Spoke angle changes relative to the lacing pattern and spoke length used.

Regards
Martin

 

[NeilP]

relative to the axle. and each other

When you are calculating spoke length for non-standard cross patterns, you need to know the spoke angle. In order to calculate the spoke angle, you first need to know the radial angle between adjacent spoke holes, relative to wheel centre, for both hub and rim. Knowing those two you can then calculate spoke angle.



Yes, looking to re-lace on to a different rim, without buying a new one. It is a wide rim on a Falcon Beach cruiser, 36 hole, erd ...approx 545mm

The front will be even more 'odd' / complex..Thompson Euro city rear hub, axle machined to fit front forks...hub hole angle on that is odd too, but at least it has a complete flange to re drill the missing holes. It is effectively a 56 hole hub, but drilled with half the holes..so 14 per side ..in pairs...that won't work, but drilling out the 'missing. holes will allow a workable, if odd pattern

 

[NeilP]

That is just one side, opposite side will be 90 degrees offset

 

[trex]

what's wrong with lacing 24 spokes to a 36 hole rim, leaving one blank after every 3 spokes?

 

[NeilP]

that relies on all spoke holes in the hub being equally spaced. This is not...it is two holes on a flange 'stub' then a 'gap of four'. I am playing with ideas now

http://www.shimano.com/media/techdocs/content/cycle/SI/Wheel/Comfort/WH-8R25/SI_4BT0C_En_v1_m56577569830607477.pdf

 

[trex]

understood but there is no other possibility.

 

[NeilP]

with that hub, that possibility is not possible, as the holes do not exist for that pattern and there is no metal there to drill the holes.

Here is v1 of an idea...one side only
Other side would be 90 degrees offset.
Not many crosses, but other ideas to come...assuming that my assumption of 10 degree spacing is correct

 

[NeilP]

again other side rotated 90 degrees...bnot worked out how to do that in Google sketchup yet

 

[shemozzle999]

I found this site - I don't know if it helps - gives spoke lengths in the pdf which could be compared using reverse engineering of a spoke calculator to find your missing information:

Product

 

[NeilP]

thanks, good idea, great minds think alike...I was lookign at doing that too...but something stopped me..can't remember what it was now. think it was either needing to know the rim erd and knowing that the cross pattern is different both sides...but neither side are perfect radial or exact cross number.

 

[NeilP]

might have got something that will work

first image is one side, then second image is with both sides shown




have not even tried to work out any spoke angles yet

 

[NeilP]

well it has taken 8hours of tinkering with ideas in CAD but I think I have it sussed

Far neater than the other designs

Pink are far side spokes

 

[NeilP]

Here we go...It can be done.

Not sure how strong,

model not quite correct. I have spokes in the image on either side both pulling in same direction, where as it should have been each pair having one spoke pulling clockwise and one counter, so pairs at the rim are left then right, as opposed to as is in the model

 

[tillson]

I had that Nexus hub on my Pro Connect. I don't think it's any good for an ebike, too few spokes for the extra weight. It is more suited to a lightweight machine.

My experience of using it on and ebike is one of breaking spokes, loose spokes and annoying clicks and creeks from the wheel. I changed it to a 32 spoke model and its been fine since. Can you find a 32 / 36 spoke shell and transplant the guts into that? I think Shimano have now given up on the model you have.

 

[NeilP]

Yes, this is from. Pro Connect too.
I was given it, the drive unit runs, but it has no original battery, and the power controller does not change power settings, and has hole in its front cover.
It may be that the power level change does not work for two reasons:
Water in handle bar power control unit, has caused damage,
OR
The original battery 'third wire' has some influence on how handlebar mounted control unit works.

I fed power to the two main power leads and bike runs, but only in one power level, so I am not going to spend £200 on battery only to find the control panel is dead.

So it is just going to be used for parts, so nexus hub going on the Cruiser, if it does not work, no issue

 

[tillson]

Yes, this is from. Pro Connect too.
I was given it, the drive unit runs, but it has no original battery, and the power controller does not change power settings, and has hole in its front cover.
It may be that the power level change does not work for two reasons:
Water in handle bar power control unit, has caused damage,
OR
The original battery 'third wire' has some influence on how handlebar mounted control unit works.

I fed power to the two main power leads and bike runs, but only in one power level, so I am not going to spend £200 on battery only to find the control panel is dead.

So it is just going to be used for parts, so nexus hub going on the Cruiser, if it does not work, no issue

I remember this now. You had a thread running about the bike a while ago. It's a shame you can't test the motor with a Panasonic battery, but like you say its a lot to lay out only to find that the motor doesn't work.

 

[NeilP]

I remember this now. You had a thread running about the bike a while ago. It's a shame you can't test the motor with a Panasonic battery, but like you say its a lot to lay out only to find that the motor doesn't work.

Well it is not so much the motor not working, it does run up, but only at the middle assist level. The handle bar controller does not change pwr levels, but why?? Handle bar unit? Motor controller or just that third wire is not connected.
Not been able to find a original battery to borrow to test