650B Test Project #1 – The Norco Sight Gets Converted

Norco Sight mountain bike 650B conversion

We have a full review of the Norco Sight in it’s natural 26″ form coming soon, but while Evan’s compiling his final notes on that, we went ahead and crammed ENVE’s new 650B All Mountain wheelset into the frame with some of Pacenti’s smallest treads. The result? A very promising mod that’s got two of our riders completely stoked on the middle child wheel size!

The Sight is a new-for-2012 140mm trail bike that’s been winning accolades from anyone that’s tested or ridden it, including us as you’ll see soon. It uses an FSR layout with Norco’s A.R.T. linkage design, and it’s travel is smack in the sweet spot for where most people see 650B wheels coming into play.

26″ VERSUS 650B/27.5″ – FIT & COMPARISONS

side by side height comparison from 26 inches to 650B Norco Sight mountain bike 650B conversion

The frame is a size small Norco Sight. Wheels are ENVE Composites 650B rims on DT Swiss spokes and hubs. Tires are Pacenti Neo-Moto 2.1 on the front and Quasi-Moto 2.0 on the rear. The original tires are Kenda Slant Six 26×2.35.

All pics below show the original 26″ wheels on the left, 650B on the right. Click on any image to see it full size. Visually, the bike looks much smaller as a whole with the 26″ wheels, particularly after seeing it with the slightly larger 650B wheels.

measuring the height difference and comparison on a Norco Sight mountain bike 650B conversion

This is how we’re measuring the height differences for bottom bracket and rear axle. One level on the handlebars ensures the bike is straight up and down, and another level on the measuring board keeps the measurements perfectly vertical.

bottom bracket height comparison on a Norco Sight mountain bike 650B conversion

Bottom bracket height (center of BB axle) started out at 336mm and grew to 356mm, about half an inch.

rear axle height comparison on a Norco Sight mountain bike 650B conversion

Rear axle started at 335mm and grew to 350mm…same rough half inch. It’s worth re-mentioning that we went from 26×2.35 to 2.1 and 2.0 tires. If we could have fit fatter tires on here, it may have given it a slightly bigger height difference. Depending on the starting point, raising the BB height too much can affect handling by raising your center of gravity. Norco is developing a 650B bike that’ll reposition everything in the best position, but so far we’re digging the increased clearance.

suspension clearance for Norco Sight mountain bike 650B conversion

When converting, there are three things you need to check before heading out on your ride. First is rear tire and frame clearance under full compression. We let all the air out of the shock and compressed the bike to bottom out. Plenty of clearance, Clarence.

The second is fork crown clearance, and we did the same with the fork to make sure the tire wouldn’t touch the fork crown. If the tire hits either one, it would stop it abruptly and likely cause you to lose control or worse. If it contacts the frame under full compression, don’t convert your bike.

rear tire clearance comparison on a Norco Sight mountain bike 650B conversion

The third is frame clearance for the tires. Using 26″ forks presents a challenge. We’ve heard Fox forks have a bit more clearance, and Magura’s updated 26/27.5 forks intentionally accommodate both wheel sizes. Rockshox has a 650B fork coming, too, as does SR Suntour.

The Norco comes with a Rockshox Revelation and the Pacenti 27.5×2.1 is absolutely the largest tire we could get in there. It rolls fine, but if a stick or something were to get lodged in there, it could mean trouble. Fortunately, the Neo-Moto’s tread pattern isn’t too deep, and the blocks are widely spaced enough that getting a rock stuck in the tread isn’t likely.

rear tire clearance comparison on a Norco Sight mountain bike 650B conversion

In the back, you need to check for clearance at the seatstays…

rear tire clearance comparison on a Norco Sight mountain bike 650B conversion

…and chainstays. Plenty of room here, we could have easily run a matching 2.1 tire here.

EVAN’S COMMENTS (5’4″)

Norco Sight mountain bike 650B conversion

Going to a 650B wheel/tire combo on the Norco Sight is my first ride on this wheelsize. 650B wheelsets and bikes are not very prolific in the market place yet and we just haven’t had the opportunity to do any deep discovery, until now. The Norco Sight 2 is not a 650B specific bike but, after getting Norco’s blessing and good ole’ fashioned trial, we discovered no hindrances in pairing the two.

The bike in the 650B configuration performs just as smoothly as it ever did. If there have been any ride qualities seriously altered, I have not been able to detect them. Braking, suspension, drivetrain are all functioning as normal. Stand over height, and bottom bracket clearance, along with overall center of gravity have increased due to the extra 1″ to 1.5” of wheel. However, the aforementioned are all minimal and seemingly negligible. Maneuvering the higher center of gravity is of trace impact. What is noticed though, is the seemingly “happy ground” between the realm of 26” and 29” MTB wheels. What I can say is probably exactly what you’d expect. 650B takes the pros and cons of 26” and 29” wheels, does a mash-up and spits out a pleasing middle-of-the-road answer. They accelerate faster than a 29”, yet provide better approach angles and traction than a 26”. On top of that, the ENVE wheelset is rock solid in regards to lateral drift and vacuums you into turns and punches you out.

I have only logged about four hours thus far, but it was over plenty of roots and rocks and down some fast, rough descents. I am truly enjoying the outcome and results and feeling pretty special with this setup. Unless something else magical comes along, I am sticking with 650B, it’s the best of both worlds.

ZACH’S COMMENTS (5’8″)

Norco Sight mountain bike 650B conversion

I was excited when Tyler mentioned he had a modified 650B bike in my size. This was not my first time on 650B wheels, though it was first time I have ridden a full suspension frame with ridiculously nice wheels. I never jumped on the 29er band wagon, as I still haven’t found one that I liked the way it rode. At 5’8″, I often found myself on small 29ers that felt cramped, or medium 29ers that felt too long, both of which didn’t fit my riding style. A few have come close, but not close enough for me to ditch my 26″ bikes. Which is why I have been intrigued by the 650B wheels from the start – could it be the happy medium for riders in my situation? Only time will tell.

