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