You must be a fast rider, [MENTION=327517]MattMem[/MENTION].

I love this! What year is it?

Thanks!

It's a 2000. However, the only thing original is the frame (and maybe the seat post and handlebars). Everything has been recently upgraded.

WARNING the frame is too small for you. It wouldn't matter that much, but you've extended the fork well above the headset top nut, and the stem is ending above the headset bearing. The steerer isn't strong enough to be cantilevered like that, and more importantly you have the stem ending in the threaded area where the wall thickness is halved, with 24 stress risers per inch. With any extended use and stress you can expect the fork to snap at the bottom of the stem.

I don't post gloom and doom warnings on stuff that might happen, but this is a SERIOUS SAFETY RISK with a high likelihood of failure.

Thanks for the warning.

As far as frame size goes, this frame is pretty spot on, for me, in terms of effective top tube length and stand over height. I wouldn't be comfortable riding anything much bigger as I am a pretty short person. As far as the stem situation goes, my local bike shop assured me it would be all right. However, in light of what you are saying I will revisit the topic with them as soon as possible.

Thanks again.

I've been fiddling around with finite elements software for estimating material stresses recently-- I'm going to see if I can model this today, because I'm curious about about how much the stress is increased here. However, that's a steel fork with a steel steer tube, right? Steel deforms plastically so much before it fails, I think the fork would be noticeably deformed for quite a while before it failed. I wouldn't think you'd have to worry about it snapping without warning. Am I wrong about that?

Thanks again for looking out! I really appreciate it.

However, I just took the stem out to see how far down it goes. It is one reeeeaaaallly long stem! The stem actually extends, in addition to what is visible, 3/4 of the length of the head tube, which is as far as it will go. With the current set up, the stem is at its lowest possible point. I think it'll be ok since it pretty much fills the entire length of the head tube area, in the fork steer tube.

You are correct. That is all steel.

When you model, be sure to factor the thread depth and the fact that the stem ends at a thread. If you're curious you might run two models, one with threads and one without. And yes, steel steerers are moderately ductile, and would tend to bend slightly before breaking, but unfortunately there's no time gap and both will happen within a microsecond as a single event. There's no way the rider could ever see a warning sign of impending failure.

I might add that forks have been breaking below the headset for a long time if threaded beyond the stem depth. That's why it's been SOP for a for forks to be threaded less than 2" or so, while stems are inserted at least that far, ensuring that the stem ends below the last thread.

OK, as long as you have an extra long stem which extends below the headset and past the last thread, then you're fine. I wouldn't have posted at all, but eyeballing the photo and knowing standard quill stem length I thought the stem was ending above the headset. I see these combinations and the results too often to let it go.

I love pictures of bikes IN the house. I think that's where they belong. Not in a cold garage or shed. A shop is ok if there are other bikes so they can commune amongst themselves for a while.

Thanks! I always appreciate the input/feedback.

I wonder about this because I ride larger bikes with tall headtubes. That means that when I bought a replacement fork for one, there is more like 3-4" of thread (if memory serves threading runs from 150-240 mm and I have a 200 mm headtube - something like that). That means I either need a super long stem like a Nitto Technomic that only has the exposed length of a much shorter stem, or I have a stem that ends up with the end over threads even though it's still in the middle of the head tube.

BITD when threaded headsets were the norm, this was a classic problem. In order to save money and reduce the number of SKUs low end forks were sold with tall steerers and long threading, so you could cut to size.

This was fine as long as enough was cut off, but they had a very high failure rate if not cut short enough that the stem extended beyond the last thread. It's unfortunate that the bike world has such a short institutional memory, and after 20+ years of threadless headsets, the experience of the prior generation is forgotten.

However, there's a sea change difference between the likelihood of failure when the fracture plane is well below the upper bearing vs. above.

I'm still skeptical about the catastrophic failure of a steel steerer tube (maybe I'm just grumpy about being an hour into a calculation and it turns out no one wants to see it. I guess it's not the first time that's ever happened though). Look at this video of the material testing of a steel sample. It basically sustains the same enormous stress until it looks like laffy taffy!
Tensile Test - YouTube

Feel free to be skeptical, and even do a real world test on your own bike. I'm not invested in what people believe or don't, and only gave fair warning based on a general concern for protecting someone from the consequences of the unknown unknowns.

However, you've discovered the difference between theorists and technicians. The former use analysis to discover what should or could happen, and the latter make decisions based on the cumulative experience of what did happen in the past.

In any case, consider the issue as applied to a threaded tube. As the tube is flexed all the elongation is concentrated at the root of the thread. Consider how far it must elongate before a noticeable bend in the tube occurs. This is exactly why threaded axles break at the first thread beyond the cone, which is a more common event because bike makers know better that to design forks prone to snapping at a thread.

This is my commuter, a 2012 Jamis Aurora. So far I've added Soma Sparrow bars and a Brooks Cambium C17 saddle. Next up: upgrade the pedals and swap that crate for baskets.

Wow, that looks great like that! I really like the aurora, but I've never seen it with upright bars on. The crate looks pretty cool too.

Thanks! They're only sort of upright bars--I have them flipped down, so they're a bit lower than the hoods on the drop bars that came with the bike (my grip is a bit lower than seat height). But they bring my grip a lot closer in. Fits my weird proportions great!

Here's my new bike.



It took me a while to get it set up, but I'm very happy with it now.

I like the red accents. I also have taken the red accent route with my LHT. SomaFab has nice red fenders.

Thanks!

I got my inspiration from the handlebar bag (which is actually a purse I found at REI). I liked the red stripe on it so when I came to add reflective tape, a seat bag, etc. I got them in red. The red B17 was good luck, I didn't even know they existed until about a month ago.

I don't know if I'll put fenders on this bike or not. I almost never ride in the rain anymore. If I do, I take a look into the ones from SomaFab.

That is one slick looking bike. Awesome.

Got the new wheels for my Breezer built and it's back out on the road with it:

Does that bike have different wheel sizes, or am I imagining that?