Heptone

Hey everyone,

New user here. I recently moved to the Bay Area and even more recently bought my first bike since childhood. All I know about it is that it was built by Motobecane in France which makes it pre-1981 but it's made of 2040 tubing which means it was built after the first model year of the Super Mirage model. If anyone knows a little more about I'd be happy to hear it. I'd include a pic but it won't let me since I've made less than 10 posts.

Anyway, I came here because it keeps breaking spokes on a visibly bent rear wheel. After the first broken spoke I had it replaced/trued up at Mike's Bikes in Berkeley, only for it to break another one a week later in just about the same spot. I can tell by spinning it that there's no bend/misalignment in the wheel hub.

Clearly I need to replace something, but I'm new to bikes so I'm not exactly sure where to start that process. For example, I've heard that you can just replace the rim itself instead of having to replace the entire wheel assembly ? I know that the wheel is a double-walled free wheel Weinmann LP18 27x1.0 ETRTO 630x14, just don't know which of that info is relevant to finding a replacement part that'll fit my bike and which isn't. If anyone can offer help/advice I'd really appreciate it! I've been fixing up cars and motorcycles for years so don't hold back on the technical stuff.

EDIT: Here's a pic of my bike now that I can add attachments






...and the broken spoke (the black one to the left is the one that had to be replaced less than two weeks ago

big john

You want to try and relace it yourself? You can but it takes practice to get it right. Better to take it to a pro wheel builder. If it's breaking spokes it's better to replace all of them. You can save the hub and the rim if it's ok. If you remove all the spokes and set the rim on a flat surface you will see if the rim is warped.

Heptone

Not trying to replace it myself, just want to figure out what parts to buy. I can already tell the rim’s warped as that’s the only part with a wobble when I spin the wheel freely, but I believe the hub is okay.

big john

I'm sure there are good wheelbuilders in the Bay Area. If you're sure the rim is toast there are many options if the one you have is no longer available. Find a person to lace it for you and they might even have a rim on hand they can sell you. Spokes are usually cut to length by the builder when it's decided lacing pattern, etc.

There is a Bike Forum member who builds custom wheels but I don't know if he will use your hub. His name is psimet.

Look what I found.https://www.walmart.com/ip/Wheel-Pai...dca135a6e4dd90

https://northwestbicycle.com/products/weinmann-lp18-27in-weinmann-j48035?variant=16704275447906&utm_medium=cpc&utm_source=bing&utm_campaign=Bing%20Shopping&msclkid=61 0f69b3a8761535f4d536ac2f516e3f

A rim is $33 plus spokes plus labor. if you order a rim check the number of spokes.

seypat

Have one of the mods move your thread to C&V. You'll get more responses there.

Homebrew01

Moved from Road Cycling.

SJX426 

A wheel is "true" only if the lateral and radial deviations ae nearly 0 and the spoke tension is uniform on each side. It is not hard to have a "true" wheel with spoke tension all over the map each side. This gives a false impression of the wheel being true. It would look physically true but mechanically out.

Spoke failure is typically a result of poor, ununiform spoke tension. An indication would be to squeeze two spokes that cross nearest the rim. The amount of effort to squeeze should be the same for each spoke and for each pair of spokes. Another is to pluck the spoke and listen to the pitch. they should be nearly the same from spoke to spoke on each side.

Check the spoke diameter at the center or near the center of the spoke length. The should be the same. Mixing double butted spokes with straight gauge will impact the tension at the rim. Tension is different between spoke types. If a spoke is replaced, it should be with the same spoke type,

Finding a competent wheel builder will know this and more.

nicam49

Hi! if you're going to the expense of having the wheel rebuilt, and it's an elderly hub, then before you do, why not take the hub apart and check that it's not worn out else you'll be throwing your money away if the hub's no good anyway.

