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Discussion Starter · #1 ·
Help me understand reach, top tube length, and new geometry.

I ride a Jones 29, which has a 584mm top tube (as I recall) and looks like the reach is around 395mm. I have been looking at getting a slack hardtail for some suspension action and am having a hard time determining what would fit as I am around 5'10 so I land in the middle of sizes for a lot of bikes.

How does one determine on newer geometries which parameter is key? I have always used a 23.5" top tube since the late 80's and since then the geometries of my bikes from Ritchey to Santa Cruz, to the Jones really hasn't varied that much. Some angles got slacker some chainstays got longer. Wheelsizes changed but it is my sweet spot.

However now looing at a bike with 77 deg seattube and a 63 deg headangle is just too much for my brain and experience to parse. Should I go comparatively with top tube length and sort comfort with the stem length/Cockpit length? Should I based it off reach? I honestly have no concept on how to get this done and frankly since no bikes are in stock at shops it is double difficult to even find a bike to try so I am assuming I will be ordering without trying so it would be nice to get close to fit and then tweak when bikes in hand.

Yours truly,
Geocurious.
 

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Having ridden hardtails forever, modern geometry is the best thing that has ever happened to them. That, and 1x12 drive trains that help up getting-older guys. Like everything, you can go too extreme. There are hardtails with 480mm reaches and 63 degree head angles, which I suppose is great if you've got something to prove to your FS buddies on the downs and don't mind a wandering, flopping limo on the ups. I'm finding the sweet spot around 66-67 degree head angles and 74-75 seat tubes, 430-435 CS length and 635-640ish ETT for your height (same as mine) for good all-around fun and fast riding on various terrain that includes climbing (talking 29ers here). Of course, that's just one random internet guy's opinion. Outside of these hard numbers, you're really going to have to throw your leg over some and see what works for you. The new HTs tend to feel more like big BMX bikes than compact, upright geometries of days past. They instill confidence and are just a lot more fun than they used to be, which I think accounts for their resurgence. Good luck, let us know how things pan out.
 

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^^^I have a Honzo ESD (63 deg HA and 490mm reach) and it climbs just as well as any XC bike I’ve ever owned, including tech climbs. The only difference is that it’s heavier, but part of that is how I have it set up.

The longer reach numbers you see now is to compensate for the steeper seat tube angles in conjunction with slack head angles.

I used to think the flip-flopping, poor climbing characteristics of my old freeride bikes was because of their slack head angles — but I now realize it was more because of the slack seat-tube angles. My Honzo climbs and descends like a rocket.

Absolutely no downsides to having the 63 HA.

However, the 490mm reach is a bit excessive for me at 5’10” — I’d like it a little better at 475 to ease initiating a manual. Not a deal breaker though.
 

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Discussion Starter · #5 ·
^^^I have a Honzo ESD (63 deg HA and 490mm reach) and it climbs just as well as any XC bike I’ve ever owned, including tech climbs. The only difference is that it’s heavier, but part of that is how I have it set up.

The longer reach numbers you see now is to compensate for the steeper seat tube angles in conjunction with slack head angles.

I used to think the flip-flopping, poor climbing characteristics of my old freeride bikes was because of their slack head angles — but I now realize it was more because of the slack seat-tube angles. My Honzo climbs and descends like a rocket.

Absolutely no downsides to having the 63 HA.

However, the 490mm reach is a bit excessive for me at 5’10” — I’d like it a little better at 475 to ease initiating a manual. Not a deal breaker though.
If you had to do it all over again would you have gone with a medium frame instead? I am looking hard at the ESD but again have to find one, which I will...maybe?
 

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If you had to do it all over again would you have gone with a medium frame instead? I am looking hard at the ESD but again have to find one, which I will...maybe?
I think I would, yes. But it’s not an issue enough that I’d consider trading it out for a medium. The extra reach only really affects me when I pull manuals on the trail when going through dips and such — it requires quite a bit more effort where my shorter enduro bike requires a slight lean back and a mild pull and the front wheel is up. When I switch from my Honzo to the enduro bike I have to be careful not to loop out until my muscle memory adjusts again.

Just going down the trail, the reach doesn’t bother me. I went down a ridiculously steep, scary trail last night on it, and never once felt like I was going to go over the bars.
 

