Why modern long-reach bikes do not actually have a longer reach - illustrated

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Why modern long-reach bikes do not actually have a longer reach - illustrated
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flag gth802s
Posted: Feb 1, 2022 at 13:31 Quote
We keep hearing about how modern bikes are longer / slacker / lower, which gives the impression that the cockpit on modern bikes is roomier, as in, there is more reach from the saddle to the handlebar. I wanted to illustrate that this is not necessarily the case using my own two bikes as an example: a) 2013 Scott Scale (69.5 deg HTA, 72.5 deg STA, 422mm frame reach) and b) 2022 Niner Jet 9 RDO (66.5 deg HTA, 76 deg STA, 475mm frame reach). I have drawn both bikes in BikeCAD, and used the middle of the saddle as a common reference point. Both bikes have the saddle clamped in the center on a zero-offset seatpost. Also, I have drawn the Niner as a hardtail out of laziness :-)
Scott Scale Geo
photo


Assuming your butt will sit on the same spot on the saddle, the sum of the two measurements shown on the top can be seen as a proxy (let's call this proxy reach or PR) for "effective reach" from the saddle to the handlebar. For the Scott, which has a frame reach of only 422mm, the PR is 708mm with a 90mm stem (typical for bikes of this vintage) while for the Niner, the PR is 680mm with a 50mm stem (also typical for modern bikes). If the Scott had a 50mm stem, it would still have a PR of about 670mm, only about 10mm shorter than the Niner, even though on paper it has a 53mm shorter frame reach.

As the images show, steepening the STA has the effect of having the rider sit closer to the BB center on the bike, and necessitates a longer reach; otherwise, the bike would be incredibly cramped. This is further exacerbated by the slacker HTA, which also has the effect of bringing the handlebar closer towards the rider, which needs to be offset by increasing the reach once again (though the effect of the HTA is not as severe as the STA).

Of course, having a steep STA has the effect of centering the rider better which is advantageous on both steep climbs and technical descents, while slackening the HTA offers a much longer front center for better downhill stability. For most riders, this is a good thing. But having your body that far forward also has the effect of putting much more pressure on the hands and putting the rider in a less-than-ideal pedaling position, which is not ideal for those who spend long days in the saddle pedaling (longer XC / marathon rides). I tried doing a 3-hour XC race on my Niner once, and it wasn't pretty. This is not as much an issue for shorter rides / races.

So in short, frame reach is not the same as effective reach from the saddle to the handlebar, and modern bikes have a longer frame reach out of necessity to compensate for steep STA and slack HTAs. Just thought I would share.
flag Gravelben
O+
Posted: Feb 1, 2022 at 14:21 Quote
Yip, plenty of people misunderstand what reach means.

The saddle/seat tube is not relevant to a reach dimension, reach is essentially the standing cockpit length. I use reach+stem as a proxy for effective reach when comparing bikes.

The dimension relevant to seated length on geo charts is 'effective top tube' (though seat height x STA influence effective seated length too).

A mate was second guessing himself for the same reason trying to choose a size when he upgraded from a Trek Roscoe to a Trek Fuel EX - his M Roscoe has a very short reach of 410mm, with a slack 70.8 STA giving an ETT of 625. After test riding he ended up with an ML Fuel, 460mm reach (which he had worried would be too big) but 75.5 STA gives an ETT of 618, slightly shorter seated length than the Roscoe despite the much longer reach.


And then there is stack, which a lot of people don't even seem to think about but is just as important as reach to me.
flag noideamtber
Posted: Feb 1, 2022 at 14:29 Quote
Gravelben wrote:

And then there is stack, which a lot of people don't even seem to think about but is just as important as reach to me.[/B]

100%%% stack and ETT are what i usally look at before reach these days.

And the relationship between actual reach and CS, many tall people dont like short CS but its more because reach is very long.
flag Gravelben
O+
Posted: Feb 1, 2022 at 15:23 Quote
noideamtber wrote:
Gravelben wrote:

And then there is stack, which a lot of people don't even seem to think about but is just as important as reach to me.[/B]

100%%% stack and ETT are what i usally look at before reach these days.

