Dirt Rag discussion on "96ers" / Silk Ti
Check out this interview on Dirt Rag's web page http://www.dirtragmag.com/web/brainfart.php?ID=202
Brownie interviews John Castellano who has a bit of a different take on these half breed bikes. I like the terminology he has come up with for them, calling them 50/50's, which makes way more sense to me than "69er", or "96er" or whatever.
I gotta admit that Brownie has somewhat of a point when it comes to fitting smaller riders, and Castellano seems to think so too. At least this discussion makes some sense to me. You guys check it out and see what you think.
One of the problems with retrofitting a bike for shorter inseams is that the top tubes on smaller bikes are shorter which tend to lead to toe overlap depending on the ht angle, rake, etc. I 50/50'd several bikes and some worked better than others.
Some of the specs on small 29ers cause me to wonder if they have toe overlap also.
Anyway, I'm running a Kelly fork on my 15" Gunnar (22" TT) and my size 40 Sidis just clear the Ignitor. A beefier shoe doesn't clear. It's a good ride for me and the only costs were spokes, rim and tire since I build my own wheels .
As far as height, I'm 5-5 and I really don't see a problem with sizing a 29er as long as it's set up right for me. I was going to have a frame made but decided to order a small Soma Juice instead as the geom looks right for me. Guess what? They're out of stock for now. Short riders want frames too!
I strongly disagree woith most that both have to say. False arguments and ones that are half-true. Main facts and factors seem to be left out of the discussion.
And I PLEAD someone explain me why a 26" rear does SO much better at short steep climbs? I dismiss the weight reason, some tires already have well over a 150g difference between a steel and kevlar version. So cheap tires are useless for short steep climbs? The weight difference gets totally lots in that of bike and rider.
If you stand in front of that short steep hill, armed with 2 front wheels (obvious reasons), one 29", or 26". Propelled with only one arm/hand (rather than two trained legs and clipless pedals), does the 26" one shoot to the summit while the 29" one stalls halfway? Seriously, Brown and Catellano, try it. You're making your living out of writing about or building bikes, back up claims with facts please.
I may be odd, but for steep climbs I tend to appreciate my traction. It's an established fact that larger wheels offer better traction. So my 29"er gets me up steeps more easily. And the rolling resistance advantage of a larger rear wheel already more than compensates for the increase in weight. On steep climbs, 90% of the weight is on the rear wheel. If that then rolls a bit easier, that's worth more than it's increase in weight. If it didn't work that way, we'd never out-grow out BMX bikes.
If the industry would just get it's act together already, any rider 5' and up would fit a 29"er fine, (s)he would not require a corrected head tube angle on it, and still get nice and quick handling. Custom rigid forks+frames can already be had for ~$900, only very few tried it, probably considering it impossible.
Q: What did the industry come up with when 26" bikes ended up with handlebars lower than the riders preferred?
-Answer : riser stems that reach higher.
Q: And when that didn't suffice?
-Answer: riser handlebars that reach higher.
Q: Now when a 29"er fit on the tall side up front, what do we do?
- Uhmmmm. That's a tough one man. I think 29" just won't work then, you see it, too damn tall! Nothing will help for that.
With those mentionned 29/26 conversions, going from an 80mm suspension fork to a rigid one, they don't NEED a 1º steeper head tube angle to get the same handling quickness!! They probably went from 38mm (typical suspension fork offset, for some reason) to 45mm with the 1x1 fork. This already overcomes the effect on trail that a 29" front wheel holds over 26". As long as the headtube ends up at around the same height as before, handling will be a-ok. Now if the 1x1 is around an inch shorter than the 26" suspension unit (it is), all is be fine.
Oh, and the extra offset already takes away a bit from the toe overlap issue by putting the front wheel a bit more forward.
Now if 29" suspension fork had a bit more offset, and people would figure out that handlebars only have an "up" and "down" because of the way the logo's are attached...
Please discuss and educate me, I still don't understand.
-Planning to have a flipped Mary setup in a matter of days.
