Three Things Your Future 29″er Should Have
July 8th, 2008 by Guitar TedRecent developments in technology are making certain things about 29″ers that were negatives less so, or eliminating the problem all together. These are a few of the technological applications that I think need to become widespread in the 29″er world.
Through axle hubs: With Rock Shox’s excellent Maxle and now, the Maxle light, there isn’t any reason to not have 20mm through axle front hubs and put them on all front suspended 29″ers. The effects of having a rock solid connection between the fork legs and wheel are immediately felt and make a 29″ers front end more predictable and fun to ride. I would even suggest that many rigid fork options have 20mm through axles. Especially lightweight carbon ones.
Full suspension bikes could really benefit with the addition of a through axle on the rear of the bike. In fact, Salsa Cycles is currently working on through axle rear drop outs for it’s upcoming Big Mama full suspension 29″er. That should tell you something right there.
Tubeless Ready Tires: There is no question that 29″ers benefit from ditching the archaic tube and going sans bladder. To do this though, you have to either “buy into” a current system such as Stan’s, Bontrager’s Tubeless Ready System, or Mavic/Hutchinson’s set up. You could go to the “ghetto” tubeless set ups, but sometimes certain tires are not so friendly, shall we say?
Anyway, my suggestion is to have all future tire introductions be of the tubeless ready type. Why not? If your tires, (as Continental’s already are) are rated for use with sealant, have a tight tolerance, consistent bead that is strong, why wouldn’t you do this? The tires could be used with tubes or run tubeless. A “win-win” for tire manufacturers and riders alike. This should be done ASAP.
Along with this, rim manufacturers should also be doing things to get their products ready for tubeless use. Bead locks, consistent, tight tolerances, and specific rim strips could go along way in making products more attractive to riders who are obviously looking for solutions to tubeless set ups.
Tapered Steer Tube Technology: My take on the front ends of 29″ers is that they could stand to be stiffer and stronger. A great solution to this problem is the tapered steer tube. The 1 1/2″ to 1 1/8″ taper on the steer tube provides more strength with a minimal weight gain, and with upper end forks and headsets, it could be the same weight as a traditional head set in 1 1/8th inch size. The bigger diameter on the bottom of the head tube means a bigger weld interface for down tubes and allows for larger diameter down tubes in the first place. Both would make the front ends of 29″ers stiffer, stronger, and steer more precisely.
Those are a few things I think should be widely implemented into new 29″er models. All three would enhance the performance and lessen the negatives of any 29″er.
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A simple rib inside the steerer tube, ala the old Control Tech seatposts would solve just about all of the front-to-back flex issues with current 1 1/8 steerers. Tapered steerers mean less compatibility and more manufacturing issues for small-fry custom builders like me. This is an issue that can be solved without resorting to expensive manufacturing methods.
Thru axles: yes
Tubeless-converted tires with high TPI: yes
A simple internal rib, ala the old Control Tech seatposts, would solve the front-to-back flexing issues found in long A-C 1 1/8″ steered forks. Tapered steerers require funky head tubes that discourage the use of steel, and are beyond the manufacturing abilities of most custom builders. If you want to be limited to Trek, Niner, and Special Ed, then this is a cool development… I guess.
The lack of problem-solving ability in the bike industry is astonishing, and it’s part of the reason why we’re constantly dealing with new, non-compatible ’standards’.
PS: Thru axles are great, but not 15mm ones. And tubeless conversions rule the school, especially if you live in an area without jagged rocks.
Why can’t I leave a comment ? (3rd try)
Steve, a Control Tech style rib would be pointless. The flex the you get from a fork comes from where the steerer tube joins the fork crown. The lowers/blades also flex. But the frame itself also takes a lot front load energy and disperses it as flex as well. Thus the reason for gussets, shaped tubing, etc. Beefing up the lower headtube/downtube junction makes sense.
Congrats…..you’ve left 3 comments!
Steve: On commenting- if you are using a FireFox web browser, it may not show your comment until you refresh the page, or until you leave and start a new session. (I experience this with FireFox, but not with IE)
Thanks for leaving a comment and I’m sorry about your frustrations.
If you wouldn’t mind, could you elaborate on why the tapered steer tube would cause you difficulties? Couldn’t tubing manufacturers help you by offering head tubes set up for this sort of steer tube?
Oderus: Yes, I think that the bracing factor is what makes me like this idea. More area to weld to, less need for a gusset, I see it as a way to also lessen the front triangle torsional flex in 29″ers as well.
I’ll pass. I really like my 29er as it is now, and frankly, even if it is an improvement I don’t want to buy into new stuff that is marginally better every time it comes out. I might get a surly bolt on hub at some point and see how that works. If a bolt on hub is good enough for my downhilling buddy, it’s good enough for me!
I kind of like the idea of tubeless tires, but I’m not interested in the sealant that goes with them.
You didn’t mention wider spaced hubs. I’d love try out a front wheel with a wider spaced hub, I’m all for stronger front wheels. Wider rear hubs is a tough one, kicking your chainstay with your heel is annoying.
