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Discussion Starter · #1 ·
Just curious about the 29er geometries I'm seeing out there...
seem's like a whole lot of 73/72ish angles on the hardtails
listed on vendors geometry tables. I've read the excellent
discussion 29er geometry discussion here:
http://www.ninerbikes.com/geometry.html
So I see that the apparently steeper HA's may not be as severe
as my 26er bias leads me to believe. I have to say
I have no experience riding 29" wheels at all.

I do see that Ventana's new offerings have a slacker HA of 70.5,
which seems quite slack relative to the other 29er geos that
I've been noticing. Also, I can't seem to find any angles on
Fishers website, so don't know what their bikes are like.

Can people comment some on the geometry?
Do all the custom HT's people are having built conform
roughly with the 73/72 angles with a 3-4" suspension fork?
OR, are slacker angle being used on bikes
being built with the intended use of technical trail riding?

Over time will the 29er HT geometries evolve into something
different than what they are today, since the 29er movement
is so young?

I ride very technical steep terrain here in the front range of Colorado.
On a steel HT with a 5" fork and a 69 degree HA. I've found
over the years that this slacker geo is just a whole lot more
fun than the 'twitchy' XC oriented HT's I've had in the past.

With an interest in getting a 29er HT with a 4" fork, I just
want to understand what 29er geometry is preferred for tech trail
riding, and, ultimately which 29er HT's on the market are
the best candidates for my style and trails.

Sorry for the verbose post and I appreciate any input.
thanks-RIP
 

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Premium Member
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7,491 Posts
Look at trail numbers.

Head angle is only one part of the equation - familiarize yourself with the trail measurement (do a search and you'll find lots of good discussions) and you'll have a good yardstick for how to set up a 29er. Given forks with the same rake, trail stays about the same with a 29" wheel when you steepen the head angle by about 1 degree - hence the plethora of 72/73 29ers, which are intended for the same all-around riding/racing as the 71/73 26" wheel bikes.

I live in the front range too, and I've found that a head angle about 71.5 (if you're stuck with a 39mm rake suspension fork) works best *for me*. Everyone is different, though - I like a bike that many people (except for MC the High-Trail Weirdo) would consider sluggish in terms of steering response.

Many manufacturers spec a head angle with an unsagged suspension fork, as well - you may want to check carefully. The difference in head angle with no sag vs 20mm can be a couple of full degrees.

Fisher removed the angles from their 2006 models on the site for some reason, but they have no changed from last year - just find the 2005 numbers if you're curious. I believe the head angles ranged from 70.5 (small) to 71.5 (X-large).

-Walt

ripley said:
Just curious about the 29er geometries I'm seeing out there...
seem's like a whole lot of 73/72ish angles on the hardtails
listed on vendors geometry tables. I've read the excellent
discussion 29er geometry discussion here:
http://www.ninerbikes.com/geometry.html
So I see that the apparently steeper HA's may not be as severe
as my 26er bias leads me to believe. I have to say
I have no experience riding 29" wheels at all.

I do see that Ventana's new offerings have a slacker HA of 70.5,
which seems quite slack relative to the other 29er geos that
I've been noticing. Also, I can't seem to find any angles on
Fishers website, so don't know what their bikes are like.

Can people comment some on the geometry?
Do all the custom HT's people are having built conform
roughly with the 73/72 angles with a 3-4" suspension fork?
OR, are slacker angle being used on bikes
being built with the intended use of technical trail riding?

Over time will the 29er HT geometries evolve into something
different than what they are today, since the 29er movement
is so young?

I ride very technical steep terrain here in the front range of Colorado.
On a steel HT with a 5" fork and a 69 degree HA. I've found
over the years that this slacker geo is just a whole lot more
fun than the 'twitchy' XC oriented HT's I've had in the past.

With an interest in getting a 29er HT with a 4" fork, I just
want to understand what 29er geometry is preferred for tech trail
riding, and, ultimately which 29er HT's on the market are
the best candidates for my style and trails.

Sorry for the verbose post and I appreciate any input.
thanks-RIP
 

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112 Posts
29er geometry food for thought

29er geometry evolution

Rigid WaltWorks:
Fork- Kinesis Crosslight Cyclocross Fork, 38mm offset
HT- 70 degrees
ST- 74 degrees
Chain Stays- 451mm/17.75"
BB drop/height- 94mm/11.25" with Maxis Ignitor F/Nanoraptor R
WB- 43"

I asked Walt to build a bike that would be very stable at 30-40 mph on steep gravel/dirt double track, recognizing that it might be a little slow for the tight stuff. It is very stable, doesn't skip around at the slightest off center bump or rut, requires deliberate steering but is not sluggish. The pleasant surprise is that it handles tight single track quite well. In particular I like its manners in uphill switchback, the front end tracks and lets me steer, I can climb things with it that I can't with my small wheel 4" DS. I don't seem to strike my pedals, so I wonder if I could go lower with the BB. I think this has something to do with its good manners going up tight corners without the front end getting light. I am not sure I have figured out all the aspects of what it is that Walt built and why it works, but dang it sure is a great bike, and exceeded my expectations. :D http://forums.mtbr.com/showthread.php?t=120656
 

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Non Dual Bliss
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6,240 Posts
lithiapark said:
In particular I like its manners in uphill switchback, the front end tracks and lets me steer, I can climb things with it that I can't with my small wheel 4" DS.
74 degree STA with a zero setback seatpost has something to do with it too. :)
 

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112 Posts
lanpope said:
How's that finish holding up? Looks real nice in your original post.

LP
Bare sandblasted ChroMo with some boeshield or WD-40 on it, and it was holding up well when it rained. Then it got hot. Didn't think much about sweat falling on the frame until the next time I rode, looked like I had bled on the frame. Sweat=Salty Water=Rust. DOH!!!! The rust isn't deep, steel wools right off. I plan on stripping it down and clearcoating it once my garage warms up enough to pain. At least I can speak with authority about what happens when you leave the ChroMo bare. In terms of having to learn the hard way, at least this wasn't a painful lesson. :D
 

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Hybrid Leftys aren't real
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16,469 Posts
Built my own frame, cause I didn't like all the twitchy XC rigs out there either. Mines got a 70.5 HA, with a Reba set @100. This feels like a winner to me, controlled, comfortable, look ma, I'm not a racerboy=:) Funny, I left mine raw too, I like the rust, it adds character!
 
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