I have no clue about this, but maybe post in the DIY/MYOG forum. This sounds like a fun project, and although I can and enjoy mig welding, I know for a fact that I do not have the attention to detail for building a bike frame nor know how to tig weld aluminum. Not an issue with steel I suppose. But from what little I do know, you'll need to build a jig.

 

Thanks for the reply. I have a pretty extensive welding background myself and could TIG a steel or aluminum frame with ease. In an ideal world, sure, I would just make my own frame. That would be a fun project. And yes, it would require a jig. Unfortunately, I don't have the equipment or access to a shop; I gave up working for a living to become an engineer lol.

 

I also started back into riding many years ago on a Giant Sedona. The big thing to consider with this process is just how different its geo is from a bike that is more discipline specific. I went to road and track riding first before getting back into mountain bike riding. Once getting into road riding and going back to the Sedona on occasion to go for rides with my kids I found the riding position horrid. Going to an XC Scott Scale MTB after the Sedona had a similar feel.

In saying all of that, I think you need to be looking at XC bikes. You're looking at trail bikes which will lengthen out your reach. However also consider how these bikes shift you forward in the bike to be more centred between the wheels. The benefit to the handling is phenomenal. Stick to models that have up to 74° seat tubes. Any steeper and it will definitely feel weird. I ride a Pole Taival for mostly XC duties and the seat position (75.5° STA) is fine for traversing flatlands. I would say that seeing as you've been able to sit on some of those bikes, you should try and get a ride on them too. They will feel very different to the Sedona, but the handling benefits on trails will be off the charts in comparison.

I wouldn't geek out too hard on geo just yet. You're going from one type of geo to another, and they have very different purposes. Like comparing apples with oranges. Either try to ride some models or just take a dive into something that fits reasonably well but is properly off road focused and then work out if that suits and where you might want to go from there

 

I also started back into riding many years ago on a Giant Sedona. The big thing to consider with this process is just how different its geo is from a bike that is more discipline specific. I went to road and track riding first before getting back into mountain bike riding. Once getting into road riding and going back to the Sedona on occasion to go for rides with my kids I found the riding position horrid. Going to an XC Scott Scale MTB after the Sedona had a similar feel.

In saying all of that, I think you need to be looking at XC bikes. You're looking at trail bikes which will lengthen out your reach. However also consider how these bikes shift you forward in the bike to be more centred between the wheels. The benefit to the handling is phenomenal. Stick to models that have up to 74° seat tubes. Any steeper and it will definitely feel weird. I ride a Pole Taival for mostly XC duties and the seat position (75.5° STA) is fine for traversing flatlands. I would say that seeing as you've been able to sit on some of those bikes, you should try and get a ride on them too. They will feel very different to the Sedona, but the handling benefits on trails will be off the charts in comparison.

I wouldn't geek out too hard on geo just yet. You're going from one type of geo to another, and they have very different purposes. Like comparing apples with oranges. Either try to ride some models or just take a dive into something that fits reasonably well but is properly off road focused and then work out if that suits and where you might want to go from there

Thanks for the 2 cents. I have read about, but haven't much considered XC bikes, mainly because they're meant for racing and, therefore, light-the opposite of what I need. Another main difference from a trail bike is that the head tube angle is just a little larger for XC. Maybe I'll take another look at the geo though, and XC bikes in general. But it sounds like when you went from the Sedona to the XC, while it felt off at first, at some point you began to prefer it? Thanks.

 

Going from a Hybrid to a Trail bike the geo changes as will your body position but they design and engineer them that way for a reason. There isn't really any reason you need a trail bike for mellow single track. I have a really fun single track behind where I live that is more fun under biking with a cross or gravel bike than my FS bike.

Check out a Surly karate monkey or Krampus, I think they fit what you're looking for really well. Both have a stack height just over 30mm less than the sedona but you can run a riser bar to adjust for this. Reach can also but brought back by reducing your stem length.

 

Going from a Hybrid to a Trail bike the geo changes as will your body position but they design and engineer them that way for a reason. There isn't really any reason you need a trail bike for mellow single track. I have a really fun single track behind where I live that is more fun under biking with a cross or gravel bike than my FS bike.

Check out a Surly karate monkey or Krampus, I think they fit what you're looking for really well. Both have a stack height just over 30mm less than the sedona but you can run a riser bar to adjust for this. Reach can also but brought back by reducing your stem length.

Thanks. I have looked into the Karate Monkey online. One thing that bothers me a bit are the slotted dropouts. I understand they must work since people ride them, but at 350lbs, I'd feel a whole lot better with a solid thru axle. Similar issue with the Honzo; it isn't slotted but has a separate bolt-on to hold the hub. So far, the Niner is the only non-boutique maker of a steel bike with solid thru axle, but their **** is ridiculous expensive. I have no problem with small makers, except $$$. The Sir 9 frame only is ~1200. Anyway, thanks for the input. I'll keep it in mind.

