# Bicycle Mechanics - spoke length for idiots?

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View Full Version : spoke length for idiots?

Johnonaschwinn
10-29-12, 07:39 PM
Hi Everyone, I am trying to figure out what length of spoke I need for a 126 spaced hi flange record hub laced to a mavic reflex 700 c front is 100 spacing mavic reflex 700 c both are 36 hole. I can not understand the formula or sites explaining it. Thanks , John Los Angeles CA (home of PLVMB)

jimc101
10-29-12, 08:01 PM
Have a look at this, should explain some / all of it http://lenni.info/edd/howtomeasure

zandoval
10-29-12, 08:06 PM
Good grief I have been down this road before - Try to find one already laced and get the size from there - This is an admission from another guy who could not get the tables to work for him...

ultraman6970
10-29-12, 08:45 PM
W/o even putting that in a calculator I can tell you that the the front one will be around 302.. the rear one will be like 300 at one side and 297 at the other side, doing 3x crosses.

A bunch calculators around and those hubs and rims are in all the calculators just google it.

ps: the spokes will be like 5 mm shorter, just noticed you are using reflex rims, just google spoke calculators.

onespeedbiker
10-29-12, 09:01 PM
Hi Everyone, I am trying to figure out what length of spoke I need for a 126 spaced hi flange record hub laced to a mavic reflex 700 c front is 100 spacing mavic reflex 700 c both are 36 hole. I can not understand the formula or sites explaining it. Thanks , John Los Angeles CA (home of PLVMB)Well according to the http://lenni.info/edd/ site that I use and have added to, there are two possible scenarios because the Mavic Reflex rims come in two different ERD sizes, 316 and 313. For the rear with 613 ERD and 3 cross lashing 292.3 left and 290.8 right. For the front I get 292mm. With the 616 Erd I get rear I get 293.7 and 292, for the front I get 293.5. I give you these not to use, but to verify you are using the charts correctly. First, the ERD is simply the interior diameter of the rim plus about 3mm; the point being measuring through the spoke hole to where the head of the nipple will be.

If you go the the spoke chart, first click on Campagnolo under the Rim box. That will activate a drop down list and you need to find your hub; hint: they are named Campagnolo all 126mm hi-flange, rear and Campagnolo all hi-flange models, front. Depending only which one you are going to use just click on it and it will open a blue box; you need not do anything with the dimensions unless you want to double check the measurements; simply leave the box open. Next, go to the box under the Hub box and click on Mavic. Again that will activate a drop down list. scroll down and look for Mavic Reflex. Your will see numerous matches each saying Mavic Reflex---MEASURE TO BE SURE!!. Once you measure your rim and determine the ERD, simply chose Mavic Reflex that has the same ERD and again leave the box open. Next go to the top and choose number of spokes and crosses and the spokes length necessary will be in bold numbers on the right.

Drew Eckhardt
10-29-12, 09:32 PM
Hi Everyone, I am trying to figure out what length of spoke I need for a 126 spaced hi flange record hub laced to a mavic reflex 700 c front is 100 spacing mavic reflex 700 c both are 36 hole. I can not understand the formula or sites explaining it. Thanks , John Los Angeles CA (home of PLVMB)

Measure the ERD of the actual rim you own. Take a pair of spokes of known length, stick them in opposite holes, thread the nipples on as far as you'd like (some people aim for the slot, some the nipple top), measure across the elbows with your calipers, and add to twice the spoke length. Do that in a couple places (some rims are a little ovoid, the extrusion thickness can vary, etc) and do something sensible (ex - if you were aiming for the slot you might take the minimum) to reconcile any differences.

Johnonaschwinn
10-29-12, 10:02 PM
what and how do you measure ERD

BikeWise1
10-29-12, 11:03 PM
what and how do you measure ERD

The internet is easy to use! :)

mrrabbit
10-29-12, 11:04 PM
Mavic Reflex came into being as a clincher and also a tubular:

http://www.mrrabbit.net/wheelsbyflemingapplications.php

Before you start, you need to decide where you are aiming depending upon the nipple and thread behavior:

That video explains why you need to test the nipple you intend to use with the threads you will actually use as part of deciding on where you want to aim in terms of ERD.

Old school folks might still have 10mm standard profile nipple might and aim for the top. Modern day folks are typically using 12mm standard profile nipples and are aiming for the screwdriver flat or slightly above.

