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29" DH bikes

trib

not worthy of a Rux.
Jun 22, 2009
1,636
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All of Vouilloz's wins should be retroactively given an * to denote that he was on better equipment.

That's what the 29er hate sounds like.
 

6thElement

Schrodinger's Immigrant
Jul 29, 2008
17,151
14,627
11 years ago I got my first 29er and I think I've owned at least one in my stable since then. My point was that I'm 6'2" and would still have concerns about tire buzz in the steeps.

Take some of the shorter male riders or most of the womens field and they're going to be even worse off.
 

toodles

ridiculously corgi proportioned
Aug 24, 2004
5,824
5,201
Australia
11 years ago I got my first 29er and I think I've owned at least one in my stable since then. My point was that I'm 6'2" and would still have concerns about tire buzz in the steeps.

Take some of the shorter male riders or most of the womens field and they're going to be even worse off.
I can't dunk but they won't lower the basketball hoop to 7' so I can be in the NBA.
 

Gary

my pronouns are hag/gis
Aug 27, 2002
8,493
6,380
UK
Why do people think that '29er hate™' is based on anything but having ridden the damn things?

It's not "just" internet hate, it's a distaste based on experience.
+1

I know. right. All the fatbike fannies round here get upset when you tell them their bikes are shit. They then try to tell you you need to ride one. It's not irrational wheel size bigotry it's a concise review based on riding loads of them and hating every single one based on their handling.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,790
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borcester rhymes
This article reflets the opinion of Chris Porter at the time the article was written. He has changed his mind now and runs the standard offset on the geometron bikes he sells.
the article was written by seb stott. it's his opinion. now, it's only the opinion of one rider, but I feel as though it's as close to a scientific test as anybody has given us, running the same bike with three different offsets back to back.

As for chris porter, did he give an explanation for why he runs standard offset? because the simplest explanation that I can come up with is that fox doesn't sell 650b forks with 37mm offset. I'd like to run a 45mm offset crown on my 36, but apparently that's not possible, as the offset is in the CSU and not the lowers, and fox doesn't make a 45mm/29" crown.

If there's data out there that suggests why he switched back, I'd love to see it, because he certainly is pushing the edges of geometry.
 

go-ride.com

Monkey
Oct 23, 2001
548
6
Salt Lake City, UT
Holy flashbacks! I haven't posted to RM in 5 years, but was amazed to find that the OG gang is still here. I think I will try to hang out a bit more myself.

I randomly stumbled on this post looking to read what riders are thinking of the prospect of 29er DH bikes. Personally I don't think our local UT DH race courses are fast enough for the current crop of 27.5 DH bikes to be an advantage over the last of the 26 DH bikes. However, my long-shocked Santa Cruz Hightower is bloody fast at the local bike park. Don't know what to think.
 

kidwoo

Artisanal Tweet Curator
Holy flashbacks! I haven't posted to RM in 5 years, but was amazed to find that the OG gang is still here. I think I will try to hang out a bit more myself.

I randomly stumbled on this post looking to read what riders are thinking of the prospect of 29er DH bikes. Personally I don't think our local UT DH race courses are fast enough for the current crop of 27.5 DH bikes to be an advantage over the last of the 26 DH bikes. However, my long-shocked Santa Cruz Hightower is bloody fast at the local bike park. Don't know what to think.
You're old scott. You're just old.


and I miss you :cupidarrow:
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
2,066
1,437
SWE
the article was written by seb stott. it's his opinion
I my world, journalists are not allowed to express their opinion in articles... or maybe only very mildly and between lines! ;) the lizard people are very powerful and will make sure that any diverging opinion will be restrained. See what they did to teamrobot!

As for chris porter, did he give an explanation for why he runs standard offset? because the simplest explanation that I can come up with is that fox doesn't sell 650b forks with 37mm offset
from the 2015 review here https://www.pinkbike.com/news/nicolai-mojo-geometron-first-ride-2015.html
Pinkbike said:
He also built the fork using a crown/steerer assembly from a 26" travel Fox 36 fork, which has a shorter offset than the 27.5" version, meaning the steering feel will quicken slightly to offset the lag given by the slacker head angle.
Working at Mojo give him the possibility to swap crown assy.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,790
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borcester rhymes
I my world, journalists are not allowed to express their opinion in articles... or maybe only very mildly and between lines! ;) the lizard people are very powerful and will make sure that any diverging opinion will be restrained. See what they did to teamrobot!


from the 2015 review here https://www.pinkbike.com/news/nicolai-mojo-geometron-first-ride-2015.html

Working at Mojo give him the possibility to swap crown assy.

don't have time to do a full read through, but a ctrl+F "offset" suggests that he swaps a 26" crown on his 27.5" forks for reduced offset....which is what other dude said and what I'm saying...so er, what?

what did happen to team robot?
 

