I'm looking at getting a custom hardtail built up. I'm looking for something that is more XC/bikepacking focused and fun on the flats than a downhill ripper. I got the Geo chart back from the builder and some of the numbers seem off the charts with a 494mm reach and 607 stack. This is my first custom bike, so maybe I don't know what I'm talking about. For reference I am 6'-0" with a long torso/short legs. Thoughts?
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Custom Geo - Too long?
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Look at Stanton Sherpa. The numbers on their chart are based off of 20% sag on the fork though. So the static numbers for reach on a large is more like 475mm. Sherpa Gen4
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The Neuhaus Hummingbird has good all around geo numbers. And a very good geometry chart for comparison.
www.neuhausmetalworks.com
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As I am built similarly (5'11.5" and a bit torso long) I will share with you the geometry of my second custom frame that refined what a pretty a good fit for me into a perfect fit for me. As others suggested, also look closely at Neuhaus's geometry charts for the Hummingbird. Nick has spent a ton of time working on geometry, and he is a bit over 6' tall so has a good reference for your height (he is also a hell of a rider).
Thinks to look at when comparing my geometry and what Nick's default would be for me. First and most important, his numbers are unsagged, mine are sagged. As as result, when comparing, you would need to subtract about 1 degree of head and seatube angle from my bike and add about 20mm to the stack measurement to compare.
From a design perspective, I like higher bars than most, hence my headtube is longer than you would normally see (Nick also makes his bikes bit more upright than many manufactures). As you go either slacker, or with a taller head head tube (or both), chainstays need to grow in order to have a bike that remains balanced you don't have to ride over the front to keep traction. I also like the stability of longer stays, hence mine are 445mm vs Nick's use of 430 as a default in your size range. For your stated riding goals, Nick's geometry hits a pretty nice spot.
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I live in North Florida and I own a Hummingbird. Expensive but worth it!!
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Thanks for the feedback. Y'all are awesome to spend the time sending me all this info. It's massively appreciated and after a couple nights of research and a six pack I feel like I have my hands around the basics.
I've been digging into the Neuhaus geo, and it seems to be just about right for what I'm looking for. I think I like the shorter 430 chainstays (and shorter wheelbase) as I want to emphasize the quick turning ability. I have a modern full sus for trail riding ('23 Trek Top Fuel). It's fun for the mountains, but feels like an 80's Cadillac on the flats. For that same reason, I was thinking a 66.5 or 67 (unsagged) HTA makes sense.
If a custom builders geo is so shitty that you need to go rip-off someone else's geo...I would question the original builders ability to build anything worth riding.
A bike is not just geo numbers.
If you just want something cheap(er) that works. Go buy a hardtail from the variety of big brands that make them. You get something better than whatever this "custom" builder can give you.
That anyone would think 494 reach, 67 degree HA, and a 65mm stem is a good fit for someone who is 6 feet is wild. Like, never designed and built a bike before level of wild.
If you want a bike with Hummingbird geo. Buy a Hummingbird.
A bike is not just geo numbers.
If you just want something cheap(er) that works. Go buy a hardtail from the variety of big brands that make them. You get something better than whatever this "custom" builder can give you.
That anyone would think 494 reach, 67 degree HA, and a 65mm stem is a good fit for someone who is 6 feet is wild. Like, never designed and built a bike before level of wild.
If you want a bike with Hummingbird geo. Buy a Hummingbird.
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I received an updated design and it's way better! It's 99% of the way there. I think I may shorten up the chainstays by 5-10mm to make it a bit quicker in the turns. Also thinking about dropping the headtube by 10mm so I have the option to increase my saddle-to-bar drop without using a negative stem.
I looked on bikeinsights and the only number that was out of the normal range was the 116mm trail. But, I don't see any way of changing that without tweaking the HTA
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I looked on bikeinsights and the only number that was out of the normal range was the 116mm trail. But, I don't see any way of changing that without tweaking the HTA
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IMO, if you're springing for a custom frame and you want a custom geo, the builder is probably not the optimal source for that.
I'd go to a really good fit specialist who has something like one of these (with mtb handlebars of course) so you can try out frame geometries.
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Custom bicycle fitting system for bike fit professionals, Bicycle Fitting in Seattle
I'd go to a really good fit specialist who has something like one of these (with mtb handlebars of course) so you can try out frame geometries.
Custom bicycle fitting system for bike fit professionals, Bicycle Fitting in Seattle
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I always send in my own numbers. Sometimes they seem outlandish like low long and slack well before it was a thing. I would tell them I'm experimenting. Usually the geo is reasonable for hardtails. Sometimes I'll copy production geo like I did from an Ibis Tr@nny.
I was once told "No" on a fork build. He refused my A2C. I didn't argue and after it was installed I sent a text telling him it was perfect and thanked him for talking me off a ledge.
I was once told "No" on a fork build. He refused my A2C. I didn't argue and after it was installed I sent a text telling him it was perfect and thanked him for talking me off a ledge.
Ask for a drawing with the fork at your preferred sag (20-30%). Static numbers don't mean much with a hardtail. STA, reach, and saddle-to-bar drop will all grow when the fork sags.
So we went from a 95mm head tube to a 155mm head tube?
I'm all for tall head tubes, and I run plenty of spacers and riser bars, but that's massive. I don't think i've ever seen a 155mm head tube on a modern MTB with a suspension fork. I don't get that 70mm stem either.
I'm all for tall head tubes, and I run plenty of spacers and riser bars, but that's massive. I don't think i've ever seen a 155mm head tube on a modern MTB with a suspension fork. I don't get that 70mm stem either.
