MTB, anyone riding a 29er?

[MountainBiker]

Lateral stiffness: Some people have a feel for it, and some don't. Of course weight and height play a factor as well, since you can get more lateral loading on the wheels.

I haven't ridden a 9'er more than a few hundred yards, but as a long time rider of motorcycles, bicycles and being a mechanical design engineer, I have an opinion! :gunt:

-a 9-6'er sounds like a good idea, the rear tire can get over most stuff, it's the front one that really needs to be larger. This also gives more room for suspension linkage without making the chainstays too long
-a 9'er fork will also suffer from more lateral flex, unless they make it a lot heavier than the equivalent 6'er fork. I'd like to see 36mm stanchions and a 20mm axle, especially for your size
-your test ride on the SS is probably too weird to be of much use. You were likely traveling faster whenever you were pedaling uphill (due to the gearing), and this will help you roll over everything really well. The tall gearing also means that you won't see how the big wheels feel when you are going slow in the granny gear.
-I doubt that there is much consensus on what geometry to use on a 9'er or 9-6'er, so if you aren't careful, you could end up with a non-optimized design... that always happens to early adoptors. For reference, frame and fork designers are still trying to figure out the optimum rake, trail and fork offset combo for the current crop of 120mm travel forks.

Good luck! Researching/buying a new bike is always fun!

 

[Pokey]

At 6'5 i would seriously consider getting something custom built. Theres just soo few choices out there in the stocker sizes--and typically they all have some sort of flaw in my thinking on geometry(usually in the wheelbase/chainstays).

For the 29er i have only seen one design- by Steve Stickel which had a seattube that was offset forward on the BB shell and slightly into the downtube. He was able to get 16.25-17.5" rear stays with a 29er comfortably. (see pic attached) The chainstays are boxed sections out of the bb shell and taper til they meet the actual chainstay which has mitered and sealed ends. very sexy and the only 29er ive seen to date that has a real geometry that doesnt have to compromise with ht angle/sa/wheelbase etc.

Im a huge fan of going bigger in the wheelbase but having spent a fair amount of time on a 46.5"+wheelbase fr/dh bike----theres no way any 29er with a wheelbase aproaching that length makes any sense for what we all deem to be standard singletrack. A quarter inch change in wheelbase is vastly noticable--and many of these 29-ers are reaching traditional dh lengths(in our sizes).

The wheel issue is a serious one given you are 235+. As i said previously--this issue was the sole one which steered me away from the 29er market until i thought about having a custom builder do a 135mm spaced rigid fork.135 spacing with bladed aerolites should be nice and light and exponentially stronger both laterally and vertically.(good article on mtbr about spacing and the added strength for us big lads). Unfortunately a rigid is the only option right now if you wanted to talk someone into building you a 135spaced one.
And thats just the front we are speaking of......the rear i personally think would take a 150+mm and blades to do justice for us big guys on a f/s29 or 29er ss.

My only advice is to not get caught up in the 29er hype that may work for some and not for you. Little guys can take a jump in wheelbase and still fit on a trail.....but big guys taking a jump might as well be trying to take a Tundra Crewcab to the Rubicon.

 

[Pokey]

Okie-got curious about the newest frames that you mentioned out and given your size heres some thoughts.

Sultan- xl would be right wheelbase wise....xxl waaay wrongo from a wheelbase perspective.
xxl would be better in ht length.......xl waaaaywrongo from a ht perspective.

VEntanas. el ray and patron suffer from short ht also.

Both bikes are way off for you due to that high saddle position and short headtubes. The good news is that im sure both Turner and Sherwood would throw on a longer heattube no problemo.

 

[Christophe Noel]

I had a fun night, took out the demo 29er single speed... Gary Fisher Hardtail, :

I've spent a lot of trail miles on that "Rig". The eccentric BB sucks, but for spec and geometry it's a great bike.

It sounds like you noticed many of the same positive attributes of a 29er that I noticed in the first few rides. That rear wheel hook up is sweet. Climbing techy stuff is a breeze as the front wheel locks on the line and rolls over everything. It takes several weeks of riding a SS to really physically adapt to it. You spend enough time out of the saddle, your back needs more umph than usual. Those first weeks on a SS my back hurt.

