(Bike) Tires: how best to protect them

Factual Questions
1

Okay, following scenario: When riding my bike, I often have to go over the cornerstones of the walkway/ bike path. The corner stones have sharp angles, which are generally considered as damaging to tires (at least, that’s what the ADAC says about car tires, which are much thicker).

So I try to both dampen the impact to my back(side) and to lighten the load by standing up on my pedals and balancing the weight evenly as possible - if I remain seated, most of my weight is on the back wheel, naturally.

However, the answers to the riddle about the pigeons in the van* make me wonder: am I helping my tires, because my leg muscles absorb some shock when I’m standing, or am I only helping my backside, but the tires will be ruined in the long run?

Or does anybody have other tips for driving over sharp angles? Besides “don’t do it”, which is the ADAC’s advice - most often, that’s not really possible.

Related: do the shock absorbers that all the new mountain bikes have built in make a difference for the bike - no rattling of the frame means longer life for the components - or only for the comfort of the rider?

*A van is driving along, and every few minutes, the driver leaps out and smacks the side with a board. An onlooker asks why. “Well, the van is rated for 150 kg. of weight, but I have 300 kg. of pigeons aboard, so I keep half of them in the air”.
Cecil explained somewhere that this wrong, because a bird flying will exert a downward force with his wings equal to its weight, so nothing would be gained by flying vs. sitting.

2

What you’re concerned about is the load on the tires at the time you impact the curb. You can minimize the load by “bouncing” the bike so you’re lighter at the time of impact. This is different from the birds in the van scenario because you’re not trying to reduce the load for any significant period of time. You’re basically placing greater than average load on the tires immediately before you place less than average load on them.

3

There are solid foam cores available, which keep the tire from going flat even if punctured. They would add a good bit of weight to the tires, so they are generally used only in applications where weight is not the major concern.

4

just before the curb pull hard back on the handle bars and lean back on the seat (or better lean back standing on pedals) and you will lessen the weight on the front tire, maybe even lift it off the ground. when front tire is over the curb then raise off the seat (or remain standing) and lean forward and this will take weight off the rear wheel.

5

The best way of mounting curbs in most settings is not to mount curbs. Bicycles are vehicles and entitled to space on the roadway. Learn to share the road with motor vehicles is my advice. In most jurisdictions bicycles are forbidden from being on the walkways. However, if you must mount/dismount a curb, I’d recommend practicing the bunny hop.

Enjoy,
Steven

6

Um, we do have bike paths in my city. However, I do have to cross them for traffic lights, or when getting on the walkways to park, for example. (And where I live, they are just re-building the surface after building a tunnel for the cars, so during the process there are sharp edges everywhere, until the nice new smooth bike paths are done.

Well yes, only children up to age 10 are allowed to cycle on the walkway. But I still need to get on/off it when looking for a parking space, or crossing it. Mostly, however, it’s from road to bike path - when the bike path is not continuous, and it’s an old curb which has not been evened - which are high.

I thought only young hip BMX-drivers could do that :). I try sometimes hopping the front wheel; I’ll have to try if I can lift my heavy city bike all the way!

7

First off, be sure you have plenty of air in your tires. Taking curbs with low air pressure can cause flats and/or wheel damage.

If you’re riding a mountain bike, it’s built to take hits. Don’t worry about it. Even a hybrid or a cruiser should be fine. A light-weight racing bike, not so much.

A bunny hop will help, even if you don’t actually leave the ground. A full-air hop is just a more extreme version of what other people are talking about in this thread. You temporarily take your weight off the bike, hopefully just at the right moment when you hit the curb.

The front-then-back method suggested before is probably the easiest to start with. You’re already halfway there with your current stance. All you need to do is lean back just a little as the front wheel hits the curb, and then lean forward a bit as the back wheel goes over. It’ll take a little practice, so don’t get too stressed about it.

The shock-absorbers are mostly for rider comfort. They probably do reduce some wear on the bike, but they’re not worth it IMO unless you’re actually riding serious trail. They’re heavy and significantly reduce the power of your pedalling strokes.

