The Dangers of Narrow Tires

It is unfortunate that most “road” and even “hybrid” bikes are sold with tires so narrow that you cannot cross streetcar tracks at an oblique angle without risking a fall.

The Seattle Times reported recently about a rail line that crosses a city street not far from my house. “A bicyclist falls there daily,” the article reports. A business owner at the tracks found that “bike wrecks are so constant he keeps a first-aid kit at his front door.”

Over the past decade, there were 66 crashes serious enough to call out the fire department. Then there are the accidents on Seattle’s drawbridges, where cyclists fall into one-inch-wide cracks, sometimes with horrific consequences. There has been much talk about what could be done to make these places safer for cyclists, but gaps and tracks simply are part of the urban landscape in which we cycle.

I know that a skilled rider can bunny-hop across tracks and cracks, no matter at what angle they run. However, the fact is that many people ride bikes who are not that skilled. Nor should they need to be.

With the 42 mm-wide tires of my Urban Bike, I have experimented (at low speed) with the gap next to the rails. Even when crossing the tracks at a very shallow angle, the tires just rolled over the gap.

Since we cannot eliminate tracks and cracks from all roads, why don’t we fit 42 mm tires to the bikes that are sold to most cyclists? Wider tires would make cycling much safer. Besides, the current research indicates that wide tires are at least as fast as narrow tires. In fact, I never felt that I was handicapped during Paris-Brest-Paris last week by the 42 mm tires on my new randonneur bike. Of course, bikes with narrow tires would still be available for enthusiasts who really like the look and feel of narrow tires – but they’d come with warning labels.

About Jan Heine, Editor, Bicycle Quarterly

I love cycling and bicycles, especially those that take us off the beaten path. I edit Bicycle Quarterly magazine, and occasionally write for other publications. One of our companies, Bicycle Quarterly Press publishes cycling books, while Compass Bicycles Ltd. makes and distributes high-quality bicycle components for real-world riders.
This entry was posted in Cycling Safety, Rides, Testing and Tech, Tires. Bookmark the permalink.

27 Responses to The Dangers of Narrow Tires

  1. Mike J. says:

    Those tracks are so bad, I’m not sure 42’s would be enough. I took a spill on a borrowed mountain bike on those tracks. Extending the trail would be great.

    • I’ve tried it, and even at low speed, without unweighing the bike, the bike went straight across the tracks, I didn’t change my line at all, just ignored the tracks as if they didn’t exist. Perhaps the knobs on mountain bike tires are getting caught in the tracks?

      In any case, wider tires will help.

  2. Wayne Sulak says:

    Wide tires are great but in our world most people choose fashion over function. Ex: high heels and tattoos.

    Carry on the good fight – Wayne

  3. GuitarSlinger says:

    Totally agree . Its nice to have the sports car ( race bike ) for the odd occasional ride , but in reality , its the commuter ( in my case a Moulton APB ) that gets the miles , takes you over and around the obstacles , as well as safely negotiating the madness that is Urban riding .

    As to the fashion comment , WS is spot on . It’d be nice to see a bit more common sense Middle Ground as seen here in cycling instead of the hard right Racing cycles and the extreme left Fashion over Function coming out of the EU ( their bikes are brilliant , their riding gear especially heels on cycles is absurd )

  4. john says:

    I came off on a road bike crossing a rail tracks, you only do it once.
    Mountain bike tires without any centre tread bead would be better.
    I had mountain bike tires with a centre bead and they were deadly, they soon came off!

  5. To fit wider tires we need more frames that have room for wider tires. I’m sure this is obvious to readers of your blog and periodical, but still, it was a mind-boggling experience recently to shop for a road frame that would accept sensible tires. I ended up using an old ten-speed for my purposes, basically side-stepping the issue of the average new frame having crazy-tight tire clearances for no good reason.

  6. Melinda says:

    The way that I crashed on the Westlake streetcar tracks was in the rain, in the dark, during a lane change. Admittedly, I was on 32-mm tires or 35-mm tires, I don’t remember which. I definitely think that both the water and the shallow angle at which my rear wheel came in contact with the tracks played a factor.

    Most of the other train/streetcar track crash anecdotes I’ve heard have involved the tracks being wet, too. Do you think wider tires would help when they’re slippery?

    • When the tracks are slippery, and cyclists try to line up their bikes to cross them perpendicularly, they often tend to be still turning as they cross the tracks. Of course, that makes you more likely to slip and fall. If you go straight across the tracks, because you know your wide tires won’t fall in, then you are faster and don’t have sideloads on your tire, so you are less likely to slide. Unweighing your bike as you cross the tracks probably helps, although you can only unweigh the front tire, or the rear, but not both, unless you are _really_ fast.

  7. Nathan says:

    Quite often it’s not the actual tire going into the tracks that causes the falls. It’s the front wheel sliding laterally across the (wet/lubricated) curved rail at speed. It might only be 1/10th of a second but that momentary loss of front end traction/control COULD BE enough to cause a nasty fall. Another cause of falls when crossing tracks is psychological. The cyclist sees the tracks rapidly approaching, tries to decide what to do, does a head check to look for autos, tenses up, tries too hard, over compensates for any front end wiggle (that 1/10th of a second loss of control could cause a 1/2 over-correction).

  8. Nathan says:

    Having said that, there is absolutely no reason for narrow tires, especially for urban bikes.

  9. Chris Lowe says:

    Honestly I think people in Seattle are making a mountain out of a mole hill and the danger of these tracks is being promoted for political reasons related to the completion of the bike trail. I’ve ridden those tracks on fairly skinny 25mm tires and don’t see what the big deal is. If people in Seattle find those tracks difficult I can’t imagine what they’d think of the cable car tracks in San Francisco. In addition to the two rails, cable car tracks also have a foot wide steel plate in the middle with an inch plus wide slit cut in it. They are far more treacherous than anything in Seattle yet SF cyclists manage to cross them all the time without crashing. I just don’t get what the big deal is about these tracks.

