Thursday, we had -- and lost - an altercation with a mini-suv. We t-boned her at around 20mph. (20 to 0 in one second!) (We both have a general bruises and road rashes plus a bruised knee and for me, a broken finger. I think we'll be fine for GTR-2015!) Our Spinergy T-2 appears to have escaped damage (rim's true, no broken spokes, and the tube didn't pop). Anyway, we have a Wound-Up/Co-Motion carbon fork. I didn't see any cracks in the fork, but the whole bike is at the shop getting the fine tooth comb-thing for insurance and piece of mind. When does a fork need to be replaced if there there are no cracks? I found this article, but it's not exactly a new piece:
Technical FAQ with Lennard Zinn: Carbon Forks - VeloNews.com . And another thread off of Bike Forums:
https://www.bikeforums.net/general-cy...r-3-years.html . I haven't back from our LBS. This was also our first real crash (tandem or half-bike), so we have no experience in the matter.

Report back after the Shop has done the In Person inspection.., the Online guessing thing is unreliable.

1) Primarily, stick to what the experts said in the link you provided:
ie:
2) If still not satisfied/comfortable, call WoundUp to see if they would feasibly certify the fork or at least provide their usability assessment.

3) If still not satisfied/comfortable, simply buy another fork and try charging it to the responsible party. $500 might be good insurance against possible fork failure due to the collision. Perhaps WoundUp might offer you a special crash replacement price too... ask.

We also have a Wound Up. My opinion, and yes I have a bit of composites experience in other industries, is that if your fork has the aluminum drop outs, scrap it.

The carbon composites may have survived, however the bonded joint to the aluminum will often begin to disbond in situations such as this.

PK

I'm surprised you don't have more obvious damage if you did hit at 20mph. I had a car pull out of a parking lot into my path at around 22mph about 10 years ago. I apparently slammed straight into the front left quarter panel and ended up front flipping onto their hood. I only know this from what the EMT told me when I woke up in the ambulance, I have a faint idea that the car was green... otherwise I basically never saw it and hit it without ever even touching my brakes. In other words: I really t-boned a car at around 20mph and with less than half the weight/force of your tandem team (I weigh about 140 and your team is ~320?).

My bike, a heavy 4130 steel surly cross check was destroyed completely in the process: Front wheel was taco'ed more than half way (36 spoke Sun CR18 rim). Steel Front fork was bent and twisted. Worst damage was the frame though: Crumpled the top tube and Down tube to the point that the good half of the front wheel was pushed back to the point that it overlapped what remained of the downtube by 2+ inches. Had I had a carbon fork, it would have definitely sheared off at the least under that impact, and again that is a lot less force than you were theoretically putting out. I'm only saying all this because I think it gives a clear idea of just how much damage can be done by a 20+mph t-bone crash into a big solid object.

So my guess is you hit either a lot less directly or with less speed than you originally thought (grabbing the brakes in advance perhaps). If the accident was the driver's fault, I would err on the side of caution and let their insurance company replace anything and everything they are willing to. Heck, if you are worried, I would just err on the side of caution no matter who paying. As a result of my accident I got my doctors bills paid for (concussion, stitches to a tear in the lobule of my ear, torn muscles in my back and wrist) as well as full replacement value of the bike part-by-part. The bike component was enough to replace it with a much nicer bike (Independent Fabrications used frame) as the components from the back half of the bike were all perfectly fine. Heck, if you are worried, I would just err on the side of caution no matter who paying.

We had a similar accident a couple years ago. (Went into the side of a smallish SUV that ran a stop sign, hitting the rear quarter panel.) As with you, the wheel had surprisingly little damage. We brought it to the LBS to do a damage assessment as you did, and they did not pick up on the fact that the fork (steel) was bent. I didn't figure that out until months later when I actually tried to start getting the bike rolling again. Another subtle issue that we didn't figure out until later was that the rear derailleur hanger was bent.

The shop said they always recommended replacing the wheels for a case like ours, though ultimately I kept the wheels after retruing them.

I would replace your fork. It's not worth a future accident.

Sounds like your injuries were not too bad, that's good.

I would suggest speaking to a lawyer before contacting the driver's insurance company further. You may be able to find one that specializes in bicycle claims.