If you look at my spreadsheet I have the following for Reflex:

Tubular 610 SSD

Adding 2-3mm get you the screwdriver flat of a 12mm nipple or a hair higher.

Clincher 603.8 Flat of 12mm
Ciincher 605.0 Top of 10mm?

Here's what I roughly get:

Reflex Tubular + NR High Flange Front and Rear 3-Cross + 12mm Nipple

292, 292, 290

Reflex Clincher + NR High Flange Front and Rear 3-Cross + 12mm Nipple

12mm Nipple = 288, 288, 286

=8-)

mrrabbit
10-29-12, 11:21 PM
Well according to the http://lenni.info/edd/ site that I use and have added to, there are two possible senarios becasue the Mavic Reflex rims come in two different ERD sizes, 316 and 313. For the rear with 613 ERD and 3 cross lashing 292.3 left and 290.8 right. For the front I get 292mm. With the 616 Erd I get rear I get 293.7 and 292, for the front I get 293.5. I give you these not to use, but to verify you are using the charts correctly. First, the ERD is simply the interior diameter of the rim plus about 3mm; the point being measuring through the spoke hole to where the head of the nibble will be.

If you go the the spoke chart, first click on Campagnolo under the Rim box. That will activate a drop down list and you need to find your hub; hint: they are named Campagnolo all 126mm hi-flange, rear and Campagnolo all hi-flange models, front. Depending only which one you are going to use just click on it and it will open a blue box; you need not do anything with the dimensions unless you want to double check the measurements; simply leave the box open. Next, go to the box under the Hub box and click on Mavic. Again that will activate a drop down list. scroll down and look for Mavic Reflex. Your will see numerous matches each saying Mavic Reflex---MEASURE TO BE SURE!!. Once you measure your rim and determine the ERD, simply chose Mavic Reflex that has the same ERD and again leave the box open. Next go to the top and choose number of spokes and crosses and the spokes length necessary will be in bold numbers on the right.

ERD = Effective Rim Diameter

Effective rim diameter is the distance from the end of one spoke to the end of the opposite spoke at 180 degrees in an already built and functional bicycle wheel - not the rim itself.

Problem is that the wheel builder like a weather forecaster doesn't have the luxury of stepping into a time machine, grabbing the wheel already built in the future, measuring the ERD and then stepping back into the present to plug the number into a spoke length calculator.

Like the weather forecaster, the wheel builder in the present has to come up with a guesstimate using a handful of variables. (The weather forecaster has 10 times more variable to consider...)

The variables are:

- the nipple type
- the nipple and thread min/max insertion behavior
- the rim itself
- the rim joint sleeves if present AND if raw or non-countersunk
- the wheel builder's personal aiming preference

...ultimately, the wheel builder decides - no one can decide it for them. Hence why it is really best whenever possible to measure your own.

ERD, is not static, a white paper spec, or and industry standard. It it dynamic and largely driven by the wheel builder. The same wheel can have easily 3-4 ERDs as a function of changes in the nipple type, size and behavior.

For measuring ERDs, I use two Phil Wood 14g spokes (they have 90 degrees elbows), two 12mm nipples, and a quality steel caliper.

Each spoke is exactly 249.50mm

I set the nipples such that the spoke ends just touch the screwdriver flat. Position in rim. I then use the calipers in a snug fashion to measure the distance left between the insides of the elbows.

249.50 + 249.50 + Caliper Reading = ERD

I try to measure 4 different spots in rough half circle and average out the results.

If the rim has an unfinished joint sleeve, I'll use a nipple on a stick to determine the additional thickness and then decide if it's safe to add for all spokes - or only the two holes that reside in the joint sleeve. Carbon rims tend to have a spot that will 2mm more as opposed to .5mm or 1.0mm - so I often will have 2 ERDs for a carbon rim.

=8-)

Johnonaschwinn
10-30-12, 07:26 AM
I got 288.3 for the rear left 286.8 right side 36 hole 126 spacing erd 603
front left 288.1 front right 288.1 100 spacing 36 hole erd 603

onespeedbiker
10-30-12, 12:40 PM
I got 288.3 for the rear left 286.8 right side 36 hole 126 spacing erd 603
front left 288.1 front right 288.1 100 spacing 36 hole erd 603The spoke lengths you are giving are for a 605 ERD not a 603 so I assume you chose Mavic Reflex (ERD is Mavic's Nipple Seat Dia + 3mm for nipples) with a 605 ERD and mis-read it as 603. If that is the case, you have figured out how to use the spoke length calculator. Now you need to double check the ERD. The preferred method is shown below and better described by Mr Rabbit. The 605 ERD shown in the calculator was derived by measuring the distance from opposing nipple seats and then adding 3mm for the head of the nipples. The latter method will work most the time, but if you want to be sure, best to use the former as rim ERD's can very even amongst the same model over time.