ETA after preview: bunny hops are fun. Don’t try to learn over curbs, learn out in a flat dirt lot. Flat because you won’t be able to get the timing right at first, and hitting a curb coming down from a hop can go badly. Dirt because dirt hurts less than pavement when you fall. Wear your helmet!

Momentum helps, so get a little speed up. You kinda push down on the bike for a second and then jump up, rebound brings the bike with you. It’s fun, give it a try.

8

In fast off-road riding they’re not just for comfort; they have the practical benefit of keeping the tire more consistently in contact with the ground in rough terrain.

But they’re not likely to extend the life of any component, because there’s nothing on any but the very cheapest bikes that won’t take all the “rattling” that is likely to happen in any normal riding. Until just several years ago, few serious mountain bike racers even used suspension forks, because the added weight was seen as a liability that wouldn’t be made up by that cushioning. And still even under severe race conditions, components and frames would do just fine.

As suspensions got lighter and race courses got more technical because of their use, they’ve become almost necessary in MTB racing.

The components most likely to fail, though, in racing or in more casual riding, will probably be related to the shocks. Even the most expensive top-end models require regular maintenance if you ride a lot.

9

I ride 4-5,000 miles a year and have never lost a tire from curb angles or abrasion. I just wear them out. However, my crotch does not like to hit bumps too hard. As posted elsewhere, leaning back on the seat takes a load off the front end. The jolt I feel is less and it must be less on the tire too. I find a suspension fork is mandatory.

10

Assuming you are not doing anything that would abrade the sidewall, there is no real danger to your tires here, only to your tubes. It is possible to inflict what is called a pinch flat on your tube with a combination of too-low air pressure and significant force against a hard surface. With insufficient pressure, the tube can squirm around and become pinched between the rim and whatever you’ve just slammed into. Should you do this, the damage will become quickly apparent.

As for shocks and component wear, again there is no danger in exposing simple bike components to the mild g-forces of bumps and jumps. As they say, it’s not the fall that kills you but the abrupt stop at the end.

A reasonable technique for limiting pain of impact is to let your weight remain over the rear (and thereby keeping the front end light) but lifting yourself off the saddle slightly and using your legs to absorb the impact. Keeping weight off the front will allow it to clear the obstacle easily, and by not resting yourself on the bars you will not experience a significant shock to your hands/shoulders.

11

At a tangent to the OP - I’d say a rear shock does extend frame lifetime, and also makes a big difference to the rear wheel’s longevity, but only if you’re talking about reasonably serious mountain biking. I tend to crack an aluminium hardtail frame after 3-4 years, for example, that’s been my experience over a few bikes (I’m talking about hairline cracks from fatigue, rather than a catastrophic crack from a crash or such like).

OTOH, I’d be disappointed to discover a crack in my full sus. It takes so much of the impact out of the back that they really can go on for a long time nowadays.

12

Well, that’s what you get for riding aluminum, silly! Steel is real, baby. :stuck_out_tongue:

  • redtail, unsuspended chromoly, TYVM

well, except for the tandem. I don’t think they make off-road tandems without at least a front suspension fork. We never got a double-boinger, though.

13

Well, I have what’s called a city bike - hybrid mountain-bike tires, lowered top bar. Better than a thin racing bike.

So I can save my money - I had wondered if I should buy them as add-ons.

Thanks for the advice, I’ll try to find practice time and place. And I always wear my helmet - my head is important to me!

14

Thanks, that’s good to know. Ever since reading the ADAC article on how damaging for car tires it is to go up on the sharp border stones when parking, I thought the similar reasoning - damaging the rubber walls of the tube/mantle - would also apply to bike tires.
Is the difference the bigger weight ratio (>1 t / 4 tires for car, 60-70 kg / 2 tires for bike) that makes the difference? Or that with the higher speeds, car tires have to endure much more stress, so smallest weakness can lead to a blow-out, whereas a bike tire can go much longer before a real hole can develop?

