Your top speed

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8541Hawk
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Re: Your top speed

Post by 8541Hawk »

http://www.insidemotorcycles.com/blogs/ ... -slip.html

Written by IM Admin on Thursday, 17 May 2012 15:21
Andrew Trevitt



In my article in the current issue of Inside Motorcycles ("Computing Speed II," April/May 2012), I briefly discuss measuring wheel speed and calculating slip as part of a data acquisition system. "Slip" is a broad-meaning term and a difficult parameter to quantify accurately, and I thought it deserved some more attention here. When we talk about slip, we are generally referring to wheelspin and a loss of traction, and there are a couple of ways to consider it. One is the difference in speed between the front and rear wheels; if the rear wheel is turning faster than the front, that is positive slip. Under braking, the rear wheel can turn slower than the front, resulting in negative slip. Slip can also be considered as the difference in speed between either the front or rear wheel and actual ground speed as measured by GPS. Knowing an accurate value for slip in a data acquisition system helps point out areas where the rider is spinning the rear tire or wheelying on corner exits, or skidding either tire on corner entries. Additionally, an accurate slip measurement is the cornerstone of a good traction control system.

A very rough value for slip can be calculated by simply comparing front and rear wheel speeds, or comparing wheel speed with GPS speed. Since most motorcycles are already equipped with rear wheel speed sensors for their speedometers, it's simple enough to record rear wheel speed and calculate slip as a percentage compared with GPS speed. The first and largest error introduced is due to the tire's changing circumference as the motorcycle leans, which affects the speed calculated - just as your speedometer reads higher as you arc into a turn. This can result in a slip calculation of more than 10 percent (the difference in circumference between the center and the edge of the tire) even when there is in reality no wheelspin at all. This error can be reduced by using a math channel to take into account the actual circumference of the tire based on lean angle as measured by a sensor or estimated from GPS data. Some tire manufacturers release this information, as Dunlop does for its spec AMA tires, but a fairly accurate estimate can be made using an arc or parabola formula based on a couple of measurements. BMW's DTC (Dynamic Traction Control) system uses this approach, with a lean angle sensor and maps inside the ECU to take changing tire circumference into account. The ECU can be reprogrammed using the company's HP Race Calibration Tool to account for different tires.

A second error is introduced when the tire deforms under load. As the motorcycle accelerates and decelerates, weight transfer loads and unloads the tire and changes its circumference accordingly. The load on the tire can be calculated based on static weight and longitudinal acceleration, either from an accelerometer or from GPS data. Knowing some values for tire stiffness, or again having actual specifications from the tire manufacturer, an estimate can be made for the change in circumference from tire deformation. Several Kawasaki patents for traction control describe a system that uses compensation maps inside the ECU to adjust measured slip, based on rpm and the gear selected, to account for tire deformation.

If you are generating a slip channel for data acquisition, the more accurate you can make the data by accounting for these errors, the better you will be able to find and analyze areas of actual wheelspin that need attention.

And before you dig a deeper hole by saying Andrew doesn't have a clue either:
https://ca.linkedin.com/in/andrew-trevitt-39500a1a
Last edited by 8541Hawk on Fri Jun 28, 2019 6:02 pm, edited 2 times in total.
Loud pipes don't save lives, knowing how to ride your bike will save your life.
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8541Hawk
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Re: Your top speed

Post by 8541Hawk »

Well it has become quiet now.....

Guess I would hope this thread would disappear also if I had been as aggressive as you guys in stating something just can't be and only a fool would even consider tire slip a possibility...... only to be proven 100% wrong. It is completely real and a proven scientific fact.

Funny that if you actually do any research on the topic you can find things like this:

"an accurate slip measurement is the cornerstone of a good traction control system."

Does this mean tire slip is real or do the guys making the traction control system not have a clue either.....do they add 2+2 and get 5?

Or how about:

" Several Kawasaki patents for traction control describe a system that uses compensation maps inside the ECU to adjust measured slip, based on rpm and the gear selected, to account for tire deformation."

Guess Kawasaki is clueless also as they are just throwing money away filing patents and making software to compensate for something you guys have decided can't or doesn't happen.

Just like the bike can't rev to the limiter in either 5th or 6th.....
If you say so....

Also the "there is no possible way the speedo could ever get to 180 MPH", even though the math states that is what will be displayed and easily seen on a dyno...

Take it to the limiter in 6th ( unless the you believe the bike can't see 10.3K RPM on a dyno either) and look at the speedo....want to bet on what it will be reading?

Sad that folks refuse to even consider the possibility of a concept due to some personal vendetta.

