spoke length

[e-rider]

so, in the past I've never managed to get the correct length spokes first time and end up buying more.

I usually use the DT Swiss calculator.

if anyone wants to do the calc. to see what they get here's the info.

Hubs: Shimano M525 (front and rear) 36h 3x pattern

Rims: 700c Mavic A319

I'll probably use 14mm nipples (but could use 12mm)

these are hybrid wheels with mtb hubs

 

[Gerry Attrick]

Try the calculator here as a comparison.

 

[e-rider]

Try the calculator here as a comparison.

I got the same results.

is it best to round up or down?

also, most shops only sell even numbers so if the length comes out at 285mm should I go for 284 or 286?

 

[Gerry Attrick]

I shouldn't think that 1mm will make a deal of difference either way. After all, you can adjust individual spokes by that much just to get a rim true.

 

[Gerry Attrick]

What exact size do the calulators suggest?

 

[e-rider]

What exact size do the calulators suggest?

Front

L=286.7
R=285.7

Rear

L=286.8
R=285.6

I decided to buy 36x 286mm to start with and I'll build the front wheel with them. Perhaps 286mm will be fine for both sides but if not it will be easy to see if I need 18 spokes 2mm longer or shorter; and then rebuild. This will save buying spokes that I end up not using.

I should add that I'm now going to use Rigida Sputnik rims rather than mavic A319 becasue they were a lot cheaper and get very good reviews.

 

[Gerry Attrick]

I am puzzled as to why you are coming out with diffrent lengths for each side on the front. I would normally expect them to be equal lengths. However, I would agree with your choice of 286 overall in that that is the length I would choose. It is not an exact science however.

 

[e-rider]

I am puzzled as to why you are coming out with diffrent lengths for each side on the front. I would normally expect them to be equal lengths. However, I would agree with your choice of 286 overall in that that is the length I would choose. It is not an exact science however.

it's a disc hub, which also explains why the rear lengths are almost the same too.

 

[yello]

so, in the past I've never managed to get the correct length spokes first time and end up buying more.

I feel your pain. I've just built my first wheel and the spokes (after checking the calcs 3 times) are too long really. (I used the site mentioned above, this site and this one - the latter is my fave! There's also a very good XL spreadsheet calc tool - on Sheldon Brown I think).

My initial calcs gave me (rounded up) 296. It was soon apparent on lacing that this was too long. So I checked my calcs again and got (first time!) 292! I checked that again and again and confirmed 292! Just HOW I got 296 first time around, I do not know!!

I built the wheel anyway - for practice as much as anything else. The spokes do poke out the back of the nipples by a couple of mm (not a problem in itself with the deep socket hole type, double lined rim - Mavic A719) but the nipples are close to bottomed out (if that's the right expression) so I have next to no thread left to tighten if needed.

I have got sufficient tension in the spokes so I'll just cross my fingers and see how it rides. Worst case scenario is that I have to swap them out for shorter ones as/when/if the current ones loose tension... or get longer nipples. Maybe that might give me more thread to wind on but I feel that's not the right solution.

The most annoying thing is that I don't know where I went wrong with the calculation first time around. I'd like to know exactly where I've made the mistake.

 

[e-rider]

I feel your pain. I've just built my first wheel and the spokes (after checking the calcs 3 times) are too long really. (I used the site mentioned above, this site and this one - the latter is my fave! There's also a very good XL spreadsheet calc tool - on Sheldon Brown I think).

My initial calcs gave me (rounded up) 296. It was soon apparent on lacing that this was too long. So I checked my calcs again and got (first time!) 292! I checked that again and again and confirmed 292! Just HOW I got 296 first time around, I do not know!!

I built the wheel anyway - for practice as much as anything else. The spokes do poke out the back of the nipples by a couple of mm (not a problem in itself with the deep socket hole type, double lined rim - Mavic A719) but the nipples are close to bottomed out (if that's the right expression) so I have next to no thread left to tighten if needed.

I have got sufficient tension in the spokes so I'll just cross my fingers and see how it rides. Worst case scenario is that I have to swap them out for shorter ones as/when/if the current ones loose tension... or get longer nipples. Maybe that might give me more thread to wind on but I feel that's not the right solution.

The most annoying thing is that I don't know where I went wrong with the calculation first time around. I'd like to know exactly where I've made the mistake.

interesting as mine always come out 2mm too short.

problems arise from ERD measurements not being accurate - I know that Mavic rim ERDs quoted on the mavic website are not accurate and you should measure them yourself (DT swiss claim this anyway)

sounds like you need to rebuild you wheel with spokes 2mm shorter but we both know that decent quality spokes are not cheap!!!

what do you think of A719 rims? I looked at those (and A319) but opted for Rigida Sputnik because they were significantly cheaper.

 

[MartinC]

I think Mavic give the spoke bed diameter not the internal height of the of the eyelet so they're about 3mm out from 'normal'.

 

[Gerry Attrick]

I have A719 rims on my tourer which have carried some heavy loads over some grotty roads. I have never needed to true them in two years.

 

[yello]

what do you think of A719 rims?

My experience is similar to the one below!

I have A719 rims on my tourer which have carried some heavy loads over some grotty roads. I have never needed to true them in two years.

...though in my case it's my audax bike and they've not needed truing in the 15,000km that I've had the bike. I have had no complaints with them at all.

 

[e-rider]

My experience is similar to the one below!



...though in my case it's my audax bike and they've not needed truing in the 15,000km that I've had the bike. I have had no complaints with them at all.

I'm sure that they are good rims but they now cost £40-45 per rim

The rigida Sputniks cost £17 per rim and get good reviews (from Spa cycles and Chris Juden too!)

Hopefully I've not made a bad decision on this - they will be used for commuting anyway so I think they'll be fine.

 

[yello]

I'm sure the Rigidas will be fine.

Tbh, I have no idea about costs, having never needed to replace a rim. Though given my experience with the A719s I don't think I'd baulk at paying £45.