Review: KHS Zinn Flite 747. This is a big deal.

 

 

Flite 747.

 

The KHS Flite 747 is a bike of epic proportions. First the frame is an XXL mucho grande 65cms and it’s designed by Lennard Zinn specifically for big and tall riders. That’s from 6’4″ to 6’6″ and up to 250 pounds.

That is oversized news for big guys who have suffered one of two fates: riding on uncomfortable and compromised smaller stock frames or those forced to break the bank for expensive custom geometry. There isn’t a huge category for “Best Bikes for Big & Tall Riders — this is it.

200mm cranks. Big man's hammer.

The possibility of riding a bike dialed in for the unique demands of a big rider yet one that retails for just $1699 is a dream finally come true. Keep in mind that the few frames listed as 63 or 64cms don’t reach those numbers when you examine the actual measurements.

We’ve been riding the Flite 747 for two months and the short review is, we’re impressed by the whole package — responsiveness, stability, stiffness and bio-mechanical efficiency. Finally, us freaks of nature have our own bike.

Any review of the Flite 747 has to start with the man behind the machine. You’d be hard pressed to find another frame builder with more skills designing big bikes than 6’ 6” Lennard Zinn.

46cm wide handlebars.

For thirty years he’s been mastering the details at Zinn Cycles and the joy here is that he’s taken that cumulative experience about what works and doesn’t and poured it into the Flite 747. While this isn’t one of his custom bikes — his least expensive steel model runs $2699 for frame and fork — the Flite is as close to custom as a big man gets off the rack.

The frame is where that accumulated wisdom pays all the dividends. The rear triangle is compact and stiffened up torsionally. Zinn also lowered the top tube while still keeping a sloped and shortened seat tube. Along with that design work, he raised the bottom bracket and fitted the Flite with 200mm cranks (more on that shortly). Head tube angle is a shallow 72 degrees for greater stability and vibration dampening.

Take those decisions out on the road and the benefits are instant: Even given the extra weight of the Reynolds 520 steel tubing, this bike climbs beautifully. The first time we jumped out of the saddle we were shocked how stiff the back end felt. For perhaps the first time, we had the impression that our every watt went into the pedals.

In fact, we got a little bitter thinking how many years we’d been cheated on power output. The little guys are still going to drop you on long steep grades, but you will hand out punishment of the shorter power climbs. While the stock Weinmann rims were fine, we couldn’t help but fantasize about switching to a set of Zipps, Eastons or the big man’s wheel-set of choice, the Mavic Ksyrium Elites.

Shimano 105

Once you reach the summit, there’s extra good news — the Flite 747 bombs descents. In coversation with Zinn, he stated that high speed instability is a major issue for big riders. Thanks to tight, compact frame design, that shimmy is history. What was interesting was the progression we experienced in our risk-taking. In the first week of test, we went conservative on descents but soon we were taking tighter, more aggressive lines than on the Serotta we’ve been riding seven years. We can’t think of more compelling evidence for how well this bikes reads body language and responds to high speed inputs. As Zinn put it, the design goal is to “maximise confidence.”

It’s worth a few words on frame material because Zinn and KHS made a conscious decison to go with the Reynolds 520 double butted steel tubing. Stability was half the imperative and high fatigue life was the second requirement. That story comes back to the size, weight and power of bigger riders. We’re outside the norm, an engineering headache, all stress limits exceeded — in other words, we break things.

Zinn felt the benefits of stability and higher fatigue life were worth a small sacrifice in frame weight. An increase in tube diameter and wall thickness reinforce strength and your peace of mind. This isn’t a bike you’re gonna trash in a few years because it simply can’t handle the extra work load.

XXL. 65cm frame.

In our test rides, that weight is noticable but far less obvious than the improved stiffness and stability, climbing power and sense of confidence. At $1699, you’d save enough money over a custom bike –or the expense of modifications to a smaller frame — to drop that overall weight with carbon bars, post, pedals and a lightweight set of hoops.

One of the major draws on the Flite is the 200mm cranks. Our concern was that after decades on smaller cranks, the change would feel bio-mechanically bizarre and possibly even lead to knee pain. Five minutes into our first ride that issue disappeared forever replaced by the thrill of new found power.

Tight rear triangle. Go climb.

We’ve envied the littel guys and their blistering acceleration up hills; at last we have our own weapons. The analogy is trying to break rock with a claw hammer and someone hands you the big sledge. Suddenly life is good and the work comes easy. On psychological benefit alone, the 200mm cranks are a huge boost to your perception of power. The elongated cranks also eliminate what Zinn calls the “sewing machine effect” — your long legs pumping up and down fast on small cranks like a crazy sewing machine needle — talk about repetative stress.

While the performance of the Flite 747 is terrific, the visual effect is on the conservative side. Depending on your definition of frame art, it’s either a stylish classic or dull. What is nice is that the scheme is understated so upgrades will automatically style up the entire package. The front fork is a style killer so we’ll go ahead and recommend Zinn’s own XBigMan carbon fork. Again, at this price, you’ve got funds to redecorate. One of the advantages of superior fatigue life is the Flite is down for the long haul — there’s plenty of time to dial in personal esthetics.

