Author Topic: Merry Christmas, does anyone happen to know the ERD of a MP2 or GM 26" rim?  (Read 13500 times)

Offline Andrew

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Seasons Greatings everyone :). I am currently doing yet another bike build. I have been doing a bit of mountain and forest riding on a hard tailed bike but have decided to build a full suspension bike.

  I want to re-lace my pie motor into a mavic heavy duty rim. I have the pie spokes ready, but just need to know if I can do a straight rim swap.  The effective rim diameter of the mavic rim is about 538mm if you include the the rim thickness.  Or about 534mm if you just measure eyelet to eyelet.

I hope that makes sense.  Anyone have the measurements at hand for a GM 26" rim

Also, will pie spokes fit through a normal wheel eyelet? Are the pie spokes 12 or 13 gauge?


Rgds
Andrew
« Last Edit: December 21, 2012, 09:04:24 PM by Andrew »

Offline MAGICPIE3FOCUSPOWER

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Why don't measure the rim by yourself?


Offline Andrew

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Good question.  I will have to take apart the current wheel / motor/ spokes  to measure the rim accurately. I would rather find out I can replace the rim and purchase a new one before the current wheel is in bits with no replacement at hand.

My main concern is the mavic rim I want to use has slightly off-set eyelets, and I also need to measure the pie spokes gauge to make sure they will fit through the eyelets of the new rim.

I just thought that Alan may have a GM rim diagram ;)

Offline MAGICPIE3FOCUSPOWER

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Mavic nipple eyeles are 14G, but you can buy 14G nipple to 13G spoke.

Offline Bikemad

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Re: Rim measurements
« Reply #4 on: December 22, 2012, 04:14:09 AM »
I just thought that Alan may have a GM rim diagram ;)

Sorry Andrew, but I only have a built up wheels too, and the measurements I took for my diagrams were not that accurate. :(

Check out this video regarding nipple clearance in the rim.

Alan
 

Offline MAGICPIE3FOCUSPOWER

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Waauww that's too much work.
You can buy 13G nipple to 12G spoke.

Offline Andrew

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Both of your suggestions seem like a good way to go. Filing down a £45 rim will take a little bit of courage, though it is possible.

The photo here shows a wheel build I did recently with a downhill mivic rim. I had the spokes made by tiller cycles.uk.  And I am sure they were 13 gauge sapim spokes. I will need to check, though going out in my cold damp garage is not too appealing at present.


14 to 13 nipples sound like a sensible idea. I wonder where they can be got?

Offline MAGICPIE3FOCUSPOWER

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Well I have bought them from a Dutch shop.
But I think in UK you can also find them.

http://www.sapim.be/nipples/brass/reduction

Offline Andrew

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Thanks for that. 

Are the pie 2 spokes 12or 13g ? 

Offline MAGICPIE3FOCUSPOWER

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I don't know my Magic Pie 3 spokes were 12G.
But just measure them? 12G = 2,6mm.

Offline Andrew

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Re: Merry Christmas, does anyone happen to know the ERD of a MP2 or GM 26" rim?
« Reply #10 on: December 22, 2012, 10:58:14 AM »
I have no digital device to mesure the spokes. :(

And,  I think I had reduction nipples for my last wheel build.  13g sapim spokes with a 4mm diameter nipple rather than a 5mm.


Offline Andrew

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Re: Merry Christmas, does anyone happen to know the ERD of a MP2 or GM 26" rim?
« Reply #11 on: December 22, 2012, 11:16:01 AM »
I have just purchased an ebay digi caliper, been needing one for a long time :D

Offline MAGICPIE3FOCUSPOWER

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Re: Merry Christmas, does anyone happen to know the ERD of a MP2 or GM 26" rim?
« Reply #12 on: December 22, 2012, 11:23:55 AM »
Aaha while it's quite simple, you can see with your eye 12G is much thicker then 13G.

Offline Andrew

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Re: Merry Christmas, does anyone happen to know the ERD of a MP2 or GM 26" rim?
« Reply #13 on: December 22, 2012, 12:22:28 PM »
Thanks for those words of wisdom  ;D.  Ha ha


Right then,   Ventured out to my garage to find it covered in puddles of water from the constant rain finding its way under the old wooden side door  ::).       The pie spokes I have are definitely not more than 2.3mm, in fact they seem a touch thinner than the 13g spokes I had made.  Te nipples are definitely 4mm wide so they will fit in a mavic rim eyelet  8)

Only problem, I think the pie spoke lengths may be a touch too short more a mavic rim ERD.  The GM rim has a deep V-shaped cross section so the ERD at a guess is only 325mm. The mavics are around 335 to 338mm. This leaves a lot of excess space at either end of the spoke radius. That is around 5mm extra spoke length needed.  It will be a tight fit... Lol.  The spoke threads a 10mm max.



If I can get some PIE 2 motor measurements I can try and work out the spoke length suggested by a spoke calculator.
« Last Edit: December 22, 2012, 12:25:39 PM by Andrew »

Offline MAGICPIE3FOCUSPOWER

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Re: Merry Christmas, does anyone happen to know the ERD of a MP2 or GM 26" rim?
« Reply #14 on: December 22, 2012, 12:47:23 PM »
Hahahaha

Yeah save your money and time and don't use those spokes.
Sapim is much better..... :)

Which model of Mavic rim do you have?