I'm not sure I have ever felt the wheel flex everyone is so sensitive to. For the record my basement is full of about $10,000 worth of road racing wheels and XC hoops. I'm a wheel junky. Everything from 1000 gram climbing wheels to 60mm rimmed carbons and full discs. Many of those wheels notorious for flex. I feel the softy, softy nature of a 29er tire inflated to a squishy 32psi, but not "wheel" flex so much. My other SS has V brakes and even on that bike I've never heard any brake rub or felt any flex. But every rider feels their own feedback from any bike.

As for fit and the particulars of bikes, I used to be really fickle. I always rode custom machines....always. Since about 1999 we've had sponsors give us bikes, often ordered with the most basic of dimensions. I'm actually amazed how well I can adapt to a bike I would have though wouldn't fit or be the right geometry. For example, when Voodoo gave us our road bikes last season we ordered them with JUST top tube measurements since they hadn't even designed the bikes yet. I not only made it work, but it feels great. Anyway, that's a long way of saying as a good rider, you can often adapt to any bike as long as it's in the right size for the most part. You can obsess over a half degree here or 5mm there, but sometimes it isn't necessary.

 

[Christophe Noel]

Speaking of single speeds.....Anyone see the prototype Poly Drive system Spot has on their site? Belt drive single speed. I'm all over that.

 

[dieselcruiserhead]

Thanks for the comments Pokey I appreciate it.. Also pardon the novel here. But these are the questions/thoughts running through my head. Again this is a big purchase in the end so I want to get it right).

There are two sort of trains of thought there, what I maybe "should be" on (ie much longer top tube) and what I "like to" be on. Again even though I'm 6'5 I'm riding a XL stumpjumper. I also always considered myself a "XL" kind of guy. Largely related to the "odd" part of me being my legs only. the rest of me is common XL size, feet (size 12), sweater size common XL. Because I'm 6'5 people assume that because of my height that I'd need something massive. Been happening my whole life. When I was a snowboarder in my teens in high school, someone sold me a "fat bob" once because I was "so tall" even though I told them I'm only a 12 foot (which fits fine on normal even narrow snowboards.

It worked but was a tank and why would I want to haul around a tank? That is what I'm worried will happen with the XXLs and what everyone wants to put me on. My next board was a 158 Burton Custom, the smoothest/slickest and lightest board made back then... And guess what, the lighter smaller more agile board worked 20 times better than the Fat Bob for me and I was super stable... Admittedly I should have been on a 163-165 but if I took a store or common sizing advice I'd be on a 172. --No way for me!

So anyway, my current Specialized Stumpjumper that I love and feel that I fit on great and get around on great is: 24.3 virtual top tube, 16" chain stays, 43 1/4 wheel base. 73 degree seat tube, 71 degree head tube. Small, light, nimble, super solid at all speeds, cruises.. My only complaint again (related to the long seat tube) is a slightly longer wheel base (about 1" I figure), move the seat tube back about 1/2" or even 1" maybe, and longer seat tube and taller head tube to make things a little heigher up front.

But even with this relatively small bike, and the 2.4 MotorRaptors I have been riding, I actually keep up with my buddies on 5" Ventanas and such both uphill and downhill (and these guys are good even semi-pro riders). I do not eat it too often over the front (I have but seldom) and have been able to stick killer descents, 100 yard long super steep loose rocky descents and not eat it.. A lot of it also attributable to super wide and stable handlebars too..

Nothing insanely technical (but it happens too once in a while). But difference is I have to work my ass off to keep up and I'm hurting at the end of the day (only 28 so I can pull this off, for now)... They keep saying "imagine Andre on a full suspension!" I actually like and have nailed some 2' drops even with the hard tail... So in all a little crazy..

So I started doing the math based on what I like and what works for me, which is this Stumpjumper. This is my big geometry dillemma: base off what I like and what I know (aka this Stumpjumper, which I like so much that I went and bought another one), or start from scratch based on what someone else is telling me?

And no big deal but so far, I sort of respectfully disagree with your comments on mostly the Sultan.. It is the same head angles and steering angles, 1" longer in the top tube (which would be about perfect IMO), and I like the longer chain stays (18" is admittedly long) but would help alot with keeping the wheel down.

