Oct 22, 2011

What's with Stopping Distance Tests?

Motorcycle Consumer News publishes a Performance Index summary on all of the bikes they have tested over recent years (for example: 2007/2008 and 2010). There are always some interesting statistics in those evaluations. For those of who are lazy and looking for an executive summary, skipping the list and heading for the Ten Best categories at the end of the article is the easy way to get a look at the year of motorcycling products.

One of the stats I've been most interested in is the 60-0 stopping time measurement, since that directly relates to safety performance. 0-60 is interesting and 0-100mph is information only for squids and racers, but stopping distance is a big deal for all of us. So, I manipulated the MCN data into a spreadsheet and played with it for a bit. what I found was an indirect correlation between what I expected and what actually happened. The ten quickest stopping bikes MCN tested in the last 5 years are:

Triumph Speed Triple 1050 '06 104.8 ft.
BMW Megamoto 106.4
Triumph Speed Triple '99 106.7
Honda F6 Valkyrie 107.4
Honda Marauder 800 107.6
Honda VFR800FI Interceptor '98 107.9
Yamaha YZF600R '97 108.2
Suzuki SV650 '99 108.8
Ducati Monster 750 109.1
Suzuki TL1000S 109.4

None of these bikes were among the lightest tested. In fact, five of the 50 fastest stoppers were over 700 pound porkers. All of those were metric cruisers (Honda's F6 Valkyrie, Valkyrie Tourer, VTX 1800, and Kawasaki's Vulcan 1500 Classic FI and Suzuki's VL1500 Intruder LC). Even Harley's 620 pound VRSC V-ROD puts on the brakes in 109.5 feet. The lightest of the quick stoppers is the '99 Suzuki SV650.

There is some connection between the lightest motorcycles and fuel efficiency. MCN's ten top fuel misers were:

Yamaha XT250 67.8 mpg
Yamaha Virago 250 66.9
Kawi Ninja 650R '06 65.3
Kawi Ninja 500 64
Honda Rebel 250 62.6
Honda CRF230L 61.6
Suzuki SV650S '07 58.3
BMW G650 Xcountry 56.4
Buel Blast 55.4
Moto Guzzi California 55.2

The Hondas and Yamahas were in the 10 lightest bike group, too. The Moto Guzzi was the heaviest miser at 540 pounds. You have to filter down to 45 mpg before you see the first over 600 pound bikes show up in the efficiency column. That was no surprise. Suzuiki's DR650 was the only light bike to push 40 mpg, which isn't a huge surprise, since the DR is also the quickest 0-60 mph bike in the group.

MCN does a lot of testing and collects all sorts of data on the bikes they test. I'm marginally embarassed to admit that I only care about one other measure; weight. MCN's ten lightest bikes were:

Yamaha XT250 288 pounds
Kawasaki KLX250S 294
Yamaha WR250X 301
Yamaha WR250R 302
Kawasaki KLX250SF 305
Suzuki DRZ400SM 319
Yamaha Virago 250 325
Suzuki GZ250 334
Suzuki DR650SE 358
Suzuki DR650SE '07 368

All things considered, the Virago 250 and the GZ250 are the only bikes of that bunch that I wouldn't like to own. So, maybe my first big issue is weight. If I only get to pick one value, maybe that would be the top of my motorcycle values. MCN doesn't rate suspension travel, turning radius, off-pavement handling, street vision (seat height), visibility, reliability, winter starting, ease of maintenance, parts cost, fuel tolerance, LD comfort, or many of the things I try to look at when I review a new motorcycle. Sometimes, I wonder if including a "can I pass a BRC on this thing" category would be helpful This was, however, an interesting experiment and I'm going to put the resulting Excel spreadsheet on my website.


Paul said...

If MCN included all the data you wanted in those charts they would become so cluttered as to be unreadable. Fortunately, you can go back and check the road tests and collect a lot of what you need.

The top three stoppers are doing it all on 1 wheel; relatively tall bikes with that much negative g-force are probably only getting around a 5-10% contribution from the rear brake. The Valkyrie and Marauder are very heavy with long wheelbases, and rearward weight bias, which makes the rear brake very effective, hence the short stopping distance. Unfortunately, most cruiser riders don't bother to learn max braking techniques, leading to "Yup, I had to lay er down".

Anonymous said...

I've read and believe that a lot of accidents could have been avoided if the rider had used evasive action other than braking. How often do we read of someone wiping out when they grab too much brake rounding a tight corner? A more interesting test would be speed through a tight slalom course. The other thing is that in the real world braking performance is hugely related to many other factors: tire type and state, road service, weather, etc. Max braking performance on a closed course is interesting, but only part of the puzzle.

T.W. Day said...

I don't think "too much braking" is the cause of the crashes you describe. Improper braking, incompetent braking, inappropriate braking might be more in line with those situations. Max braking in ideal situations is as good as that statistic is going to get, so it is useful. Having test rode a hippobike before doing this investigation, I am still amazed that anyone can stop one of those monsters quickly. Clearly, they are better riders than me and way more committed to riding; even if the motorcycle is an engineering disaster.