And the relationship between actual reach and CS, many tall people dont like short CS but its more because reach is very long.

I do check reach before ETT, I don't want to be too stretched out or too cramped while descending and I know I can make a fair difference to seated length by adjusting saddle position.

But I find it easier to adjust my riding position to a longer or shorter reach than a low stack - relatively long legs and short torso for my height so I prefer a high stack, I usually end up swapping to a higher rise bar on most bikes anyway.
flag noideamtber
Posted: Feb 1, 2022 at 15:28 Quote
Gravelben wrote:

But I find it easier to adjust my riding position to a longer or shorter reach than a low stack - relatively long legs and short torso for my height so I prefer a high stack, I usually end up swapping to a higher rise bar on most bikes anyway.

Exactly the same as me haha
flag huvudvind
O+
Posted: Feb 1, 2022 at 15:47 Quote
Gravelben wrote:


And then there is stack, which a lot of people don't even seem to think about but is just as important as reach to me.

but you can change your stack up to +50mm for the price of handlebars you cant change reach on most bikes without changing the geometry of the steering lever
flag noideamtber
Posted: Feb 1, 2022 at 16:09 Quote
huvudvind wrote:
Gravelben wrote:


And then there is stack, which a lot of people don't even seem to think about but is just as important as reach to me.

but you can change your stack up to +50mm for the price of handlebars you cant change reach on most bikes without changing the geometry of the steering lever

Everybike needs adjustable headsets, they dont for the sake of the next years model "new angles" blah blah
flag huvudvind
O+
Posted: Feb 1, 2022 at 18:42 Quote
pvd666 wrote:
'Frame reach' is not a driving parameter.

https://www.peterverdone.com/frame-reach-isnt-a-driving-dimension/
okay old man
flag gth802s
Posted: Feb 1, 2022 at 19:49 Quote
ETT - effective top tube, at least the way it is conventionally defined, also does not account for the seat tube or head tube angle. However, it does work better to compare two different mountain bikes in terms of handlebar reach because unlike road bikers who try to keep the saddle in the same position relative to the BB between bikes with differing STAs (by using different offset seatposts), mountain bikers often don't care about this and just run a zero-offset seatpost (mainly because dropper seatposts only come as zero offset). In the example I have given here, the Niner has an ETT of 631 mm and the Scott 620 mm. If we do the trick where we add the stem length to the ETT, the Niner would be ~680 mm and the Scott would be 710 mm.

Frame reach is indeed not a driving parameter; it is also one that is very misunderstood :-)
flag Kidklayko
O+
Posted: Feb 1, 2022 at 20:06 Quote
Yes, but there is definitely a difference handling-wise for reach, My old HD3 has a 431mm reach, compared to my Ripmo which has a 475mm reach. Due to the longer reach, I ride in a more balanced position and have a greater range of movement. Additionally, due to the longer reach and ETT, I can run a shorter stem, which can result in different handling. This is not true that long reach bikes are not longer though, the wheelbase is increased heavily with a longer reach. Yes the cockpit dynamics remain the same but standing up downhill the bike is much longer.
flag Gravelben
O+
Posted: Feb 1, 2022 at 20:22 Quote
huvudvind wrote:
Gravelben wrote:
And then there is stack, which a lot of people don't even seem to think about but is just as important as reach to me.

but you can change your stack up to +50mm for the price of handlebars you cant change reach on most bikes without changing the geometry of the steering lever

Yip, but for an example:

I have a M Reign 29, 455 reach / 619 stack. I'm running a 40mm rise bar, so stack+rise of 659mm (plus spacers, but lets just assume the same spacers to keep it simple). Before that I had the same 40mm rise bar on a M Trance 29 (442 reach / 612 stack), but with a 10mm longer stem, not exactly the same but a pretty similar fit for both.

