[James Romeyn]

...I have to say, I'm sold on the 29'ers.  Given the amount of roots and rocks I rolled over with ease while my guide was picking more lines, I have to say I see the draw for why they are popular out here...

I'm 6-3 and owned two FS 26 Specialized, the first a $2500 MSRP Stumpjumper, the second a $4k Epic Carbon.  Since trading the Epic for a $1900 29 HT aluminum I don't even consider 26 mountain bikes anymore.  Next is the 29 HT steel frame mentioned earlier, with 2x10 gears and new WTB tubeless (wheel arrive this fall).   

[PhilNYC]

The 42/29 front and 11-36 rear will work. However, most of your riding will be on the front 29 ring. Use Sheldon Brown's gear calculator and compare the gear combination that you are using now.

There is a good iPhone apps that I use... "bike gears". 

After thinking about it a bunch, I think I'm going to stick with a triple in front (going 3x9 or 3x10 instead of 2x10)...

Oh wait...I'm changing my mind again...

[Levi]

To each his own Phil.  BTW, are you still using triple in your road bikes?  My new road bike uses 2x10 which I think works truly great!

[PhilNYC]

To each his own Phil.  BTW, are you still using triple in your road bikes?  My new road bike uses 2x10 which I think works truly great!

I've never used a triple on my road bikes...for road, I use pretty standard race stuff (53-39 chain-rings and 12-23 cassette in the back).  On my Spectrum (the bike I ride the most), I am using a 9-speed cassette....

My hesitation with 2x10 for the mtb comes from thinking about entering Leadville next year.  Both of my friends who raced it this year said that they used all the extremes on their 3x9 gearing (22-34 for climbs and 44-11 for downhills/flats) with lots of sections of 20% gradients that extend for long stretches.  With 2x10, those extreme ratios are missing by about 10%, and that spooks me just a little bit.  On the other hand, riding out here in NNJ, I don't think I've ever used those extreme ratios riding on local trails, which is what made me think about going 2x10 in the first place...

Certainly I won't select my gearing based solely on the possibility of riding Leadville once...and I'm still checking to see if my 2004 frame will be "compatible" with the 2x10 crankset (which has a narrower Q-factor)...but even just from the perspective of my getting older makes me think about those smaller gears...

[JoshK]

I am definitely loosing my big chainring in favor of a bashguard.   After riding JH yesterday, my suspicions were confirmed.  There really is no reason around here to use the big ring off-piste.  It only serves to lower your clearance.   

In fact, yesterday, except for one steep road climb near the end of our trek, I never used the FD at all.  I am not ready to loose the granny gear, but it is tempting to set it up 1x9. 

Jungle Habitat did make me pause a bit about the 29er.  I'd have been more comfortable in length and turning radius with a 26'er.  The single track at JH is very narrow with super tight turns which was a challenge.  That trail was made for 26'ers.

Still I think I was benfitting for a better roll-over in some places and had a higher clearance for some of the "trail features". 

[Levi]

Hey Phil, If you use a 22 or 24 granny and 34 rear in my opinion it is so slow that I'd rather cx the bike (cx is cyclocross ).  You might not make it to the cut off point at Leadville.  Imagine missing it by 10mins.     LOL!

[PhilNYC]

Hey Phil, If you use a 22 or 24 granny and 34 rear in my opinion it is so slow that I'd rather cx the bike (cx is cyclocross ).  You might not make it to the cut off point at Leadville.  Imagine missing it by 10mins.     LOL!

I thought so too, but on a 20% grade, being able to ride at 2mph is faster than walking the bike at 1mph...and having to do that over an 8-mile climb definitely runs the risk of missing the cut-off.  One of my friends did, in fact, miss the final cut-off by exactly 10 minutes...over the whole 100 mile course, that is missing it by about 6 seconds per mile...   So having an edge on the low-gears for the hills is a big deal.  And for that matter, so is having the appropriate big gear for the flats and downhills...

(note: the 8-mile climb has an average grade of 8%, so it's not like it would be 2mph up the whole thing...but there are *long* stretches of 20% grade on three of the major climbs...)

[Levi]

My gear calculator gives my 39 front and 36T rear = 28.4 gear inch.  That is at 90 RPM will be 7.6mph which is 7m53s per mile.  Fast enough for racing on a 10-20% grade.  Lewis Morris Park has 4miles incline of loose gravel and roots at 10-15% grade.

I barely redline a 39 front and 11 rear on a dirt road.  That is good for 25mph on a gravel spinning at 90RPM.  That is extremely fast and you cannot make sharp turns.     

[PhilNYC]

My gear calculator gives my 39 front and 36T rear = 28.4 gear inch.  That is at 90 RPM will be 7.6mph which is 7m53s per mile.  Fast enough for racing on a 10-20% grade.  Lewis Morris Park has 4miles incline of loose gravel and roots at 10-15% grade.

There's no way I could do a 20% grade using a 39 in front...   I will have to try Lewis Morris Park, but I will say that there is nothing I have ridden in Ringwood or Blue Mountain that comes even close to the hills at Leadville in terms of a combination of grade and length.

