Slack head angle myth, geometry voodoo and the inevitable Cotic Soul

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Slack head angle myth, geometry voodoo and the inevitable Cotic Soul

66 posts & 43 voices | Started 5 months ago by hock | Latest reply from ijs445ra

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hock - Member

Hi there,

today I finally came to grips with what I don't like about long travel slack head angle hardtails.
BUT I still want to understand what the hype is all about. Maybe I missed the point.

First of all quick background: I am a cross country type of rider but want it to be FUN rather than just a mere exercise. I love a 2h blast of tight and twisty singletracks in the local woods. It's just great to flic-flac through the twisties and swing the bike through s-bends. I don't mind to bunny hop a log but I am not a jumper and I don't have a clue what a rock garden looks like. I want a bike to be taut and compact with round and natural steering and a neutral grip balance. I'm used to conventional 71/73° 80mm travel 100mm stem cross country geometry. In theory I like the "long top tube/short stem" part of the UK hard tail concept as I expect it to deliver more direct steering.

THE SLACK HEAD ANGLE GEOMETRY PART

Testing a 68.5° 130mm front travel 70mm stem hardtail (and yes I know that all other variables of the geo are important, too) I found it - once again - fairly irritating that the front-end felt so detached, loosing traction and going wide. For my liking the front wheel was too far ahead of me, not "under" me, not under control, being in (and almost through) the bend before I lean into the bend, tilting into the bends rather than steering aROUND it.

OK, so am I the only one who doesn't get the "long travel slack head angle" magic?
Or is the 71/73° convention just better suited for my type of riding?

THE COTIC SOUL PART

I am asking out of interest and because I could get my hands on a Cotic Soul frame. People say it has it's sweet spot with 120mm (69.5° HA), is OK for cross country racing with 100mm (70° HA) and would be far too twitchy with 80mm (71° HA?!).

What's your experience with 100mm travel on a Cotic Soul?
Do you reckon it would still feel too "slack" for my type of tight'n'twisty singletrack riding?

Has anybody experience with 80mm travel or equivalent rigid forks on a Cotic Soul?
Is it too twitchy? Or maybe just perfect for me?

I know, in the end I will have to find out for myself (and I am happy to share my experience here when I am through with it). But to have some of your insights and benefit from your experience might spare me a few steps and some money (buying/not buying the Soul, buying 80mm or 100mm forks).

Many thanks for any input!

Hendrik

P.S.: Or is there a fun and agile 80mm travel steel frame alternative for my case?

Posted 5 months ago #
davidtaylforth - Member

OK, so am I the only one who doesn't get the "long travel slack head angle" magic?

No. Running a hardtail with a 140mm fork pretty much ruins it as a bike that you can ride properly.

I have a Cotic BFe (it has the same geometry as a Soul) and I run it around 100 - 110mm. It rides really nicely. The ideal bike for shortish forks. Go for it.

Plus you have the option of being able to change the forks to 140mm and ruin your bike if you feel the need to

Posted 5 months ago #
seanoc - Member

Sounds like you hang off the back rather than load the fork; that'll make the front end wandery. I had a Soul and it felt perfect with 120mm forks, wound down to 100mm they would tuck way too quickly. I've got a Simple now with 440 rigid forks on and it feels okay (but only because there's no dive); ideally I'd like a longer rigid fork.

Posted 5 months ago #
davidtaylforth - Member

I dont think I've ever found the "tucking under" a problem with mine at 100mm. I think my forks are pretty hard though so that could be why?

Posted 5 months ago #
oxnop - Member

I ride a soul.

It rides best at around 120mm, I rarely run it at 140mm as it fells dead on most but the steepest techfests (where I'd prefer my FS anyway) . Rides perfectly well at 100mm though.

Posted 5 months ago #
Del - Member

what width bar do you use? a wider bar will pull your weight forward with a short stem, putting more weight back over the front wheel. i just ask because if you've been riding xc for a long time you may be very accustomed to narrow , <650mm, bars.