Mr Popkat, don't know what I did to wrong you so that you have the need to disparage me at any opportunity.
Doesn't matter if there is proof or not....anything I say is wrong or I'm just a flat out liar.
Again, just like your stance on tire slip.....No proof is needed, if you say it, it has to be true.

As for the other guy....well maybe I know a touch more about chassis dynamics than you want to give me credit for.

Just like my bike can't get to 10.3K even though you have no idea how it has been modified.
Want the complete list of mods so you can rethink this statement?

Then there is no way I could figure out chassis dynamics, understand anything that is actually going or be able to actually do the calculations myself even though you have no idea what my background may contain.

So if being a flat earther means I actually understand what the chassis is doing and can even show (with that pesky math) why a VTR is actually very prone to tire slip. So be it.....I actually I prefer the term Luddite as it just rolls off the tongue better :wink:

Though flat earter will due....though it's Mr. Flat Earther to you guys.
Have a nice day :thumbup:
Loud pipes don't save lives, knowing how to ride your bike will save your life.
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8541Hawk
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Re: Your top speed

Post by 8541Hawk »

tony.mon wrote: Thu Jun 27, 2019 1:39 pm Shall we do religion next?
The difference there is unlike tire slip there is no scientific proof available for that discussion.
If folks can not accept documented facts how could they ever even think about having a conversation on an abstract topic?
Loud pipes don't save lives, knowing how to ride your bike will save your life.
thelens
Posts: 135
Joined: Sun May 26, 2019 5:49 pm

Re: Your top speed

Post by thelens »

8541Hawk wrote: Fri Jun 28, 2019 5:56 pm
tony.mon wrote: Thu Jun 27, 2019 1:39 pm Shall we do religion next?
The difference there is unlike tire slip there is no scientific proof available for that discussion.
If folks can not accept documented facts how could they ever even think about having a conversation on an abstract topic?
Ironic :lol:
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Wicky
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Re: Your top speed

Post by Wicky »

https://www.bikesportnews.com/features/ ... e-of-slide

I'm confused - so everyone inc. cyclists/ moped riders / middle weight commuters etc. without realising is constantly tyre sliding/ wheelspinning even when on the road travelling at whatever speed rather than confined to high performace track riders.

To be honest I've only noticed it when on damp roads when heavy handed on the throttle or when launching of urban traffic lights where its oily / wet. That's when mainly accelerating only time I think I maintained a wheelspinning 'drift' with a constant throttle was many moons ago acrosss a wet roundabout on a GS650 Katana shaftie in the winter.

Surprised you claim your VTR does true 180mph (do you mean indicated on the speedo?) - As that's apparently the top speed of the Super Blackbird putting out 160odd bhp. IIRC VTR with rider & mirrors tucked in can just about do 150mph.

What is the proportion ratio of tyre slide in relation to speed / horsies on the road (not just sliding on the track). Would high speed runs be faster if held on 'sticker' tarmac strips instead on salt flats (not accounting for the slippage/sliding purely from acceleration).
It may be that your whole purpose in life is simply to serve as a warning to others.

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VTRDark
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Re: Your top speed

Post by VTRDark »

I think there is some confusion here over slip versus contact / grip. Tyre makes contact with ground and when you accelerate there naturally has to be some slip to get grip which is more contact than slip really on a good surface with good tyre which causes wear. It's like the physical motion of rotation could be called slipping round and round instead of spinning. But is it slipping...not really unless you on a slippery surface or have no tread but technically it could be called slipping round and round I suppose from a mechanical engineering angle. But really, slipping to me means loosing some contact so you slide whereas without that it's more a controlled contact slip which gives grip without the slide. Does that make any sense or am I talking bollox. It's all being a bit pedantic really.

Now as for flat earth...no no no...I'm not going there. My tin foil hat doesn't extend that far. :lol:
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Wicky
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Re: Your top speed

Post by Wicky »

That's why I'd like to see any figures beyond extreme race track circuit racing - On a race track extremes yes as we know their are US racers who happily employ tyre sliding whilst leaning without fear from experience gained from dirt track racing - but how common is that everyday on the road and to what degree and in what circumstances. Esp when upright on a high/top speed run which is where the argument started.

Motorbike Rear End Slide / MOTO GP / King of the Slide/ Marc Marquez
It may be that your whole purpose in life is simply to serve as a warning to others.

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thelens
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Re: Your top speed

Post by thelens »

8541Hawk wrote: Thu Jun 27, 2019 4:51 pm Yeah I am such a tw@..... Doesn't really matter that the math and physics back up what I have to say.
You guys have decided it is untrue, with no offered proof except your opinion but it is all good.

