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Buell Forum » 1125R Superbike Board » Archives 001 » Archive through June 13, 2011 » 1125R aerodynamics and their effect on high-speed acceleration « Previous Next »

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Thefleshrocket
Posted on Thursday, June 09, 2011 - 03:30 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I've been spending a good bit of time riding my 1125R and my Daytona 675. One thing I've noticed is how the 1125R's acceleration seems to fall off at high speeds. Under 100mph, the 1125 clearly has the advantage over the 675. From about 100-120, that advantage seems to decline, and over about 120, the 675 feels like it's pretty darn close to the 1125.

Considering that the 1125 should have ~30hp advantage over the 675 (mid-100s compared to mid-130s), the 1125 should have a pretty good advantage over the Daytona across the board. But while the 1125 seems to accelerate noticeably slower at high speeds, the 675 doesn't feel like acceleration drops off all that greatly at higher speeds until the upper 140s.

Both bikes seem to run out of steam around 155mph (indicated). There's probably a few mph left in both of them (if I tucked in a little tighter, or kept the throttle cranked open for a longer stretch of road). Since the 1125's horsepower advantage should translate into a noticeably higher top speed, all I can surmise is that the 1125's large front fairing has a pretty big surface area (no sh!t, right?) and a relatively high coefficient of drag. The 675 looks tiny from the front by comparison and looks slipperier overall as well.

None of my observations are obtained scientifically--they're all seat-of-the-pants and aren't from side-by-side comparisons of the bikes, just me riding them separately--so take this with a grain of salt.

In unrelated news, I think I'll take my 1125, my 675 and my CBR600F2 to the local Harley dealer some time this summer and dyno them all back to back. I'm curious to see how much power they all make, relative to each other.

(Ah, crap. The grammar Nazi in me just realized that I should have used "its", not "their" in the thread title. LOL)

(Message edited by thefleshrocket on June 09, 2011)
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J_copeland
Posted on Thursday, June 09, 2011 - 03:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I owned both bikes at the same time and kinda agree with you!
I believe what you feel is the power of the triple is more constant thru the entire power range. I know that's what it felt like to me.
I still liked the overall feel of the Buell better, so I sold the 675.I never rode it anyways.
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Court
Posted on Thursday, June 09, 2011 - 03:45 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

You are both correct . . . . . Some of the shape of the 1125R may not do it great favors as it enters triple digits.
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Littlebutquick
Posted on Thursday, June 09, 2011 - 03:51 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

i trimmed 30mm off each side and drilled holes in it it seemed to help and have had 152 mph over the quarter since
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Avalaugh
Posted on Thursday, June 09, 2011 - 04:03 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

mine certainly pulls very well right up to 160mph, takes a bit longer to get to 170mph.

I have the Erik Buell Racing ECM and a APH exhaust, im convinced the free flowing exhaust helps, but the ECM more.
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Fresnobuell
Posted on Thursday, June 09, 2011 - 04:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I believe what you feel is the power of the triple is more constant thru the entire power range.

You mean the Twin is more constant, correct? And it's very likely the triples more peaky powerband feels "faster" when you come off the dip in the power curve. The first gen Duc 1098 motors felt faster because of this phenomena.
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Xl1200r
Posted on Thursday, June 09, 2011 - 04:33 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

My CR has seen 150mph and it felt to still pull strongly up there - If I had a little more room I have no doubt I would have touched redline in 6th without much fuss from the bike. The fairing could be part of it, but I'd bet the 675 (like my CR) has shorter gearing, so it's easier to keep the revs where they need to be for that kind of pace.
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Fast1075
Posted on Thursday, June 09, 2011 - 04:43 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Resistance increases as the square of the speed...Aero is everything.
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Duphuckincati
Posted on Thursday, June 09, 2011 - 05:27 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

So how long a stretch of road do you need to get to 150+? Mine gets to indicated 140 pretty quickly but as stated seems to be tapering off on the pull at that point.
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Jules
Posted on Thursday, June 09, 2011 - 05:41 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

