Corner speed(The displacement dilemma)

[Azzy_031]

First I wanna say hi.I'm a new rider,bough my bike just a month ago,with no parental help,all the money was hard earned/saved,first bike if you don't count my moped

 

However I have been in love with motorbikes since the age of 9(18 now) so I'm not exactly new,which brings me to the subject.

 

A discussion has been started on motori.hr(hope links aren't prohibited here),Croatia's biggest motorcycle forum and I stated that a 250cc 2 stroke is faster in tight bends than a 600cc 4 stroke,as is a 600 4 stroke faster than a 1000 4 stroke.

 

Later on,they pretty much started mocking me.I politely tried to tell them that I know that a literbike will absolutely destroy a 600 in a straight line,but that curves tell another tale.They said I've been spending too much time online,so I've tried to show them that MotoGP has faster lap times since they've switched to 800cc despite the huge power difference from the 990cc.And once again I've stated that the rule pretty much gives corner speed advantage to the lighter and slimmer bike,but once again,they're only commented on my claims with contempt.

 

Now I reserve the possibility to be wrong,I'm not ancient in the motorbike world,hell,I'm just a kid,but I'm pretty much sure the laws of physics dictates the rules of lighter and slimmer bikes having more corner speed.

 

Now I have come to you,as a neutral forum,with people who mostly race on track,hoping you could solve my dilemma and if I'm wrong teach me a new thing or hopefully if I'm not,teach them.

 

Thanks

 

EDIT:BTW if you're wondering,my new bike is a wonderful and beautiful '06 Aprilia RS125...no 600cc for a starter bike silliness,still way to powerful for me TBH

[Kyrul]

well wat u say is possible.. but its all abt the rider not the ride

[nuad]

hey azzy, im no pro track rider, but i think you have a valid point with lighter bikes with a distinct advantage in bends.

 

 

"The simple answer is weight and power delivery. The 600's are easier to ride but their lower weight allows them to carry more corner speed and be easier on tyres" (vs 1000cc's)

 

 

article on how a well modified gsxr 600 destroyed the Nurburgring's record laptimes, it even beat the Ducati Desmosedici too.

 

they chose the 600cc's on the theory that of a lighter bike's ability to carve corners better, but still have the highly tuned 600 cc's power output.

 

so it seems, you are right in the sense that a lighter bike would have corner advantage, but power & power delivery still plays a part.

 

hope this helps, only my 2 cents

http://londonbikers.com/news/10702/witness-the-p3-suzuki-gsxr600-k8-superlite

[bernardk]

When entering a curve, the weight of the bike plays a major part in the kinetic force which in this place call "G"

 

Heavier bikes give more kinetic force when entering the corner with their weights.

 

Thats from wat i understand. In terms of science.... And im quite sure that you put a same rider on the different CC bike, will give you different results. Thats why even the track route also gives different performance.

 

Bigger cc bike will prefer track with more straights. But a more technical track course, a smaller bike will be more favourable.

[Wayang]

interestin article nuad.. but readin tru it.. esp the end it kinda felt like a sale gimmick.. nvrtheless i like dis pic though..

 

http://londonbikers.com/img.ashx?id=dsc_8351.jpg&w=766

[Hartholomew]

You're 100% correct.

 

Screw the naysayers.

[nuad]

interestin article nuad.. but readin tru it.. esp the end it kinda felt like a sale gimmick.. nvrtheless i like dis pic though..

 

http://londonbikers.com/img.ashx?id=dsc_8351.jpg&w=766

 

 

hmm who knows? its a Fastbikes magazine project though, so that lends some credibility.

[bernardk]

http://londonbikers.com/img.ashx?id=dsc_8351.jpg&w=766

 

I believe it is that light. Cos there is no engine on the bike. plus no fuel. could be less than 100kg.

[Azzy_031]

Thanks for all the help guys

I presumed I was right since this was just a matter of physics.Most of them blamed it on my inexperience which now seems funny since my inexperience and inability to buy a bike for years has led me into studying bikes a lot.

 

Now I finally have a bike and can bring the best of both worlds together

[Wayang]

hmm who knows? its a Fastbikes magazine project though, so that lends some credibility.

