Words and pics by Sanny
Ever fat curious, Sanny has been dabbling in the dark arts of plus size wheels to see whether the outsize new kid on the block, 650B+, is all it is cracked up to be or whether it is just another new standard to add to the list of “new standards” that seem to grow inexorably year on year.
“Not another new standard!”
Admit it, even if you are a dyed in the wool, “26 inch will never die” rider (and let’s face it, despite what you might think, most of us continue to ride on the currently unfashionable wheel size), like me, you’ve probably at least been intrigued by the latest fashion for all things 650B+. As a confirmed fan of all things 26 inch and fat as well as 29 inch, my curiosity got the better of me so I decided to find out whether there is something to the wide eyed enthusiasm which 650B+ offers or whether, as my old boss Bill put it so eloquently, is it just a case of “all fart and nae sh#te!” Eloquence to match even Oscar Wilde, methinks.
So just what is 650B+ (other than a pain to type!), where does it come from, how does it work, do I really need it?
In the beginning, there was Surly and lo, they created a monster wheelset that was neither super skinny nor full fat, the 29 inch Rabbit Hole and the Knard 3 inch tyre. Of course, given that nobody was producing a frame designed around these balloon tyres, they made a dedicated frameset too, the Krampus. And so it was that the plus size revolution was born. Recognising the traction benefits from running wider tyres and rims from their years at the forefront of the fat bike revolution, Surly applied their learnings to produce a style of bike that enjoyed many of the positive qualities of fat bikes with fewer of the downsides. Improved traction, able to run tyres at a lower pressure but with less rolling resistance than a full fat tyre and an increased sidewall diameter to enable the rider to bomb through rocky terrain while maintaining composure; the benefits were obvious. Plus size had arrived. It’s no exaggeration to say that the Krampus caused quite a stir. For what is just a rigid bike, an awful lot of respected journo’s tried it and came away with big grins on their faces.
They say imitation is the sincerest form of flattery. Step forward a couple of years and WTB dipped their substantial toe in the waters and produced the first plus size tyre and wheel combo based on the oh so hot right now 650B+ wheel size. Their 45mm internal diameter Scraper rim and the 2.8 inch Trailblazer tyre made their first public appearance on a Rocky Mountain Sherpa concept bike at the 2014 Sea Otter Classic. Based on a 29er Element frameset, whether deliberately or unwittingly, WTB and Rocky Mountain awoke a sleeping giant. If 650B+ wheels and tyres could fit into an existing 29er frame, was it possible that this new technology could be adopted by riders without having to shell out their hard earned cash on entirely new framesets? The revolution had begun.
So what makes plus different from everything else?
First off, just like Terence Mann put it in “Field of Dreams” as he is about to hit Kevin Costner on the noggin with a golf stick, “Rules? There are no rules here!” As a useful starting point, let’s look at rim width. It’s here that internal rim measurements come into play. Some would argue that you have to be 40mm plus to be a plus size tyre while others are content to settle on a something narrower. Obviously, the wider the internal width, the more plus size a rim becomes until that point at which it becomes full fat. From my perspective, I reckon that anything between 30mm and 50mm is on the money. Normal mountain bike rims start at around 17mm with a pair of Mavic Deemax downhill rims coming in at 21mm internal diameter.
With tyres, there is less consensus with the key elements being tyre width and sidewall depth. Even more than with traditional 26 inch tyres, there is a huge disparity in what different manufacturers refer to as a particular width of plus size tyre. What one calls a 3 inch tyre may look more like a 2.5 inch tyre from another manufacturer. Sidewall depths vary too meaning that for two tyres of nominally the same dimensions on paper, one may fit a frame whereas the other doesn’t. As such, it can be something of a minefield when trying to decide which tyre and wheel combo are right for you and can lead to an expensive game of trial and error. Thankfully, help is at hand courtesy of the Singletrackworld Hive Mind in this enormously useful thread where forumites have shared their real world experiences of tyre, rim, frame and fork combinations.
So why go 650B+?
