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Gearing...

10307 Views 68 Replies 16 Participants Last post by clay, Jun 4, 2006

YellowDuck

Discussion Starter · Apr 26, 2006

I am going to be test riding the 1000 Sport and the S2R 1000 next week. Very excited.

Anyway, looking at specs I notice that the gear ratios are the same, but the SC has much taller final drive (15/38 vs 15/41, I think). Any idea why they would have gone that route? Also, any of you try 14/38 or 15/41 on the SC yet? I would like the bike to be geared low enough to at least do some little baby power wheelies at WOT in second.

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clay

· #2 · Apr 26, 2006

Just did the 41t Ergal rear and it makes a HUGE difference. The stock gearing is very high but now it's hard to keep the front end down in first.

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ducremus

· #3 · Apr 26, 2006

I went one down in front and one up in the rear (14/39) and it still doesn't feel like enough. I've got about 800 miles on it now, but I'll wait for more break-in before I really get into it and see if need to go to 14/40. :think:

ducnutt

· #4 · Apr 26, 2006

clay said:
Just did the 41t Ergal rear and it makes a HUGE difference. The stock gearing is very high but now it's hard to keep the front end down in first.

Clay,
I went with a 14 in the front,like ducremus I dont think thats enough. I think I am going to go up 3 in the back like you did. Did you have to go with a bigger chain? Or did the stock one work?

Thanks
Nutt

clay

· #5 · Apr 26, 2006

Stock chain worked fine, I was more concerned with the chain guard clearance but that was ok too. I did have 600 miles and had adjusted the chain once. Highway cruising still tolerable in 4th so a 14 tooth with the 41 on the back should be fun without sacrificing any top end.

ducnutt

· #6 · Apr 27, 2006

clay said:
Stock chain worked fine, I was more concerned with the chain guard clearance but that was ok too. I did have 600 miles and had adjusted the chain once. Highway cruising still tolerable in 4th so a 14 tooth with the 41 on the back should be fun without sacrificing any top end.

HMMMMMMMMMM,I think I will have to give this a try. I would just hate to have to by a new chain if the stock one was still good.

Thanks.

Nutt

bassphreek

· #7 · Apr 27, 2006

clay said:
...without sacrificing any top end.

You are actually going to sacrifice a good bit of top end. If you go 14/41 you will drop 13.35% top end. That means 140mph drops to 121.

14/38 is 6.65% 140 drops to 130mph.
15/41 is 7.33% 140 drops to 129mph.

Sorry guys...those college math classes were kickin me in the brain.

-phreek

clay

· #8 · Apr 27, 2006

That's assuming that the bike is geared so that 140 mph is at rev limiter in 6th gear. These bikes are geared so tall that even with 14/41 gearing I think the limiting factor for top end is going to be horsepower. However, as soon as I pull the Euro 3 baffles out this afternoon I will do some high speed testing and report back. I wasn't too good at college math...

RocketJohn

· #9 · Apr 27, 2006

bassphreek said:
You are actually going to sacrifice a good bit of top end. If you go 14/41 you will drop 13.35% top end. That means 140mph drops to 121.

14/38 is 6.65% 140 drops to 130mph.
15/41 is 7.33% 140 drops to 129mph.

Sorry guys...those college math classes were kickin me in the brain.

-phreek

What would that make 6th gear 75mph rpms at?

ducnutt

· #10 · Apr 27, 2006

bassphreek said:
You are actually going to sacrifice a good bit of top end. If you go 14/41 you will drop 13.35% top end. That means 140mph drops to 121.

14/38 is 6.65% 140 drops to 130mph.
15/41 is 7.33% 140 drops to 129mph.

Sorry guys...those college math classes were kickin me in the brain.

-phreek

For me its not top-end.I like that low-end pull coming out of the corner,over top speed.

bassphreek

· #11 · Apr 27, 2006

RocketJohn said:
What would that make 6th gear 75mph rpms at?

I could figure that out for you this weekend, but I'm sure you would still be fine. I do 85 in 5th comforably right now...I barely use 6th.