It's for short people
Cloxxki: I hear you on your points and I agree with them. I thought that Castellano and Browne hit upon something here for the exact same reasons you are upset with the suspension fork manufacturers for. That being the rake that is a fixed number right now with suspension forks. I do disagree with Castellano's assesment of who these 50/50 bikes are for. I think the upper limit of the range should be set at 5'5". Anyone that tall or taller should be on a full on 29"er. But until the fork trail conundrum is solved for those wanting a suspension fork, I can see where this 50/50 idea might be a solution.
Now I know that Bigwheel, mikesee and a couple of others have shown their significant others/ friends on very small 29"ers, so I know it can be done, but I think the problem is the suspension fork geometry, which causes some problems for frame designers.
White chimed in here at one time and said that different fork crowns for different sizes,( which would be the ideal, no?) would be very expensive and therefore not practical. I can see that point, and I agree. So, what we are left with is what we have. Perhaps someday we will see someone produce a more 29"er friendly, small person friendly fork crown/ trail figure that will render the mere idea of a 50/50 bike a joke. Until then, I gotta say they have a point there.
50/50 is not a solution for short people, the same toe overlap issues persist. Rigid bikes are the solution for everyone 4'11" and up.
small frame size issues
Welcome to my private hell..... I've been struggling with toe overlap issues on our 13" 96er frames for months. There's only so much distance between the BB and the front hub. When you start whittling away at that distance with 170 mm. cranks, an eccentric BB in a rear position, an assumption that a 13" frame size rider has small feet (not always true), and a reasonable tire width, it can be done, but there's not much room left over. Sure, we could lengthen the top tube, but what's the point? We've redesigned our frame three times, and come to the conclusion that there will always be a "limiting factor". Our three choices were to...
1. Build a 13" frame with the top tube of a 15". Not so bad for a short inseamed rider, but sluggish and uncomfortable for a normally proportioned shorter rider.
2. Stick with a short top tube and slacken the head angle. Lots of low speed wheel flop when climbing and generally funky handling characteristics.
3. Go for the shortest top tube possible, a normal head angle, and the limitations of 2.1" tires or less, 170 cranks, and a shoe size of 41 or smaller.
Just curious what you all think???
Just don't offer the 13", or do so with a rigid fork built especially for it and the 15". Throw in 50mm offset of more (Jones makes them 63mm). And as you're going rigid anyway, make it non-suspension corrected to get the bars at desired height. Now THAT would be a great ahndling bike!
On Eurobike I saw some modern flex stem ideas. JUst might not suck, especially for 13" and 15" riders. Just might be the way forward if you MUST have front squish on a quick ahndling small 29"er.
I can only imagine how it must be to stand 5' tall, and ride a 29"er with short top tube that fits like a glove, with some decent stem length even, and only 70mm or so trail. HOW to endo such a bike? And worse for me : how to ever keep up with such a rocket midget?
What I forgot to mention ealier : the 29" rear wheel is hardly a factor for small riders, unless they insist on hanging way over the back of their seats. Being so short and with such a long 29" wheeled front center, I can barely imagine that to be required more than once in a while.
What about standover height?
You guys have discussed the front/ center problem, but no one has touched on the stand over issue that was brought up in the Dirt Rag piece. I gathered from the interview that the reason Castellano uses the 50/50 is to gain a bit more standover height in smaller sizes. This reason that you bring up here, Cloxxki, might also be another influencing factor.
Originally Posted by Cloxxki
My opinion about the standover issue is that it's a bogus reason to go to a 50/50. I thought that perhaps someone would pick up on that.
Judging from what I'm seeing here, it might be easy to draw the conclusion that short folks should just stick to 26 inchers, since there would be far less hurdles to overcome to get on a bike and ride. Correct?
30 years since the first mountainbikes, probably 100+ years of mixte frames, and we would not be able to get standover right on smaller frames?
The 13" bikes should anyway be equipped with 165-170mm cranks, allowing for a lower BB already. 75-80mm BB drop shouldn't be a problem at all. The cross-brace solution is very common on Softtails and FSs already.
Maybe some day we'll see special 29"er rear fender that allow a short rider to safely hang behind theirs seats and even lean on the fender. Perhaps *gaps* use it even as purposely designed ass-brake.
