Friday, April 30, 2010

Meaty beaty big and bouncy.

It's not often that I geek out technically here, but I'm long overdue on sharing a new product that I've been involved in bringing to market. Plus, I really oughta write about wheelbuilding once a year or so, dontchathink? Today is gonna be a geek-out day. Deal with it!

More and more often I've been spending my on-bike time aboard 6 and 7" travel machines. Light they are not, and fast climbers they are not. If, when riding, you're in a hurry to get uphill, they are probably not for you. But if you'd rather look around a bit and be social while climbing, or climb the chunk line with some success instead of simply racing on hardpack to the top, what 6+" bikes can do for you on the way back down is truly amazing. Especially for those of us weaned on hardtails before they were called hardtails.

Because my riding time is increasingly on these much-more-sure-footed machines, I've gotten very interested in rims and tires capable of handling what the bikes can. 99% of the time an on-trail mechanical for me means a pinch flat, simply because the bikes can handle a lot more than a standard XC tire can. You go fast, you get air, you smile huge, you rail a corner, you plow through a rock garden, and suddenly you hear air escaping because the anemic little tube got smashed to bits inside of the anemic little tire that should never have been on this bike in the first place.

Thanks largely to Mark Slate at WTB, the wimpy tire conundrum was solved last year with the introduction of Dissent in 29".

It is NOT a something-for-nothing tire as so many on the market purport to be (Weighs nothing! Does the dishes! Carves in antigravity! No unsightly stains! Flat proof!). It is big, meaty, and yes, heavy. It is also very difficult to flat. I was fortunate to be able to work with Mark a bit on the development of Dissent, and got to see the evolution of the casing from underkill to massive overkill and then back to just about perfect. I haven't ridden, seen, or owned a tire that I can ride the way I ride Dissent.

Until Dissent came available we could only dream about pushing this hard on big wheels, but now that it's here the sky's the limit. With any other tire any kind of hard impact (whether from landing a drop in chunk, smacking an errant ledge, or manualing through a boulderfield) meant a quick flat and often a dented rim. It isn't fair to expect a single ply XC tire to be able to hold up to that kind of riding.

Even the 800g+ tires (Nevegal, Stout, Ardent, etc...) couldn't come close to surviving. Tubeless was tried and although tubeless has come a LONG way the past few years, it still wasn't the solution as the tires still weren't durable enough: Instead of basic pinch flats we'd punch rocks right through the casings of the tires, resulting in holes big enough to stick the meat of your thumb through, which (often) meant that the rock kept on going and dented the inside of the rim as well. Sub-optimal. And expensive, and often the rim would be so jagged inside we'd need to walk the bike out.

Anyhoo, the advent of Dissent meant that the tire part of the equation had been solved.

But what about rims? A year ago I was pretty frustrated at the available choices and some of their bad habits. If you wanted a beef-baloney rim in 29" that could handle aggressive use, abuse, bashing and banging day in and day out, essentially you had three choices. On paper they look good, but in practice they all have a fatal flaw. Some have more than one flaw. Beating the daylights out of them on our local and regional rides was an easy way to expose these flaws, but sometimes they never made it out of the truing stand before the flaws became apparent. In other words, bad quality control often followed bad manufacturing, and in one case a rim redesign meant that overnight it became a poor choice for the intended use.

I'm not going to list names or go into any further detail, I'm simply going to sum up by saying that a year ago there wasn't a rim on the market that could handle what these bikes can dish out for more than a few weeks. Every option was explored, built, and ultimately kilt, and usually pretty dang fast. We're talking about a rim a week at times.

For my money, I need to get *at least* a season out of a rim to call it money well spent. Anything less is unacceptable.

Like I said, a year ago I was frustrated.

So I went shopping.

I wandered around all of the bike shops in the valley as well as a few in Moab, asking the shop rats about their experiences riding, building, and maintaining their own personal wheels, as well as what they see come through the shop. As you have no doubt guessed, there was no consensus about any *one* rim (they're shop guys after all--as biased as can be!) but there were only a few that were spoken of favorably by all, and among these was the 26" SunRingle MTX 33. I hadn't the time to build and ride a bunch of 26" wheels, nor did I have a bike to put them on, so to some extent I was going on faith. But I also know and ride with lots of these guys, and I know the trails that they're riding even better. I had a pretty clear idea what I'd be getting with the MTX 33.

So I contacted Scott at SunRingle and he agreed to have a few samples made. When the samples arrived I laced them, tensioned them, and rode them, making notes all along. The MTX 33 rims are a few MM taller than their closest competitors, meaning that you end up using shorter spoke lengths. Taller rim + shorter spokes = stiffer wheel. Not an earth-shattering difference in stiffness, but every incremental improvement matters here. Lacing was normal and they came up to tension in an odd but ultimately good way. Odd? At ~95kgf the tensions weren't balancing out quite the way I would hope, but as the wheel got tighter the balance got better. At ~110kgf everything seems to fall together, so to speak, and they balance out beautifully between 110 and 120kgf. I haven't built them any higher than that--I haven't seen a need to.

And the ride? Just a solid, dependable, predictable rim. All else equal, they have a stouter feel laterally than the competition, and somehow feel slightly less harsh at the same time. I won't go so far as to call them 'compliant', but there is a difference. My seat of the pants is not that finely tuned that I can say *why* it feels different, I can only say that it *does* feel different.

A harsh winter has limited the number of hours I've been able to put on production versions of the rim, so I cannot yet comment on long term durability. They are aluminum rims so they will not be indestructible--no rim truly is. But they seem to resist dents and flat spots better than anything else available, and tension has been holding steady at 110+kgf so they've already surpassed the competition. All signs point to this being the most durable rim available for 29" bikes today.

Lastly, when the samples were made I was most concerned about tire fit. We wanted the MTX to be more friendly to the burlier meats, so we relaxed the fit by just a few millimeters. Not enough to call it loose by any stretch, just enough to be able to get Dissent on and seated without need for multiple DH levers, or massive air pressure, or a mandatory Turrets moment.

To sum up, I'm no longer frustrated! I've now got a trail bike and a DH bike with appropriate rims and tires, allowing me to keep up with any pack of riders on the trail, and sometimes even push them farther than they'd like to go. Hard to imagine such a turn of events just a few years ago.

Your favorite LBS can order Dissent from BTI.

The MTX 33 rims are available directly from SunRingle in 32 and 36h, black.

There are a limited number of the MTX 33's in winter camo as seen above. Those are a exclusive.

Thanks for reading.