We were in a bike lane when the accident occurred. She was running straight across the road & never saw us even though our lights were on. She was cited for failure to yield. But I digress. It's possible that I was hitting the brakes as we hit. One second, I had a clear view, the next was full of Chevy. We hit her in the passenger side quarter panel. My left brifter was knocked (rotated) inwards towards the headset. And it's my left ring finger that's broken. I dropped by the shop this afternoon and talked at length with the owner about the fork. (He did say that the front rim was slightly out-of-true.) He will be disassembling the fork and doing a full inspection. Otherwise, things appear to be going o.k. I've already shot emails off to both Wound Up Composites and to Co-Motion.

It's nice to see I'm not the only chicken-heart who would replace the fork after such a crash.

I suspect the insurance company is being very cooperative. I would not even chance it, replace the fork.

Somehow, I thought it was mentioned a while back that Co-Motion will not take any opinion other than frame replacement on account of possible hidden damage.

That may not seem best for the owner, but it is a safe position to hold as the oem and certainly avoids liability to some extent.

PK

I'm not a lawyer or an insurance guy, but if Co-Mo the manufacturer does indeed take that stand (about the frame, but also the fork too) and you can get them to put it in writing-- that would seem to me to provide you with a VERY strong argument that the at-fault driver's insurance company owes you for the cost of replacing the frame and fork. And if they refuse to pay, it seems that you have a very strong claim to take to a lawyer and press in court.

FWIW: a somewhat similar situation: in my car, I t-bone'd a car which ran a red light. My car was total'ed. The other driver's insurance company somehow argued that it was partially my fault ??!!??, and offered a settlement which only covered part of the value of my car. I engaged a lawyer who handled the negotiations from there. Without getting to court, the other party's insurance company raised the settlement to cover the full value of my car, plus some, AFTER the lawyer's cut.

In general I am VERY sceptical about the "plaintiff's bar" and the "sue 'em" mentality in this country. But I have to say in this case, that the other insurance company seemed to simply be abusing their perceived power and short-paying the value of the damage that their insured caused; and I was relieved to be able to call on a lawyer and the threat of a suit to avoid that abuse.

All that said, glad you're alright; good luck with it.

^ I'd definitely argue for getting the fork replaced as part of the damages. However, there's no need to replace the frame out of fear of latent damage. The frame is steel, and its not going to fail catastrophically from damage you can't observe.

The LBS can look the frame over, if its not twisted out of alignment, and there's no dents, buckling in the tubes, or cracking in the paint, the frame is likely as good as ever. If the frame took a hit that wasn't sufficient to cause any of the above, and it rebounded to its original shape, it didn't cause it long term damage, which is a good thing about steel. You can bend it over and over, and as long as you don't bend it too far it doesn't hurt it.

As someone who has had several steel bikes fail at the seat tube/bottom bracket junction, including a tandem, as well as a few fail at the top of the seat stays, I'm not sure I buy that. In my failures, there was no visible damage, not even paint cracks, and it's not like simply pedalling down the road (no wrecks) should bend the bike too far, and yet there they were, all broken. Obviously I applied forces that were beyond the capability of the metal to withstand over time.

I would be concerned that an impact like the OP's would hasten such failures. I suppose one of our materials folks will set me straight here, but I wouldn't be quick to dismiss the possibility of the frame failing prematurely because of the wreck.

Big difference here:

Wreck is one big energy impulse.
Riding is MANY energy impulses as you pedal and bounce. Thus metal fatigue becomes an issue. The problem is in the crystal alignment of the material. In it's initial state the crystals are somewhat jumbled but as the material is worked the crystals rearrange becoming aligned. The aligned state is harder but more brittle.

Just a follow up. We will be getting another Wound Up fork. While our LBS owner is very meticulous and didn't detect any cracking, we still need the piece of mind. Ditto for the front rim going back out to House of Tandems for another going over. (Co-Motion punted and said to contact Wound Up [who definitely said to replace]). Just as a fyi, both Wound Up and HOT have a crash replacement program. Can't say that about my carbon bar. (I thought that the left brifter had just rotated on the bar -- nope, the bar was snapped clean through with just the bar tape holding everything together.) Thanks for everyone's input.

Now as soon as the new fork comes in, both old & new go back to Co-Motion to match the paint fade. And might get another ride in this calendar year.