As far as the component group, the assessment would be well-matched and solid but nothing spectacular. Remember the $1699 price tag and you’ll feel way better. We had no complaints and no issues with drivetrain or components. After the initial break-in period the Shimano 105 ten-speed shifters ran smooth and quiet. Of particular note for big guys,  the wide 46cm FSA RD-250 aluminum bars. The only negative we could find was the brakes could use a touch more stopping power.

As a final crituque, we’ll admit this bike has caused some unexpected trouble. While our trusty 66cm titanium Serotta is a great bike, we found that gradually, the Flite became the ride of choice. We like stability and that power to the pedal stiffness. Which makes it tough to box up the Flite for the trip back to KHS.

The ride is everything and as big guys know, stability, stiffness and confidence are not easy things to find in a big frame. The Flite 747 should go to the top of the consideration set. It’s not the exorbitant cost of custom or the freaky-looking and ineffective compromises inherent in trying to make a smaller frame work.

This is the sum of Lennard Zinn’s mastery of big bike design at a price that doubles the buzz.

KHS website

KHS Flite 747

 

 

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  • Mat Orefice

    What is the weight as shown/ridden/tested?

    • http://www.atwistedspoke.com TwistedSpoke

      Mat, there is no weights listed and to be honest, it being a shell frame for big guys, weight wasn't so much a factor. However, when I asked Zinn, he said about 6 pounds for the frame. Matt

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  • http://www.facebook.com/profile.php?id=1454422613 John Ohnstad

    Thanks so much for your review of this bike.  I am considering this bike…moving over from a Soma 66 cm frame.

    The only thing I thought about upgrading prior to this review was the brakes…to Shimano 105s…looks like that was the concern you had as well.

    Just curious, what is the crank arm length on your Serotta?  I have a 175mm campy compact.

    Thanks again.

    • http://www.atwistedspoke.com walshworld

      DOn’t ask me why but they fitted 175 cranks on mine. I had no idea and when I found out I was kinda annoyed. Matt

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  • eric671

    The review is spot on!  I am the proud owner of one as well.

    The only issue I had was thse short seat post.  I’m 6’7″ with a 37″ inseam.  With the bike out of the box I had the seat post maxed out and the seat itself adjusted all the way back.  The stock setapost at 310mm was barely into the frame.  It only took a few good sized bumps with my 240lbs body to jam the seat right out of position.  Eventually, the friction groove were almost completely wirn out.

    I switched to a Thomson Elite 410 setback seat post and life is good.  Seat is centered and the post is well into the frame now.  Solid as a rock.

    Did I mention I LOVE this bike.  200mm cranks, can’t imagine anything else now.

     

    • http://www.atwistedspoke.com walshworld

      Eric, you are right about the seatpost — I had to swap out the stock for a longer one. And yes, I love the 200 cranks. I have to figure a way to get a new bike with 200s. I’m sold. I’m hoping that they sell the frame only next year. Best, Matt

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  • johnnyo

    Awesome review… I’m looking for a road bike (have a XXL Salsa Fargo) and am wondering what the largest tire the frame will accommodate.

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  • Dave O Brien Cycling

    Super bike. I bought one in March 2013 and rode the West Coast USA on it with a rack and two small rear panniers. Absolutely GREAT bike for tall riders. The only factory bike with a raised bottom bracket and 200mm cranks. Lennard Zinn has designed a fantastic, versatile bike for tall and big guys. It is also THE BEST descending bike I’ve ever owned as well as the overall best handling bike I’ve ever owned. Even though I’ve had to install a shorter 90mm stem as I have long legs for my height – 6’4″ (194cm).

    The 200mm cranks feel very natural and do let me tap into my power and I can go longer every day because of them. The geometry of the bike is excellent. It’s a very tight bike, not at all flexy and gives real assurance that you’re not going to snap this one. The 36 spoke wheels do the job. I snapped a couple of spokes while doing the light touring and had the wheel rebuilt with DT Swiss spokes for $50 all in and now it is a good strong wheel. Front wheels don’t take nearly as much of a beating so I wouldn’t worry about it.

    I have upgraded to a carbon fork to reduce the weight and a lighter pair of wheels and a carbon setpost for a little more give (I’m only 85kg). Riders over 100kg may be safer with an alloy seatpost? The gearing is ideal for most situations. I’m getting another frame built – custom – as I love the KHS so much in almost the same geometry but from lighter, more expensive Columbus Spirit and Life tubing. I think if you are 6’4″ up to maybe 6’7″, this bike should fit you.

    The proportional length cranks are a breakthrough. My old 180mm cranks feel tiny and pathetic now. They even look tiny in photos with me on the bike. The approx. calcualtion for your ideal cranklength is 0.21 to 0.216 of your actual inseam. Highly recommend!

    Steel is fantastic for bigger riders. I have played with 100′s of bikes. I work in the bike industry. Yes, it is not a light bike but it feels and performs brilliantly. With a few upgrades like wheels, it’s easy to get it down under 10kg weight. I’ve taken mine all around France, over the Alps many times during the Summer and even raced with it. I can’t really flaw it. Also, it’s a bargain. If you’re in the UK, Steve at KHS UK can order one in for you for about GBP1500.