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Sub-65 HA on trail/mountain/endopru bike - who’s doing it?

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,779
7,044
borcester rhymes
Totally agree with horses for courses. I don't think I could ride a sub-67 head angle (with a 29" wheel) out here on the east coast. Too much wiggling and ramen noodle type trails. If I was grinding up a fireroad to fuckin' totally shred down bro, then I think I'd be on board. As it is, I like having a bike that can cut a little bit harder rather than carve up smooth lines. Most of our downhills last like a quarter mile.
 

Cerberus75

Monkey
Feb 18, 2017
520
194
Totally agree with horses for courses. I don't think I could ride a sub-67 head angle (with a 29" wheel) out here on the east coast. Too much wiggling and ramen noodle type trails. If I was grinding up a fireroad to fuckin' totally shred down bro, then I think I'd be on board. As it is, I like having a bike that can cut a little bit harder rather than carve up smooth lines. Most of our downhills last like a quarter mile.
Mine is 66.5 but the wheelbace is short and my fork sag is set to 25% I dont want it any more slack for sure.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,589
2,021
Seattle
Totally agree with horses for courses. I don't think I could ride a sub-67 head angle (with a 29" wheel) out here on the east coast. Too much wiggling and ramen noodle type trails. If I was grinding up a fireroad to fuckin' totally shred down bro, then I think I'd be on board. As it is, I like having a bike that can cut a little bit harder rather than carve up smooth lines. Most of our downhills last like a quarter mile.
Sounds like you need better trails :D


But yeah, I'm with you on the gist of that. I've got a couple silly slack/long bikes, but my stable would look quite different if I lived somewhere else.
 

Wuffles

Monkey
Feb 24, 2016
157
98
I actually thought the whole article was quite good and sheds light on a lot of caveats with geometry tables (particularly "why the seat angle number alone means nothing"), without making (m)any incorrect statements.

It's just the last paragraph (the writer's opinion on the matter) which ruined it, hopefully people can ignore that. What would have been better is some practical info on how to better understand/utilise the info given, and perhaps to ask for more complete data instead of none at all.
I'm not ignoring that last paragraph, it's the key to the madness. Also, this is just a convenient opportunity for a rant because that article ticked me off.

"However, they don’t nearly reveal how the bike rides downhill. And there is a lot more data besides that doesn’t say anything on its own."

That's what kinematics graphs are for. Those do in fact tell you quite a lot about how the bike rides downhill. Manufacturers should include those as well.

"Although you can find information about the top tube length in the geometry table, this doesn’t usually tell you what the saddle position is like when the dropper is fully extended."

Flat out incorrect- if the actual seat tube angle is included you can calculate exactly where your saddle will end up if you can do basic trig. If the axle path is included you can find out where the seat will be at sag too.

"But reducing a bike’s handling to individual geometric data is fundamentally wrong. The geometric factors are interdependent and influence one another."

Somehow this makes it okay to neglect this information?

"For example, the reach on a mountain bike tells us nothing about the seated position of the rider. On a bike with an extremely long reach (e.g. Pole MACHINE Reach 510 mm in L) as well as a steep seat tube angle (79°) you’ll sit a lot more upright and closer to the bar than on a bike with a short reach but a slack seat tube angle."

Again, flat out incorrect. With actual STA and ETT measurements, you can calculate these values with basic trig and yes, discover that Pole will indeed not feel all that long in a seated position.

"If, for example, a bike has a rear linkage with a lot of anti-squat where the chain tension pulls the linkage in the opposite direction of the rider’s weight, the seat tube angle will remain steeper on climbs than on a bike with less anti-squat that runs deeper into the travel. On descending, the influence of the suspension is even greater. A good rear end sensitively filters out bumps without letting the rider’s input go to waste. However, if the rear end isn’t plush enough, it won’t be as smooth and composed. If it’s too plush, it’ll lose its agility. You won’t, however, find this information on a geometry table."

Given an anti-squat, anti-rise, leverage ratio, and pedal kickback chart, and what shock it's attached to and you can deduce these things. Why is he making these statements?

"To find out how a bike rides, you need to look at the big picture, not at individual figures. And for that, only credible reviews and an extensive test ride will help. "

Oh- that's why. It's a "trust us you plebians, we're experienced industry experts who know best. This message brought to you by the same people who tried to convince you Plus size tires were the future for everyone."