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Discussion Starter · #7 ·
I think I would, yes. But it’s not an issue enough that I’d consider trading it out for a medium. The extra reach only really affects me when I pull manuals on the trail when going through dips and such — it requires quite a bit more effort where my shorter enduro bike requires a slight lean back and a mild pull and the front wheel is up. When I switch from my Honzo to the enduro bike I have to be careful not to loop out until my muscle memory adjusts again.

Just going down the trail, the reach doesn’t bother me. I went down a ridiculously steep, scary trail last night on it, and never once felt like I was going to go over the bars.
How about jump performance? How does it handle that?
 

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How about jump performance? How does it handle that?
I haven’t noticed any negatives, but then again, we don’t have a lot of jumps on our trails. I hit some drops on last night’s ride but bypassed one of the only jumps, as it is a step down with a shallow landing and quite often I bottom out both ends of my enduro bike on that feature.

I did take it to our dirt jumps one day and was starting to get into the groove right before I had to leave.

On natural “trail” jumps it is nice and poppy — no issues there. Anyway, sorry I can’t be more descriptive about its jump performance— the harder trails I ride really aren’t jump trails as much as just pure, steep DH with rock rolls and drops.
 

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66-67 is all thats needed on hta.

5-10 should be fine w a 460-475 reach.

bars and stems adjust the rest.

dont know what to tell you about picking a bike you havent ridden.

go buy it and test when it shows up. w bikes in high demand the shop shouldnt care to sell it on. your realpy not buying as much as pre reserving a spot in line
 

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I’m having the same dilemma. So I’ve been thinking about it quite a bit lately as well.

With super modern bikes like the Privateer 141/161, Transition Spire, Norco Sight, it seems like you have to decide between sizing by reach, or ETT.

I wish I had something concrete to tell you. But so far I’ve been flip flopping on my own thoughts every day or two.

Half the time I think “keep the same ETT, grow some reach”, while other times I’m thinking “keep RAD about the same, and deal with a 30mm shorter seated climbing position”.

My main thought is I absolutely need to find a demo on some similar bikes/geo, to sort out my own feelings about it.
 

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"Modern geo" becomes "modern geo" every two years. The industry needs to cling on somehow. For us older guys who don't ride sidewalk flow trails, the chopper HTA really suck in tight twisty singletrack*. I like 66/74 for what I ride. Watch the big rig wheelbase too.

The last enduro race I was in was sad, watching the kids tack back and forth up the fireroad to the start. It was either wheel flop or teenagers are weak this generation. The elevation was 8k but that's no excuse. I had six cogs at their age.
 

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How about jump performance? How does it handle that?
I'm 5'10" also and my newest bike isn't as slack as yours, 77/66/475 reach. I have short legs/long torso and went with a large instead of a medium. The bigger bike is nice and stable out on the trail but it's a bit less agile than I was hoping for. Depends on what your looking for. Stability, go large. Agility, go medium.
 

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66-67 is all thats needed on hta.
Sounds like you haven't ridden anything slacker. I thought my original Honzo was pretty sweet at 66 degrees after upgrading the fork to a 140mm model and a -2 angled headset. Then I got my ESD. I wouldn't go back to anything steeper.

The thing to remember with hardtails is they only get steeper than their static heat tube angle as you ride them. So a 63 degree HA really rides more like a 65 degree full suspension bike.
 

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Sounds like you haven't ridden anything slacker. I thought my original Honzo was pretty sweet at 66 degrees after upgrading the fork to a 140mm model and a -2 angled headset. Then I got my ESD. I wouldn't go back to anything steeper.

The thing to remember with hardtails is they only get steeper than their static heat tube angle as you ride them. So a 63 degree HA really rides more like a 65 degree full suspension bike.
Making this even more confusing is that some mfgs measure HTA at 20% sag of the recommended fork travel, and some don't, and often they don't even mention that.
 

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Discussion Starter · #15 ·
I’m having the same dilemma. So I’ve been thinking about it quite a bit lately as well.

With super modern bikes like the Privateer 141/161, Transition Spire, Norco Sight, it seems like you have to decide between sizing by reach, or ETT.

I wish I had something concrete to tell you. But so far I’ve been flip flopping on my own thoughts every day or two.

