bikeveloce

Am I crazy? I have an older Co-Motion Cappuccino, with a boat anchor front fork, threaded headset, and quill stem. I also have a Wound Up road fork in my parts collection. Would I be crazy to put this fork on the tandem? We are a 290 lb team and do not plan to do any touring. The tandem has a drum brake, so the fork will not be subjected to extreme braking forces seen with discs or even cantilever or v brakes that are not complemented with a drum...

$400+ is a little steep for me for the carbon tandem forks I've seen online, and I cannot find any used ones at a reasonable price, so I was wondering if using the Wound Up road fork is too much of a stretch. These forks are known for being bomb proof, and are the first choice of Clydesdales on singles and cyclocross. Considering that we are not a heavy team and my wife's weight is far back on the frame, it doesn't seem that we would put much more stress on the fork than a big guy on a single.

Does anyone have a used wound up or co-mo carbon tandem fork? This would obviously be best, but for now I'm wondering if I'm crazy with the road fork.

merlinextraligh

Personally, I wouldn't use a fork on a tandem that the Manufacturer did not approve for use on a tandem. The Wound Up road fork would likely not be a problem. However, in the unlikely event that's wrong, the downside is just too great.

If you look at Wound Up's specs, their road fork weighs around 500 grams, their Tandem fork 800 grams. That extra weight is presumably serving a purpose.


Also, if the goal of this exercise is weight savings, you'll save more weight by getting rid of the rear drum, and at 290lbs, good rim brakes will stop fine, without a drum.

waynesulak

I agree with merlinextralight. How much time and how many rides would be ruined worrying about a possible failure? Not to mention how much dental work can you buy for $400?

TandemGeek

You could certainly call the folks at Wound Up (Advanced Composites) and see if they might be able to offer a definitive answer just to clear up any doubt in your mind.
https://www.woundupcomposites.com/

diabloridr

There are handful of bike components I will not buy used because there is no definitive way to be assured of their history/condition and the consequences of failure are too high.

Forks are on that short list.

YMMV.

Sprout97 

We've been running a Co-Motion/Wound-Up (CM/WU) tandem fork for the past 18 months, IRRC. It's been a nice retro upgrade for our Speedster. It is a little bit twitchier on initial turn-in, but is a more comfortable ride and adds to the bike's agility. The carbon also does a fairly good job of damping road imperfections. As to your parts bin piece, I'm guessing that it's a half-bike (single) version. I do agree with Merlin & Wayne that you're courting disaster if you use a non-tandem fork. No telling how long it'll last before it grenades. Just as point of order, the CM/WU has a steeper rake than the oem chro-moly fork. (FYI, we bought our fork through Co-Motion vice directly from Wound Up or a third party vendor.)

bikeveloce

Sound advice. Playing devil's advocate, we live in real hilly terrain, and I believe a drum is needed to avoid brake fade. Our bike does not have canti tabs. Also, I wonder how much of the 282g difference between the road and tandem versions is due to the addition of canti brake mounts on the tandem fork. 150g? 100g?

How does the ride compare between a wound up fork and a stock chromo/quill setup?

bikeveloce

Thanks Jeff, I made my last post before seeing yours.

bikeveloce

Im pretty sure they will say no to tandem simply due to liability. Another devil's advocate thought: At 528g, the WU road fork is heavier than the Alpha Q tandem at 375g. Edge 2.0 is also used on tandems by some, and it is 350g...

TandemGeek

Like I said, all you can do is ask just to remove all doubt.

The Wound-Up (and Reynolds Ouzo Pro) tandem forks were both introduced as "lighter than steel" forks that were very robust while providing excellent vibration dampening. The Alpha Q pushed the edge of the envelope and gave up a lot of stablity when it was about a 500g fork being produced by AME. After True Temper bought the rights and began producing them, they improved the quality and eventually reduced the weight. Even the Reynolds Ouzo Pro lost a lot of weight in subsequent iterations.

Much of what was learned early on was applied to the forks which is why a fork like the Edge/ENVE 2.0 that was not really designed for a tandem was found to be suitable for tandems... within limits.

waynesulak

For me a response that the fork is ok for tandem use would make me feel better but not remove all doubt. Unless I knew the specific individual on the other end of that simple phone call and willing to bet our health on his/her opinion then I would hesitate to use the fork. The fork was not originally sold for tandem use. It is possible that was an oversight at the time or possibly there was a reason unknown to the person that you talk to that it was not cleared for use on tandems.

The fork may be fine. Everybody has a different risk tolerance so in the final analysis the decision is yours because you are the one riding it.

B. Carfree

I was chatting with the owner of R+E Cycles this Spring as my wife and I were getting fitted for a new tandem. The conversation wandered into the realm of forks and Dan told us a little story about a sales rep. who had put a non-tandem carbon fork onto his tandem. Dan told him he was crazy, but he insisted on doing it. The next time that rep. came into the shop, he had several new scars on his face. The fork had failed and parts of it had gone through his face. I would guess the hospital bills were larger than the cost of a proper fork would have been.

I don't believe I would ever put a fork on a tandem that isn't designed for tandems. If I want to carry less weight, I just get rid of the excess carbon on the engine. That's the low-hanging fruit (and nuts, and cakes and...)

bikeveloce

Haha! I like your sense of humor!

Do you happen to remember what fork this person put on their tandem?

obrentharris 

Yes!

We can each give our answers to your question of whether you are crazy but none of us can decide how crazy you want to be. We routinely use brakes, chains, chainrings, tires, even wheels and tubing that were not designed specifically for tandems. But some more-or-less crazy person tried them and discovered that they worked well enough without catastrophic results. We are fortunate to have reaped the benefits of these "crazy" experiments. On the other hand not all of these sorts of experiments had pleasant results. The failure of a fork could very possibly lead to much more painful results than the failure of a chain.