281142

Johnonaschwinn
10-31-12, 05:37 AM
Does anyone have a set of magic reflex rims? still trying to get the correct red and spoke length

mrrabbit
10-31-12, 08:21 AM

"rimchart" tab under "Mavic < 2002" section has an ERD for the clincher model (603.8) that I measured...go ahead and round it up to 604.00 - plug into spoke length calculator.

288, 288, 286 for 3 cross 36h on Record High Flange Front and 126mm Rear.

Short of measuring yourself, you have all the information you need...

=8-)

Johnonaschwinn
10-31-12, 05:12 PM
A friend brought over 190's and we laced the front only to find out they are to long. BUMMER I now have to unlace the damn thing.

The hell with it I cut the thing apart so I don't scratch the brand NOS rim very bummed out. The Hetchins won't being going anywhere soon :(

mrrabbit
10-31-12, 07:32 PM
Assuming the "190s" was a typo and actually it was "290s", why did you do that when the max according to a spoke length calculator is 288?

Slow down...

=8-)

Johnonaschwinn
10-31-12, 07:57 PM
TYPO 290 my friend thought they would just poke through the double wall and the spokes were free. lacing a wheel is easy. the hard part is finding the magic spoke. I am pretty bummed and just put the whole project in another area out of site.

onespeedbiker
11-01-12, 01:35 AM
Lets see Mr Rabbit gave you the lengths for the "magic" spoke, then I reinforced that with a pmail, but you ignored all the advice from this site because a friend said spokes 2-4 mm too long would work. I believe this is refereed to as setting oneself up for failure..

Johnonaschwinn
11-01-12, 05:58 AM
Lets see Mr Rabbit gave you the lengths for the "magic" spoke, then I reinforced that with a pmail, but you ignored all the advice from this site because a friend said spokes 2-4 mm too long would work. I believe this is refereed to as setting oneself up for failure..

I have a set of wheels for another bike where the dumb a\$\$ who laced it did not have a spoke cutter and used longer spokes and it works. I had time to burn and spokes to throw away. My 93 year old friend would say it was free and did not cost anything to try it. I will confirm later with Mr. Rabbit about the "magic" size spoke. Thanks for the reply and help

Drew Eckhardt
11-01-12, 01:07 PM
I have a set of wheels for another bike where the dumb a\$\$ who laced it did not have a spoke cutter and used longer spokes and it works. I had time to burn and spokes to throw away. My 93 year old friend would say it was free and did not cost anything to try it. I will confirm later with Mr. Rabbit about the "magic" size spoke. Thanks for the reply and help

A DT spoke has up to 9.5mm of thread

A 12mm DT nipple has 8mm of thread measured from the top of the nipple so it's possible for the spoke to protrude 1.5mm beyond the top before it runs out of thread.

Assuming that you're aiming for the nipple slot and get no stretch you can use spokes that are at most 2.5mm too long. You get about .5mm of stretch on a 2.0/1.8 spoke which leaves 2mm.

If you were aiming for the top of the nipple 1mm too long can bottom.

Other spokes and nipples are similar.

himespau
11-01-12, 01:18 PM
When I first tried to build a wheelset, I didn't have any spokes to use to measure ERD, so I had to hunt around on the manufacturer's website to find out what they said (Mavic likes to hide this info, especially about old rims), but it turns out what they said worked for me. Now that you've got some spare spokes, keep them so you can measure ERD for yourself in the future.

onespeedbiker
11-01-12, 01:30 PM
I have a set of wheels for another bike where the dumb a\$\$ who laced it did not have a spoke cutter and used longer spokes and it works. I had time to burn and spokes to throw away. My 93 year old friend would say it was free and did not cost anything to try it. I will confirm later with Mr. Rabbit about the "magic" size spoke. Thanks for the reply and helpSo what you are saying is the whole point behind your post was you wanted to know if the 290mm spokes would work with the rim and hub you wanted to lace. If that is the case, we would have approached this issue from another direction so try and be more specific when your asking questions. Good luck with your project when you get back to it!

mrrabbit
11-01-12, 01:41 PM
A DT spoke has up to 9.5mm of thread

A 12mm DT nipple has 8mm of thread measured from the top of the nipple so it's possible for the spoke to protrude 1.5mm beyond the top before it runs out of thread.

