Physics of Speed Bumps

[BKKFZ6]

Today I had an interesting experience. Checking my mirrors for taxi's on my tail, I hit a speed bump (not painted of course, black on black high contrast type!). I was in first gear going slowly maybe about 20km/hr.

This is what seemed to happen. Front wheel bumped up on the bump, causing my bars to rotate back and therefore decellerate. Front wheel went down causing the bars to rotate again an roll the throttle open and accellerate pushing the front end down even harder as the rear dug in as well as mounted the bump. The net result was a neck snapping jerk. Quite an awakening after scanning my mirrors! No, accident, not even close, but a good shake! Has anyone else had simililar experiences?

Just wondering what kind of hazard speed bumps present to motorcyclists (the blind stupid type, like me!)

 

[fz6joker]

I drive down my college campus constantly and there are at least ten speed bumps. The thing about them is that there are two that are "bigger" than the others and you really have to watch out for them. It's really cold down here and my tires rarely warm up when I'm just driving from the dorms to class so I don't have the best of traction to begin with. I've popped over them going pretty slow (spped limit on campus is ten miles per hour and YES I've gotten pulled over and ticketed for going sixteen) just to have the back tire "kick out" a little. No wreck or anything severe, just enough to make you weary.

 

[fz6joker]

Boo speedbumps. The cagers just zoom through campus so they don't actually serve the purpose that they are intended for. Boo unsafe cagers too.

 

[ozzieboy]

I don't get speed bumps. I'll get a pick of one in particular on the Esplanade at Pt. Noarlunga which has an advisory sign posted of 20km/h and ten metres before it is a speed limit sign of 50km/h. WTF?

If the speed limit says 50 then it should be ok to do 50. These humps should be designed to allow cars to do the speed limit, otherwise you get the speed up/slow down thing happening which is bound to cause trouble.Or you get the dweeb who has to do 5-10km/h for the whole road, causing impatience and agro in other drivers.

The point is, I do the speed limit at speed bumps no matter what. If I have to ride around them, between them or stand up and use my whole body as a shock absorber I'm not slowing down:spank::Flip::rant:.

Rant complete...lol.

Cheers
Mike

 

[Kilbane83]

If I can't go around the speed bump I stand up off the seat let my legs absorb the impact (don't lock your knees). Same with any kind of hard object, or hard drop off in the road I can't avoid.. maybe left overs from riding off road.

 

[BKKFZ6]

Boo speedbumps. The cagers just zoom through campus so they don't actually serve the purpose that they are intended for. Boo unsafe cagers too.

whatza "cager"

 

[mastakilla]

if your bike decellerated while going up the bump, because you cut the gas, then I think you have a problem with your riding position. Your wrists should be loose and relaxed, and aiming downward, not upward like motorcrossers.

 

[Donnie869]

If I see the bump i'll gas it and do a semi-wheelie hop over it with front tire.(standing up). If it has the gap for water drainage i'll aim for that, or if there is not a curb i'll go for the gutter. If I don't see the bump, HOLY CRAP!!! that would scare the hell out of you!

 

[Donnie869]

whatza \"cager\"

People driving in cars (stuck in a cage)

 

[MarinaFazer]

Yea I've done that early in the morning while I'm waking up going to work on the bike. haha, try waving to a neighbor with your left hand and having that happen LOL

 

[sideslider]

Today I had an interesting experience. Checking my mirrors for taxi's on my tail, I hit a speed bump (not painted of course, black on black high contrast type!). I was in first gear going slowly maybe about 20km/hr.

This is what seemed to happen. Front wheel bumped up on the bump, causing my bars to rotate back and therefore decellerate. Front wheel went down causing the bars to rotate again an roll the throttle open and accellerate pushing the front end down even harder as the rear dug in as well as mounted the bump. The net result was a neck snapping jerk. Quite an awakening after scanning my mirrors! No, accident, not even close, but a good shake! Has anyone else had simililar experiences?

Just wondering what kind of hazard speed bumps present to motorcyclists (the blind stupid type, like me!)

