For the last year, I have had only one bike:
It has been far and away the best mountain biking year of my life, but it is still a slack, long travel hardtail with a fairly steep ST angle.
I would like to build another bike that is made to go farther a bit faster, but one that has as many parts in common as is reasonable and can still handle basically any terrain, except the really nasty stuff I have to drive to.
Because of this, I am building a super boost drop bar bike.
I have used no-offset 3-bolt chainrings to achieve about a 55-56 mm chainline and I think I can find a 42t chainring made for short spindle bb30 with no offset, so it should work out with a 73mm t47 bb and some mountain crankset that’s out there. I will use trp/gevenalle hydraulic drop bar disc brakes with a 11s sram drivetrain to integrate everything.
It will look something like this, but the fork is a stand in. I will probably work on that next.
Tubes: DT and TT are thick 853. .049", 7/8" chainstays. I don’t want to build this bike again! I’d much rather be making 29" BMX bike…
Cool project. What’s the drop between top of saddle and top of bars? Looks like a fair bit. Probably best to leave a couple of inches of spacers above the headset while you dial in your fit, especially since your mtb bars are higher than the saddle. Looking forward to progress pics.
I have been 6’9” a lot longer than I’ve been building bicycles, and I’ve gotten used positions more aggressive. I think a lot of tall cyclists do! I should be honest, I’m building this to race. I’m also using all available 12” of the tapered steerer. Any adjustments will require a custom stem or longer fork legs!
I designed the mtb around 30 percent sag, so the bars are effectively a bit lower in practice. It’s still not ideal. It’d be better shorter, with a shallower seat angle. It was designed for 190 cranks and was my second go at it. For a high cadence, fast bike, im using 175s.
OK, cool. I’m 6’3” and generally need all the steerer I can get. Reynolds sells steerers in both 400mm and 420mm, if that’s any help for you.
Zinn has a line of big and tall forks that may be useful:
They are heavy-duty and have extra long steerer tubes.
I am curious, what is the exact TT and DT you are using? Its such a big bike, I cannot Immagine!
Thank you, Daniel.
I have tested this position extensively on my “size cycle”
I even tried to break my friend’s fancy fit bike doing a bit of testing:
It’s stretched out and looks aggressive, but when you’re this tall and have as much torso as me, a relaxed position is like unfurling a big sail to catch the wind!
The downtube is: REYNOLDS BX2168XL DOWN TUBE 853 38.1x1.15/.85/1.15x850
The top tube is also a downtube: REYNOLDS BX3030XL DOWN TUBE 853 DZB 34.9X1.10/.9/.6/.9X760
They are the same tubes I have used for the last 3 frames I have built. I have been very happy with them
Have you considered building with a sus corrected fork? At your height they can make gravel bikes look much more proportional. @adamsklar made one of the best looking tall human gravel bike I’ve seen back in 2018. Check it below!
It is a good looking bike and definitely looks better than most xxl bikes! I quite am used to staring at big, ungainly looking bikes though, and they appeal to me. Also, think about the frame bag…
I have seriously considered a carbon, sus-corrected fork and made a few bikecad drawings. It would solve a lot of problems and I would love not having to build a fork! What has stopped is the cost for what I seem to get as a retail price-payer and my experience with carbon forks. I suppose I could buy a steel salsa fork, but I would rather build something without suspension correction and have a long headtube.
I am heavy. Even if I do manage to get fit this year, I will still weigh like 260 pounds or so. I had a suspension corrected carbon fork on a single speed mountain bike maybe six years ago, and there was something vague and insubstantial about it. It had too much flex and judder under braking and I could watch the wheel track lazily underneath me in disconcerting ways. Back then, I kept both wheels on the ground because I could imagine snapping my fork like a toothpick. Like everything else on this earth, it did not feel like it was designed with me in mind.
Steel is no panacea though, I have also bent fork blades while riding on steel forks that I made using nova disc fork blades. (This is after I noticed and tried to break it.)
I am currently tooling up to build a unicrown fork and I won’t go below a 1.2mm wall on this.
I’ve only ridden ENVE, Columbus and Whisky Forks and have never experienced vagueness or excess flex from those forks. If anything I wish they had a bit more flex. I have ridden several Steel Forks with lots of flex and brake shutter. If strength, rigidity and precision are what you’re looking for in a fork the I’d go ENVE over Steel for sure. I believe most of the Production Steel forks are in the 1.5mm to 1.7mm wall thickness
If you want to go carbon, I would highly recommend the ENVE MTN Fork. Especially if you can find the older 15x100 version (same one Adam used on the bike above). MTB Tandems did independent testing of all the top carbon mountain forks on the market and found that to be the strongest by a large margin.
If you want a beautiful production steel fork worthy of a custom frame , Check out the Steve Potts MTB Fork made by Tange. Steve is one of the nicest humans in the industry and would probably hook you up with builder pricing.
Custom Unicrown is a great way to go too! If you’re segment curious, Check out the Walt Works Fork Blades!
Aw thanks Kevin.
To your point Nick, I built a lot of really tall bikes over the custom years and it was always tricky to balance what someone got used to not really being able to buy a bike that fit “properly” with that “proper fit”. I think it was a good lesson in design. Just because something is the right way doesn’t always mean its the best way.
I fully agree Adam. The first thing I did when I first started building bikes was assume that everything I was used-to was wrong, especially after years of riding 62-64cm/XXL frames. 4 years ago, I built an all-road bike with level bars, and didn’t especially like it after one season of riding. It made me ask myself, at what point can a person no longer fully adapt to something new after doing it wrong for so long? There is a lot to consider!
Riding a bike is a weird thing to do with a body, and figuring out how to do it right is difficult for everybody. The sheer number of variables is dazzling… When you have to figure out how to design and build it without representative examples you can trust and materials designed for much smaller people it is sometimes crazy-making. I will try and remember this is fun!
The discourse on this forum has caused me to rethink my the geometry as well as the design of this current project. I’ve raised the A/C a bit to get the bars up and I am reconsidering the fork construction.