Posts
1329
Joined
8/1/2009
Location
IL
Edited Date/Time
2/23/2019 6:16am
With the mountain bike industry fully in the grips of the "lower longer slacker" fever, it's easy to lose perspective and get carried away by the hype sometimes. For example, when we recently posted an article about Canyon's new Strive, we were somewhat taken aback by the number of comments on social media calling the bike out for being "not slack enough". At 66 degrees, this 29er was even labeled "unridable" by some particularly vehement keyboard warriors. This stood in stark contrast to our experience with the bike on the trail, which should come as no surprise to experienced riders who know that the whole of the bike is always different to the sum of the parts no matter how good you think you are at reading geo charts. Also, in some of our recent testing we found a few bikes with just slightly steeper head angle to be a bit easier to ride and a whole lot of fun on a great variety of trails. Maybe that 64-degree head angle looks good online, but do you actually have the trails and/or the skills for it? Not that many years ago, proper enduro bikes had a 67-degree head angle and once you went under 66, it was DH bike territory. We're not so crusty as to want us to go back in time (we love our dropper posts too much!) but there does come a point where a lot of people are probably best served by a little less extreme angles. With all that said, what are your thoughts and experiences? Have you gone super slack only to then backtrack? Have you embraced the stretch geo and the super slack head angle? Vote and discuss!
(Yes, we do realize that this question is a bit strange in isolation, given the large number of other variables in frame design and intended use and all that, but we still think there is merit to discussing it in its own right.)
Poll
Currently on the new GT Sensor (130x130)* as my trail bike.
Granted the bike is a custom build, one of the first things I wanted to do was bump the fork up to 140mm. This effectively changed the HTA from 65.5°(130mm Fork Travel) to 65°(140mm Fork travel). (low positioned flip chip). See some notes I just wanted to put that disclaimer first and foremost.
*Geo Context (Based with 140mm fork):
140mm Front Travel, 130mm rear
65° HTA, 75.5° eSTA
470 Reach, 435 chainstay length
35mm spacers under stem(including bearing cap), 40mm stem length, 780 x 25mm rise bars.
So far I really enjoy this bike in its current setup. The fork change slackened my eSTA a touch but it doesn't really affect my opinion of ride quality. (It's a rocket ship when pointed down hills. I'm not the fastest nor fittest guy going uphills so optimal pedal efficiency doesn't weigh too much in my book).
Here in the New England (US) its quite rocky/rooty and this time of year the frozen dirt mixed with some wet leaves is generally the norm. That being said with the 140mm fork I openly welcome the added BB clearance while simply pushing the seat forward alleviating at least some of the slacker pedaling position (76° to 75.5° eSTA with the larger fork (Again, bike lives in low flip chip setting).
I'm sure that a steeper HTA and eSTA may make a more efficient handler on paper but having a pedal-able bike on the slacker side that is still perfectly at home pushing the limits on descents really plants me firmly on the slacker side of this debate. If you made it this far, I applaud you.
TL;DR - I'm very much enjoying a slacker trail bike. Descents are always more fun than climbs. Even on a 140x130 29er.
Pike 29" 140mm axle-to-crown: 541
Moving to a 150mm fork might be worth a look as well.
Pike 29" 130mm axle-to-crown: 531
Pike 29" 150mm axle-to-crown: 551
64 degree 160/150 travel
65 150/140 travel
But its all dependant on the reach number being spot on too, ive found as I have gone towards longer bikes (im 6ft 3) that the reach (515mm on the trail bike 510 on the DH bike) has given me more ability to really weight the bike correctly, or better anyway. Longer chainstays would be a bonus.
I rolled my eyes at canyon's 66 headangle on a 2019 enduro race bike, especially considering the shapeshifter.
But... The slackest enduro bike I have owned is my commencal meta with 66, my previous 2 bikes were 67, always with a 40mm stem.
Hoping to get down to 65 for the next one: don't think you will gain much descending ability going lower, but climbing and slow speed should start to suffer beyond that.
That said, I'd like to suggest mountain bikes will eventually figure out what moto figured out 30 years ago. 63-64 is good for just about everything.
Get offset right, get the rest of the bike's geo right and I could see a time where XC bikes have very similar geo to enduro bikes.
"But it'll wander while climbing" - no, not really, you just need to get used to how a slacker bike handles going uphill
"But the front tire will come up while climbing" - not with appropriately sized chainstays
"But it'll only be good in the steep stuff" - Not once you learn to weight the bike properly.