 

This from another forum -

"
Swapped wheels between my road and tri bikes last night. Didn't think much about it.

About ten miles into my ride today on the tri bike I had to hit the brakes to avoid a car. All of a sudden I hear a loud clunk and my back end starts to fishtail. Luckily I was in a place where I could immediately pull over and figure out what the hell was going on. I hop off, look at my rear wheel, and notice that the wheel had come out of the dropouts. The cassette was still connected to the chain, but the skewer was about two inches behind the dropouts and the brake arm was resting one the tire, holding the frame up and keeping the derailure from smacking into the pavement.

Obviously, I must not have tightened the quick release as much as I should have last night. It scared the crap out of me. Needless to say, the QR is now about as tight as I can get it. But I spent the rest of the ride nervous that I was going to 'ride out' of the dropouts again.

So, just as a public service announcement, make sure your QRs are tight! Bikes handle better when the frame is firmly connected to the wheels.
"
I hear what you're saying. I do. For me, I'm going with a through axle. While I don't jump anything now, I'd like to begin taking incrementally larger drops to build confidence.

Thanks. All of your replies have helped and I have a new line of thinking now about alternative ways to achieve the geo I'm looking for. I may look for a hybrid frame for 29s and build it up with heavy-duty components. Or, look for a trail frame with more upright or less aggressive geo and use risers or an angled stem, or both. Or I may just buy a pre-built and see if I can get used to it, and upgrade as I destroy things,

Cheers.

 

Sounds like he did not do a good job putting on his quick release skewer. The krampus or karate monkey would be a thru axle. One it’s properly torqued it’s not going anywhere

 

Sounds like he did not do a good job putting on his quick release skewer. The krampus or karate monkey would be a thru axle. One it's properly torqued it's not going anywhere

I have to admit, I thought through axles were synonymous with an enclosed..drop out? I'm guess it wouldn't be a drop out if there are no slots, ie. no ability to drop out or slide out. Where the chain stay and seat stay meet that holds the hub. I'm sure there's a name.. Anyway, I see on the KM it is a through axle and not a QR. I want is an enclosed hole so that even if it becomes loose, it is less likely to disassemble mid-ride. I understand you have confidence in Surly's system. I'd be more likely to consider Kona's Honzo, which has an enclosed hub holder, even if it is Al. There is a steel version which is enclosed, but the frame doesn't hold the hub directly, and basically has a bolt-on through axle.

 

My best recommendation is to call Ventana Mountain Bikes (near Sacramento, CA) and speak to Sherwood or Teresa. Ventana offers stock, semi-custom, and full custom frames. All made in house in their shop in Sac. This may be the most co$tly option. Regardless, I'd recommend at least having a conversation to explore options and gain insight. Sherwood and Teresa are super good people.

 

I appreciate that you know of some good people. I'm not looking to spend 5k, more like 2k complete. And I think from some of the ideas posted here I'll be able to piece something together that will end up being tough and comfortable. Now I just need to make a frame decision and begin hunting components.

 

You can find anything you want on the internet to justify any position or idea. QRs have been around for a very long time and worked fine. Human error is what causes most things to fail. There's 12mm bolt thru axles that work on bikes with drop outs. DT Swiss were the originators I think.
At 350 you want a strong frame and strong components. Hybrid style frames are not designed for trail riding at any weight so I would strongly recommend staying away from them as a basis for your build.

 

You can find anything you want on the internet to justify any position or idea. QRs have been around for a very long time and worked fine. Human error is what causes most things to fail. There's 12mm bolt thru axles that work on bikes with drop outs. DT Swiss were the originators I think.
At 350 you want a strong frame and strong components. Hybrid style frames are not designed for trail riding at any weight so I would strongly recommend staying away from them as a basis for your build.

I understand. Among the information on the internet is valid data someone can use to make a rational decision. The quality of the source determines how well it supports a point. In this case, it doesn't really matter if the testimonial I found was fabricated, or documented in a national security briefing, since the intent wasn't to convince someone of something but simply to illustrate a point, which is a vulnerability that I perceive to exist. The same objectivity that brought me to that conclusion, helps me to recognize there may be compensating factors, ie. forces applied by the bolt system, that prevent that vulnerability from being exposed. All other things being equal, an enclosed bolt hole is more secure than an open one. Physics.