 

fast bike ? hmmm.. actually i have a PB (performance bike) mag wif the exact same article.. if they used a r6 they might have been able to lap under 6mins

[Raptor]

There is truth in this.

 

I do faster lap times at Tuas on a race ready Y125Z than on my Husqvarna 510 SMR which is putting out close to 60 HP.

 

Its just that the corner speeds on the Y125Z is much faster than the Husky.

 

But could be rider problem also.

[bernardk]

There is truth in this.

 

I do faster lap times at Tuas on a race ready Y125Z than on my Husqvarna 510 SMR which is putting out close to 60 HP.

 

Its just that the corner speeds on the Y125Z is much faster than the Husky.

 

But could be rider problem also.

 

Hahaha unable to handle the torque? :D:D

[squarebox]

TS: Ask them to race against supermoto riders.

Supermoto is proof that lighter is better in corners.

my logic as i know it : Lighter bike = less centrigual force = more lean angle than heavy bikes. the rest is up to the rider's capability.

 

 

http://www.masmoto.net/blog/wp-content/gallery/albert-roca/supermotard_6.jpg

http://www.vancouversupermoto.com/cms/files/image/YZ-supermoto-extreme-lean.jpg

Edited November 30, 2009 by squarebox

[ambasnakeman]

limit of corner speed is generally affected by wheelbase( distance between wheels ).

 

250 machines have short wheelbase, 600 longer, and 1000 even longer.

 

weight of the machine affects riders capability in corners. if u look at some of the professional riders in person, they have a very tough built.

 

so smaller wheelbase, lighter bike leads to higher corner speed provided rider has talent.

 

for set up issues at certain tracks, both 600 and 1000 will either extend or shorten their wheelbase. sometimes small adjustments make big difference. but when 600 and 1000 shorten their wheel base too much, tyre grip is also questioned, as bike is significantly heavier. in world level racing, u have different compounds and tyres to assist. but weekend riders, on DOT race tyres, push the bike with control.

 

as for lean angle, low doesnt necessarily mean u r fast in the corner.......how much throttle position u can open makes the difference.

[ambasnakeman]

just to add on, when i was doing 43s in johor circuit on my r6, siew charn ho(5th rider) was doing 38s on his r1, and he overtook me from the outside in turn 1. we both knee down, but cornering at high speed with control, results in good laptimes

[bernardk]

TS, there you have it from the Ying Yang Mohawk racer. :D:D

[areal]

TS: Ask them to race against supermoto riders.

Supermoto is proof that lighter is better in corners.

my logic as i know it : Lighter bike = less centrigual force = more lean angle than heavy bikes. the rest is up to the rider's capability.

:eek: albert roca..AMAZING!!

[zyrofillica]

wow. so how if u have a 500cc 2 stroke sports bike which is lighter than a 600cc and also provides an equal amount of power of a 1000cc. Wouldnt that be the best combination? Aside from all that pollution and constant top overhauls lol.

[32SeBBaX]

wow. so how if u have a 500cc 2 stroke sports bike which is lighter than a 600cc and also provides an equal amount of power of a 1000cc. Wouldnt that be the best combination? Aside from all that pollution and constant top overhauls lol.

 

On paper, yea, but a 2 stroke engine has a much narrow power band, the rider would realli have to make a constant effort trying to ride within its band, whereby a 1000cc 4 stroke has a wider reservoir of rev for the rider to draw power from,(e.g)u can ride through a corner on a taller gear alot of times.. making it much much more forgiving compared to a stroker.

I presume this is why ppl do say the 2 strokes often spit the rider off the bike (highsiders)

 

anyway power is for the straights portions(of a track), torque plays a more major part thru the bends, thus i would think the meatier torques of the 4strokes allows for alot more cornering speed compensating for the machines' heavier weight.

 

all said, i would think a rider will need to ride quite differently on different engine configs, the gr8 riders are the ones who can adapt and still bring back the results (biaggi,rossi, capirossi have won on both 2strokes and 4strokes 990/800 machines)

Edited December 1, 2009 by 32SeBBaX

[spiderman]

difference in wheelbase - mountain bike will never be faster then a bmx in a tight turn becos of wheelbase difference.

 

weight and tyres - weight of the bike vs tyre compounds are very much one of the reason for extreme lean angles.