On the long straight road between my place and Swindon I can get an indicated 160+ MPH with a bit of effort (tucking in, elbows clamped, thighs clamped, chin up etc).. But that road is 17 miles long and I probably need a good 4 or 5 miles to get up to the very top of the speedo...
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Xl1200r
Posted on Thursday, June 09, 2011 - 06:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I hit 150mph at NJMP Lightning. The track is only 1.9 miles long, so it's not taking miles and miles to reach it. I have no idea how long the front straight is, but I'm doing something around 95mph coming out of the bowl and I give myself plenty of time braking into turn one. If I had to guess, there's probably about 3/4 of a mile between going WOT @ 95mph and where I was braking. I'm wide open through the kink about 1/3 the way down the straight as well, so factor that in.
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Duphuckincati
Posted on Thursday, June 09, 2011 - 06:30 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I should have mentioned I have a CR with the high bars and I'm watcha call "stocky" (5'10" 200lbs 56yo). So anyone know either on paper or real world what the top end on a CR should/could be? Taking into account the difference in gearing (pullying?) from the R?
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Xl1200r
Posted on Thursday, June 09, 2011 - 07:21 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Funny you should ask:
http://www.badweatherbikers.com/buell/messages/290 431/402575.html
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Tpoppa
Posted on Thursday, June 09, 2011 - 10:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

hmmm. Didn't someone on here once claim that the 1125R went through more wind tunnel testing than any Japanese bike?

(Message edited by tpoppa on June 09, 2011)
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Ratbuell
Posted on Thursday, June 09, 2011 - 11:24 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

It did.

But like HP and Torque...ultimate numbers aren't the whole game. Top speed isn't "it". There's stability. Quiet rider cockpit. Predictable handling. Rideability.

90% of owners don't ride all the time on the track. The bike has to be good...EVERYwhere.

Are there shortcomings? Sure. There are always shortcomings. The balance is, figuring out where to put those shortcomings and how to arrange them, to get the best possible motorcycling experience for the owner.
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Father_of_an_era
Posted on Thursday, June 09, 2011 - 11:53 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

What Ratbuell says is correct and (in my opinion) I think that the R is a very formidable machine on and off the track.
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Ogobracing
Posted on Friday, June 10, 2011 - 08:13 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

My take is this, the 1125r is an easy bike for anyone to ride fast -- and by that I don't mean just twisting the throttle on a long straight. Top speed is not "it", just one of many factors that make for a great bike. There are faster bikes, there are slower bikes, bikes that might handle better and a lot that handle worse, but few are more fun -- with the exception of the heat.
That's my story and I'm sticking to it.
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Tpoppa
Posted on Friday, June 10, 2011 - 11:15 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I dig my 1125. Saying that is went through more wind tunnell testing than any Japanese bike is an odd claim.

How could you know how much wt testing Suz put into the Hayabusa...or any other bike for that matter. The big 4 have deep pockets for R&D & they don't release their R&D information.
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Thefleshrocket
Posted on Friday, June 10, 2011 - 11:24 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ratbuell, the funny thing is that I think that the 1125R's cockpit is actually the worst one I've ever experienced from the points of view of quietness, smooth airflow and rider stability. I get by far the most wind noise and buffeting while riding the 1125R than I do on my 675, 600F2, my SV650 and 1000, GSX-R1000, GSX-R600 (track bike) and even my old Z1000 which had a small windscreen on it. The 1125R is the only bike I've ridden where I feel compelled to wear earplugs while riding due to wind noise. Also, as the air passes over my back while tucked at high speed, it really seems to tug and my jacket and make it want to whip around, despite being a pretty tight fit. I've thought about upgrading to a bigger windscreen but haven't done so yet.

It may because the bike was designed for a shorter rider (I'm 6'4")--for example, when my knees are properly slotted into the curves in the frame, my crotch is slid back a few inches from the airbox cover. When my crotch is up against the airbox cover, my knees are past the frame curves and splayed out into the wind.

Despite those complaints, the 1125R is either my favorite bike or really close to it. (I really like all of the bikes I've got now and it's hard picking a winner.)
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Carbonbigfoot
Posted on Friday, June 10, 2011 - 12:37 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Aerodynamics? We don't need no steenking aerodynamics!

Signed,

The CR Riders.

(Message edited by carbonbigfoot on June 10, 2011)
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Duphuckincati
Posted on Friday, June 10, 2011 - 01:07 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

YEAH! Windshields are for sissies! Wimmin and motersickles are supposed to be nekkid!
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Chessm
Posted on Friday, June 10, 2011 - 01:27 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

+1 hell ya! we CR riders look down at you nancy boy R riders with your wind protection! bah!
















BTW anyone know how i can adjust laminar lip to go up higher?
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