I am also not crazy about the top end thing, I was just correcting the fact that he said you would not lose any top end. Wheelies are much more fun.

clay

· #12 · Apr 27, 2006

Just took it out and it runs into the rev limiter at about 120 mph in 4th gear (22/24 ratio) and sixth gear is an overdrive (28/24 ratio). If I'm doing the math correctly that equates to a top speed of just under 153 mph if the bike had the aerodynamics and horsepower to pull that off and that is with a 15/41 combination. I think I'll go ahead and order the 14 tooth front because that gets 142 mph + top end and a whole lot more low speed entertainment. Of course my math could be wrong and that's gonna force me to take another ride

wa6usa

· #13 · Apr 28, 2006

I've had 14/41 for a while, with a better new chain. It runs at about 4000 at 70 in 6th.
The best part of the 41 tooth is the quick run thru the gears from a light. It pulls hard thru 4 quick shifts to break out in front, couldn't do that with the 38, it wanted to stay in the 3 lowest gears to long to feel the HP.

clay

· #14 · Apr 28, 2006

I just took it out for a quick spin and in 6th gear it runs a tad under 3500 rpm at 60 mph. 60/3500 x 9000rpm = a theoretical top speed of 154 mph. I really don't think a bike with 83 hp at the crank and a partial fairing is going to do much over 140 let alone the 7.33% increase to 165 mph that stock gearing gives. Doesn't matter anyway, if I wanted to go 180+ I'd get a ZX-14R.

ducnutt

· #15 · Apr 28, 2006

clay said:
I just took it out for a quick spin and in 6th gear it runs a tad under 3500 rpm at 60 mph. 60/3500 x 9000rpm = a theoretical top speed of 154 mph. I really don't think a bike with 83 hp at the crank and a partial fairing is going to do much over 140 let alone the 7.33% increase to 165 mph that stock gearing gives. Doesn't matter anyway, if I wanted to go 180+ I'd get a ZX-14R.

One day,this guy told me

....Way out in the sticks,with a 14 front and 38 in back, he got her to top out at 135, That is all she had in her. Thats what he said

.

YellowDuck

Discussion Starter · #16 · Apr 28, 2006

Given that these bikes won't pull redline in sixth, there is a decent chance that lowering the gearing would actually INCREASE top end speed, since you could actually get it up into peak hp while trying to move all that air out of the way. That certainly has been the case with the smaller 2V motors.

Anyway, I am happy for you guys who have the opportunity and courage to run at way over the ton. Not this ducky. Too spooky for me, at least on the roads around here.

clay

· #17 · Apr 28, 2006

lowering the gearing would actually INCREASE top end speed, since you could actually get it up into peak hp while trying to move all that air out of the way.

I think you hit the nail on the head. If top speed was just a matter of tall gearing the Bonneville records would be held by the guy with the smallest rear sprocket. Overcoming aerodynamic drag takes horsepower.

Bottom line is do whatever makes the bike work best for you.

RocketJohn

· #18 · Apr 28, 2006

I emailed my racer buddy that has a 900SS/FE about what he uses here in Colorado for gearing on that bike:

"most street bikes are geared way too tall.
mine came with 14/39 (2.6). too tall to pull to max HP in top gear, and almost had to slip the clutch to get a fast start. not to mention using 1st to get out of slower corners with any grunt of torque. (i don't like using 1st once i get started)

the past couple of years i've tried 15/41 (2.73) and 42 (2.8). i liked the 41 best for all around riding. the 42 was fun for local canyon and track riding. always surprises other bikes when i'm quick enough to stay with them, and pull away when i'm in front off slow corners.

i recently replaced the chain and sprockets on my FE. (BTW: with my careful chain care, i got 15,500 miles on the OEM D.I.D chain.)
i got a 14 & 15 tooth front as replacement, with a new 41 rear. i put on the 14 front and the little used OEM 39 rear (2.78), with an RK Gold chain. ratios are close to the 15/41 i used. i'm going to try the 14/42 (3.0 ... yippie!) on a SuperTune track day (i will announce as the next riding class) on Friday May 5th. i'l bring the 39 and 41, too.

i advise using the 15/41 combo as a regular set-up. we can try any combo you want once you get the bike. i'l check if the sprockets are interchangable to an '06 DS."

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YellowDuck

Discussion Starter · #19 · May 4, 2006

Just re-read this thread and found this:

clay said:
I really don't think a bike with 83 hp at the crank and a partial fairing is going to do much over 140 let alone the 7.33% increase to 165 mph that stock gearing gives.

Hey! Not at the crank, at the wheel! 91 at the crank (or thereabouts).

clay

· #20 · May 4, 2006

From the dyno sheets I've seen you are correct, the 83 hp at the crank came from my owners manual. Doesn't really matter though, the 80 bucks I spent on the 41 tooth sprocket has already been worth every cent in entertainment value

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