I spent a day at a bike park on a rental L Remedy, similar reach at 459 but only 596 stack. Internet says it has a 27.5mm rise bar, so stack+rise = 623.5. I didn't get on with it well at all, just didn't fit me and felt like I was getting pulled forward a lot and bucked on jumps. Had to hold a rather tiring deep squat position to feel balanced on the bike downhill.

To get a combined stack+rise on a Remedy that I'm comfortable with (assuming the same steerer length for spacers), I'd need 60mm or so of rise. I'm not sure if MTB riser bars that tall exist, but they probably look silly if they do.

So I wouldn't buy a Remedy because it isn't a good fit for me, even though the reach part of the equation is ok.

Don't get me wrong, I wouldn't buy a bike with a reach too far outside my preferred range just because it had a good stack either - just saying both need to be in the right range (close enough to adjust with cockpit setup etc).
flag gth802s
Posted: Feb 1, 2022 at 20:23 Quote
Kidklayko wrote:
Yes, but there is definitely a difference handling-wise for reach, My old HD3 has a 431mm reach, compared to my Ripmo which has a 475mm reach. Due to the longer reach, I ride in a more balanced position and have a greater range of movement. Additionally, due to the longer reach and ETT, I can run a shorter stem, which can result in different handling. This is not true that long reach bikes are not longer though, the wheelbase is increased heavily with a longer reach. Yes the cockpit dynamics remain the same but standing up downhill the bike is much longer.

What makes modern bikes longer mainly is the front center, which is achieved by slackening the HTA and increasing frame reach. As I mentioned before, the increased reach is a necessity when steepening the STA otherwise the bike would be incredibly cramped. And while a longer front center is great for descending stability, it is not so great if you want a bike that turns very well. Shorter stems do not make up for a 3-degree slacker head tube angle; go ride an older XC bike with 70 deg HTA and it becomes apparent very quickly how much easier that bike will want to turn, even with a longer stem. It is one of the things I love about my Scott, how well it goes around tight turns and twists.

The feeling of being able to "move around easier" on a modern bike has to do with the forward seating position (steep STA) that promotes a more open hip angle combined with increased frame reach. While that has advantages of having the rider be more centered on the bike and works better for steep climbs, it comes at the expense of a compromised seated pedaling position and more weight on the hands. There is a reason you do not see 76 degree STAs on road bikes, where a premium is placed on seated pedaling efficiency (tri bikes are a different story altogether).
flag justwan-naride
Posted: Feb 1, 2022 at 20:54 Quote
A point that I think is missing from this conversation is dynamic geometry and where mtb's are used. Apart from pure racing XC bikes, almost everything else has some influence from enduro (racing, or your average weekend ride where you just climb for the descends). Steep seat angles appeared to counterbalance a sagged rear suspension and a steep incline. The concept is to put the rider in a relaxed and comfortable position for the uphill leg of the ride/race. Then you have the descending position where the rider is standing and reach/stack are the important measurements. It's true that this usually means a somewhat compromised pedalling position during flat sections, but you don't usually find these when riding in the mountains.

Currently the ETT of the most progressive brands appears to be too short compared to a few years ago. We will see whether this balances out in the next few years. Waiting on a new frame myself, so will soon have a taste of the latest geo trends.
flag noideamtber
Posted: Feb 1, 2022 at 21:10 Quote
ETT for me on a large HAS to be closer to the 610 mark where as alot of other bikes are 640+ i instantly notice this when i sit on a bike. i will not own a bike over 640 thats just dumb long.

stack and ETT effect my "comfy" position when just cruising up the hill ie sitting and spinning (i dont care for efficiency and tbh im more efficient when im comfy)
Stack/reach/hta are my confidence numbers when heading down.

If i was to create a Large size Good fun bike, thats comfy to to get up the hill, bomb back down with plowability while remaining fun and poppy... 100% i would pick the Marin alpine trail numbers.
Everything on that bike including spec is perfect, ie Threaded BB, low ratio, progressive and low price.

I demo'd an XR version, if i was blind folded i easily would of thought that was a botique brand with Factory kit worth 10k.

Only thing that lets that bike down is Frame QC, terrible.
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