Considering Surly in particular, the center of gravity at the moment of maximum inertial force during a drop will be between the wheels, causing both ends of the frame to elastically deform in the opposite direction, resulting in a non-zero force component on the hub in the direction of the horizontal slot. More technically, the wheel will want to squirt out. More so, if you weigh 350lbs.

 

I'm 6'4 327. I do drops and jumps and ride aggressively on a Krampus. Best bike on the market in that price range for us bigger guys. As suggested above, I run a shorter than stock stem and riser bars.

 

Serious question, what redundancies does Surly have that makes this system a good choice for offroad? I've ridden track bikes for years and have a lot of experience with horizontal dropouts, but it's not a system I would choose to use offroad. The old school dropouts with their lawyer tabs have their redundancies. I've no experience with Surly as due to my size, they've never been on my radar so I am legit curious. No one anywhere near me has one or deals in them, so I've never cast an eye over one.

 

City and trekking bikes are built to different standards than road bikes or mountain bikes as defined in an ISO (4210). Mountain bikes are designed to withstand more abuse. Most rigid bike frames follow the same design language so you can do all the analysis you desire about transmission of forces. As for structural analysis and material thickness and butting - you can do all of that or you can read what bikes are recommended in this forum by people who ride them.Materials are one thing, construction is another and you can't quantify that in abstract.
For geometry, look at 99spokes and use what they have as a basis.

 

Thanks for the info. I do genuinely value and consider the points made by experienced riders in this forum. That's why I posted. I appreciate those who've taken the time to respond, and the points presented have adjusted my thinking. As an engineer, however, expecting me not to make my own appraisal based on details would be like asking a free-rider not to send it. I'll have a look at 99spokes.

 

Why is it always engineers that think they're masters of all things bicycle? I swear it never fails. Don't have a clue and yet they're fully convinced they know better than people with decades of experience in the industry.

If I came to your office and started telling you a design didn't look sturdy and I know what I'm talking about because I knit sweaters for a living, would you value my opinion?

 

Why is it always engineers that think they're masters of all things bicycle? I swear it never fails. Don't have a clue and yet they're fully convinced they know better than people with decades of experience in the industry.

If I came to your office and started telling you a design didn't look sturdy and I know what I'm talking about because I knit sweaters for a living, would you value my opinion?

Maybe you don't get the respect you feel you deserve in the rest of your life. Maybe you feel you should receive unquestioning reverence from someone with less experienced in something you perceive yourself to be good at. I don't know. To be honest, I don't care. What you don't recognize, because you can't see beyond your fragile ego, is that I have not had, nor do I have now, the desire to have a conflict. It's neither the purpose I posted in the forum, nor does it hold interest for me. But since you seem to want to continue your tantrum, I'll clear some things up for you.

As an engineer, I don't think that I'm a master of bicycles. That doesn't mean that I've never banged on a piece of metal or bolted something together, and therefore have some basic understanding of mechanics, at least that of a child, which is all that is really necessary to have an understanding of this issue. I don't even need to cite the fact that I was a journeyman millwright before college, and built things with my hands that would impress anyone, everything from pressure vessels and auto plant conveyor systems to bridge trusses and structural foundation weldments for 2 major league baseball stadiums, Miller Park and Comerica Park. From scratch. I don't need to explain that I have a hands-on mechanical aptitude most probably so far superior to you that I can't even explain how ridiculous it is to see someone get offended that I would voice dissent about a bolt hole. That's not even considering an MS from a top graduate engineering program, and by top, I mean #1. I don't really need to bring any of that because, again, it's a bolt hole, and any sentient lifeform with more than 2 neurons can see that an enclosed hole is more secure than one with an opening in it.

I included no disrespect while expressing my opinion about open drop outs. I simply stated concern and indicated I would lean away from a horizontal dropout design. Did I call you an idiot? Did I say that you didn't know what you were talking about? No. What I did was express appreciation to those who took the time to reply, and I genuinely meant it. I'll use the data points to make my decisions. But that wasn't enough for you. You needed blind obedience. Well, I'm sorry but I can't give that to you. After all, you knit sweaters for a living.

 

Actually I'm not talking about myself, not in the least. More the professionals that design and engineer bike frames. You realize this happens in a CAD program and/or Solidworks?

It's just amusing to me. You ride a hybrid and poo poo a MTB design from a brand that's well known for it's durability. It's quite amusing. That's all, I'm out. -Cheers

 

Peace.

 

Ended up with this. Large stack, short reach relative to similar bikes. Added 140mm fork (130mm stock), left the steerer long enough for 60mm of spacers. The relation between the contact points (pedals, seat, bars) are nearly what I had on the hybrid. With an effective 66° HTA and 29s, however, it's much more stable, and much faster on the trail. I love it.

Thanks again for the advice.