Wider rear hubs, like the 150 mm width on my Cruz VPFree likely necessitates a wider BB axle to fix the chainline issue. Would we get used to the wider Q-factor? If we’ve gotten used to the existing measurements, we’d likely get used to something wider.
Tubeless shmubeless…..
Tubeless: took me about one hour to convert both wheels using Stan’s. This includes taping the rims with Stan’s yellow tape. Since then, everything has been great and the tires hold air longer than when I used tubes.
One thing to remember: once a month, check that there is still some liquid sloshing around in the tire. It will dry up over time and then stops being able to seal punctures.
The inner tube is archaic in every other pneumatic tire application. There’s no reason this shouldn’t be the case for bikes too.
I’ll try to do this just once. Sorry, everybody.
Anything other than a straight tube is difficult for a small manufacturer to deal with. Trying to miter a tube to fit against anything tapered or shaped is really tough. Big manufacturers make these miters with lasers. There are some machined parts available to make integrated headsets available, but they’re not very popular.
Integrated headset bearings are a great idea on the top of a 29er head tube because they allow the top tube to weld in, overlapping the area occupied by the bearing. This either allows for more surface area and less overlap on TT/DT or makes it possible for a shorter head tube. On the bottom bearing, it’s less of an advantage because unless you can curve your DT, ala SPecialized, the tube is going to hit your fork crown. Without a curved tube or serious gussets, you end up with a lot of unsupported head tube sticking below the DT junction, and an integrated bearing just makes it worse.
Integrated bearings require larger diameter headtubes and more material, which is OK with aluminum and carbon, which typically use larger tubes, but becomes quite heavy in steel. Add the mismatched aesthetic of giant headtube to slim steel main tubes, and it ’s not so appealing.
I’m open to the idea that a steerer rib wouldn’t work, but I just don’t understand the assertion that the junction of the steerer and crown is ‘flexing’. I understand how material can flex, but not the junction of two materials. If anything bad is going on at the junction, it would be movement, not flex, right? Any movement would cause wear. I haven’t heard that 1 1/8 steerers are moving at the crown, but maybe that’s so.
There are lots of long travel forks out there with these steerers and they’re doing just fine. I suspect that the oversized tapered steerer is a way to maintain strength at a lower weight. As seen in the road world. And product managers love cool new sh!t.
Steve: Thanks for your input. I can see your concerns for the steel, handmade end of things, and you are correct, there are a lot of forks out there with long travel that are not using this tapered steer tube.
What would you say to a head tube that used a 1.5″ diameter all the way up and then use a reducer at the top. Wouldn’t that get you into the tapered steer tube ranks and still retain ease of building/aesthetic qualities? Again, maybe it is overkill, but in certain applications wouldn’t that be an advantage?
Anyway, I thank you for chiming in here again.
“If anything bad is going on at the junction, it would be movement, not flex, right? Any movement would cause wear.” -Steve_
If it’s flexing, it’s moving! When you take a front impact, there is flex in the front end of your bike all the way up the length of the fork. Joints of any kind tend to be the weakest link in many structures. That’s why bikes have gussets, ovalized tubes, bridges and butted tubes. These things are all found near the welds or the weak spots. It’s much easier to break an ankle or knee than a shin or thigh. Joints require reinforcing because they are inheritantly weaker. Ask Cannondale about the recall on there 1992-1993 Pepperoni forks. Aluminum blades with steel steerer tubes. Multiple cases of failed steerer tubes. Hell, they were offering Rock Shox Quad 10s for $100 for anyone with one of those forks. I know, I had 2 of them. Raleigh once made mountain bikes with aluminum main triangles and chromoly stays….didn’t work out to well. Steel and Aluminum don’t hold well together when welded together…..flex helped to separate the back end of the back for a few riders. In regards to requiring a bent downtube to make room for an intergrated headset….rubbish. Road bikes have had intergrated headsets for years without deviating from their “classic” stylings. Schwinn and Giant ran integrated on the Homegrowns and XTC respectively many years ago before a bent downtube was ever thought about. If you have a chance, watch the Tour de France. The slow motion shots that show the guys head on in time trials or sprints can show you how much a frame flexes when it is being ridden.
Good call on wider hubs. It would be great to see some non spiked wide tires, ala pugslies for 29ers. Just narrow enough for KH rims would be ideal.
Oderus: Just to clear one thing up from your comments, the old Raleighs were bonded, not welded. Point still stands though..
One of the really cool things about all this new technology in helmet cams is that now you have a tool that shows you what a frame goes through as it is being ridden. I was watching a demo of a recently released camera and they had it strapped to the handle bar, looking back and downwards towards the bottom bracket on a road bike. They showed the bike as it was being ridden. Man! the thing was flexing like it was made of some sort of liquid all throughout its structure. Crazy!
I’m a tall guy and I ride big bikes but even on my 21″ Karate Monkey and Salsa El Mariachi they both used shorter steerer tubes than either of my Ibis or my Spot.