FlipSide

Turbo Monkey
Sep 24, 2001
1,432
888
I guess Sponsel got bored of the stupid comments that, for some reason, never died out? I really never understood the piss-flap nonsense. I just assumed it was a bunch of 14 y.o. fucktards being "funny"...but there may be something I'm missing.

It's unfortunate he stopped updating it...I really enjoyed his blog.
 
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jonKranked

Detective Dookie
Nov 10, 2005
88,660
26,898
media blackout
I guess Sponsel got bored of the stupid comments that, for some reason, never died out? I really never understood the piss-flap nonsense. I just assumed it was a bunch of 14 y.o. fucktards being "funny"...but there may be something I'm missing.

It's a unfortunate he stopped updating it...I really enjoyed his blog.
likewise. if nothing else it was a different perspective from the usual industry drivel.

trivial hasn't been updated in just as long.
 

slimshady

¡Mira, una ardilla!
Honest question, which might be extrapolated to 27.5 bikes: why do they need to put such irrational seat tube angles in these bikes? wouldn't a more vertical seat tube get them more tire clearance, improve the pedaling position and avoid unneeded ass crack grinding?

 
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4130biker

PM me about Tantrum Cycles!
May 24, 2007
3,884
450
Honest question, which might be extrapolated to 27.5 bikes: why do they need to put such irrational seat tube angles in these bikes? wouldn't a more vertical seat tube get them more tire clearance and improve the pedaling position and avoid unneeded ass crack grinding?

I would assume it will be fixed (seat having to be run slammed forward) in the production version. As I understand, that is a production 650b front end pictured. And the seat needs to end up in the right position, so slanted will probably be necessary with that much travel.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,790
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Honest question, which might be extrapolated to 27.5 bikes: why do they need to put such irrational seat tube angles in these bikes? wouldn't a more vertical seat tube get them more tire clearance and improve the pedaling position and avoid unneeded ass crack grinding?
 

mtg

Green with Envy
Sep 21, 2009
1,862
1,604
Denver, CO
Honest question, which might be extrapolated to 27.5 bikes: why do they need to put such irrational seat tube angles in these bikes? wouldn't a more vertical seat tube get them more tire clearance and improve the pedaling position and avoid unneeded ass crack grinding?

The bent nail seat tube angle actually helps with tire clearance at bottom out...if you are trying to keep the saddle at a certain distance behind the BB at a given height. Now, if you just steepen the seat tube angle and allow the saddle to go farther forward, that also helps, but the super slack actual seat tube angle with a lot of offset in front of the BB gives more tire clearance at bottom out than anything else.
I had the same question until I designed a few frames trying to stuff wheels/tires that keep getting bigger into chainstays that keep getting shorter, at a reasonable BB height, with anything other than a hard tail. The slack seat tube with a lot of offset in front of the BB (ie steep effective SA, yet slack actual SA) is the easy button to make it all work.

Now, a different angle to your question: yes, if you move the saddle forward, you can steepen the actual seat tube angle, decrease offset in front of the BB, and maintain bottom out clearance.
 

trib

not worthy of a Rux.
Jun 22, 2009
1,636
639

Ancilloti have a near vertical seat tube on their bikes - so should be nicely between the knees when seat is down and a less 'on the nose' position when climbing.

Looks rather odd though
 

slimshady

¡Mira, una ardilla!

Ancilloti have a near vertical seat tube on their bikes - so should be nicely between the knees when seat is down and a less 'on the nose' position when climbing.

Looks rather odd though
That's what I was thinking about. The detailed post by Mr. @mtg helped me to understand it finally, but I still find myself wishing for more bikes designed like that Ancilloti, at least in regards to seat tube angles/position.
 

Lelandjt

adorbs
Apr 4, 2008
2,636
997
Breckenridge, CO/Lahaina,HI
Matt (mtg) and I had a conversation at a race years ago about seat tube angles. We both agreed that a near vertical seat tube would be ideal for keeping the seat in the best for/aft position while raising and lowering it but tire/suspension clearance is the issue. I said the solution is for the industry to adopt 40mm or greater setback seatpost heads as the standard and design frames with forward and near vertical seat tubes. My recollection is that he agreed but we both see that sort of industry wide change being impossible or at least many years away. Also, so much setback is hard on seatpost bushings.