I remember a "ride better" book explaining just this scenerio...

basically it said to ride with flat wrist to avoid just this thing... I can try to find it but it was in one of the books recommended here....

 

[Mattberkshire]

To understand how best to deal with these malicious infractions on our highways you have to understand the physics.

When you brake the weight is thrown forward onto the front wheel, therefore if you brake and hit a speed bump you will have a heavy impact which will do you and the bike no good

If you accelerate over a bump the load on the front wheel is lightened so the impact will be less but the higher the speed the higher the impact

The best way to deal with a speed bump is to cruise up to it at a reasonable speed and brake just before, making sure that you let go of the brake just before the bump thereby unweighting the front wheel. The resultant decompression allows a smoother passage over said carbuncle in the road.

And don't forget to curse the w*nker who decided it should be put there in the first place

 

[Stumbles06]

Only ever had trouble once... and it wasn't really a "speed bump".

A gas station near work was renovated (a while ago now), but had new tanks put in underground. Where the "filler pipes" came up, they put a massive concrete mound around the steel plates used to cover the pipes. They never bothered to paint these for motorists to recognise, just a concrete driveway with a concrete mound in the middle.

I've gone to pull in there on my old bike (GPZ 1100), and I hit this mound doing about 20Km/h. Scared the hell outta me, my gearsack went flying, and I narrowly missed hitting the gas pump.

I don't think I've been back to that gas station since...lol

 

[bluenova]

To understand how best to deal with these malicious infractions on our highways you have to understand the physics.

When you brake the weight is thrown forward onto the front wheel, therefore if you brake and hit a speed bump you will have a heavy impact which will do you and the bike no good

If you accelerate over a bump the load on the front wheel is lightened so the impact will be less but the higher the speed the higher the impact

The best way to deal with a speed bump is to cruise up to it at a reasonable speed and brake just before, making sure that you let go of the brake just before the bump thereby unweighting the front wheel. The resultant decompression allows a smoother passage over said carbuncle in the road.

And don't forget to curse the w*nker who decided it should be put there in the first place

+1, speed bumps should be treated like corners, slow down BEFORE and accelerate through.

 

[wrightme43]

I just hit them. It seems that if the bike just hits them square and at a reasonable speed the fork and shock just take perfect care of it.
Just load the pegs, unload the seat, arms and wrists loose, hit, and sit back down.

 

[Wolfman]

I slow down before i hit em, then stand off the seat, and accelerate over the top, a bit like going over a berm on a trial bike......or even better, if they taper off into a gutter, so water can pass through the gutter, i just ride around them, through the gutter!

Worst idea ever these things...they dont slow cars down, they just trash suspension!

 

[afpreppie04]

Fortunately around here there aren't many speed bumps, and those that are there have "motorcycle holes" (water drain spots). They seem to keep motorcycles in mind since there are quite a few here, they even put smooth gaps in the rumble strips on the roads for the motorcycles to go through. Off topic, but I hate speed bumps in my car, I have to crawl over them to save my suspension then the SUVs don't even notice them :rant:

 

[antijoy]

To understand how best to deal with these malicious infractions on our highways you have to understand the physics.

When you brake the weight is thrown forward onto the front wheel, therefore if you brake and hit a speed bump you will have a heavy impact which will do you and the bike no good

If you accelerate over a bump the load on the front wheel is lightened so the impact will be less but the higher the speed the higher the impact

The best way to deal with a speed bump is to cruise up to it at a reasonable speed and brake just before, making sure that you let go of the brake just before the bump thereby unweighting the front wheel. The resultant decompression allows a smoother passage over said carbuncle in the road.

And don't forget to curse the w*nker who decided it should be put there in the first place

Yeah, this answer is the best. It's also how it was explained to me way back in high school drivers ed.

Don't brake when going over speed bumps, brake before. Braking will shift the vehicles weight forward, compressing the suspension, making for a much sharper impact.

It's best to brake first, then coast over it. Even light acceleration is better than braking.

Works the same when driving a car as well.

 

[Zack]

Hate speed bumps regardless if I am on bike or in the car!