Posted 5 months ago #
Scamper - Member

Recently started riding a Soul, currently with lightish 100mm forks and 75 stem. Not twitchy at all, in fact perfect for the very tight and twisty singletrack I largely ride at the moment.

Posted 5 months ago #
Northwind - Member

hock - Member

I am asking out of interest and because I could get my hands on a Cotic Soul frame. People say it has it's sweet spot with 120mm (69.5° HA), is OK for cross country racing with 100mm (70° HA) and would be far too twitchy with 80mm (71° HA?!).

What's your experience with 100mm travel on a Cotic Soul?
Do you reckon it would still feel too "slack" for my type of tight'n'twisty singletrack riding?

Well, for racing the first obvious comment is that it's not all that light. I loved my Soul, but I wouldn't really consider it a sensible base for an XC race bike (I did race XC on it, but I'm slow and unfit so it didn't really matter)

At 100mm it was certainly agile but I almost never ran it so short, 120 was much more to my taste. It's not a slack angled bike but you obviously like steep bikes so it's possible you won't like it for that reason.

Posted 5 months ago #
crotchrocket - Member

you may as well describe your favourite food as curry, then ask the internets if you will enjoy a kebab.
any of the above combinations will work to one degree or another. I think you just needs to try them & see what you actually get on with.

Posted 5 months ago #
Ewan - Member

You've not ridden a slack bike for one thing... 68.5 is not slack. Slack starts at 67... 65 would be slack!

Posted 5 months ago #
BadlyWiredDog - Member

Hi there,

today I finally came to grips with what I don't like about short-travel steep head angle hardtails.
BUT I still want to understand what the hype is all about. Maybe I missed the point.

First of all quick background: I am a northern, trail-riding type of rider but want it to be TERRIFYING rather than just a mere exercise. I love a 2h blast of rocky, steep techy stuff up on the moors. It's just great to pop the bike over bed-rock steps and finesse my way down steep, rocky, staircases. I don't mind a bit of flat, twisty singletrack, but I'm not an XC racer and I don't have a clue what a wood looks like. I want a bike to be stable and robust with real composure on steep stuff, be good on steep, technical climbs and capable of blasting down rubble fields without heading for the scenery. I'm used to slack head angles and steep seat angles with a long-ish top tube and a short stem. In theory I like the sharp-steering bit of racer-ish hardtails as I might be able to go round tighter corners if I find any.

THE STEEP HEAD ANGLE PART

Testing a 71˚, 80mm front travel 120mm stem hardtail (and yes I know that all other variables of the geo are important too, too) I found it it - once again - fairly irritating that the front-end felt so ridiculously unstable on anything steep, over-reacting to steering input and feeling incredibly nervous. For my liking the front wheel was tucked too far in, not "in front of" me, not under control, hitting loose rocks knocked it sideways way too easily and on anything steep, the combination of twitchiness and short travel made the bike quite unstable feeling.

OK, so am I the only one who doesn't get the "short travel steep head angle" magic?
Or is the 66/73° convention just better suited for my type of riding?

I like the "long top tube/long stem" part of the UK hard tail concept as I expect it to deliver pints of semi-skimmed milk regularly and maybe the odd box of eggs.

THE COTIC SOUL PART

I am asking out of interest, but if I put a Boxer on a Cotic Soul would it still be too steep for my type of riding? What if I stuck a 29er carbon race fork on the back end, grew flowers from the head tube and called it Agatha? Has anyone done that? Would it feel ideal for my type of riding or would it make more sense to simply buy a frame designed to do what I want it to?

Ultimately I shall find out for myself, but it might save me a few trips to the florist if anyone else has already tried it. Why would anyone put a pug-ugly dog on a steel bike anyway?

Many thanks for any input!

Cecil

ps: Is there a fun and agile luggage trolley for my case?

Posted 5 months ago #
hock - Member

Many thanks! Summary of the above steers me to give Soul with 100mm a go.
(one should have ridden a Soul at least once anyway and if it's just to be able to have a halfway qualified opinion on what seems to be a third of the forum topics)
Would still be interested in 80mm (or rigid) fork experience!

