GoldenMotor.com Forum

General Category => Magic Pie & Smart Pie Discussions => Topic started by: Magzy on June 14, 2011, 12:36:04 AM

Title: 4 spokes broke in the space of one week
Post by: Magzy on June 14, 2011, 12:36:04 AM
6 spokes have broken in the space of a month (4 in the last week) and used up all my spares.
They all broke on the curvy notch section that touches the MP wheel...

The cause was either down to:

1. The unusually cold weather here in AUS (shortening the spokes that were already tightened in the heat)
2. having just fitted a infineon lyen edition 9 fet controller pumping out 32A peak @~48v)
3. my portly 100kg round figure being too heavy for bike (my wife thinks is the cause but she's not technically minded)
4. hitting bumps too fast (with my hard tailed mtb)
5. A combination of all four...

In any case, I'm out of spokes and I fear that I'll be popping them out like the clappers without any backup spokes to replace them.

Where can I get a good, fast, reliable, cheap source of spokes for a MP on a 26" wheel?

I mailed Golden motor China (with a simple email) about 3 weeks ago but I got no response (...and this does not surprise me)

Title: Re: 4 spokes broke in the space of one week
Post by: Bikemad on June 14, 2011, 01:02:22 AM

I would try Gary at goldenmotor.ca, as he normally keeps these in stock.

Alan
 
Title: Re: 4 spokes broke in the space of one week
Post by: Magzy on June 14, 2011, 01:45:26 AM
Thanks Bikemad - he has a page:
http://www.goldenmotor.ca/shopping/pgm-more_information.php?customernumber=&id=81

Incidentally, the guy who sits next to me at work says that a rubber washer where the spoke contacts the hub may reduce friction... It's the heat buildup at the weak point that just causes it to snap off.


Same thing happened this week on his road bike and the guy in the bike shop told him it would prevent snapping spokes...


Title: Re: 4 spokes broke in the space of one week
Post by: GM Canada on June 14, 2011, 01:54:55 AM
Hi Magzy

I find it odd that very few people break spokes, but those that do break spoke after spoke after spoke. I did have a wheel that was doing this to me on a regular basis thi spring. Since I had done a few wheel builds with success I decided to loosen all the spokes on the wheel that was breaking them. I re-tightened all the spokes truing the wheel better then it was before even. Now I have not broken a spoke in months. I think some wheels have the spokes to tight. There is a delicate balance between to tight and to loose that is imposible to describe.

Gary
Title: Re: 4 spokes broke in the space of one week
Post by: Magzy on June 14, 2011, 02:11:27 AM
Hey thanks Gary.

Yeah, I remember tightening them really tight because a couple of them were coming lose after a couple of k's and maybe the extra strain of (1592 W  :)) is too much to bear for them...

Maybe a blob of super glue on a "reasonably-not-so-tight-but-tight-enough" set of spokes will do the trick.

Thanks for the tip.
Title: Re: 4 spokes broke in the space of one week
Post by: Cornelius on June 14, 2011, 07:48:17 AM
Sound are a good way to tell if a spoke have the right tension. (Plonking a spoke creates a specific tone at a specific tension.)

If for example Gary could agree with himself when each specific wheel are true and have the right tensions, he could publish the note for each size. ;) There would be a different note/tone for each size, and for pie/prokit... :)

Ofcourse, not all spokes can be set to exactly the same tone, since trueing would mean slightly different tensions of the individual spokes, but having a base note would be a good start.

Searching the net for 'spoke tension by tone' gives a good deal of info...
Title: Re: 4 spokes broke in the space of one week
Post by: DirtyGinge on June 14, 2011, 10:15:20 AM
Spokes, like all metal, fatigue over time....for instance sapim strong spokes are rated at 1.6 million revolutions, where as sapim leader spokes are rated at 800,000 revolutions.....basically your wheel sounds metal fatigued......change all the spokes out now......

Go to somehwere like a BMX shop, who may create "racing" or "jumping" spokes of a specific length for you...

May also be worth considering changing the rim also, as this will follow shortly :)

Here was my rebuild on MTB downhill extreme kit

http://goldenmotor.com/SMF/index.php?topic=3187.0
Title: Re: 4 spokes broke in the space of one week
Post by: Magzy on June 23, 2011, 03:36:49 AM
6 more have broken now - even after losening them

That's 12 broken spokes in 2 weeks  ??? ??? ???

Anyone any idea what's going on?

The bike is now unusable.