Half the time I think “keep the same ETT, grow some reach”, while other times I’m thinking “keep RAD about the same, and deal with a 30mm shorter seated climbing position”.

My main thought is I absolutely need to find a demo on some similar bikes/geo, to sort out my own feelings about it.
Seems we are in the same spot. Worst thing for me is I ride a jones with the 45° back swept jones bar. My hands are in line with my steerer tube and then the bike has a 55mm offset fork so it doesn't really mesh with anything similar. I feel like I could pull the rad measurement and find something similar and it might be fine but the ride is going to be so much different than a rigid bike with short trail and agile steering.

I kinda feel like I wanna pull the trigger on a Sick bikes geometry bike just to get to the extreme end of the geometry world, though maybe that is just pushing it too far. However if it is perfect i could save my cash money for a Chromag Doctahawk and check that box.
 

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I've been riding and experimenting with what some on here may call extreme geometry bikes for around 5 years now and have a few views which may be relevant based on personal experience.
As a reference, I'm 5,10 to 5,11 and ride a Geometron G1 in size large/longest as my daily fun bike with a pipedream Moxie hardtail in size XL with a -2 degree angleset fitted to take the head angle to 62 degrees. This is my XC rig for flatter/longer XC rides and slithering around in the winter. I bought the Moxie after the G1 and wanted to see what an even longer bike was like and I would suggest I've found my limit with the Moxie. It's great for what I want it for but I deffinitely find it harder to chuck around than the G1 despite being lighter.
I would say that there are some superb bikes out there now and it's possible to find one that suits you and your terrain really well BUT as there is so much variation between bikes now, in my opinion it's more important than ever to test ride before you buy which is ironic as there are more and more direct order bikes and due to covid, less shop stock.

I've been on a bike with a 62-63 head angle since 2017. All my mates told me it was ridiculous back then. They are all now riding bikes that are very close and claiming them the best thing since sliced bread.

Reach is really an irrelevant metric for determining bike size/fit now because seat tube angle, head angle and stack have a massive impact on where the bars are in relation to the bottom bracket and so both seated and standing cockpit feel. Modern bikes with short stems and slack head angles tend to ride significantly smaller than the reach number would suggest.
I tried a medium geometron and it really was too small for me despite a reach of 490mm. The slacker the head angle, the greater the reach needs to be to compensate as the bars are brought back towards you relative to the head angle. Even ETT can be miss leading as manufacturers measure differently and BB height and stack come into play.

Bottom bracket drop also has an impact on how easily the front wheel comes up.

A slack head angle has NO negative impact on climbing. None, Zip, Nada. Anyone who tells you different is talking rubbish. My personal experience is it puts the wheel at a better angle of attack for technical climbs. Wheel flop is massively exaggerated as a problem. It isn't. The further your hands are behind the steering axis the more of an issue it can become so fork offset in relation to stem length has more of an impact IME. My G1 outclimbs any other bike I've ridden despite being way more capable downhill than any other single crown addorned bike I've owned.

Really nailing bike fit with modern bikes is all about getting your mass located correctly within the wheel base. Your personal physiology plus your riding style and position have an impact on this so you cant really say that two people of the same height will gel with the same bike. Front and rear centres have a big impact on this. I have a longish torso in relation to my legs and relatively heavy arms and shoulders so I prefer a long front centre and short rear. A person with long, heavy legs and a skinny torso may prefer the opposite, especially when climbing.
Get it right and your long slack bike that all the keyboard experts tell you will handle like a barge may well actually become the most agile, fun and fastest bike you've ever owned.
One of the reasons I got a Geometron was that it allowed me to play with chainstay length and bottom bracket height independant of everything else. My large G1 is without doubt the most agile bike I've owned (I had a pivot switchblade and a yeti SB6 alongside the first geometron at one point) BUT it takes a while to adapt to the style of riding to get the most out of it. You need to stay centred and REALLY lean the bike over as there is so much more grip than on a bike with a shorter wheel base. I would say it's probably taken me 18 months to 2 years to fully adapt to not moving back when it gets steep fast and tight when I'm out of my comfort zone and this is the reason you are seeing bikes evolve by a degree a year. I've had 30 years (I'm over 40) riding mountain bikes that were quite frankly sh!t and it's takes a long time to unlearn the muscle memory that tells you to move back when it gets vertical and really rough. Racers simply could not adapt to such a change in 1 season.

