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So, have sold the Hardtail and doing the research on my 50th birthday gravel-bike-with-big-clearance present to myself ... which has been the subject of another thread elsewhere ...
And also been reading today's GritCX 'first look' at the Rondo Ruut, with its 'flip chip' that can slacken/steepen the geometry by a whole half-a-degree ...
And I got to wondering why is no one making a #dirtydropbargoodness bike with (approaching) modern trail MTB geometry?
'Slack' drop bar gravel bikes tend to be 70-71.5° head angle ... Which is not very slack in MTB terms at all.
So, why can't we have something with say 67/68° ... and what would happen if we did? How would it ride? And if combined with 2-2.2" 650b tyres, wouldn't it make that a reasonably competent off road weapon?
No need/point for something not ridden technically/steep stuff
Ps time for a new login LOL?
Look at Jan Heine's writings on 650b geometry. He's 'out of step' with current thinking regarding trail etc.
A friend is about to receive a custom disc 'all day' gravel drop bar bike based on that thinking.
But, it could be ridden on steeper more technical stuff if they came slacker?
That said, people ride CX/gravel bikes down Ingleborough, Whernside and PyG once a year (me included for the first time this year) ...
It went OK, and I didn't come off.
But, for that kind of event, and for some of my local trails that are rideable (but only in a mincing fashion) on such a bike, slacker = better, right?
(I clocked that I'd need to change my username too!)
Why not ride a rigid MTB?
They don't need to be slacker. I ride a parallel 73 degree frame off road and it is fine, I ride mostly gravel but also a bit of singletrack. I like the responsiveness of it and wouldn't want to change it at all.
The limitation when it gets very technical are the relatively narrow and low drop bars and relatively skinny tyres compared to an MTB combined with a lack of suspension. The frame angles are really not the thing that needs to change if you want to ride knarlier stuff.
The point of a gravel bike is that it's rubbish at offroad, surely? Just like a cross bike. Ideal for riding along fire roads and round fields. If you want something more capable offroad you wouldn't start with the head angle, you'd put proper tyres and bars on it
But, it could be ridden on steeper more technical stuff if they came slacker?
Sort of but not really, generally. I've tried it, I've had a few frames and forks made with ideas like this in mind, over a few years now.
Conclusion is that drop bars don't work with the handling that slack angles give. A drop bar bike isn't an MTB and you don't handle it in the same way. If a drop bar bike becomes much better off-road (within the limits of a 460-550mm bar or a more road/XCO position on the bike) it then feels poor on road - hairpin corners for example where you're too high up / back to start with and where you need weight on the front wheel since you can't rely on breaking traction at the rear like you can off-road. Cornering and handling the 2 types of bike largely starts with the bar and general positioning and no geometry changes fix a low-ish drop bar that works on road to make it a good off-road bike. imo if a drop bar bike is poor on tarmac, who cares how good it is off-road, an MTB will be better.
The point about Jan Haine's low trail stuff is sort of valid but that's more about carrying a load on the front only, allowing skinny tubes for frame flex. Not a fan of either here, low trail isn't a fix for having weight pivoting around the steering axis and on soft ground it's not good for handling imo - the fact that they like them so much shows how personal all this stuff is though. The issue I have with it is the weight of the bag doesn't really change what's going on at the steering axis and contact patch, stuff going on that I'm not into : )
Edit to add, try riding the ruts of the Ridgeway at speed on drops with a slack feeling geometry, it's almost impossible as the wheel wants to flop from side to side.. The sort of experience that makes you remember why nimble, more neutral handling is a good thing.
just swapped from Gravel to CX. headtube steeper (0.5 deg) stays much shorter (25mm). ride is completely different - much more direct less stable.
point is - it's not just head angle.
my Bokeh at 70 degrees, is slacker than my Open XC Bike at 72 degrees
Haha - yes, we know both sides of this new bike. We ride with the owner and herself is in the process of agreeing the build geometry for a steel 650b drop bar frame with the builder.
But, it could be ridden on steeper more technical stuff if they came slacker?
Why not ride a rigid MTB?