I know the published papers mean nothing..... you guys have decided.

It is also sad that sites like gearing commander are so bad at math that they can't do the simple calculations to figure out how fast the rear wheel is spinning at a given RPM and how far it should travel. Guess Honda sucks at math also as they use the same calculations.

I am sorry that your bikes can't pull to the rev-limiter. Some can though again you guys have declared it impossible.

If it were possible to pull to the limiter, the math states the speedo will be reading over 180MPH.
Again that pesky math proves it unless you can show where the calculations are wrong.
Which would answer the question of why are you not moving at the speed the math says you should be?
The wheel is spinning at a set RPM so it should travel a set distance. Instead the wheel is traveling a shorter distance.
Why?
Math to hard to figure out?
Where is the loss?


All this chatter about you can't get to 10,300 RPMs.....Ever consider my bike is far from stock?
That it just might be a possibility that with over 110HP at the rear wheel I can get to and past 10.3K RPM as I also am running an HRC ECU and a Full Akra exhaust, besides all the rest of the bits which lets the bike rev in the upper limits much better than the stock ? Though I'm sure you will claim this is somehow untrue also.

So me looking at the speedo pushed past 180 is just a lie because you guys say so... No proof but you know.

So again I am refereed to as a flat earther because I am using math and physics to explain why a scientifically proven phenomenon is occurring.

The whole...oh that's about 4 wheels not 2......Sorry wrong.
Latitudinal Tire Slip or Angular slip, to not use big words, is related to 4 wheel vehicles
Longitudinal Tire Slip or Straight forward doesn't care and in fact is more pronounced in bikes as you have a smaller contact patch to apply the power.
Pretty obvious....the more tires or contact patch, the less slip.

So if those papers where only about 4 wheel vehicles one would have to extrapolate that a 2 wheel vehicle would experience a higher rate of longitudinal slip due to less available starting traction. So all the provided graphs should be more pronounced.

So even though you can not find one shred of evidence anywhere to dispute Longitudinal Tire Slip or any of the published papers on the subject, it doesn't apply here because you say so.

Ok fine you win and have a nice day :beer:
You hear more about tyre slip on cars because of a number of things. Mostly aqua planing and there is reason cars have a limited slip differential. It’s not that these people are wrong it’s you that’s wrong. You have misunderstood what they are talking about.
You bang on about ignoring evidence yet it is you that is doing this, not others. Every thing is proven and common knowledge. Aero dynamics is easily proven... you only need to sit bolt upright, or tow a caravan with your bike and see how fast you go ! ( power to weight ratio ) notice ! ! ! I did not say it did not exist.... I said it did not exist as you describe !
AS YOU DESCRIBE !
You are surrounded with evidence. Enough evidence to drown yourself in !
What causes a high side ? That one thing alone should be enough to convince you that you have obviously and clearly misunderstood things. You need to start over and go back to the beginning.
Google tyre slip !
There maths are probably correct. It’s you that is misinterpreting the results. It’s like looking under a microscope at minute details to detect what exactly the tyre is doing beneath you. Tyres are made of rubber... they distort and stretch and catch up with themselves and do the same in the opposite direction under breaking forces. It would seem you are under the impression that all of this describes it as a continuous motion. That we travel along with the wheels spinning !
I am sorry but common sense should tell you otherwise.
I said I had my last word but that is deffo my last word on this subject. I’m only saying this because I think you genuinely believe what you say. Where I was suspicious about you being one of the many internet trolls. If it turns out your just trolling you deserve a medal lol. This subject has already taken up wayyyy to much time and effort. If you still can not see how wrong you have got it then you never will. It’s like your totally blinkered. I’ve a feeling this is going go down like water off a ducks back.
Have a great day my flat earther friend :D
Sorry about that by the way.... just trying get a point across.
Never going happen I feel lol.. but good on you for holding your ground. :D
Just so you know... I only replied in the first place as misinformation on the net is ripe and yours is a good example.
Albeit, seemingly unintentional :D :x
grumpyfrog
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Re: Your top speed

Post by grumpyfrog »

Can we get back to the topic in hand please?
And mine is : who knows cause I'm a fanny....
Don't hassle me
I'll get there at some time
thelens
Posts: 135
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Re: Your top speed

Post by thelens »