The steerer tubes on both my Alibi and on my Spot 26″ wheeled bikes were so long that I didn’t have to cut the steerer tubes! The steerer of the Marzocchi forks for my Alibi and my custom made Sycip forks for the Spot were HUGE so I guess the whole issue of steer tube flex for 29″ bikes is a little lost on me.
Don’t bother with the taper system, that’s Special Ed’s own brand of weirdness and they are welcome to it. If the issue of flex bothers you then I think a 1 1/2 steerer tube will be the simplest solution. Also, do you really want to have to pay for a licensing fee to one of the biggest and most aggressive companies in the bike industry ? I’ll reload your gun while you shoot yourself in the other foot.
That said: Through axle hubs - good idea.
Tubeless Ready Tires - good idea. But I think it is somewhat ironic that Salsa’s disc rims are not tubeless compatible.
Hmm, seems like my Cannondale’s with Lefty’s already have some these attributes. Integrated headset, 1.5″ steerer, through axle (sort of), and with Stan’s rims I’ve got the tubeless part covered.
yo Satan Spacemonkey… I know Salsa doesn’t condone this, but I’ve been running certain tires (most WTBs, Maxxis and Bontrager models) on their rims with my getto tubeless system for two full seasons now without significant issues. I can’t run every tire on the market, but I can run most of ‘em.
I also know that the reason Salsa recommends against running their rims tubeless is because they are taking the “standards” issue very seriously, and they want to make sure whatever product they eventually do release is consistent with that standard. I’m confident that when they feel there is enough of an established standard, they will jump into the fray with a compatible rim.
Let’s not fight over flex vs movement.
Any bonded or presses junction should not move AT ALL. If it does, it is a failed joint. Cannondale, and others, have had failures, but there are far more successful pressed/bonded junctions out there. Going to 1.5 doesn’t eliminate the joint, and there’s a discussion about diameter/length of a junction… one that I don’t want to get into.
If you try building a normal 29er frame with a straight downtube and you join that downtube at the bottom of the head tube, even with a conventional headset, it will interfere with the suspension fork crown. Trust me. I know this. An integrated headset would allow the tube to be mounted even lower, making the problem worse.
Integrated bearings are a great way to shorten the head tube length and still allow room for joining of the main tubes on some bikes. Problem is that they are difficult to manufacture with and without a curved downtube, one that can clear the fork crown and still mount low on the head tube, they provide little advantage for 29er.
Steve, please go to your LBS and talk to someone who knows bikes. You need knowledge based in fact, not magazine articles and hearsay.
May I humbly offer that dual chainrings be added to the list? I would really like to get away from a triple on my next XC racing 29er hardtail. Would this not improve chainline (among other things)?
As far as the headset / steerertube issue goes, I like the direction Gary Fisher went with the low stack - I think this helps standover.
Batman, don’t be a snot. It degrades the quality of discussion, because it isn’t discussion, it’s just aggression.
@ Batman.
I’m not 100% certain, but I’m guessing that Steve is Steve Garro, owner/fabricator of Coconino cycles.
If I’m right, he know more about bikes than you could imagine.
Or maybe Steve Potts. One never knows, which is another reason to be nice. But back to the discussion, what might be universally useful? I’m looking at components, and wonder, does it make sense to have a Campy Ultra-Torque BB setup for MTBs? I really like the Hirth joint idea for road bikes, but (a) how would it hold up compared to other BB designs? and (b) would it be practical given the varying spindle lengths needed depending on chainstay clearances?
Also, what about the carbon fiber belt drive from Gates? Is the need for belt tension and a breakable rear triangle or elevated stays a deal killer?
I saw a small S&S coupling on a chainstay recently, for belt drive compatibility. I thought that was pretty smart.
Didn’t those old Sweet Wings cranks use a similar setup to the Ultra-Torque?
That SnS coupled chainstay looked pretty nice. Pardon my ignorance, but did elevated chainstays go by the wayside? Maybe they only work well as part of a suspension system?
>Didn’t those old Sweet Wings cranks use a similar setup to the Ultra-Torque?
Apparently it was most of the way there.
http://pardo.net/pardo/bike/pic/fail/FAIL-006.html
Just to get things back on track…….
I agree fully with the 3 future must haves on your 29er, better tracking and stiffer steering are issues that have become more apparent on 29ers. Cannondale addressed the exact same issue on the 26 inch platform with the Lefty, both fork and head tube stiffness are addressed with it. The Caffeine 29er frame was my choice in terms of handling and feel.
I have ridden and trained for 2 Cape Epics, doing my third next year, tubeless tires are a no-brainer, best available combo I have found for my 29er thus far has been stans rims , Stans tape and Hutchinson Pythons tubeless, a bit narrow, slippery and have a short lifespan but fast and resilient. I wouldn’t choose that on a 26 inch bike in fact have always used Mavic 819’s and Maxxis CrossMark tubeless on 26 inch. I have found Stans sealant to seal best (particularly sidewalls) but has shortest lifespan so has to be replaced every 3 months.