Don't be afraid of a slack head angle, especially on a hardtail as it's arguable more important. I would be wary of sizing down on modern bikes unless you really prefer manualling over rollers and out whipping your mates on table-tops.

So, getting the most out of a modern bike may seem like a minefield BUT you've got to remember it WILL feel very different to start off with and altering bar roll, saddle position for and aft and to a certain extent stem length can all make a very noticeable difference.

It's a pretty cool time to buy a new bike, it's a just a shame demo's are difficult at the moment. If you do get to demo one, a car park ride will tell you jack. You need to ride some trails you know well and tackle some familiar climbs and descents.
 

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66-67 is all thats needed on hta.

5-10 should be fine w a 460-475 reach.

bars and stems adjust the rest.

dont know what to tell you about picking a bike you havent ridden.

go buy it and test when it shows up. w bikes in high demand the shop shouldnt care to sell it on. your realpy not buying as much as pre reserving a spot in line
What makes you say that 67hta is enough?

I had an Enduro with 66.5 and i think the current bike, 64.5, descends much better and safer.

Climbs the same

Sent from my Redmi Note 8 Pro using Tapatalk
 

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Seems we are in the same spot. Worst thing for me is I ride a jones with the 45° back swept jones bar. My hands are in line with my steerer tube and then the bike has a 55mm offset fork so it doesn't really mesh with anything similar. I feel like I could pull the rad measurement and find something similar and it might be fine but the ride is going to be so much different than a rigid bike with short trail and agile steering.

I kinda feel like I wanna pull the trigger on a Sick bikes geometry bike just to get to the extreme end of the geometry world, though maybe that is just pushing it too far. However if it is perfect i could save my cash money for a Chromag Doctahawk and check that box.
For what its worth, I asked the same question a few weeks ago.


I've been riding and experimenting with what some on here may call extreme geometry bikes for around 5 years now and have a few views which may be relevant based on personal experience.
As a reference, I'm 5,10 to 5,11 and ride a Geometron G1 in size large/longest as my daily fun bike with a pipedream Moxie hardtail in size XL with a -2 degree angleset fitted to take the head angle to 62 degrees. This is my XC rig for flatter/longer XC rides and slithering around in the winter. I bought the Moxie after the G1 and wanted to see what an even longer bike was like and I would suggest I've found my limit with the Moxie. It's great for what I want it for but I deffinitely find it harder to chuck around than the G1 despite being lighter.
I would say that there are some superb bikes out there now and it's possible to find one that suits you and your terrain really well BUT as there is so much variation between bikes now, in my opinion it's more important than ever to test ride before you buy which is ironic as there are more and more direct order bikes and due to covid, less shop stock.

I've been on a bike with a 62-63 head angle since 2017. All my mates told me it was ridiculous back then. They are all now riding bikes that are very close and claiming them the best thing since sliced bread.

Reach is really an irrelevant metric for determining bike size/fit now because seat tube angle, head angle and stack have a massive impact on where the bars are in relation to the bottom bracket and so both seated and standing cockpit feel. Modern bikes with short stems and slack head angles tend to ride significantly smaller than the reach number would suggest.
I tried a medium geometron and it really was too small for me despite a reach of 490mm. The slacker the head angle, the greater the reach needs to be to compensate as the bars are brought back towards you relative to the head angle. Even ETT can be miss leading as manufacturers measure differently and BB height and stack come into play.

Bottom bracket drop also has an impact on how easily the front wheel comes up.

A slack head angle has NO negative impact on climbing. None, Zip, Nada. Anyone who tells you different is talking rubbish. My personal experience is it puts the wheel at a better angle of attack for technical climbs. Wheel flop is massively exaggerated as a problem. It isn't. The further your hands are behind the steering axis the more of an issue it can become so fork offset in relation to stem length has more of an impact IME. My G1 outclimbs any other bike I've ridden despite being way more capable downhill than any other single crown addorned bike I've owned.