Been doing research on 29er on MTBR mostly and turns out there are a lot of 'clydes' as (we?) are called riding 29er and doing OK. Just with a decent wheel set. So this is what I was thinking if I did go 29er. Something like a stans set and something with a burly ultra rigid hub with probably straight spokes 14g as mentioned or something else and maybe even more bling-ie like even an I-9 hub/spoke setup. Super straight, super strong, super rigid, super expensive

So far the more I do the math it seems the more I like the sultan geometry... Almost sort of exactly what I am looking for. My only complaint would be fairly low steerer-tube, height wise (this can be adjusted through with different forks), the 21" seat tube (again this is where I'd want 23 - but 21" works fine), and the 1" longer ETT is perfect IMO..

If I can get a wheel set to hold up, I think 18 long ass rear chain stays would be great and with the added traction of 29er I think it would be fine.. Even if not I considered using this bike and doing maybe a 650B wheelset now that they are available (sort of crazy to hop on the band wagon immediately - but that would be killer and I am a fan of the Rampages - the tire available for this size), or maybe even 26er in this size if 29er will not hold up to me. A little 'odd' too but nothing wrong with riding 26er in a 29er frame almost But that said if I ended up this way I would prefer a regular old 26er frame for the obvious advantages and would buy a Spot or El Ciclon.

My complaint about 26er (which I like so I haven't ruled it out) is feeling every bump even with a plush suspension... Again like wheeling really hard terrain in 31s or 33's versus 35s.. Works and does OK but you feel it versus the larger tires that roll over everything and make everything so much easier. Different can of worms but I think it is a reasonable comparison...

That said again I'm not 100% sold on it either. Will go ahead and spend more time on this 29er (I got the OK from the LBS to take it out whenever I want for free, which is cool). It is rainy and nasty here today and I'm stuck at work for most of the day so looks like Wednesday afternoon for me most likely again...

But I did a lot of research on this and looks like with a well built 29er wheel set I'll be OK. I think I'm on the light side of some of these clydes riding 29er, for what its worth!


Other than all this, I fully agree about the "tundra on the Rubicon" comment for the same reasons too... thanks!

Okie-got curious about the newest frames that you mentioned out and given your size heres some thoughts.

Sultan- xl would be right wheelbase wise....xxl waaay wrongo from a wheelbase perspective.
xxl would be better in ht length.......xl waaaaywrongo from a ht perspective.

VEntanas. el ray and patron suffer from short ht also.

Both bikes are way off for you due to that high saddle position and short headtubes. The good news is that im sure both Turner and Sherwood would throw on a longer heattube no problemo.

 

[dieselcruiserhead]

Speaking of single speeds.....Anyone see the prototype Poly Drive system Spot has on their site? Belt drive single speed. I'm all over that.

Yes saw this. According to the MTBE reviews it does great and the belt stays on and tight... Pic right on the page. I have a friend ordering a 29er version, should be here in the next couple weeks.. http://www.spotbikes.com/

 

[Christophe Noel]

I'm not sure I understand what you're suggesting by bumping up the front of the Sultan with a longer fork. More travel will mean more slack HT angle and ST angles. Pair that with those ridiculously long stays and you'll have a Mack truck on your hands. Forget "nimble."

 

[dieselcruiserhead]

Here is a thread I started about building a strong 29er wheelset. Good responses from some of the i-tards on MTBR IMO, but good info..
http://forums.mtbr.com/showthread.php?t=347444

 

[Christophe Noel]

Dude, MTBR and Roadbike Review are full of terrible reviews and opinions. REALLY bad. For every excellent opinion there are 5 lame opinions. I noticed your question about Velocity hoops. All in all, not the best available. Much of this rim business has to do with manufacturing quality. That's why DT, Mavic and others have been doing so well. The Stans get good trailside reviews, but then again, my Bonti rims have held up like aces and I'd put them middle of the road or a teeny bit higher. King hubs are my personal favorite. The rear hub is awesome, especially for off roading and SS riding. The instant engagement is pretty slick. I have a set of Kings on my road bike with more than 35,000 miles on them. Great stuff.

Well chosen spokes will make the difference with regard to stiffness. The rim has perhaps less to do with it than the spokes. I'm liking the added depth of Bontrager's rims as defence against flat spotting.