Anecdotal Proof: The best handling bike I rode in 2018 was the Stumpjumper Evo. I smoked more uphill KOMs on that bike than any other bike I've owned in the last 3-4 years. Raced XC and did well. Was faster on any kind of single track on this bike. The bike had other shortcomings (stay tuned for the full review) but yeah, my YZ250 handles well in the woods, and so does a mountain bike with the same headtube angle...
On the more serious note, a little more food for thought here: suspension forks (at least the current ones) tend to work better when they get to absorb impact forces along the direction of the stanchions. Hits that deliver force at an angle can lead to bushing bind issues.
So what if the real magic pill isn't to make a bike longer AND slacker, but JUST longer? Push the reach out, and then bring the head angle back just a tad? That will keep the wheelbase in check which is probably a good thing for many riders, AND it will allow the fork to work more along its preferred direction of travel. Once the reach has been made long enough, you don't need all that head angle to help keep you centered in the bike, you've already taken care of that issue with the length. Now you can move forward in the bike and put your weight above the front wheel, with the fork at the right angle to deal with the terrain. Like I said, food for thought (which is the point of having this discussion).
And to point out the obvious again...it does of course depend on all those other things. If you care about bar height then you can't have the same head angle for a 150mm fork and a 180mm fork, that kinda goes without saying. But the real underlying question here is whether or not we've reached (or gone beyond) the optimum baseline head angle for enduro and trail bikes already?
Try it.
There will be a special sauce ratio between reach, rear center, head angle, STA (for climbing) and bb height that'll make for magical handling.
I do think people need to throw out the preconceived notion that "this wheelbase is too long, short, whatever" - again, i go back to moto - I watch dudes do things on far longer motos in tight terrain that the internet would say "that's fake news".
Don't worry about length. Worry about figuring out how to get a bike to handle, then build the rest of the measurements around your body.
My $0.02 - 63.5 deg HTA, 35-40mm offset, 40mm stem (depending on stack/bar height)...Then get your reach and rear center to compliment...which is really the tough part of the equation.
On another note please stop saying bikes are getting slacker, longer and lower. Most bikes are getting slacker and longer but not lower. We have already figured out what is too low a while back. I don't see any 300mm bb heights on any full suspension bikes do you?
I'll agree if you throw a 63ish HTA on a bike that isn't well balanced (too much rear bias) it sucks. But if the stays are the right length for the reach, offset thought about appropriately, I find a slack bike rails corners no matter how flat (or steep) the terrain.
If I was wrong, wouldn't moto bikes have steeper HTAs? They are always going around a flat track...
I do agree with you that mountain bikes are taking a hell of a long time to figure out what motorbikes figured out years ago geometry wise. This is why I laugh when people say Pole and Nicolai/geometron are too extreme. All the big brands are playing catch up and we see that when every year the same model trailbike gets longer and slacker. It makes me question whether or not they even test geometry at all...Pole and Nicolai/Geometron don't keep going longer and slacker because they have pretty much figured geometry out (aside from seat tube angle which they have been making progressively steeper).
I don't think that is the case any longer. The reason we felt that way is the bikes were (and many still are) very rearward bias. Hence going to a slack HTA makes it harder and harder to properly weight the front tire. See also: my silly chainstay thread.
If stays are appropriately sized, reach appriopriate too, you won't have to ride with the bars in your belly to weight the front tire on flat ground.
As far as what you said about a dirt bike, you are actually wrong, they get slacker under sag, not steeper. The front fork (or forks lol) does compress both statically and when the rider sits on it, but the rear end's sag is far greater. I can measure, but I'd wager I'm actually riding at a HTA that is less than 63.5 on trail on my moto.
800mm bars have done a great job of stabilizing a front end at speed, while a steeper HTA allows a lot of side to side play on the trail.
But I like to have fun on trails, I don't need to go faster in a straight line and make a trail boring.
Racing is different as it's 100% speed, 100% of the time, which is more plow bike territory.
Maybe mixing Enduro with Trail bike in the original question is too broad.
P
But you're right, I probably should have used at least 8 question marks to be noticed by Iceman!
On my trail bike I've a 66 degree HA. It works fine on flatter trails, the bike doesn't need to be leaned to get around the corner. But doesn't let me down on extremely steep stuff either. But the 64 degree HA on my enduro bike does give me a lot more confidence on that steep stuff. On flat trails, the enduro bike is a hand full to get around the corner. Both have the same reach.
My current daily riding bike is 64.5 degrees
depends
https://enduro-mtb.com/en/best-enduro-bike-you-can-buy/
Can't wait for vital test!
Post a reply to: Where is the Head Angle Sweetspot for Enduro/Trail?