Really nailing bike fit with modern bikes is all about getting your mass located correctly within the wheel base. Your personal physiology plus your riding style and position have an impact on this so you cant really say that two people of the same height will gel with the same bike. Front and rear centres have a big impact on this. I have a longish torso in relation to my legs and relatively heavy arms and shoulders so I prefer a long front centre and short rear. A person with long, heavy legs and a skinny torso may prefer the opposite, especially when climbing.
Get it right and your long slack bike that all the keyboard experts tell you will handle like a barge may well actually become the most agile, fun and fastest bike you've ever owned.
One of the reasons I got a Geometron was that it allowed me to play with chainstay length and bottom bracket height independant of everything else. My large G1 is without doubt the most agile bike I've owned (I had a pivot switchblade and a yeti SB6 alongside the first geometron at one point) BUT it takes a while to adapt to the style of riding to get the most out of it. You need to stay centred and REALLY lean the bike over as there is so much more grip than on a bike with a shorter wheel base. I would say it's probably taken me 18 months to 2 years to fully adapt to not moving back when it gets steep fast and tight when I'm out of my comfort zone and this is the reason you are seeing bikes evolve by a degree a year. I've had 30 years (I'm over 40) riding mountain bikes that were quite frankly sh!t and it's takes a long time to unlearn the muscle memory that tells you to move back when it gets vertical and really rough. Racers simply could not adapt to such a change in 1 season.

Don't be afraid of a slack head angle, especially on a hardtail as it's arguable more important. I would be wary of sizing down on modern bikes unless you really prefer manualling over rollers and out whipping your mates on table-tops.

So, getting the most out of a modern bike may seem like a minefield BUT you've got to remember it WILL feel very different to start off with and altering bar roll, saddle position for and aft and to a certain extent stem length can all make a very noticeable difference.

It's a pretty cool time to buy a new bike, it's a just a shame demo's are difficult at the moment. If you do get to demo one, a car park ride will tell you jack. You need to ride some trails you know well and tackle some familiar climbs and descents.
The difficulty of demoing is definitely a problem right now.

For the Geometron, do you find that the bike that fit you is still close to your RAD measurement (if you've ever checked that)? Or is the longer bike simply longer in many ways?

I've got a giant spreadsheet of bike frames that I'm looking at (usually in L, and XL, as I'm between sizes most of the time). I recently added my measured RAD, and did my best to calculate it. And what I'm finding, is that on "most" bikes, I can get them to fit me correctly. But it might mean a 50mm stem and a 38mm riser bar on the size L, while the XL model would have me on a 35mm stem and 15-25mm rise bar.

But mostly that is making me (currently) think that sizing by RAD may be best, and then "dealing with the cramped climbing position" for the rest of the time.
 

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How do you ride the bike? fast glued to the trail , climb steep? or jump all , spin 360 ? never use granny and use chairlift ?

for average riding the longer/slacker/longer CS the better, since it is safer, more stable, more planned feel
29 wheels allow riders to have more bb drop which leads to stability ;

RAD is great starting point however I found all of Lee recommendations way of either bar width or RAD and RAAD based on apex index of the tallish people, however applicable more for 5'8-5'10 majority of population
 

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^^^I have a Honzo ESD (63 deg HA and 490mm reach) and it climbs just as well as any XC bike I’ve ever owned, including tech climbs. The only difference is that it’s heavier, but part of that is how I have it set up.

The longer reach numbers you see now is to compensate for the steeper seat tube angles in conjunction with slack head angles.

I used to think the flip-flopping, poor climbing characteristics of my old freeride bikes was because of their slack head angles — but I now realize it was more because of the slack seat-tube angles. My Honzo climbs and descends like a rocket.

Absolutely no downsides to having the 63 HA.

However, the 490mm reach is a bit excessive for me at 5’10” — I’d like it a little better at 475 to ease initiating a manual. Not a deal breaker though.
I got a custom steel hardtail made. I am 5'11" - 160mm fork, 470mm reach, 63HA, 76 ST. It's killer. Thing I notice the most compared to my custom "downcountry" hardtail, is that it just doesn't want me to push it as hard on the ups. It does it fine, but doesn't urge me to pedal harder up hill.
Bicycle Tire Wheel Sky Plant


440 reach / 66HA / 75 ST
Bicycle Tire Wheel Bicycles--Equipment and supplies Bicycle wheel


Each bike is good at different things. Flatter routes without as much jank / longer rides - yellow bike. Up and then straight down, where descending matters more than all around I'll take the green bike (it it is no slouch on the flatter routes, just doesn't excel like the yellow bike.)
 
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