What spoke length?..

[zigzag]

i'm planning to build a (first) set of wheels for my project bike, got the rims and the hubs, only can't decide regarding spokes. according to "edd spoke calculator" i need 287.3mm for the front wheel and 286.7mm for the rear, combined with 14mm spoke nipples. now, spokes are sold in 2mm increments (e.g. 286, 288..). am i correct in thinking that 286mm spokes will work for both wheels? or i need 288mm for the front? ta muchly

[hubner]

You can be a few mm short of the ideal length and the only difference is in appearance, ie a few threads will be exposed.

[zigzag]

i also plan using alloy nipples, will there be enough engagement threads with the shorter-than-ideal spokes?

[LittleWheelsandBig]

It usually isn't a problem. Brass is about the same strength as most aluminium alloys but fatigue might be slightly worsened.

Some folk have a habit of breaking nipples when the spokes are too short. Not something that I have experienced yet.

[zigzag]

thanks for the answers! regarding strength and fatigue, the minimal number of spokes recommended for my weight is 20 front and 24 rear. going 32/32 i'm hoping that the wheels will be massively overbuilt and in some way compensate the usage of weaker materials? still deciding on spokes (dt revolution / cx ray / dt aerolite)

[LittleWheelsandBig]

I prefer Sapim but DT is fine. I don't rate anything else. Spoke fatigue characteristics are not just a result of the wire used but also the subsequent cold-working.

[LittleWheelsandBig]

Sapim rates their Al nipples as stronger and more durable than their brass ones. I assume that doesn't include salt-induced corrosion.

[zigzag]

yes, i'm not planning to ride this bike during the "salty" months, unless it's dry.

[andrew_s]

I do take it that the rear wheel is for fixed/singlespeed/hub gear?
The rear generally takes 2 sizes of spoke for a cassette wheel.

[zigzag]

I do take it that the rear wheel is for fixed/singlespeed/hub gear?
The rear generally takes 2 sizes of spoke for a cassette wheel.

yes, they are both symmetric, only the front hub has it's flanges slightly further apart. (annoyingly)

[teethgrinder]

I've had "issues" with aluminium nipples corroding, breaking and seizing up on spokes.
On a ride, I noticed my wheels were a bit odd. They had disk brakes, so I never noticed how out of true they were untill I had a look at them. I pinched a few spokes and some were very loose. Not just lose, the nipplae had broken and several were detatched. I couldn't even put extra tension in the other spokes because the other nipples were seized up and wouldn't turn.
Could be that whoever built my wheel never used greae, which I doubt. Maybe not enough grease? It was done at a reputable bike shop. The wheels were on my mountain bike which has seen a lot of rain and been through many floods and the wheels were about 5 years old.

I rebuilt the wheels with new spokes (couldn't be arsed to pry the aluminium nipples off some old spokes. It'd have probably taken a very long time and a lot of effort) I used brass nipples and Coppa Slip type stuff and they're still good. But not seen much action.

[Somnolent]

Does the rim need 14mm nipples rather than 12mm? 

Depending on which manufacturer, the threading on some 14mm nipples means that although the nipple is 2mm longer overall than the 12mm "standard" the spoke itself should only be 1 mm shorter (in the ideal condition)

I'd be inclined to go 288 for both (rather than 286) just in case the nipples you get are like this.

[Biggsy]

Not all aluminium alloy nipples are the same.  I think/hope Sapim's are more durable than common unbranded ones that get alloy nipples a bad name.

[zigzag]

@teethgrinder: i understand they would seize in the conditions that you describe, especially if the spokes were not suitably prepared. i intend to use anti-seize grease and avoid riding in deep/salty water (i'd rather carry the bike over my head if i had to ..)

@PpPete: the rim doesn't need 14mm nipples, but if i get cx-ray spokes, they already come with 14mm alloy polyax nipples. how do i know what the threading inside the nipple is like?

[Biggsy]

@PpPete: the rim doesn't need 14mm nipples, but if i get cx-ray spokes, they already come with 14mm alloy polyax nipples. how do i know what the threading inside the nipple is like?

The thread length is similar enough to a normal 12mm brass nipple that you can forget any difference.

I've used them and I didn't deviate from what I would have used with 12mm nipples.  But get 12mm alloy Polyax if you fancy a bit of extreme weight weenyism.

[zigzag]

just entered the numbers into dt swiss spocalc tool, and it rounds the spoke length down to 285mm, strangely. so i think it's safe to go for cx rays of 286mm.

[Sergeant Pluck]

Where would I find the required info for Shimano "non-series" hubs HB-R505 and FH-R505? They are not listed in Spocalc, unless I have missed them.

[Tewdric]

Just google them or dig into the Shimano techdocs. No time just now but I'll have a look around later if you haven't cracked it.

[Sergeant Pluck]

Thanks Tewdric, I'll have a better look later. No urgency, it just occurred to me that as I have a frame with spoke holders, I may as well have spokes. I'm also curious to see if front and rear discs means 4 different spoke lengths...

[Chris N]

You already have the hubs (on the LHT)?  Measure them yourself.

For most (other) Shimano Hubs, the dimensions are listed on the Shimano North America Tech Tips site: http://bike.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.html
http://bike.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50rparsys-0034-downloadFile.html/07)%20Hub%20Specs.pdf

[Sergeant Pluck]

You already have the hubs (on the LHT)?  Measure them yourself.

Ouch! I could even measure the actual spokes I suppose.

[Chris N]

Indeed.  From the inside of the elbow to the base of the nipple + the nipple length (probably 12mm) = spoke length.