Assuming that you're aiming for the nipple slot and get no stretch you can use spokes that are at most 2.5mm too long. You get about .5mm of stretch on a 2.0/1.8 spoke which leaves 2mm.

If you were aiming for the top of the nipple 1mm too long can bottom.

Other spokes and nipples are similar.

If it is a DT Swiss brass 12mm nipple, their 9.5mm threaded spokes will stop about .50 - .75mm past the top.

DT Swiss alloy 12mm nipples tend to be a little more liberal and will often allow the same spoke to protrude as much as 2.0mm past the top.

Not sure why they do this - I've never asked...

=8-)

Drew Eckhardt
11-01-12, 03:39 PM
If it is a DT Swiss brass 12mm nipple, their 9.5mm threaded spokes will stop about .50 - .75mm past the top.

DT Swiss alloy 12mm nipples tend to be a little more liberal and will often allow the same spoke to protrude as much as 2.0mm past the top.

Not sure why they do this - I've never asked...

=8-)

I've been using the alloy flavor.

To speculate I'd guess the threading allows you to aim for the top with the same error tolerance for long (run out of threads) and short (don't make it through the rim, load the nipple in tension, and break it) spokes provided that you're using double-walled rims where the excess length won't hurt.

With brass nipples you can get away with being a lot shorter

himespau
11-01-12, 03:47 PM
I've been using the alloy flavor.

To speculate I'd guess the threading allows you to aim for the top with the same error tolerance for long (run out of threads) and short (don't make it through the rim, load the nipple in tension, and break it) spokes provided that you're using double-walled rims where the excess length won't hurt.

With brass nipples you can get away with being a lot shorter

So what you're saying is the weight advantage of alloy nipples might be lost in longer spokes?

cny-bikeman
11-01-12, 04:39 PM
So what you're saying is the weight advantage of alloy nipples might be lost in longer spokes?

That's funny to even consider. The weight advantaqe of alloy nipples for two 32 spoke wheels is about 40 grams. Their main benefit is that you can get them in colors.

himespau
11-01-12, 04:45 PM
That's funny to even consider. The weight advantaqe of alloy nipples for two 32 spoke wheels is about 40 grams. Their main benefit is that you can get them in colors.
Yeah, that was why I'd considered them, but I've known of weight weenies who want them to shave that extra 20 grams from their 16+20 low spoke count wheelset. They're out there.

Johnonaschwinn
11-02-12, 05:50 AM
Laced the front again, but the valve came out in-between to spokes that are tighter together. It looks like I could move all the spokes one hole to line the valve stem hole better. I will wait to see what my friend thinks. got the spokes I had already cut at a LBS

Johnonaschwinn
11-02-12, 05:53 AM
So what you are saying is the whole point behind your post was you wanted to know if the 290mm spokes would work with the rim and hub you wanted to lace. If that is the case, we would have approached this issue from another direction so try and be more specific when your asking questions. Good luck with your project when you get back to it!

No, The set I am trying to lace are different. I had some older spokes I had laying around cut down to 288 and 286

onespeedbiker
11-02-12, 12:18 PM
Laced the front again, but the valve came out in-between to spokes that are tighter together. It looks like I could move all the spokes one hole to line the valve stem hole better. I will wait to see what my friend thinks. got the spokes I had already cut at a LBSThis will depend whether you laced wrong to begin with or not. The spoke holes are drilled close to one side or the other (sometimes it's very slight, but all rims have offset spoke holes); right spokes go in the right drilled spokes, left to left. If you laced the wheel wrong with the spokes in the wrong side holes, than yes, you can move all the spokes over one hole. If not you will need to start over..

Johnonaschwinn
11-03-12, 06:36 AM
Hi Everyone, I finally wound up lacing the rim twice and taking it apart twice. I took it in to a beach cruiser place who has a phil wood spoke cutter they cut the old spokes I had for 8.00 I finally brought it back to them and paid 15.00 per wheel. I told him I was close and had watched you tube over & over he said he fixe lots of you tube ttys at wheel lacing :) I told him to post a video on you tube to say they fix your spoke lacing job.

Thanks for the help with this. John