Bent Frame Question

[Tymncycle]

Hey Gang!

Just a question for the group.  I own a retail bike shop, and we've done our share of straightening bent dropouts, the odd steel fork, etc, but now I'm faced with a customer who managed the classic "buckled top and down tube" from a front impact.  Due to the fact our shop has been around a long time, we actually own one of the gigantic Park tools HTS-1 "head tube straighteners" but have never used it.  My question is... would you do this?  Or is the prospect of future failure/liability something that would make you walk away, or suggest the only option is replacing the tubes?

It's an old lugged steel Trek, and the guy JUST got it all dialed in and this happened on one of his first rides, thanks to a riding buddy doing something stupid.  He'd really like to save the bike, but...

Thoughts?

Thanks!

Tim

[Lora Van Dixhorn]

Tim - You are smart to reconsider this fix.  If you do take on the liability, check wirh ypur insurance agent to be sure you have coverage. It should be easy to include. Lora VanDixhorn

Sent from my Verizon Wireless 4G LTE smartphone

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[Jon Norstog]

Tim, list:  that frame is a wall hanger! Unless you replace the top tube and downtube, that is.

Good luck!

jn

"Thursday"

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[omar-...@cox.net]

Most framebuilders that I know would want to see this frame before making ANY kind of decision on whether or not to fix/replace.  There are many ways to fix bikes, as I am sure you know.  You also know that every problem and it’s repair are not the same.  Send us a few pictures and you may get some answers.

Omar Khiel

Oasis Custom Cycles LLC.

F

rom: Tymncycle

Sent: Saturday, March 26, 2016 9:23 AM

To: Framebuilders

Subject: [Frame] Bent Frame Question

[Tymncycle]

Good point Omar!  I've asked the owner to send me some pictures.  I have not yet laid eyes on the bike.

Thanks to all so far!

Tim

[Tymncycle]

Well, two added bits of news, one of which makes the question pretty much moot, but I thought I'd post the pics anyway for discussion.

The guy who caused the crash has apparently found an identical frame on eBay for my customer, for a very reasonable price, so that's the path he's going to take.  That being said, I'd be curious to see what folks say about the damage shown in the pics.  I can't imagine anything short of replacing both tubes would work.  I've seen frames with minor kinks there, but this on is pretty severe.

Tim

[M-gineering]

If you're stuck down deep in Africa and want to get home you could give
it a go, but otherwise it is scrap and not worth repairing unless
emotions overrule economcis

On 3/26/2016 6:44 PM, Tymncycle wrote:
> Well, two added bits of news, one of which makes the question pretty
> much moot, but I thought I'd post the pics anyway for discussion.

--
mvg

Marten Gerritsen

Gerritsen & Meijers, Ingenieurs
Framebuilding & Imports

Dorpsstraat 132
9605 PD Kiel Windeweer
Netherlands

Tel: +31 598 491865


www.m-gineering.nl

[Mark Bulgier]

Way too kinked to salvage. That Park straightener, or the old Li’l Brute brand, were useful on old heavy small-diameter thick-wall frames, the classic example being the ”electroforged” Schwinns (Varsity et al.) They tended to bend in a mellower way, not such a sharp kink or buckle.

I have ridden three different cracked frames until the crack grew all the way around, and the tubes parted -- for fun and to see what it would take. Not recommended, for obvious reasons, kinda stupid actually. But all three were frames that had been slightly buckled in a front-end collision and then developed fatigue cracks later right at that spot. All were MUCH less buckled than the one in your pictures, more along the lines of "barely visible".

I didn't try straightening them because the increase in head angle was small enough I didn't mind, I just rode 'em as-is. I doubt straightening them would have reduced the tendency to crack there; in fact it probably would have only increased the damage.

I think any kinked frame will probably crack there if ridden much.

Mark Bulgier
Seattle

[Tymncycle]

Well, I'm not at all surprised that the general reaction is "don't do it!" Especially given how bad it is now that we've all seen the pics.  Really glad my customer found a replacement frame so easily.

I guess our Park HTS-1 will continue gathering dust and being a conversation piece among the younger staff...

Thanks to all!

Tim 

[Andrew R Stewart]

Tim- Like many repairs the devil is in the details. In this case aspects like the tubing wall thickness, the amount of bend back, any buckling and if so the presence of kinks or folds with sharp edges. The size and temperament of the rider, one’s confidence in doing the repair and also in the rider’s understanding of the repair.

 

I’ve done quite a number of these repairs but most were on heavy walled tubed bikes with mild bending, having no sharp tubing deformation shapes, with riders who knew that they had to monitor the bike from then on.

 

Depending on the straightening tool used some secondary damage can happen. Head tube ends can become deformed (leaving the cups in place helps here). The fork can end up with a forward bend/increased rake. Usually the localized rippling won’t be totally stretched out smooth. Knowing when to call it good enough is important. lastly there can be a side force aspect resulting in some twist between the HT and ST. Andy.

 

Andrew R Stewart
Rochester, NY USA

 

From: Tymncycle

Sent: Saturday, March 26, 2016 12:23 PM

To: Framebuilders

Subject: [Frame] Bent Frame Question

 

[DancesWithCars]

Chop tube and make a rear fork bar stool...
Glad he found a replacement frame.

[Tom W]

Toast