Lizard people.
 

slyfink

Turbo Monkey
Sep 16, 2008
9,784
5,601
Ottawa, Canada
"To find out how a bike rides, you need to look at the big picture, not at individual figures. And for that, only credible reviews and an extensive test ride will help. "
hahahahahaha
hahaha
hahhhahahahahah

"trust us. we're professionals".

hahaaha
hahahaghahahahaghahg
jajajajaajjajaja
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
Flat out incorrect- if the actual seat tube angle is included you can calculate exactly where your saddle will end up if you can do basic trig.
Again, flat out incorrect. With actual STA
Most manufacturers don't provide "actual STA" (instead they provide a virtual STA, useless for direct comparison) so you're ripping this guy apart over the most valid point he's making.

It's a legitimate issue even if his conclusion / solution to the problem was wildly incorrect. At the very least I think it'll make people reconsider before taking those numbers at face value.

As for kinematics, preaching to the choir - not hard to map things yourself in linkage though. Also agree on the self-proclaimed-expert-reviewer BS (see my past threads on Mike Levy).
 

Wuffles

Monkey
Feb 24, 2016
157
98
Most manufacturers don't provide "actual STA" (instead they provide a virtual STA, useless for direct comparison) so you're ripping this guy apart over the most valid point he's making.

It's a legitimate issue even if his conclusion / solution to the problem was wildly incorrect. At the very least I think it'll make people reconsider before taking those numbers at face value.

As for kinematics, preaching to the choir - not hard to map things yourself in linkage though. Also agree on the self-proclaimed-expert-reviewer BS (see my past threads on Mike Levy).

True on the STA- the only geo chart's I've been reading lately are from GG and Pole, both of whom (bless their souls) list actual STAs. Forgotten that it's a rare thing, and it sucks companies don't do it.
 

Gary

my pronouns are hag/gis
Aug 27, 2002
8,490
6,377
UK
Most manufacturers don't provide "actual STA" (instead they provide a virtual STA
Which doesn't matter because ALL manufacturers provide side on pictures of their bikes.
I don't want a fucking stupid straight above the BB saddle as found on Pole/Porter bikes though. Or a fucking stupid way back over the rear tyre saddle like we had on most DH bikes in the 2000s. Anything inbetween is fine because... you know...
Saddle rails, micro adjust seatposts and an allen key.
 

Kurt_80

Monkey
Jan 25, 2016
491
420
Perth, WA.
I've done it with a few frames. With the same AC as your equivalent 27.5 fork you drop about 0.6-0.7"

I'm running a current model V10 with 26s on it but in the high setting and the the fork dropped to maintain stock geo.
I'm starting to think pretty seriously about doing this too.

My plan was to run my 26 fork dropped to the max, 26s front and rear, high setting on the rear. Looks like there would be enough stanchion to play with.

But just to get my head around this properly..are you using a 26 or 27.5 fork? And did you have to buy a drop crown, or was there enough stanchion length to drop the fork with the stock crown?
 

StiHacka

Compensating for something
Jan 4, 2013
21,560
12,508
In hell. Welcome!
New franken bike: long shocked SC Hightower with 27.5 wheels and 160mm fork, with the chip in the low setting. 12.7" BB height, 150mm travel, 66-ish HA, 435mm stays. Fucker rails and pops-off stuff eagerly. The A-C of my fork is similar to a 140mm 29er fork so I could go 170mm without overstressing the frame.

 
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kidwoo

Artisanal Tweet Curator
I'm starting to think pretty seriously about doing this too.

My plan was to run my 26 fork dropped to the max, 26s front and rear, high setting on the rear. Looks like there would be enough stanchion to play with.

But just to get my head around this properly..are you using a 26 or 27.5 fork? And did you have to buy a drop crown, or was there enough stanchion length to drop the fork with the stock crown?
26" fox 40, stock crowns, and yes, just about maxed.

That's with a medium 27.5 V10, with a little bit of stack height from an offset headset (works components). Using a flush headset you'd have a little more wiggle room.

But yeah via dumb luck it's exactly the same geo as with 27.5 wheels/fork in the low setting. I dig it.
 

Kurt_80

Monkey
Jan 25, 2016
491
420
Perth, WA.
26" fox 40, stock crowns, and yes, just about maxed.

That's with a medium 27.5 V10, with a little bit of stack height from an offset headset (works components). Using a flush headset you'd have a little more wiggle room.

But yeah via dumb luck it's exactly the same geo as with 27.5 wheels/fork in the low setting. I dig it.
Thanks, that's good to hear. One step closer to the dream.

I believe it's a different sized shock... 2.75"? Since I'll probably have to change from my 3" Float X2, what would you recommend?

Also, is that works headset for reach adjustment or angle adjustment? What have you changed it to if you don't mind me asking?

Thanks again!
 

kidwoo

Artisanal Tweet Curator
It's like a 4mm reach adjust. Nothing huge but it does add stack. I tracked down a dhx that came on the first release of that frame. Not a fan of the dhx2 that came on it, at least not with that super progressive leverage curve. And yeah, 8.75x2.75