But in answer to your question, yes, without some good reason to believe that the fork is up to the job, I think you're crazy to use it.
Brent (crazy sometimes myself)

B. Carfree

I'll try to remember to ask Dan in one of our next (email) conversations. Hopefully it wasn't the same as you are considering using.

TandemGeek

Doubt as to the design limits of that fork...

Not knowing anything else about the fork other than, "I also have a Wound Up road fork in my parts collection" current specs may or may not mean anything. If after providing the fork's serial number to Wound-Up they determined the fork year/model was produced to support a max weight limit below 250 lbs, that would be pretty definitive. If it had a 300 lbs max weight limit, that's still short of what the OP needs, as he's got 40lbs of tandem to add to that 290 lbs team weight.

The point being, when you have a question about how suitable a component might be for use on a tandem the best place to go is the manufacturer's technical support team, often times just a couple of folks in these smaller companies who have detailed knowledge regarding what the design limits were for each product, as well as any issues associated with those products.

Because of product liability I'm pretty sure they'll also be bound to say that a product that was not designed for use on a tandem where it might have a bearing on suitability should not be used on a tandem. We've all come to expect that.

waynesulak

In addition to weight limits in general I would consider that my tandem forks take more serious hits than my single forks. On a single it much easier to protect the front wheel and fork and my speed on a tandem is at times much higher. I know I have plowed through some holes and bumps on the tandem that I would have easily lifted my single front wheel over or bunny hopped. Heck I once drove our tandem straight over a curb at a 90 degree angle to avoid a car. I automatically tried to pull up on the bars to help the front wheel over the curb. Needless to say that was wasted effort and the front end remained firmly on the ground as we smacked into and over the curb. Both wheels tires and fork survived.

Of course this is dependent on your personal riding conditions and so may not be as much of an issue for other riders.

diabloridr

My gut tells me that unless you are hitting with sufficient force to pinch-flat the tire, you are unlikely to be putting any usual stress on the fork, but the only way to be sure would be throw some strain gages on a fork and go looking for big potholes.

Dean V

I have used a single bike fork on our tandem for time trials. When considering the wisdom of this there were a few things I considered.
-Bending moments due to braking will be larger as the front brake can be applied harder on a tandem.
-Still only using a caliper brake from a single bike.
-Impact loads can be larger.
-I would expect the fork on any bike not to fail before the front wheel on impacts (rim damage or similar).
-I have never damaged a front wheel on the tandem (usually using single bike wheels).
As has been said it comes down to what you are comfortable with as the consequences of failure are not good.

Ritterview

Yes, the Enve 2.0 has been used on a lot of tandems for several years now, and often with an OEM imprimatur. I wondered with a history of successful use, Enve had relented at all on its Not for Tandem Use stance. No, they have doubled-down, including the no tandem warning front and center on the web listing.



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msvphoto

So as to avoid this being a thread hi-jack, I'll ask a question.

What alternatives are there to the ugly chrome custom Tange Unicrown for a 1" (threaded or not, doesn't really matter) steerer tube fork to replace the fork on a vintage Santana (who state that all crown type 1" steel forks must be replaced after 15 years regardless of mileage)?

I looked briefly at the Kestrel EMS fork on one of my road bikes (a vintage Kestrel 4000) but thought to myself, uh uh, really bad idea.

For now we continue riding the bike with the original fork with regular visual inspections. I do need to cross this fork bridge at some point and want to know what options there may be besides the way over-priced Unicrown. (I say way overpriced because similar forks from Surley, marketed as a Cross fork) are less than half what Santana charges and even a very well known local Santana dealer who I have done business with for decades now was shocked by the price.) Any ideas?

TandemGeek

Contact a frame builder who offers tandems and see if they'll give you a quote for a custom chromoly replacement fork. Chances are, it won't cost more and probably be finished in a color that's more to your liking.

Steve Rex / Rex Cycles, Dennis Bushnell (via his personal Email), Dave Porter / Porter Cycles, Steve Bilenky / Bilenky Cycle Works are names that come immediately to mind.

Then again, if you believe you can be diligent enough and know that your fork has the reinforcing sleeve already installed, continue to keey an eye on the thing for any early signs that might suggest a replacement is in order, e.g., a crack in the paint, new creaking noises or any change in front end handling.

obrentharris 

Right in your home town is my cyclocross sponsor, Paul Sadoff of Rock Lobster Cycles who has been building all sorts of custom frames for the past 35 years.
Brent

msvphoto

Great advice, as always, TG. The sleeve is there and there are no signs of failure. The steerer tube is the biggest concern so I guess the best bet in the meantime (or maybe longer) is to pull the fork and inspect the steerer tube often. I have cracked both steel and carbon frames in the past so I have heard and felt the warning signs of failure before.

@obrentharris, good tip on Paul. He is actually a friend of a friend so I'll talk see what he says too.

I assume there was no such thing as a tandem rated carbon fork with a 1" steerer tube? (Though after reading this thread I'm not sure a used or old stock carbon fork is such a good idea anyway...)

Sprout97 

Unlike some other components like fd, rd, gears, etc., the fork is a structural component like the main frame. While I'm not an engineer, the torsional loading on both the fork blades and the steerer itself should be a great deal higher in a tandem configuration vs. one designed for a single bike. Also, bonded steerers like our 1 1/8" is likely weaker than those forks that are carbon throughout. (Bonded steerers tend to be a few years older design-wise. As others have already chimed, it is possible to both lighten & strengthen a carbon fork