It'll come when droppers get integrated into frames.
 

slimshady

¡Mira, una ardilla!
Matt (mtg) and I had a conversation at a race years ago about seat tube angles. We both agreed that a near vertical seat tube would be ideal for keeping the seat in the best for/aft position while raising and lowering it but tire/suspension clearance is the issue. I said the solution is for the industry to adopt 40mm or greater setback seatpost heads as the standard and design frames with forward and near vertical seat tubes. My recollection is that he agreed but we both see that sort of industry wide change being impossible or at least many years away. Also, so much setback is hard on seatpost bushings.

It'll come when droppers get integrated into frames.
Yeah, but take for instance this pic of my current steed (Orbea Rallón R4). You can see the seat tube doesn't go past the vertical of the BB before the kink. This leads me to think you could make a vertical or near-vertical ST and still get away with the necessary clearance (sans the kink). In my Orbea this works with short 420mm chainstays and 160mm of rear travel (boostashitted in the last incarnation, but not in my 2015 model).



I'm not saying it's achievable with every other suspension design, but at least the single-pivotesque family should be able to run very upright seat angles.
 
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Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
Honest question, which might be extrapolated to 27.5 bikes: why do they need to put such irrational seat tube angles in these bikes? wouldn't a more vertical seat tube get them more tire clearance, improve the pedaling position and avoid unneeded ass crack grinding?
Cool question, funnily enough I had two almost identical DH bikes with very different seat angles - the 26" Gambler and the updated 650b model.

The previous version had quite a steep seat angle and I loved it - it just made any small flat sections before the start of a run (or getting to the chairlift base station) a lot less painful, and it also meant I could run the seat higher without it getting in the way which made the former situation even better. I'd never had this feeling with a DH bike before since they all seem to have stupidly slack seat angles.

On the new model they slackened the seat angle so the benefit is gone. The old model had clearance for 650b both ends anyway so I don't think that was the reason.
Not mine but pic of old one for ref.
 

mtg

Green with Envy
Sep 21, 2009
1,862
1,604
Denver, CO
Matt (mtg) and I had a conversation at a race years ago about seat tube angles. We both agreed that a near vertical seat tube would be ideal for keeping the seat in the best for/aft position while raising and lowering it but tire/suspension clearance is the issue. I said the solution is for the industry to adopt 40mm or greater setback seatpost heads as the standard and design frames with forward and near vertical seat tubes. My recollection is that he agreed but we both see that sort of industry wide change being impossible or at least many years away. Also, so much setback is hard on seatpost bushings.

It'll come when droppers get integrated into frames.
Yep. I keep asking dropper post manufacturers for offset posts, but they keep making zero offset because of consumer demand as a band aid for the bent nail seat tubes on so many bikes. This is why I design bikes with some amount of recommended saddle offset on the rails. We used to include the saddle offset in the ETT measurement, but it confused too many people.

This whole philosophy is in the Pedälhead, Trail Pistol, and Megatrail/Megatrail SS.

Justin_Megatrail_Porcupine_Rim[1].jpg


Edit: And, just to be clear, when I'm talking about seat tube angles, I'm not taking a dig at Santa Cruz, or the V10. DH bikes are a different animal to a certain extent, and they are stuffed a 29" wheel into an 8" travel bike and made it through a world cup race with impressive results.
 
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EVIL JN

Monkey
Jul 24, 2009
491
24
Slack seat angle I would assume is to maintain seat position relative to rider "stance". I know that it was alot easier to use the saddle on my V10 than on my Scalp. More recently I built up a trail bike with a shorter shock that gave it a 67 seat angle, compared to my Ragley ht it makes it so much easier to hang further back while attacking (even on flatish trails). Same saddle, more or less same relative height.

So my conclusion is that with a steep seat angle you need to have the seat lower to clear it with your thighs for when you need to really get back on the bike. A slacker seat angle aloows you to keep the seat higher and closer to your thighs even when the trails get steep and rowdy, allowing the rider more control since he can use the saddle too. Does it matter? Meh.
 

tabletop84

Monkey
Nov 12, 2011
891
15
All of Vouilloz's wins should be retroactively given an * to denote that he was on better equipment.

That's what the 29er hate sounds like.
The thing is that compared to the dh-hardtail-era the average joe could have probably won a race back then on a IH Sunday but the comparison doesn't work if you bring current dh bikes and possible 29er-dh bikes to the equation. What we are talking here are Milliseconds to seconds - at best.