Now that 700 x 47c is a preferred tyre width for gravel bikes, you only need to go up one more tyre width, and the only thing stopping it being an old school 29er rigid is the drop bars and groupset brand that's typically seen on roadbikes.
Gravel is about going anywhere. If you want a bike where going down is the important bit and the rest is just a necessary evil to get to the top, then get an MTB?
What are you even talking about?But, it could be ridden on steeper more technical stuff if they came slacker?
You don't need a slack head angle to ride down steep inclines. or to ride technical trails.
Slack head angles are more stable at speed. That's it.
This whole "gravel" thing seems to be made up by american roadies afraid to ride bicycles on a road.
Aren't some of the Whyte adventurecrossgravel bikes a bit more slack and longer reach than others of that ilk?
This whole "gravel" thing seems to be made up by american roadies afraid to ride bicycles on a road.
Wouldn't blame them if they were. It's not a contest to see how much risk you want to expose yourself to. Who cares anyway if the bikes are good?
Quote"Haha - yes, we know both sides of this new bike. We ride with the owner and herself is in the process of agreeing the build geometry for a steel 650b drop bar frame with the builder."
So what are the figures being talked about?
I get the point some are making that why don't I just get an MTB?
I've got MTBs for *proper MTB stuff, and I get that a drop bar bike will be limited off road to some extent by narrow(er) bars and not having suspension forks (and on a more traditional CX bike, narrower tyres)
I've really enjoyed riding my Saracen Hack for the last 4 years, local trails, 3 Peaks CX, Dirty Reiver as well as commuting and the necessary evil of tarmac! I want a better (lighter etc) version of the same that does all those things but is also even more capable off road, without it being a flat bar MTB ...
The trend in MTB geometry in the last few years has been longer,lower, slacker, and I've found this makes them more capable and more confidence inspiring on steeper, technical, rocky/stoney terrain.
I don't pretend to understand the complexities of geometry, rake etc etc, but assumed (maybe naively ... but that is why I'm asking!) that Head Angle is a key factor, and slacker makes a bike more confidence inspiring and capable in the rough stuff ...
So, what I'm asking, I guess, is whether a 68° HA, with 2.2in tyres (and I wouldn't run the bike like that all the time; part of the appeal is being able to switch to 700c wheels with narrower ... even slick (hush) tyres) would be better than a 72° HA with 38mm tyres on an otherwise equivalent drop bar bike?
I traded in my hardtail for a NS Rag+ and I’ve not had any issues riding the same stuff I did previously, albeit a bit slower. It definitely suits me more as I need one bike to cover all my riding due to cash and space restrictions.
Stuck some cowchippers on it and would like to try 650b wheels at some point. One of the most fun bikes I’ve had for ages. Just rides differently and is a tad more frightening off road
This whole "gravel" thing seems to be made up by american roadies afraid to ride bicycles on a road.
53% of american roads are unpaved
There are over 1.6 million miles of unpaved roads (53% of all roads) in the United States.
from here
The 'mercans are also deliberately grubbing up metalled roads and replacing them with gravelled roads. Give it 2 years and we'll be doing the same thing in the UK.
I've just switched from a Saracen Hack to Holdsworth Stelvio tourer. More relaxed geometry, more upright riding position. Very stable compare to the Hack which felt too low at the front door me.
650b conversion has added more off-road capability. Any slacker and I'd probably head towards a rigid 29er.
OP you should listen to this excellent podcast and hear Cesar Rojo's thoughts on xc bike geometry, basically it's crazy they aren't as slack as 'trail' mtbs, applicable to gravel too
You don't need a slack head angle to ride down steep inclines. or to ride technical trails.
Slack head angles are more stable at speed. That's it.
😆
What H/A does a park BMX have Jim?
And what gradient is the first part your wheels roll down as you drop in to vert ramp?
Those of us who learned as kids to ride vert on a BMX have no trouble riding a nice steep short travel dirt jump hardtail down what you 'on trend' #Enduro boys seem to consider steep.
When it gets rough suspension is handy.
When it gets faster slacker Head angles (are just one way to) help keep things stable.