I really don't get this statement - how do longer bars which slow down steering response 'compensate' for slower steering from a larger trail figure? I'm not doubting Castellano, just would like to hear his reasoning behind this statement - anyone got any ideas?
Originally Posted by John Castellano
I can see how a SUPER HEAVY front wheel will make a wider handlebar useful, but for 26" vs. 29"...I'd like to know too. I do know that if you have a long-for-you toptube, a stort stem and wide handlebar work just fine. If downhillers like their <40mm stems, why not short 29" riders? Keep toptube long, head tube angle steep, and end up with quick handling anyway. Normal width bars might be fine for short riders though.
Kill your... television
tons of Stand-over, 22.5" top-tube and lots of toe clearence:
Originally Posted by Guitar Ted
"Whereas Motoman's bike looks like an industrial, TinkerToy experiment gone horribly wrong." - Aquaholic
Ya, Castellano doesn't know sh*t about bike frames, you should give him an education. How many frames have you built by the way?
Originally Posted by Cloxxki
I don't have to be a master builder to disagree. I can be clueless and still disagree.
I've got two left ands and can't ride worth ****, but I do have an opinion on this topic.
The "handlebar comment"
I think what was trying to be said was that in order for the smaller frame size to work out with the fixed trail number/ head tube angle (to preserve handling traits) the top tube could only be made short to a point, which for the really small sizes, wasn't short enough. To compensate, Castellano was saying a short stem/ wide handlebar combo could offset this problem.
I think a really interesting comment was made by mikesee about his Black Sheep single speed, (a darn fine looking machine, by the way!) when he said that his trail/ head angle was a quick handling combination, and I seem to remember that head angle was something like 69 degrees, no? That sort of set up would eliminate the use of a suspension fork, but it would help with toe overlap and top tube length. Cloxxki, you already said this, I think, so I'm sorry if I'm repeating here!
The use of the smaller rear wheel, which really is the defining nature of this whole 50/ 50 thing, is absolutely bogus. It doesn't help you make a smaller frame, and it doesn't increase performance over a 29" wheel. I agree that most of the benefits of 29"ers are to be found at the rear wheel. If "rolling over stuff" better is the reason you stick a bigger front wheel on the front of your bike, than why in the world wouldn't you want your rear wheel to do the same? Heck, that's what suspension forks were designed for 26 inch wheels for, to get them to roll over stuff better. Then they found out that it really made a huge difference when you helped the rear end roll over stuff better with rear suspension. Now with 29"ers, people go back to riding rigid and hardtails because the wheels are doing what suspension did on 26"ers. It's also the reason that alot of folks say that 4" rear travel on a 29"er feels like more.
So, if you are too small for a 29"er, you can go 26"er, but please, let's leave this 50/ 50 stuff behind. It just doesn't make any sense on any level, to me. At least not anymore since I've read through this thread. I did have a glimmer of hope for it, though I knew it was probably in vain. Thanks guys!
Bikes like MikeC wasn't hat I meant to refer to, rahter the opposite in a Genesis kind of way : huge toptube, steep head angle still, supershort stem.
Why MikeC enjoys his unique bike as "quick" handling may be thanks to his skillz, or a unique weight distribution. For mere mortals it may not work well on box-stock frames.
Please let carver use his (way cool) family name to make 29/29 bikes! Apart from the small rear wheels, it's a fine concept in many way.
What I still don't understand about the Carvers, is that the "Mini" accepts 26" and 24" both front and rear, while even the hugest XXL 96'er doesn't accept a 29" rear wheel. In percentage of rider height (6'2"+ vs sub-5') even over a 24/24 bike the XXL should be AT LEAST 29/29.
Who'll build a 69'er? Simply your 29" hardtail or FS, mated to a typical 26" front wheel (who hasn't got one to use or borrow) and an appopriate length fork. Note that the fork would have to be ~60mm longer than a typical 26" fork to keep geoemtry level. Ideal is a Kona 2-9, with it's 71º HTA, like seen on most non-Kona 26" bikes. A long-ass fork with travel reduced to 80 or 100mm.