Now I need to get a new full set of spokes for the MP standard 26" rim   >:(



Title: Re: 4 spokes broke in the space of one week
Post by: SydneyCommuter on June 23, 2011, 12:46:48 PM
Question

What do you guys do for spoke tensioner, I tried the usual bicycle ones and they are too small for those solid PI spoke tensioners (if that is what you call them) do you have to go for a motorcycle one??
I'm about to rebuild so it would be helpful.
tks
Mark
Title: Re: 4 spokes broke in the space of one week
Post by: MonkeyMagic on June 23, 2011, 02:51:04 PM
spoke wrenches (http://cgi.ebay.com/New-Lifu-Bike-Tool-Spoke-Nipple-Wrench-3-Pieces-Set-/370518831492?pt=LH_DefaultDomain_0&hash=item5644a4b184) these fit everything I've had, but I am no spoke guru



Title: Re: 4 spokes broke in the space of one week
Post by: Magzy on June 24, 2011, 01:26:53 AM
I have found a custom spoke maker here is syd who can make 10 for considerably less $'s than buying a full set from canada ans shipping them for $20 on top of that (quite frankly I can't afford it)

I need to know what length of spoke the MP is on a standard Rim (that comes with the pie)
Along with the spoke hole diameter. (i.e. what gauge)




plus anything else I need to give the spoke guy in the shop.

Title: Re: 4 spokes broke in the space of one week
Post by: Bikemad on June 24, 2011, 01:36:09 AM
If you take your wheel in with you, he can measure the exact size spoke that is required.

He should also be able to see if the elbow of the spoke fits correctly into the hub, and may be able to advise on whether washers are required under the heads of the spokes to remove excessive lateral movement in the hub fixing holes.  ;)

(http://www.arhservices.co.uk/GoldenMotor/Spokewashers.JPG)

Alan
 

Title: Re: 4 spokes broke in the space of one week
Post by: GM Canada on June 24, 2011, 02:01:17 AM
Question

What do you guys do for spoke tensioner, I tried the usual bicycle ones and they are too small for those solid PI spoke tensioners (if that is what you call them) do you have to go for a motorcycle one??
I'm about to rebuild so it would be helpful.
tks
Mark

I Use this from Canadian tire..

(https://arhservices.co.uk/GoldenMotorCanada/GM004.jpg)

Costs a whooping 3.99 and works great.

Gary
Title: Re: 4 spokes broke in the space of one week
Post by: Magzy on June 24, 2011, 02:03:27 AM
I just need the effective MM length and the MM Diameter (gauge)

The rim is a Standard 26" MP supplied rim so the ERD is the standard.



Title: Re: 4 spokes broke in the space of one week
Post by: GM Canada on June 24, 2011, 02:29:49 AM
I just need the effective MM length and the MM Diameter (gauge)

The rim is a Standard 26" MP supplied rim so the ERD is the standard.


I get 110 mm from the tip of the spoke to the inside of the bend in the elbow. I know somewhere on the forum I measured the thickness but I can't recall where.

Gary
Title: Re: 4 spokes broke in the space of one week
Post by: Magzy on June 24, 2011, 02:59:20 AM
always delivering Gary!  :)
Next time you're in Sydney I'll buy you a beer

Title: Re: 4 spokes broke in the space of one week
Post by: SydneyCommuter on June 24, 2011, 12:50:43 PM
Gary
Thanks mate your bloods worth bottling.

The ones I have  now don't have the large size 15 guage.  I'll have a hunt around for one.

tks
Mark

Ps a guy shot past me today on an old GM 1kw machine, like I was going backwards, I can see a 48 volt battery coming on order.
Title: Re: 4 spokes broke in the space of one week
Post by: GM Canada on June 24, 2011, 02:54:25 PM
Hey no problem, Its the 13 guage slot you want to use. I have several of these and I like the fact I can use it on unmotorized wheels as well  :)

Gary
Title: Re: 4 spokes broke in the space of one week
Post by: GM Canada on June 24, 2011, 02:58:06 PM
Gary
Thanks mate your bloods worth bottling.

The ones I have  now don't have the large size 15 guage.  I'll have a hunt around for one.

tks
Mark

Ps a guy shot past me today on an old GM 1kw machine, like I was going backwards, I can see a 48 volt battery coming on order.

lol, if he was on a PRO 901 48v1000 you'll never catch him :) Those motors are fast.

Thanks for the positive comments.

Gary
Title: Re: 4 spokes broke in the space of one week
Post by: GM Canada on June 25, 2011, 12:25:41 AM
Nice picture Alan :)

This is the famed wheel that all all MP2's are designed after :) Nice to see a closeup...

Gary
Title: Re: 4 spokes broke in the space of one week
Post by: GM Canada on June 25, 2011, 12:34:48 AM
always delivering Gary!  :)
Next time you're in Sydney I'll buy you a beer



lol , I should do a world tour. I am sure there are quite a few spots around the planet I could score a few free beers :) Wonder if the wife will let me go solo ? lol  ;D ;D ;D

I actually feel a bond to my customers and people that I have helped in the forum and through my website. Its an interesting feeling. There is usually always some issue plaging me at any time. but resolve fixes it :)

I'm sure one day someone will come in the forum and complain about me.. Actually I think that has happened a few times and the memebrs usually pounce on them and beat the crap out of them till they leave   :D

Send me an Email about your spokes, I do believe thats my wheel but I cant recall when you bought it? I think you were forced to spoke that wheel yourself if I recall. Anyway take it to email..

Gary
garysalo@goldenmotor.ca