    • The photo of the warning sign was taken in Portland, Oregon. It appears that the tracks really do represent a problem for many cyclists, even if you don’t have trouble negotiating them. Unweighing the bike as you cross the tracks goes a long way toward making it across safely.

    • Rob Markwardt says:

      I, too, have no problem crossing the tracks (25mm to 36mm on my bikes) and agree that the bike lobby will use the crash stats to promote their cause….BUT…people do crash there…all the time. I’ve witnessed several falls and have helped up a couple of bloodied bikers. Most are probably novices riders, but the problem is that the tracks are located right at the end of the busiest trail in the city with the majority of riders there being novices. Big tires would certainly help but my question is where are the trains that supposedly use those tracks. I’ve lived and biked in the vicinity for over 15 years and I’ve never seen one?

      • eric_s says:

        I have seen trains on those tracks; it is an active though less used rail road spur. I have also crashed on those tracks when I was in a group and left myself nowhere to go to cross the tracks safely on my road bike. I learned my lesson: give yourself room and take your time over tracks. Seattle riders are not used to tracks in general, have little biking culture to show how it’s done, and SDOT is typically remiss in posting track warning signs and other mitigation.

  10. Ronald Lau says:

    I will give the SF Cable car tracks a try, my son’s school is a block away.

  11. Rob Harrison says:

    I’m sure the opponents of completing the “missing link” of the Burke-Gilman Trail (almost exclusively a few adjacent businesses) will find this post useful: “It’s the bicyclists’ fault!”

    When it isn’t packed with commuters the Burke-Gilman is filled with new and returning bicyclists, kids and adults, getting out in what they believe to be a safe(r) environment, which it is in terms of infrastructure if not people’s behavior–except for this part. Maybe time on the trail will give those riders the confidence to work up to a level of expertise that allows them to ride on the street. It’s not unreasonable to want to remove a barrier to increased ridership.

    That said: Yah man, I love my wider tires! I switched to a 650b bike a year ago and I haven’t looked back.

    • I’m sure the opponents of completing the “missing link” of the Burke-Gilman Trail (almost exclusively a few adjacent businesses) will find this post useful: “It’s the bicyclists’ fault!”

      Actually, the opposite is the case. The opponents of the “missing link” claim that they’d love to have a bike trail, but it’s too dangerous to allow bikes into an industrial neighborhood. When I was on the board of the “Friends of the Burke-Gilman Trail,” we went to great lengths to document that bikes and industrial businesses can mix quite safely.

  12. I think one has to be careful re fostering a false sense of security here. I know at least half a dozen people who’ve fallen on rail tracks while riding mountain bikes and Dutch bikes with wide tires. There are so many different factors that can be at play when approaching the tracks; it’s best to be cautious, stay aware, and avoid them whenever possible – regardless of tire size.

    • Greg says:

      Correct!

      Wider tires, of the maximum widths that could realistically be used on the bikes in question, would have absolutely no statistically significant effect on the number of incidents of the type invoked in this discussion. Quite frankly, the width of the (realistically useable!) tire is not the issue, so you can play with that variable all you wish, but since it isn’t part of the equation, it’s irrelevant. That said, sure, wider tires are nice, I like them, when appropriate, but please don’t try to scare people into using them.

      • I agree that one has to be vigilant when riding a bike (or driving a car or walking). However, it’s pretty clear to me that if cyclists suffers from life-threatening injuries after their tires get caught in 1-inch-wide gaps on Seattle’s drawbridges, that this probably would have been avoided if their tires were significantly wider than one inch.

        I am not trying to scare riders – most who read this blog probably know how to negotiate tracks, no matter their tire width. However, I am trying to influence the makers of bicycles to rethink whether it is a good idea to sell bikes that take a maximum tire width of 25 mm to the general public.

  13. C. Abbey says:

    The idea of switching to wider tires was a direct result of the writtings in Bicycle Quarterly. Zero crashes under my belt since then, but I’ve seen plenty with skinny tires on large charity rides. In my current search for a new “ride” tire width is big factor. Finding a reasonably priced bicycle off the rack with the tire size I want has proved to be more difficult than I expected.

  14. Tse-Sung Wu says:

    A first aid kit at his front door…. such an “end-of-the-pipe” solution.

    How about better engineering design? Isn’t there some way to build track crossings so they’re bike- (and ped- and stroller- and…) friendly? I seem to recall some interesting ways of making railways easy to get by. How wide and deep a groove do train wheels need?

    • Greg says:

      Yes, there are ways to minimize the potential for problems. For sewer grates, it’s usually just a matter of using the latest design, which puts the slots at a 45-degree angle to the road, rather than parallel to the road. The more modern railroad track crossings that use the hard-rubber mat material are more bike-friendly than the classic ‘railroad tie’ ones, and seem to hold up better over time, as well….

      • The hard rubber stuff actually is extremely slippery when wet. My only crash on a railroad track in recent decades was on the stuff. I had crossed the tracks at an angle, and a car approached. I touched my brakes and went down…

        The old-style wooden boards between the tracks are not good, either, because they never are even, and even can move as you ride across them.. Best is simple asphalt pavement…

  15. The width may not affect speed, but the weight of a 700×32 over a 700×25 is very noticeable, much less a 42.

    • When you hold the tires in your hands, the weight is noticeable. On the bike, the difference is less than a full water bottle. Anybody who notices a difference in performance of their bike when they carry only one water bottle instead of two is very sensitive indeed.

      Furthermore, if you use smaller 650B wheels, you get lighter rims and spokes…

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