Which would have the slacker head angle?

I have a set of coil spring 140mm Sektors and a choice of building them up with either an On-One 456 Evo or a mk1 Dialled Alpine.
Most of my riding is now the fun downhill stuff, uplift days at Bike Park Wales, FoD etc etc so I’d like to build the one with the best angles for this riding…. anybody know which frame will be slacker with this fork?

Evo is a 16 inch and the Alpine is 17 inch if that helps.
Cheers.

Never seen the Alpine before, but 456’s are like a plow at the front.

just to complicate things.

we like slack head angles for Dh stuff as it means the front wheel is further out in front, which helps maintain a roughly-in-the-middle forward/backward weight balance, when a mincy xc race bike would simply pitch you over the handlebars.

however, you get more or less the same thing from a long top-tube, or ‘reach’ is a more meaningful way to measure the same sort of thing.

the benefit of a using a long top-tube instead of just a slack head angle to get your Dh friendly weight balance is that you avoid the floppy, weird, heavy steering on slow/techy trails.

use wide bars to slow the steering down a bit. use a short stem to make a normal cockpit.

i’m not saying which bike is best, just that’s a wee bit more to all this than head angles.

But slack head angles give better steering at speed, long top tubes don’t do this.

i’m happy to believe that a 65 degree head angle is absolutely crucial to staying alive at 50kph.

but making a decision as to which hardtail frame to buy, simply on the slightly slacker head angle, is a little silly.

slack head angles may feel better at speed, but they’re rubbish at everything else.

in other words, a 456 evo, and an alpine, are both great. you may prefer one over the other, but it’s just possible that any preference is down to something other than head angle.

A quick comparison from available online figures tells us (16″) only;

1- 456 has a longer effective TT (Although the 18″ Alpine is almost as long as the 16″ 456)
2- 456 has a Slacker HA
3- 456 has slacker Seat angle
4- both bikes have about the same length chainstays…

for your 140mm fork OP I’d knock ~1/2 a degree off the Alpine and add ~1/2 a degree to the 456 angles perhaps, but the difference remains about the same obviously…

From the numbers, I’d expect the Apline to climb a smidge better and still be a confident, perhaps more “Nimble” handling bike on technical stuff, by comparison I’d expect the 456 to be more stable at speed and on steep sections…

Static HA means a minimal amount for HTs really, because that’s just a number, as soo as you sit on the thing and the fork sags, that HA starts to change.

ahwiles point about TT makes good sense, a Slack HA puts the front wheel further out front, to help with stability and prevent that “wheel Tucking under sensation on steep sections” but a longer TT goes some way towards achieving this also, the 456 Evo has a longer TT (Size for Size) and a slacker HA, so you’ll get a longer, more stable, DH bike-esque wheelbase from it, but those are not the only factors affecting how a HT rides…

If it’s for DH use only? I’d plump for the 456 (cheaper too), if you do want to be able to climb a little more and have a more “Alrounder” type of a bike Maybe think more about the Alpine.

*Declared interest: I am a happy 456 owner…

I should clarify, the Evo is already built up and the Alpine frame is under my bed doing nothing.
Just curious as to whether I should swap everything across onto the Alpine or just sell the frame.
Seems the 456 has the more modern geometry that suits what I ride, certainly I’ve enjoyed every ride I’ve had on it and never felt out of my depth even on really steep stuff….

… anybody want a mk1 Alpine in purple?