@seanock: a 440mm rigid fork resembles travel adjusted 80mm suspension fork, right? So if that rides OK (is that quite OK or actually just bearable?) but 100mm suspension fork was too twitchy you must have had a lot of dive?

@Del: I do ride 600mm on my trusty old Xc steed indeed bike tested had 670mm though but I will take into account that wide bars can pull me a little forward for future set-up

@Northwind: 2kg Soul is absolutely OK light by my standards and while I don't mind racing once in a while that's not the priority for the set-up, same here: level of fitness doesn't justify fine-tuning the bike for race results

@crotchrocket: well, if I like curry chances are that I'm fine with kebab (both spicy/oriental) while bored with bangers and mash so I might actually get steered into the right direction

Cheers so far!

Hendrik

Posted 5 months ago #
metalheart - Member

I've run my soul at 100mm and in some ways that's my preference. Currently riding at 120mm coz I'm too lazy (or scared to take the forks apart) to drop them (F120's).

It's certainly not what i would call twitchy at 100mm. I find even at 120mm that it's wandery on steep ups, so no may I'd run higher than that personally. This might be coz I'm 6' riding a medium with layback pin and 70mm stem.

Ive never run it below 100mm as I haven't had forks that small for over 10 years...

Posted 4 months ago #
skywalker - Member

Hi there,

today I finally came to grips with what I don't like about short-travel steep head angle hardtails.
BUT I still want to understand what the hype is all about. Maybe I missed the point.

First of all quick background: I am a northern, trail-riding type of rider but want it to be TERRIFYING rather than just a mere exercise. I love a 2h blast of rocky, steep techy stuff up on the moors. It's just great to pop the bike over bed-rock steps and finesse my way down steep, rocky, staircases. I don't mind a bit of flat, twisty singletrack, but I'm not an XC racer and I don't have a clue what a wood looks like. I want a bike to be stable and robust with real composure on steep stuff, be good on steep, technical climbs and capable of blasting down rubble fields without heading for the scenery. I'm used to slack head angles and steep seat angles with a long-ish top tube and a short stem. In theory I like the sharp-steering bit of racer-ish hardtails as I might be able to go round tighter corners if I find any.

THE STEEP HEAD ANGLE PART

Testing a 71˚, 80mm front travel 120mm stem hardtail (and yes I know that all other variables of the geo are important too, too) I found it it - once again - fairly irritating that the front-end felt so ridiculously unstable on anything steep, over-reacting to steering input and feeling incredibly nervous. For my liking the front wheel was tucked too far in, not "in front of" me, not under control, hitting loose rocks knocked it sideways way too easily and on anything steep, the combination of twitchiness and short travel made the bike quite unstable feeling.

OK, so am I the only one who doesn't get the "short travel steep head angle" magic?
Or is the 66/73° convention just better suited for my type of riding?

I like the "long top tube/long stem" part of the UK hard tail concept as I expect it to deliver pints of semi-skimmed milk regularly and maybe the odd box of eggs.

THE COTIC SOUL PART

I am asking out of interest, but if I put a Boxer on a Cotic Soul would it still be too steep for my type of riding? What if I stuck a 29er carbon race fork on the back end, grew flowers from the head tube and called it Agatha? Has anyone done that? Would it feel ideal for my type of riding or would it make more sense to simply buy a frame designed to do what I want it to?

Ultimately I shall find out for myself, but it might save me a few trips to the florist if anyone else has already tried it. Why would anyone put a pug-ugly dog on a steel bike anyway?

Many thanks for any input!

Cecil

ps: Is there a fun and agile luggage trolley for my case?

What an idiot

Posted 4 months ago #
Homesick Smoggie - Member

@BWD

Posted 4 months ago #
BadlyWiredDog - Member

What an idiot

Cheers for your insightful comment. It was just a long-winded way of saying that maybe expecting a slack hardtail to work well on tight, twisting singletrack was unrealistic.