Ah. I know how teeth-rattling and clinking it is when I ride across tramway rails or several bumps in short succesion while seated (and how much difference to my body the standing-up-on-the-pedals makes, though the loose stuff still rattles), so I wondered about possible damage. Good to know the stuff should withstand it.

15

Many thanks to everybody who answered so far, some very good tips and explanations!

16

Glad to hear this. I’m a bike commuter (not hard core-- only 16 mi/day). But I do go up and down a few curbs, through some construction, and some tough transitions between gravel and concrete where I have to go up a lip, like a sharp but small curb.

And, yes, the times I’ve gotten flats they were “pinches” from under-inflation.

And I do the “sit back and jump the front wheel up the curb” thing. Glad to know I’m not damaging the bike. My crotch’ll heal, but a bike costs money to fix…

17

Snakebite punctures (so called because of the two adjacent wounds) are a common outcome from clumsy kerb hopping, and arise when the tyre hits the edge of the kerb so hard that the tyre deforms and the rim outers hammer the pinched tyre and inner tube against solid concrete.

The sure way to save your tyres when going up kerbs is to learn how to bunny hop, and the tyres won’t touch the kerb at all. As you approach the kerb, pull the front wheel up just far enough to clear it plus a little safety margin. That’s easy enough, but clearing the back wheel is trickier. The proper bunny hop technique is to stand up out of the saddle, throw your weight forward and twist up on the handlebars to bring the back end of the bike up. I’m not much good at that, so I tend to cheat and slip in a micro-endo, where I throw my weight forward and snatch at the front brake briefly to bring the back end of the bike up.

It’s important to approach the kerb at 90 degrees, as if you get it wrong and the rear tyre hits the kerb, then the bike will just kick up until the saddle hits your butt, which is easily recoverable. I found out the hard way what happens when you screw up an acute-angled kerb hop one wet winters day at the end of a muddy ride. I had SPD cleats clamping my feet to the pedals (they’re a bit like ski-boot bindings, and release when twisted) which makes bunny hopping easier as you can pull the back end up with the feet, but on this occasion I misjudged the weight of my bike - it had several extra pounds of mud hanging of it - and the back wheel didn’t quite clear the kerb. Instead, it slid along it sideways like a greased rail, dumping me hard on my side. Normally I’d get away with that, but on this occasion a pedal clamp didn’t release properly, and snapped my left foot off. It’s been bolted back on since, I should add.

The above techniques are more for the hardcore kerb hopper, there are safer ways to climb over them at lower speeds. Again, stand up from the saddle with knees slightly bent, pull up the front wheel to clear the kerb (as before), but then to get the back wheel over when going slow you can climb it. Lean forward to unload the back end of the bike and let it pivot about your knees and the wheel shouldn’t hit with enough force to do any damage. You could play it safe and bring the back wheel up very slowly, in which case you need to avoid stalling by throwing your weight forward against the handlebars with just enough grunt to get the back wheel over the lip. Sometimes it’s possible to pedal up a kerb lip from a stop, but often there’s not enough traction and the tyre spins.

Having full suspension does indeed help protect the tyres against rough terrain as the shocks absorb most of the impact from the big hits, but I wouldn’t recommend a full-sus mountain bike for city use, as they’re heavier, pricier, and much slower on tarmac than most other bikes. What they do best is go fast over rough terrain, much faster than a bike without suspension could manage, as the suspension eats up bumps that would otherwise throw off even the best rider. And the traction and grip is awesome. The price to pay for this is increased weight, a less stiff frame, slower speeds over flat terrain, and handling that feels washy. This is with a nice full-sus bike, the cheap ones are just so horrible to ride they’re not even worth their bargain price. Proper full-sus city bikes are available; they’re more of a road bike with lighter weight and limited travel suspension arrangements, and are a good compromise between speed and comfort.

Hope this helps. Alternatively, snakebite resistant tyres are available, but they’re a bit weighty.