With the 650B wheels, the Norco sight never felt like a 29er, which is a good thing. From the first moment of jumping on, the Sight had all the playful, fun feeling of most 26″ bikes, just a little… bigger. Once out on the trail and opened up, there was an undeniable feeling of additional speed or cruising, though really nice carbon wheels can do that – regardless of size. What isn’t related to carbon wheels though, is the ability of bigger wheels to resist getting pinned between roots, something the Sight seemed quite good at. There were quite a few times that the line I was forced into, made my 26″ adjusted brain cringe as I thought for sure that I would stick my front wheel and endo, only to roll through without issue. Like all things though, there are always pluses and minuses. While the bigger wheels seemed to be better in a straight line and over roots, 26″ still have an advantage while jumping or carving berms. With the modified Sight, I felt like I had to slide back and off to the inside corner of the saddle much more to get it to really carve through a berm. Jumping was a similar affair, whereas I felt movement had to be exaggerated versus a 26″ when going off drops, or flowing tables. With that said though, I think I could get used to it with a while on the bike. I know full well that it is entirely possible to shred on a 29er, but for me, at my size, it just doesn’t feel natural. The 650B is close, close enough that I want to spend some time with one long term. Something I’ve never said about 29.

While my ride impressions were very favorable, there is no question that stuffing bigger wheels in a 26″ frame isn’t as telling as riding a dedicated 650b rig, but it does show the wheel’s promise. It does prove however, that there will be plenty of frames and forks out there that with the exception of tire clearance, riders could try out 650B for themselves without having to buy a new frame and fork. Not that it needed proving, as I have a few friends that have already done it, and are loving the results. As much as some people will complain about an unnecessary, additional wheel size, to me, the 650B shows promise. For those looking for the bigger wheel advantages, but don’t want to lose the fun, flick-able nature of the 26″, the 650B has potential.

TYLER’S COMMENTS (6’2″)

I’m too tall to ride this bike…stay tuned for another attempted hack on something my size. But, riding behind Evan, it’s surprising how much taller both he and the bike look compared to before. Given his shorter stature, it almost looks like he’s riding a 29er. Evan’s generally a pretty hoppy-jumpy-playful rider (at the expense of equipment sometimes), and he’s jackrabbit quick up the climbs. I’ve noticed he’s every bit as fast overall, maybe more so on the flat sections, but perhaps ever so slightly less jumpy with these wheels on.

FURTHER READING: Check out what the industry has to say about the coming 650B explosion here.

Comments

Peter Keiller - 06/15/12 - 10:17am

Nice boards Tyler.

I have the exact same ones.
Except, mine aren’t for taking measurements, they are for clobbering people that insist on stuffing the wrong sized wheels into a frame then evaluating it.

Love you,
Peter

Bikerumor - 06/15/12 - 10:37am

Love you, too, Peter.

Mr. P - 06/15/12 - 12:02pm

Nice informative write up on an experiment. Thanks.

Another point to check is the Fork bottom out, tire to crown. A point of instant stop on the front. Remove spring and add 10mm of travel for bottom out bumper (if it has one). All forks are different, so worth checking.

P

Fat Bike Racer - 06/15/12 - 1:02pm

This makes me want to mount a rototiller to my Rascal scooter. If only I had the crabon wheels.

Steve M - 06/15/12 - 3:38pm

Since when is 20mm (.787″) about a ‘half inch’?

zukabazooka - 06/15/12 - 5:29pm

I’m running a 27.5 on the front and a 26 on the rear on a 2011 5 Spot… and I’m love’n it ! ;-)
BIGGER on the front to run over obstacles better and smaller on the rear to get up-to-speed quickly.

chuck - 06/16/12 - 6:06pm

Not to nit-pick, but the level on the handlebar is not in the correct orientation, should be on the nice, flat, machined side.

MTB - 06/16/12 - 7:49pm

Anyone w/ a lefty front fork try putting on a 650 wheel up front and keep the 26in wheel in the back?
Curious how that would ride.

Jbird - 06/16/12 - 10:48pm

Interesting experiment. Nice seeing feedback from different sized riders. Riding both 26 and 29 (at 5.8)
I feel the “third standard” deserves at least a test ride. Damn, I don’t have room for another bike. unless…

Joshua Murdock - 06/16/12 - 11:35pm

This test should be repeated with the same model wheel, one of each size, used in the test. Who knows if some of the changes noted here were a result of the wheel size or a result of switching from alloy wheels to super-stiff, carbon wheel?

Izzy - 06/18/12 - 3:32am

Nice experiment. The Sight happens to be near the top of my lust list. I hope one of Norco’s 650B protos is a Sight equivalent.

Izzy - 06/18/12 - 3:49am

I’d love to see how a 2.3 Neo-Moto would fit in the back

Luis - 10/24/12 - 7:32am

Good job.
I did a conversion of a framework to 27.5 Jamis Dakar XLT 2005 and am enjoying.

Albert - 01/09/13 - 8:20am

What about putting 27.5 wheels to a 29er frame & fork? Or having a 650b frame with a 650b rear wheel and a 29er front wheel and fork?

Saulius - 05/29/13 - 5:55am

Mismeasurement?
How could it be: rear wheel axle difference 15mm (350 vs 365), should be the same for front wheel, but bottom bracket difference is 20mm (336 vs 356). 5mm is somewhere in suspension.

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