Fwiw, to finish Leadville in under 12 hours, your average speed over the entire course would need to be 8.333mph...more than a 3rd of the racers do not finish... 

I barely redline a 39 front and 11 rear on a dirt road.  That is good for 25mph on a gravel spinning at 90RPM.  That is extremely fast and you cannot make sharp turns. 

According to my friends' Garmins, their max speed at Leadville was 40+ mph...

[brj]

What options for tires are there that work with the ZTR rims?  And what hubs are you using?

Sorry - I hadn't checked this thread in a while...

I'm using Hadley Racing XC hubs.  They weren't the lightest option available, but they are very smooth and the rear hub has what I believe to be the fastest engagement offered on any rear MTB hub.  (5 degrees vs. 15 degrees or more for most other hubs.)  I also looked at White Industries, DT Swiss and Hope.  One nice thing about the Hadley hubs is that I can convert them to any of the currently known mounting systems.  The ratchet sound when coasting is louder than my previous Bontrager hubs, but not enough to bother me.

As for tires, many of the big MTB tire manufacturers have tires that are compatible with Stan's rims now, though I haven't done a meaningful survey lately.  I decided to try the Geax Saguaro 26x2.2" TNT ("Tube No Tube") tire.  I suspect I would have been better off with the 2.0" width instead of the 2.2", given XC type riding on typically dry dirt/sand/rock Colorado trails.  These feel looser than I'd like in sandier corners, but I can't tell how much of that is the tire itself vs the chosen width and lower pressure I'm riding at with the tubeless setup.

[Levi]

Sorry to blow your bubble.  You might want to check I9's 3degree of engagement.   


Holy 120 engagement points! How strong is your drive mechanism?  The Industry Nine drive mechanism is a fairly simple, tried-and-true pawl arrangement. When engaged, each of the three driving pawls itself has three points, providing nine points of contact to the hardened A2 drive ring. The drive ring has 60 teeth, which would normally allow a 6-degree engagement – among the fastest in the industry. Our proprietary mechanism allows for a second set of three pawls, phased three degrees from the first. This feature cuts engagement time in half, to a mind-blowing three degrees! Our lightning quick take-up has become highly desirable on singlespeeds, twenty-niners, and disciplines with gate starts. We have tested our drive system beyond 700 ft-lbs of torque, which amounts roughly to a super-chipped Ford Power Stroke turbo diesel engine. In over two years of prototyping and testing, we have had zero drive mechanism failures. 

They weren't the lightest option available, but they are very smooth and the rear hub has what I believe to be the fastest engagement offered on any rear MTB hub.  (5 degrees vs. 15 degrees or more for most other hubs.)  I also looked at White Industries, DT Swiss and Hope.  One nice thing about the Hadley hubs is that I can convert them to any of the currently known mounting systems.  The ratchet sound when coasting is louder than my previous Bontrager hubs, but not enough to bother me.

[brj]

D'oh!

Figures! 

[Levi]

3 or 6 deg they are both equally fast!  You will only notice the difference when you use slow hubs like for example Mavic hubs.

[PhilNYC]

Ok, so I have to put forth the Chris King engagement info...!


"All of our rear hubs utilize our patented RingDrive™ engagement mechanism. RingDrive™ uses 72 engagement teeth on each drive ring. That means the hub engages over 3 times quicker than the standard 24 tooth pawl-type freehub. Trying to get started again in the middle of a steep uphill section? Going for the surprise jump to drop your buddies? This unique design offers instant and positive engagement that's capable of handling a torque load of over 800ft/lbs, or over three times more than most other high end hubs we've tested. It is the heart of our hub and all the rest is built around it."

[Levi]

This is one of the many reason's I love my I9. It is also the "King of Bling". 

[brj]

Yep, I'd briefly looked at the Chris King as well.  360 deg / 72 = 5 deg engagement, matching the Hadley, but losing by 2 deg to the "king of bling"!

I don't remember off hand why I stopped considering the CK, though I was getting advice from my wheel builder at the time.

[PhilNYC]

Yep, I'd briefly looked at the Chris King as well.  360 deg / 72 = 5 deg engagement, matching the Hadley, but losing by 2 deg to the "king of bling"!

I don't remember off hand why I stopped considering the CK, though I was getting advice from my wheel builder at the time.

One of the things that some people don't like about the CK is the sound that it makes....(I actually really like the sound!)

[Levi]

The only problem I see with CK probably is the wait time ?!?

They are all great hubs! 

[DaveC113]

I've used many hubs, they all have their pros and cons.... for me the simplicity of the DT system wins, now that they have 36 point engagement. For me that is enough, and the DT hubs are also very quiet which is nice. Buzzing is only pleasant because people associate it with quality hubs, the buzzing in and of itsself is annoying, try switching back to a quiet hub and see. 

[PhilNYC]

Buzzing is only pleasant because people associate it with quality hubs, the buzzing in and of itsself is annoying, try switching back to a quiet hub and see. 

I like the buzzing because it lets the guy in front of me know that I'm there coasting...