See how it handles. Cornering of a good 26" front end, and the smooth rolling, steep climbing of a 29" rear wheel. By concept (when purposely built) identical to, or lower total weigth than the 96'er. No geometry restrictions, just a tad longer rear end. All the meaty front tires in the world to chose from for real bite. Higher straightline speeds due to lower rollingresistance regardless. Choice of Fox and Manitou forks. Lots of front rims. More brakepower from the same front rotor saize, oh man, the advantages of a front wheel are endless!
GlowBoy did that!
GlowBoy, who often posts here used to put a Gazzalodi 3.0 on the front of his Karate Monkey. He claimed it was very nearly the same ride height as a standard 29" wheel and tire combo. I remember that it didn't perform too badly, but he didn't care for the weight or something as I recall.
I know he did, but maily for ridig cush.traction reason I think. 3.0 is hardly a typical XC tire now, is it? :-)
Good for nothin'
Originally Posted by Cloxxki
On steep climbs, I'm standing up and my weight is mostly over the bars. Explain the 90% figure, please?
Your climb is not steep enough for my taste ;-) The kind I mean by steep, you can't keep your front wheel on the trail (or wall). You may have weight on the bars, but when the bars are vertically above the rear wheel, what goes does that do for the front wheel? Try endo on a steep hill.
But you're right, singlespeeders may be less of an example to support my case.
Cloxxki: My KM is a single speed and even if it wasn't, the nature of technical, steep climbing is really about the same. One must balance their body weight to a point that the front tire is in contact with the ground, but that doesn't necessarily mean you have a lot of weight over that wheel. Consider what happens if you un-weight the rear wheel a little too much during a climb. Spin out! So, even though you may be out of the saddle climbing, and it might appear that you have your front tire weighted evenly with the rear, this is not the case. Your rear tire needs more weight on it during climbing to make it bite into the terrain. Any hint of un-weighting, and your climb is over.
Originally Posted by Cloxxki
This is probably obvious to some, so please pardon me. I am only trying to show that Cloxxki is at least partially correct in his statement about rear tire weighting. It may not be 90%, but that'd be a great number to achieve as long as you could keep the front end down on a climb!
Steel and teeth.
Absolutely! It is a dynamic balancing act...
Originally Posted by Guitar Ted
Good memory! That was 18 months ago. Yes, I ran an Arrow Prime Wide 26x3.0 on the front of my KM for a few weeks. It definitely made the bike feel a bit more sluggish accelerating and climbing, but not outrageously so.
Originally Posted by Guitar Ted
Although it made the ride more comfortable and I could bash huge rocks with ease, I was surprised to find that the bike still didn't have that same feeling of "rolling over" stuff that it did with the 29" wheel up front, probably because a lot of the extra diameter got eaten up as the tire compressed.
Also, I was surprised to find that the bike lost a lot of its magical 29" stability with the 3.0 on the front. It felt like a 26"er again in that respect. I didn't have the same ability to keep the bike balanced at low speeds through rock gardens and around switchbacks as I'd gotten used to. The 26" fattie only dropped the front end half an inch or so -- at least when the tire was unweighted. Maybe that's enough geometry change to throw off the handling, or maybe it's just that real-world biking compresses the tire enough to steepen the geometry a lot more than half a degree. In any event, I couldn't believe how much better the bike handled when I put the 29" front wheel back in.
"People like GloyBoy are deaf. They are partisan, intellectually lazy & usually very angry." -Jaybo
Perhaps a fat 26" tire just has a really wide and short contact patch, vs. the long and narrow for the typical 29" tire. I can imagine that to offer a totally different feel even if the geoemtry is more or less the same.
I stumbled across this thread recently and thought a few elements had been lost in the analysis of the 50/50 for the Silk Ti. Ive spoke to John about this model and he argues that the front 29" retains 75% or so of the 29" advantage. And from what I understand ta nl 29" is a disadvantage in tight, twisty turns, and for some reason it is greater if one is shorter, perhaps due to weight/momentum issues of the rider vs. bike. The greater issue in the silk ti is that the design has limitations so that the tob tube has to converge near the the top of the rear triangle. Im sure it could be further tweeked, but it is by far the best design for a soft tail yet prodcued and a YYB or anything else does not compare. And as we know John is a particularly creative individual in working with the dynamics of metals and thinking out of the box.
Just my two cents
vaya cond dios