To note.... you also keep banging on about, given x tyre size and x rpm should equal x speed !
Let me just explain this one for you.
Yes the maths are correct. If you jack your back wheel off the ground, you can see this is correct.
However.... that is pointless and useless info, unless your interested in the maths side of things.
It does not include rolling resistance, it does not include having to push the bike through the atmosphere and is weightless !
Once you start pushing past the100 mark it takes a lot of extra horse power to gain small gains in higher speeds.
This is where aerodynamics really start to come into play.
Rpm also plays a role in top speed as you have figured out. This is why in line fours most often have higher top ends... they can rev higher. Of course it’s only any good if there is enough power there to overcome the rolling resistance and air pressure and weight.
Lifting the rear wheel does away with 99% of this of course. So is all but meaningless.
Now if you insist that you do not understand something so simple then it will be clear enough for me you are indeed just trolling.
However clever it may appear to some !
thelens
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Re: Your top speed

Post by thelens »

grumpyfrog wrote: Sat Jun 29, 2019 9:09 am Can we get back to the topic in hand please?
And mine is : who knows cause I'm a fanny....
Well as long as you have it in hand, all is well :D :lol:
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MacV2
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Re: Your top speed

Post by MacV2 »

thelens wrote: Sat Jun 29, 2019 9:27 am To note.... you also keep banging on about, given x tyre size and x rpm should equal x speed !
Let me just explain this one for you.
Yes the maths are correct. If you jack your back wheel off the ground, you can see this is correct.
However.... that is pointless and useless info, unless your interested in the maths side of things.
It does not include rolling resistance, it does not include having to push the bike through the atmosphere and is weightless !
Once you start pushing past the100 mark it takes a lot of extra horse power to gain small gains in higher speeds.
This is where aerodynamics really start to come into play.
Rpm also plays a role in top speed as you have figured out. This is why in line fours most often have higher top ends... they can rev higher. Of course it’s only any good if there is enough power there to overcome the rolling resistance and air pressure and weight.
Lifting the rear wheel does away with 99% of this of course. So is all but meaningless.
Now if you insist that you do not understand something so simple then it will be clear enough for me you are indeed just trolling.
However clever it may appear to some !
So much for ''I said I had my last word but that is deffo my last word on this subject.''

As for calling Hawk a troll I think you need to take a reality pill Mr Lens... Mike knows a fair bit more about Storms than most people on here.

Now can we drop this please & get back to the normal fun banter & general boll acks which is the norm for this Forum...Or is that only for people who havent just joined this year ?
Making up since 2007, sometimes it's true...Honest...
thelens
Posts: 135
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Re: Your top speed

Post by thelens »

MacV2 wrote: Sat Jun 29, 2019 10:37 am
thelens wrote: Sat Jun 29, 2019 9:27 am To note.... you also keep banging on about, given x tyre size and x rpm should equal x speed !
Let me just explain this one for you.
Yes the maths are correct. If you jack your back wheel off the ground, you can see this is correct.
However.... that is pointless and useless info, unless your interested in the maths side of things.
It does not include rolling resistance, it does not include having to push the bike through the atmosphere and is weightless !
Once you start pushing past the100 mark it takes a lot of extra horse power to gain small gains in higher speeds.
This is where aerodynamics really start to come into play.
Rpm also plays a role in top speed as you have figured out. This is why in line fours most often have higher top ends... they can rev higher. Of course it’s only any good if there is enough power there to overcome the rolling resistance and air pressure and weight.
Lifting the rear wheel does away with 99% of this of course. So is all but meaningless.
Now if you insist that you do not understand something so simple then it will be clear enough for me you are indeed just trolling.
However clever it may appear to some !
So much for ''I said I had my last word but that is deffo my last word on this subject.''

As for calling Hawk a troll I think you need to take a reality pill Mr Lens... Mike knows a fair bit more about Storms than most people on here.

Now can we drop this please & get back to the normal fun banter & general boll acks which is the norm for this Forum...Or is that only for people who havent just joined this year ?
Not easy when people quote my posts like you !
Mike seems a nice guy.... and he probably knows more than me and will certainly know more than me about storms !
As for a reality pill ! Really ? I can only judge by what I read. From what ive read on this particular subject says youve got it back to front.
but yeah ! Fine by me lol. Nothing would give me more pleasure
Since I started by simply quoteting the top speed i found on my bike !
Only people who have joined this year ?
Start a new thread with that one, I shall happilly join in ! :D :P
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uk13iker
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Re: Your top speed

Post by uk13iker »

135 is mine 2 up over the mountain in the Iom and started spluttering not sure if it was due to altitude but was fun.


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thelens
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Re: Your top speed

Post by thelens »

uk13iker wrote: Sat Jun 29, 2019 5:37 pm 135 is mine 2 up over the mountain in the Iom and started spluttering not sure if it was due to altitude but was fun.


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hard to complain. thats not too bad for two up and high altitude :D
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