Replacment Spokes Mismatched gauges good enough?

[Ricky_nz]

I managed to break some spokes on the way home from may last day of work for the year (Friday).
I think a couple of spokes might have gone a few days earlier unnoticed but I had been working long hours and not really been paying attention.
I knew I was due to tension the spokes up on the hub but hadn't got round to it (leaving it to do during my xmas break) although I didn't think the tension was too bad but anyway on the way home I hit a pothole and several spokes broke followed by me breaking solidly which I think took out a few more. Most broken spokes were on the disk side.
7Km from home I well away from roads I had 2 options. Walk or ride.
I chose to ride slowly and carefully. the wheel hopped and wobbled a bit but got me home.
I'm sure more broke on the way home but being the start of my xmas break I wanted to get home and have a beer :lol:.

Anyway being christmas time I figured I didn't have a hope of getting the right spokes in the correct length until I discovered that the MAC rear motor in the Alex 26" disc rim used spokes around 194mm and found that that appears to be a standard BMX spoke size .
I was going by a guestimate of the spoke length from a broken spoke I removed with the wheel on the bike allowing for the missing end.

Conveniently torpedo7.co.nz had PRIMO spokes in this length on special. $5NZ for a bag of 50 with nipples! only problem they only had red or pink in this size. Also didn't say what gauge they were.
I went with Red, they come with black nipples so look quite nice.
I ordered a set yesterday (Monday) and they arrived this morning .

When I compared them to the ones that came on the MAC the ones on the MAC are fractionally thicker, 13 Gauge on spoke wrench for the nipples and the BMX ones are 14 Gauge.

I figured it was best to at least make all spokes on one side of the wheel the same gauge as I had to replace about 1/4 of the brake side and two on the drive side.

I moved two of the unbroken black 13G ones to replace the broken ones on the drive side and removed a couple so the brake side is all red 12G and the drive side all 13G black. I guess I could swap the lot but I wanted to see how bad the rim was damaged.
These 194mm spokes fit perfictly and have enough thread length for adjustment and do not protrude into the tube space of the wheel.

After swapping/replacing spokes I gave it a quick spin and no major hopping up/down but a reasonable movement to the side in one place so a few turns of the nippes and that came into line quite quickly.
Remember the only other rim I have laced was my GM 1000 into a 26" Alex DP20 rim with thick radial spokes. I found one other spot on the rim that was moving just a tad the other way to fixed that too.
It now spins pretty good. I might play with it a bit later but I would say <1mm total sideways variation and <0.5mm out of round.

At least I know the rim is good. Those Alex DM24 Rims are really good and solid! No cracks or anything.

Am I safe to use a different gauge on one side from the other or should I just go ahead and swap the second side so I have 14G everywhere?

Also I assume 14G will be adequate. They seem to tension up nicely.
I'm only running stock power levels with the 6 FET at the moment.

 

[liveforphysics]

Its wild to me that the standard monstrously over-thick and overly high modulus spoke wheels keep getting made as the cheap wheel industry standard.

Do yourself a favour and fix the wheel for the last time. Swap all the spokes.

 

[Ricky_nz]

Do yourself a favour and fix the wheel for the last time. Swap all the spokes.

Thanks Luke,
I just swapped the other 16 so now it has 32 x 14gauge BMX spokes in it. They were at a clearance price so Hopefully they hold up. Would be nice to go back to black but at $5 for 50 spokes&nipples I'm not complaining.
I have got the wheel pretty true, and it seams to tension up much nicer than my old GM HUB with its really thick spokes that to get it to hold tension the force required was surely near the limits of the rim.
The only concern I have is the holes in the rim were the correct diameter for the 13G nipples so I hope there is still enough metal overlap with the 14G ones to be reliable.
It will be interesting to see how well these spokes last. not really sure how tight to go but I'll use one of my other shop brought non-motor wheels as a guide.
.
Yes thats an empty beer can, I had to drink somwteing while I did the boring task of replacing the spokes :lol:
I'll do a final true and tension if I get a change tomorrow and give it a test ride.

I compared the new spoke length to the originals that I removed and the new ones are about 1mm shorter which is still well into each nipple.

 

[Ricky_nz]

Just went for a short ride / grocery trip.
The wheel feels fine. No unusual noises and spokes still tight .
I'll keep an eye on it over the next few hundred Km to make sure it settles properly.
It was hard to tell if I got the tension in each spoke even due to the contact at the spoke crossing.
I've been thinking about is I laced the wheel the same way It came to me with all spoke heads facing to one side of the hub. This causes crossing spokes to touch which makes listening for tone when plucked hard, I have to force other spoke out the way.
Would it be better to lace with alternating spokes with heads in then out to avoid the contact and the crossing?


Just found the same spokes on chain reaction
http://www.chainreactioncycles.com/nz/en/primo-forged-14g-bmx-spokes-50-pack/rp-prod48275
The chain reaction ones are NZ$26.49 plus shipping where as I paid NZ$5 for a set from http://www.torpedo7.co.nz.
The advantage of chain reaction is other colours are available.
194mm is just right for a MAC motor in a rear 26" Alex disc rim.
If you can tolerate red or pink then you can't beat $5 for 50 spokes.
Actually red looks quite good on a black rim and frame, but to balance it I would really need to buy red spokes for the front rim as well.

 

[jateureka]

Interested to see how this holds up without the spoke washers.
Was there much play at the hub flange before you tensioned the spokes?

 

[Ricky_nz]

Interested to see how this holds up without the spoke washers.
Was there much play at the hub flange before you tensioned the spokes?

I think there probably was some play due to the 14G vs 13G spoke change (can't remember) but since I'm not an expert on wheel building I'm not really sure whats acceptable.
I will definitely be keeping an eye on it and will start putting some Kms on it quickly now my christmas break is coming to an end and its back to work on Monday. I've only done a few short trips on it so far without issues so the real test is next week where it will get 25Km per work day.
I have already packed the spoke key and spare spokes in my bag LOL.
I might have to track down some suitable washers if I see problems.
I will keep this thread updated with the results.

 

[Ricky_nz]

Just an update.
I have done just over 250Km on these spokes now and haven't had to touch them.
All are tensioned well and the wheel is as true as when I started.
I'm impressed for a NZ$5 spoke set . 1NZD = approx 0.83USD.
Actually I'd be happy with the normal approx NZ$25 price for the same thing from chainreaction but the clearance price was a bonus.

I'll keep an eye on them though.
I don't like the fact that lime dust from the path I ride gets trapped around the nipples because the holes in the rim were drilled for the bigger nipples leaving a small gap. There is still plenty of metal overlap so I don't think they will pull through.