daverup 

Your gallery,
https://www.bikeforums.net/g/album/18644161

Classtime 

Grab these? A pair for 40 bucks. As your mechanic skills develop, you can work on your current wheels. Cool bike you found.
https://sfbay.craigslist.org/scz/bop...164081583.html

natloz

Even if there is a warble in the wheel when laced up, doesn't mean the rim is bent...spoke tension of remaining spokes may be out of whack especially if there is a broken/missing one. I had a wheel that once all spokes were removed was perfectly true. Just required a completed re-lacing with proper tension all around to get it back to normal. Not saying that is your case, but I think it may be difficult to determine if a rim is bent if you don't know the tension is even or if you are missing spokes and the remaining are in place exerting forces on the rim. I would de-lace it and go from there is what I am saying. Once de-laced inspect all the components.

dddd

Be advised that this wheelset is for fixed/freewheel SINGLESPEED use.

Great deal if that's what you want.

dedhed

I'd think there is a coop in that area that would have a used wheel cheap

Heptone

Much appreciated! Didn't know wheel builders was a thing...will look into that as well as reach out to psimet once I have the requisite 10 posts so I can send a pm.

Heptone

Thanks, my bad if that was the wrong place to post.

big john

A lot of guys can assemble a wheel but a good,, careful wheelbuilder will get the tension right and the wheel will last. Take it from a man who has destroyed too many wheels to remember.

Heptone

Good tips here. All spokes are the same diameter, but there's a certainly a difference in pitch when plucking them. Every pair of spokes creates the same sound (pairs being those that cross each other closer to the half-radius of the rim), however no two pairs make the same sound as each other. Correct me if I'm wrong, but to me this means every 2 spokes about the hub are under identical tension with each other and only each other.

I also just noticed that the newly broken spoke come from the same side of the hub as the first one that broke, and is separated from that one along the rim by only one spoke that originates from the other side of the hub. Coincidence? I think not...

davester

Personally, I'd take it back to Mike's Bikes and complain. The reason that spokes would continue to break would likely be that the guy who replaced the spoke didn't properly tension the spokes. Mike's Bikes isn't the best for vintage bikes but they should at least know how to properly true and tension a wheel.

A much better bike shop for vintage stuff is Missing Link, literally 1 block from Mike's. The closest bike coop that would have used wheels is Waterside Workshops which is down at Aquatic Park near the freeway.

Heptone

The hub could pass as brand spankin' new, at least from a visual inspection. Kind of hard to justify taking it apart when there's barely a speck of dirt on on it.

Heptone

Thanks! I"ll check it out.

big john

It's $80 for the pair. Also, those are 32hole and I think the op has 36 so he couldn't use with his hub.

Salamandrine 

Once a wheel starts popping multiple spokes, its life is over. Time to rebuild it with a new spokes and a new rim. Spokes pop both because they are old and fatigued, and because the rim is bent and some spokes are now excessively tight to keep it straight and true.

You should be able to reuse the same hub. You can do it yourself if your good at this sort of thing, though it will take some effort and dedication. It's essentially like weaving a basket. Alternatively, look for a used wheel in good condition. Or buy a new premade complete wheel from wheelmaster or velomine. Those are often cheaper than what it would cost to buy the parts to build it yourself. The only catch is that they are 126mm hubs vs the 120mm of the original 5 speed hubs, which means that the frame will need to be respaced.

Super Mirage with 2040 started in '77 or maybe '78. I had a '78 Super Mirage. It was my first good bike. The frame and bike is better than the specs suggest. They cost $235 brand new in 1978. That's $929 in today's dollars. It was sort of entry level into the world of better sport bikes.

davester

Not true. The exterior cosmetics are irrelevant. The grease may have solidified over the years and the bearings/races could potentially be damaged if you just jumped on and rode it after several decades of being stationary. I always rebuild hubs, etc with new grease when buying old bikes.

thinktubes 

Salamandrine for the win.

niliraga 

...or if you're feeling flush, pick up these as a serious - yet period appropriate-ish - upgrade? https://sfbay.craigslist.org/scz/bop...160917444.html

edit: oops, likely for tubulars and you'll prob want clinchers.