In the end, wheels are not worth poo unless a good builder builds them and a skilled rider rides them.

I still say those stays on the Sultan are destined to haunt you on every sharp turn. We're talking 2" longer than the Fisher you've been demoing. Wait 'till you have to lift that front wheel!

 

[Pokey]

Yeah i agree with Flounder on the MTBR.....alot of useless opinions and there are a handful of real knowledgeable people who ride real world conditions.

DieselC-head- i think since you like the STumpy so much- you need to go out and ride some full suspensions with similar tt's and slightly longer wheelbases. The simple way to look at it for me is -- you have 235lbs sitting at the top of a triangle.....with the wheels forming the base of that triangle. Your triangle is rather tall due to your long legs. Whether you do a 29 or 26...increasing your wheelbase from 43(stumpy) another inch will be veeeery noticable on descents. I would never go past 45.5" wheelbase on a XC rig --hardtail.ss or f/s. In general its just about assessing which end of the wheelbase to increase for you..... If you increase it in the front by keeping the rear stays short---you will have a much more comfortable on descents(less over the bars feel as the wheel is further in front of you). If you increase the rear with long stays- you end up sacrificing some of that forward stability for sideways control and predicability.(a long rear end follows the turns of the front with a little more ease and less sharpness).

My take is- keep the rear short- and select proper grip tires for the rear and your body weight. (basically compensate for the shorter rear bias by better riding skills and tire selection). *rationale*--> 235lbs at the top of triangle that starts to tip forward going downhill is the real battle....kinda like a fj55 with an extra 235lbs on the 150lb arb roofrack.

It sounds like you are smooth rider to keep up with your F/s buddies on your stumpy. If you can translate that smoothness onto a F/s rig of your own...you might end up with them chasing you.

The rationale behind my Sultan comments were based on your lower back comments. To go with the XL would be the upper limit of wheelbase as the xxl is sorta downhill ridonkulous length. But going with the xl and a short headtube is potentially going to have the bar to seat drop too low. Unfortunately the truth will be looking at the downtube length and tt angle. If the downtube is longer and the actual tt lenght is at a steeper angle.....Turner may have compensated for that short headtube somewhat. This is where bike co. specs- (or lack thereof) can get annoying. You can always use a shorter stem and a few spacers/riser bar etc. But i would make sure to ride the XL paying particularly close attention to the bar height in relation to your tall seating height. The bike is likely to feel much more stable......but you may be feeling the wheelbase initially and realize down the road that your back starts bugging you and you go into spacer-dom with more and more spacers. Its funny to see sooo many bike pics and even custom frames on the MTBR with whacked out spacer use---because people havent properly assessed saddle to bar drop. (usually because its virtually impossible with the few specs given on bike websites). Virtual toptube is meaningless if you dont know what the downtube/headtube and tt angle is. In reference--im 6'4-fairly avg torso-leg length- and all 4 custom builders spec'd 6.5-7" ht and all came out with a floor to bar height of 42.5". My saddle height from floor to saddle top of center is 44.85 with a 13.5"bb height.

If you measure your stumpy bar to floor-bb to floor and bar ends to floor....i can probably tell you if the Sultan xl will have an issues with ht length for your size.

Speaking of which---you should measure your STumpy dt and ht and have that ammo handy when comparing frames. Or easier yet-- bar to floor height and saddle to floor height and saddle tip to bar at the center of the stem. You will start to see how these variations can wildly effect positioning on bike and contribute to its feel.

 

[dieselcruiserhead]

RE stumpy geometry, I can tell you almost all of that info off the top of my head... (Going back to that question of if I should base my measurements off what I like/know or if I should start from scratch on what other people are telling me).

BB height, I think its 12.5 or 12.75, less than the Sultan and other frames I seem to like. Heigher BB goes a long way with full suspension though as we know. Stumpy standover is about 32-33", the seat tube and head tube angle of the Stumpy are 71/73, same as the Sultan, and the VTT is 24.3, the Sultan is about 25.5 just a hair over an inch longer. On their 5" models it is closers to what I have with the stumpy with a 69" head angle hence the increased wheel base to about 45" (the stumpy is 43 1/4"). I do not know the other measurements off the top of my head but will remeasure when I get home and post up...