As I explained earlier, 650B+ promises the benefits of a wheel and tyre diameter that very closely mimics that of a regular 29er set up thus offering the inherent advantages of a 29er (faster and easier rolling than a 26 inch set up, more capable through rock gardens, improved stability) while bringing a wider contact patch (thus improving traction and grip levels) and the ability to run tyres at a lower pressure. On paper, it is a very compelling argument. With careful design, the overall weight does not have to be substantially greater than that of a regular 29er set up. It sounds like a real win win, doesn’t it? Assuming that you can find a combination that you can run on your existing bike, should you be tempted?
Practicing the dark arts
In the name of scientific advancement, I decided to build up a 650B+ set up for myself to see whether it actually lives up to its lofty aspirations. I am always naturally suspicious of claims that everything new is good and immediately renders existing technology obsolete. Had I not cracked the frame after several years of loyal service, I would no doubt still be riding my original Horst Link Turner 5 Spot even to this day. You would think that inch and an eighth headsets, 9 speed and square taper bottom brackets have no place in the armoury of the modern rider but I still happily ride all of the above. My ride experience doesn’t feel in any way diminished by not having the next big thing to play with. However, sometimes you need to try something new before making a judgement.
The important stuff
In order to embrace the new, I started with my current weapon of choice, a Turner Sultan 29er built up with Fox 34 forks, Mavic tubeless rims and 2.35 inch Schwalbe Hans Damff tyres. Taking my cue from Dave Turner who displayed a Sultan fitted with 650B+ rims and tyres at the Taipei Bike show last year, I knew that I stood a reasonable chance of success.
For wheels, I wanted a pair that was wide enough to give me the benefits of a wider rim without straying into too wide territory. Dave Turner used 35mm external diameter rims and as good fortune would have it, Matt at ISON Distribution came to my aid in the form of the very first production Halo Vapour 35mm wheels. With an internal diameter of 30mm and a depth of 19mm and featuring eyelets for strength, these seemed like just the ticket.
I have enjoyed great success running Halo wheels in the past. They have proven to be extremely durable despite their XC designation thus I was keen to see how these would fare. Marketed as being suitable for 2.25 inch to 2.8 inch tyre, I opted to push the design spec a little and fit them with a full 3 inch tyre. Well, if it is good enough for Dave Turner! As if by magic, Matt came up trumps again and was able to offer me the first to land in the UK production Schwalbe Nobby Nics in the 3 inch version and Rocket Rons in a 2.8 inch version. They were destined for his personal set up so big thanks to Matt for coming up trumps for us.
Do they fit?
Removing my existing Mavic and Hans Damff set up, I decided to start conservatively with the Rocket Rons. Set up of the tyres on the tubeless ready Halo Vapour rims was straightforward. Fitting them to my Turner, there was still plenty of space front and rear at the critical rear triangle and fork brace points, both height and width wise. While girthsome compared to the Hans Damffs, they didn’t measure up in terms of overall wheel height and were approximately an inch smaller in overall height. While clearly bigger than a normal 650B tyre, they didn’t quite match up to the 29er wheel size. However, being a shallow tread tyre, it’s perhaps an unfair comparison and I would be keen to see how they measure up to a normal 29er Rocket Ron set up as I suspect there would be much less of a difference.
Switching over to the 3 inch Nobby Nics, the increase in both volume and height is noticeable. The 2.35 inch Hans Damffs look positively anorexic in comparison. The Hans Damffs are what I have always considered to be a good, aggressive trail tyre that is particularly well suited to high Lakeland adventures. Having also run 29 inch Nobby Nics in the past, I have built up a lot of pilot time with Schwalbe tyres and am familiar with their traits. In terms of height differential, the Hans Damffs edge it by less than a centimetre while comparing with 29 inch Nobby Nics, the difference is negligible. Width wise, there is no comparison.
The 650B+ Nobby Nics look truly humungous and remind me of the old Nokkian Gazzalodi tyre, albeit without the enormous weight penalty of those puppies. It’s easy to be caught up in the hyperbole of 650B+ giving 29er size with plus size performance, given the massive disparity in height and tyre width between manufacturers. However, on the basis of this set up, the size claims hold true.