I don't quite understand why people can't just accept that some people like and suit one type of bike, depending on their riding style, terrain etc and others like another. There's no magic bullet. No right answer. Just what's right for you.

But why use common sense when black and white thinking is so more helpful?

Posted 4 months ago #
PrinceJohn - Member

No. Running a hardtail with a 140mm fork pretty much ruins it as a bike that you can ride properly.

Can you please expand on that comment?

Posted 4 months ago #
argoose - Member

been running 140mm on one c 456, really good on the wall and whites level, same set up for the gap and my usual 22mile round Pontstick res all fine and dandy. maybe i'm easy pleased

Posted 4 months ago #
GW - Member

What a~~n idiot~~ legend!

Posted 4 months ago #
Farmers Choice - Member

I run my Soul with On One rigid 26er carbon forks. As has been said above, one mans twitchy is another mans very responsive ride. I used to run it with 130mm revelations but much prefer the rigids.

Posted 4 months ago #
chiefgrooveguru - Member

Or is the 71/73° convention just better suited for my type of riding?

Yes. If I was you I'd be looking at something like an Enigma Ego ST (something like being similar geometry but less pricey!) I had a Boardman HT Pro (100mm forks) which although 70/73 static is more like 71/74 or 71.5/74.5 at ride height due to fork sag. Switching all the parts onto a Soul I noticed the extra stability of the marginally slacker geometry but I wouldn't say it was detrimental to the nimbleness.

Despite the right honourable Taylforth's views I've since delighted in sticking on 140mm forks (and other bigger/stiffer components) and I much prefer it like that but you have to ride it more aggressively or it does all the bad things you've noticed with slacker angles. I ride a straight post with the saddle forward on the rails so it goes uphill remarkably well and descends and corners with appropriate attitude.

Posted 4 months ago #
getonyourbike - Member

That is something I've noticed in moving from my 69 degree 120mm XC hardtail to the 67 degree 160mm Lapierre Spicy is that you've got to get more other the front and really push the bike to get the most out of it. When you do and the speeds get high, it comes to life.

Posted 4 months ago #
davidtaylforth - Member

I think the best thing to do is ride a 100mm hardtail "aggressively" and "over the front end" - best of both worlds. At least you're not stuck in an extra 40mm worth of travel and riding aggressively.

Posted 4 months ago #
boriselbrus - Member

I have a Spesh S-Works hardtail with 100mm fork and a Soul I run with 140mm Thors.

The thing is, you have to ride them very differently. With the Spesh, I ride it in almost a road bike position with my weight on the saddle and the pedals. It feels fast steering but stable within the limitations of the fork. The Soul needs to be ridden more in the "attack" or "ready" position with my weight much more on the hands. Then the bike works round the fork with the back end a bit more "skippy". You learn to just throw it around trusting the front, knowing the back will slip and slide but follow.

Both are a lot of fun and work really well. At first the differences feel noticeable and beed getting used to but now I just get on a ride them and adapt automatically the same as I do when I get on my FS bike.

So which is better? Well neither! I suspect the S-Works is faster for any given effort, but the Soul is a hooligan and what I ride most of the time - even in twisty woodland singletrack.

So maybe if you've been riding one type of bike for a long time it will take a while to adjust, but the thing with the Soul is you can run any fork from 100-140 so it can be whatever you want it to be!

Posted 4 months ago #
seanoc - Member

The 440 rigid fork is okay only because it's a rigid fork and is ridden as a rigid fork; I can't really get away with smashing it into rooty berms and expect the same outcome as a compression/rebound damped suspension unit....as soon as a rigid fork takes a wallop the front wheel is off the ground so it's not tracking, gripping or steering.

I don't think my irks were particularly divey but I guess my riding position may be completely different to yours, I've always been happy to weight he front wheel and let the rear end do its thing.

I'm adament that 120 is th Soul sweet spot for me though.