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Either OP is not communicating what they need to the frame builder and the frame builder is scrambling to accommodate, or the frame builder doesn't know what they are doing. I would expect a custom builder to design something based on the rider's dimensions and terrain/ riding style, and the the rider tweak a bit.
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Looks much better. A few things:
1) Headtube length- You run your saddle 10mm lower than I do, so your torso is still slightly longer than mine. As such, I believe you are likely to run a 50-60mm stem based on your body measurements provided in your first post. Now the issue is whether your headtube is too tall. If you run a flat bar, it will probably be pretty close with no spacers. If you run a riser (I run a 25mm Enve M6 bar) it will likely be too tall (keep in mind I like my bars higher than most). I would suggest given your lower saddle height having the headtube reduced to 135mm, which will give you flexibility in bar height. Keep in mind, when the fork is sagged, the reach and effective toptube length will both grow by about 7-10mm.
2) Tire size- This is going to be important for your chainstay length. For a hardtail that is not raced, I really like running 2.6 tires. The issue with this becomes that for a steel frame, with short chainstays you can run into clearance problems. To run 430mm stays with a 2.6 most builders will use something like a flat stay section. Neuhaus is able to avoid the issue because of their use of 3d printed lugs. Your builder should have discussed this issue with you. If not, I would be concerned.
3) Seat Tube Angle- Much better. Again, keep in mind, the numbers in your drawing are unsagged, so will steepen to about 75.5 sagged. This is fine for climbing, but if you do a lot of riding on flat terrain or shallow fire road climbs, may put too much weight on your hands.
4) Trail- Trail is a number calculated using head angle, wheel size, and fork offset. It is a resulting number, not something you adjust.
5) General concerns- I, like some others, have concerns that your builder is either lacking communication or experience. The first design should have never been sent and the builder should have explained that it is near impossible to compare hardtail and full suspension geometry and why. The second design is pretty good, but may not address what you necessarily are wanting after a good discussion. Where I still have concern is what tubing will be used, as it has a profound effect on ride. A good builder will select tubing based on your weight, riding style, preferences, and the bike dimensions. This takes years of knowledge and experience, because tubing that is too heavy will lead to a stiff and uncomfortable ride, while too light a flexy flier that may break. Part of the magic of a custom steel bike is having tubing tuned to you.
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Thanks for the feedback, all. Regarding the builder, I spoke with them about the craziness of the last design. They apologized and ended up letting the guy go that put it together (evidently he was on his way out). Now I've been working with one of their experienced hands and he has been helpful with both taking my input and guiding me along. This is my first time with a custom frame, so I'm learning. Thanks for all the help. If I do this again, I will be much better prepared.
On the specific geo, I agree on the headtube, and we dropped it to 145mm. I typically run a flat bar and this gets me to the drop that I am used to. I can always increase the height with a riser bar if needed. On the tires, I got the same feedback from the builder and he cautioned me about the clearance with the shorter stays, So we kept them at 440.
Time to roll the dice!
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Sounds good. Look forward to seeing the final bike. One last thing to consider. Do you want an accessory/small bag mount on the bottom of the toptube where you can put something like a Wolftooth B-rad? It is easy to put the water bottle holes in and they are virtually invisible if not used. Important if you do that, put it far enough forward it doesn’t interfere with your seattube water bottle.
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That's a really cool idea. I have a couple bosses on the top of the top tube for a feedbag, but I love the idea of hanging my flat repair/tubes off the bottom.
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I get that. I’ve owned 6-8 mtbs over the last twenty years. Mostly xc hardtail. But, I never paid that much attention to the geometry. Just threw a leg over it and hammered.
Now that I’m in my middle aged trail/bikepacking phase I wanted to try out a custom metal before I enter old man/ebike phase. Gotta strike while I can still ride it!
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I promised a follow-up post after the bike came and I'm here to deliver. I picked it up about a week ago and I have 60ish singletrack miles on it so far. So, enough to get a feel for how it rides.
The frame was built by Mosaic Cycles and fitted with XTR gruppo, Rockshox Sid 120mm fork, I-9 32-hole carbon rim w/hydra hubs. The fit and finish are spectacular and It weighs 25.3 lbs.
Their first shot at the Geometry chart fell flat. But, I got hooked up with their MTB guru and he dialed it in. The fit is perfect. I transferred all of my measurements over and the only adjustment I've made is to drop the last spacer under the stem and ride it slammed. The ride is almost telepathic through the turns and can dance through all of the tight twisty trails and power up over the short rooty climbs. Perfect for the woodsy trails around here. It brings me back to my XC racing days in the mid-2000s when I was on a 26" hardtail.
The next test is to take it up to the mountains and see how it does on steeper terrain. I'll report back.
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The frame was built by Mosaic Cycles and fitted with XTR gruppo, Rockshox Sid 120mm fork, I-9 32-hole carbon rim w/hydra hubs. The fit and finish are spectacular and It weighs 25.3 lbs.
Their first shot at the Geometry chart fell flat. But, I got hooked up with their MTB guru and he dialed it in. The fit is perfect. I transferred all of my measurements over and the only adjustment I've made is to drop the last spacer under the stem and ride it slammed. The ride is almost telepathic through the turns and can dance through all of the tight twisty trails and power up over the short rooty climbs. Perfect for the woodsy trails around here. It brings me back to my XC racing days in the mid-2000s when I was on a 26" hardtail.
The next test is to take it up to the mountains and see how it does on steeper terrain. I'll report back.
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