“I guarantee that at some point, everything’s going to go south on you.”
With more than adequate mud clearance both front and year when using the 3 inch Nobby Nics, I was feeling pretty happy with my handiwork. This 650B+ set up is a snap, I thought to myself. Ah, hubris, welcome back my old friend. It really had been all too easy. Frame clearance? Check! Fork clearance? Check! Chain clearance? Oh bugger!
As a committed 2 X rider, not being able to use the granny gears is not an option for me. However, with the chain rubbing the tyre on the larger cogs of the cassette, I had to science the shit out of it (or just fiddle with the bottom bracket – Ed). Sometimes , old technology brings unexpected benefits. As a user of square taper bottom brackets, I was able to fix my chain line by swapping from a 113mm bottom bracket to a 122mm bottom bracket. It was a very cheap but effective fix which resolved the issue. I was back in business.
Enough with the yada yada, how does it ride?
Having spent the last few months riding a fat bike pretty much to the exclusion of other mountain bikes, getting back on the Turner came as something of a surprise. Even 3 inch tyres look small compared to a 4.8 incher! It took me several rides of alternating between my stock 29er wheel set up and the plus size set up before coming to some conclusions.
First off, the 29er tyre continues to feel like it rolls just that little bit quicker though we are talking very much at the margin here. This is most likely due to the Hans Damff tyre being narrower and being pumped up to a slightly higher pressure. Weight wise, there is nothing to differentiate between the two. The 29er front wheel comprises a Chris King 20mm hub converted to a 15mm axle, Wheelsmith spokes, a Mavic XM 821 rim, a Specialized superlight tube and a 2.35 inch Schwalbe Hans Damff tyre. It comes in at 2061 grams on my kitchen scales. The 650B+ is Halo’s complete bolt thru Vapour set up shod with a standard weight Schwalbe 650B+ inner tube and 3 inch Schwalbe Nobby Nic tyres. It comes in a 2221 grams. Allowing for the heavier inner tube in the Halo Vapour wheel, the difference is only a matter of a few grams. Now that I was not expecting!
Ride wise, the wider tyre and rim combo really make their presence felt when the trails turn rocky and loose. The plus size tyres grip tenaciously to the ground. Off camber roots and rock gardens that would occasionally see the 29er wheels falter slightly are despatched with ease by the plus size set up. The extra width encourages you to really attack the trails to take advantage of the increased levels of grip. Though not in the same league as a full width fat set up, the plus size tyres are a significant step up from the regular sized set up. Whether real or just perceived due to their scale, the plus size wheels just feel stronger. This may be purely psychological but to date, I have failed to either bend them out of true or damage them with rock strikes. I’ve also suffered no pinch flats despite running them at a lower pressure than my 29er set up. Is this because of the increased rim diameter and tyre depth? Who knows but whatever the reason, it’s a feature I have come to appreciate greatly.
Despite the rims being rated up to a 2.8 inch tyre size, I have had no issues running the 3 inch Nobby Nics. Although tall in size, the tyres display no floppiness nor flex when pushed aggressively into rocky corners. Their wide spacing makes them good at clearing mud and compared to their 29er siblings, they ride like a much more aggressive tyre. It takes an awful lot of speed and effort to get them to kick out.
And, why not?
So 650B+? Is it worth it? On this showing, absolutely! The Halo Vapour wheels and 3 inch Nobby Nic tyres have had a transformative effect on my Turner Sultan. A great bike has been genuinely improved upon. Despite my misgivings, this combination of wheel and tyre do live up to the plus size hype and deliver on the lofty promises offered up by the manufacturers. For once, a new standard has come along that offers real world benefits to the Average Joe or Josephine rider.
Special thanks to Matt at ISON Distribution for pulling out the stops to make this article possible and to the forumites of Singletrack whose sage advice proved of great value during the build process.
Try this at home