Posted 4 months ago #
Jamesy - Member

I had an orange crush that has 140 mm hated it and quickly sold it. rode my mates soverign and loved it. some ride with longer forks better than others

Posted 4 months ago #
chiefgrooveguru - Member

I think the best thing to do is ride a 100mm hardtail "aggressively" and "over the front end" - best of both worlds. At least you're not stuck in an extra 40mm worth of travel and riding aggressively.

Or ride a 60mm hardtail similarly and not be 'stuck' in an extra 40mm worth of travel compared to the 100mm...

I've got about 50mm of travel in my tyres and 400mm of travel in my legs - is there anything more special about 100mm forks than it being a nice round number?

Posted 4 months ago #
skywalker - Member

Cheers for your insightful comment. It was just a long-winded way of saying that maybe expecting a slack hardtail to work well on tight, twisting singletrack was unrealistic.

I don't quite understand why people can't just accept that some people like and suit one type of bike, depending on their riding style, terrain etc and others like another. There's no magic bullet. No right answer. Just what's right for you.

But why use common sense when black and white thinking is so more helpful?

Yeah you're right, I take it back.

Posted 4 months ago #
mildred - Member

There's definitely a knack to riding a long travel hardtail; I've found you have to 'ride the fork' more. That is, make the fork work harder for you. Also, I found running a bit more sag helps too, but not in all situations.. A lot of us don't regularly ride the stuff that warrants masses of travel, but it's nice to have when you need it. In contrast it can be a chore too. For example, it's more work to lift the front over trail obstacles such as tree trunks as you end up pulling the fork out of it's sag, leaving the wheel still on the deck.

There's nothing to 'get' about it. I actually think you're complicating matters and just thinking too much about It; It's different & may not be for you. Some Mags & web forums would have us believe that more and bigger is better, but as many will testify on here, that's not the case. It's simply a case of horses for courses.

Posted 4 months ago #
mildred - Member

Jamesy - Member
I had an orange crush that has 140 mm hated it and quickly sold it. rode my mates soverign and loved it. some ride with longer forks better than others

I'm amazed you found this; I've had both and thought the Orange to be way better at everything. Sure, the Sov' was beautifully built (except the woeful, allergic to steel paint job), but the Orange was an absolute blast to ride. I wish I'd never sold mine.

Posted 4 months ago #
yunki - Member

is there anything more special about 100mm forks than it being a nice round number?

cos it makes them so oldschool that it hurts.. that and they're possibly being paid to market the next niche..

Posted 4 months ago #
Euro - Member

I had a decent 3-4 hour run out on my 456 SS with 150mm forks on it a few days back. On One say the head angle is 65.5 with 120mm but i've no idea what it is at 150, but i guess it falls into the 'slack' category.

The trails themselves (all natural) included pretty tech, tight, twisty stuff, a few steep climbs along with all the usual ups, downs and natural features with a few jumps and berms threw in for good measure. It did feel a little odd at first on the slow twisty stuff, but it just took a little change in riding style to get it to work. Same story for the climbs where getting the balance right for front and rear grip took a bit of arse shuffling and elbow bending. No biggie really. Checked the little rubber doofer on the fork leg after 10 minutes and discovered i'd used all 150mm of travel too.

So in summary, don't get too bogged down with numbers and angles, just ride the bloomin thing. If it feels wrong, change how you ride it 'til it works.

Posted 4 months ago #
metalheart - Member

cos it makes them so oldschool that it hurts.. that and they're possibly being paid to market the next niche..

Mebbe we're just so old school that we still think that 100mm IS a long travel fork

Posted 4 months ago #
empy - Member

My Soul has Revs set at 130mm - think it would be better (faster) at 120 but frankly can't be bothered to change it because its such good fun :-).

Posted 4 months ago #
buttercup - Member

Didn't read most of this so here is my uninformed post:

I am a cross country type of rider but want it to be FUN rather than just a mere exercise. I love a 2h blast of tight and twisty singletracks in the local woods.

right there. No need for the slack angle or megaforks. It will be totally useless. and would only really benefit if you were a total masochist who sports a solid 2 hour climb.

Posted 4 months ago #

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