I have read read and read the reviews on MTBR mostly in the forums and I think you guys are right aobut 1/5 actually being right on. The Sultan suspension seems a little plusher and deeper than the Ventana El Rey (the manufacturer I have a deal with) which is what I was looking for. But I'll come across people saying it really does handle like a 4". If this were a 26er bike I would be interested in 5", don't even think I'd consider 4" most likely. But word on the street is 4" 29er is like 5" 26er because of hte wheel characteristics.

I think you guys are right about wheel lift of the Sultan though, will be way forward particualrly with that steep angle the seat stays. Supposedly it climbs like a goat, never read anything that disputed that, a lot as saying "it is the best climbing bike I've ridden." What I like about hte Sultan versus the Ventana is the longer top tube and the slacker 73" seat angle puts the seat father back. So yes it has those long-ass chain stays but buts the seat father back and over the wheel versus in front of it. Not too far forward. And there is that 1" longer top tube but I think it will still handle well for descents. I think what is good about the 71 degree tube (I've probably mentioned this) is quick turning and more steering power, I don't think much loss of DH performance because of hte larger wheels, don't resist as much. But yes weight will be father forward. but this is how the stumpy is and again I don't think it will feel any worse. I do go over the bars here and there on the Stumpy though But have managed it pretty well and its been months and months since one of those, other than one last week

So I dunno. I am not 100% sold on this frame. The Intense Spider 29er seems like a pretty sweet option. they have a prototype 5.5" travel one they just came out with. Not sold on Intense either, suspension system seems funky but supposedly works really well. I think the head angle is 72 degrees or something like that though! turns really agressively...!

Then there is the Ventana. I might be more sold on this except the seat tube it steep and really moves your forward, same cainstay length (~18"). And does not feel as plush.

Again I've going to ride some more 29ers. I think I mentioned it, there is a local shop that now that 24 hours of Moab is over I'll take out some of their 29er full suspensions and see what I think... I dunno maybe I should go back to 26er but 29er seems like it would be a better fit... But again the geometry *does get weird* with these big ass wheels. There is a pretty good new thread on MTBR about 650B, seems to make more and more sense the more I think about it...

 

[dieselcruiserhead]

and in the end too I think most of these frames sound pretty good and will all work. the good news is I haven't spent too much time on FS or on one bike versus another, so I can still modify myself and probably feel comfortable on one bike versus another fairly easily.. that is not what I should do but with the mostly minimal differences between all of these frames, I don't think there is a real clear loser and I'll probably be happy on any of them... But I think it does go a long way to check and know these things.

I'm also excited to maybe build a frame (semi-on the cheap, with my mig welder) and experiment with some geometry this way too I'll post up if I ever do any of that...

Cheers!

 

[Pokey]

As usual it really comes down to what your intended purpose is. For me 69deg head angle is really more all mountain-ish versus true xc-ish(71). Whats nice about the 69deg. is that you can always opt for a Talus type fork and drop the front end down for climbing......giving you a bit more versatility if you want a "do-it-all-well" type bike.

 

[Christophe Noel]

What I like about hte Sultan versus the Ventana is the longer top tube and the slacker 73" seat angle puts the seat father back. So yes it has those long-ass chain stays but buts the seat father back and over the wheel versus in front of it. Not too far forward. And there is that 1" longer top tube but I think it will still handle well for descents. I think what is good about the 71 degree tube (I've probably mentioned this) is quick turning and more steering power, I don't think much loss of DH performance because of hte larger wheels, don't resist as much. But yes weight will be father forward. but this is how the stumpy is and again I don't think it will feel any worse. I do go over the bars here and there on the Stumpy though But have managed it pretty well and its been months and months since one of those, other than one last week
.

The most common mistake in road fit and almost always in mountain fit is miss-use of seat angle and fore/aft of seat rails. Where you sit over the BB is CRITICAL for proper delivery. How your hips, femur, lower leg and foot relate to the crank arm is largely effected by where your hips are over the BB. Secondary to that is how you balance over the bike. That is in part a matter of positioning over the BB but mostly relative to TT length and bar height which is a combination of HT length and stem rise.

Then again, this is all coming from a certified Serotta, Fit Kit and Fit Systems fitter who usually buys a bike, takes off with a set of allens and just RIDES.