Gearing Question?

flea954rr · 05-11-2008, 1:27 PM

i am running a 520 conv. -1 in front, stock rear, so a 15/43. Commute everyday on the highway to work, so have been basically happy with the tradeoff of better acceleration with a lack in top end speed.

My question is by adding teeth to the rear sprocket, what change can i expect?

Ol' Gravy Leg · 05-11-2008, 4:38 PM

exactly more of the same

flea954rr · 05-11-2008, 7:03 PM

i'm feelin ya leg. right now i say its around a 5mph speedo change in 6th flyin on the freeway. now will it be more like 7mph?

Ol' Gravy Leg · 05-11-2008, 7:07 PM

for +1 up in the back, yeah.

+2 will feel like the -1 in the front.

-1 felt right for me. but it depends on your freeway driving/gas mileage concerns.

flea954rr · 05-12-2008, 8:40 PM

i'm also happy with the current set up which is the -1 in the front and stock rear. i'm going to definitly keep the -1 on the front, i'm just thinking of adding +1 to the rear.

curt248 · 05-12-2008, 9:03 PM

What kind of gas mileage change did you notice? Oh wait, you can't tell because your speedo is off now. Does it seem like you get less trips to work now?

flea954rr · 05-14-2008, 9:30 AM

best i can tell is that its a little less than 30mpg. Nothing to dramatic, and the acceleration gain is worth the trade off.

just wish someone running -1/+2 would chime in and let me know what its like.

curt248 · 05-14-2008, 10:56 AM

What mileage did you get before?

How are you measuring the mileage since the odometer won't have correct information anymore. If you are using the odometer and the gas pump for the calculation, you should get an increase in gas mileage.

I always get around 40mpg (+/- 1mpg)with stock gearing.

usafric · 05-14-2008, 11:18 AM

Gas mileage... Gas mileage... Who keeps track on gas mileage while riding a sports bike.
Surely if you are concerned about mileage you should ride a Honda Rebel!!!

curt248 · 05-14-2008, 11:37 AM

I keep track to decide if I should drive my car to work or the bike. If it costs me $3 more to stay cool if it's really hot out, warm if it's really cold out or dry when there is a chance of rain, then I'll probably drive my car. When it saves me $12 to ride the bike I may ride the bike. You can always make better decisions when they are informed decisions.
"Learn as much as possible. Then use that knowledge to make a better life for yourself."

D.Nac · 05-14-2008, 2:30 PM

-1 tooth on the front = 2.866 teeth on the rear.

Speeds can be in each gear and effect of gearing changes can be seen here

http://www.GearingCommander.com

Your calculated top speed at redline in 6th (which you will never be able to get to) is

174 with 16/43 (stock)
163 with 15/43 (-1 front)
156 with 15/45 (-1/+2)

The Gearing commander site will show every gear top speed. It will not show how giant the wheelies will be if you go -1/+2

curt248 · 05-14-2008, 2:46 PM

Why would you never be able to get to the top speed? I know one of the magazines quoted a measured top speed for the 929 of 172mph.

Cool. Thanks for the info. I thought it would make more of a difference in speeds. Maybe I will try the -1 front. I just bought a full exhaust to get a few more ponies. Maybe I should have just dropped the front sprocket one tooth.

Does the bike pull harder everywhere then with the -1 front? My new 1999 (in 1998) YZ125 pulled like a 250 with stock gearing, but when I went one up on the rear, it revved out too quickly and didn't pull strong anymore. I read an explanation for this somewhere. It was a little convoluted, but explained how this was possible.

I'm just looking for what actually happens from those of you who have done it. I might as well just go to the end result as opposed to using the theory method. Right?

flea954rr · 05-15-2008, 9:19 AM

by dropping -1 in the front kurt there is a big change in acceleration. this isn't one of those random things where you are not sure of the difference. i'm not exactly sure of the gas mileage, like i said i think its around a 5mph loss on the speedo. as i only own the bike, gas mileage isn't really a concern when its no choice.

curt248 · 05-15-2008, 2:43 PM

A big change huh? I think I'll have to give the -1 a shot.

How much should I pay for a front sprocket. I know on motocross bikes they are about $10. Is there a good place to buy them inexpensively?

How about the 520 kit. If that was inexpensive enough, I might just do that with the -1 front or maybe just do a +2 rear instead (as long as I'm changing sprockets).

So you don't have a car or truck flea?

machinehead · 05-15-2008, 4:31 PM

I ran 15/42 for a while now 15/43, 15/42 is my preference.

Ol' Gravy Leg · 05-15-2008, 6:54 PM

Quote:

Originally Posted by curt248

A big change huh? I think I'll have to give the -1 a shot.

How much should I pay for a front sprocket. I know on motocross bikes they are about $10. Is there a good place to buy them inexpensively?

How about the 520 kit. If that was inexpensive enough, I might just do that with the -1 front or maybe just do a +2 rear instead (as long as I'm changing sprockets).

So you don't have a car or truck flea?

you'll notice the -1 front sprocket change more than changing out a full exhaust. it pulls hard. the gearing is too tall on a 929 for it to "rev out too quickly."

520 kit will run you a couple of hundred bucks. i'd get that if your chain/sprockets are already worn.

i've got a -1 front AFAM (steel) front, if you're interested, curt.

usafric · 05-15-2008, 8:51 PM

Hey Ol'Gravy, I am interested in the front sprocket if it is still avail??? I am looking at a getting the front up easier, don't care about less MPG, just more on the fun-o-meter...

bladeracer · 05-15-2008, 9:37 PM

[quote=D.Nac;676845Your calculated top speed at redline in 6th (which you will never be able to get to) is

174 with 16/43 (stock)
163 with 15/43 (-1 front)
156 with 15/45 (-1/+2)[/quote]

If you gear the bike _up_ it's very likely you won't be able to pull the redline in top gear.
Gearing down though you can usually pull to the limiter. The '98 GSXR750 is way overgeared (more than 300kph) so you can gear that down a fair bit and still not be able to pull redline in top.
The 929 is geared very well for maximum speed although I don't think it'll pull redline in stock trim with stock gearing.
My 929 bounces the limiter very easily in top gear with my current gearing.

Gearing calculators are often optimistic as they work on fitted tyre circumference. For accuracy you need to measure the _rolling_ radius of the tyre when it's loaded - the height from the centre of the axle to the road surface when the rider is on the bike.

bravehart929rr · 05-15-2008, 10:39 PM

i had 15/45 gearing on my 929 and while its abit more buzzy it feels perfect, yes you will lose some mpg. as far as top speed you wont notice it. with gearing calulators you have to edit the max rpm and enter the rev limit rpm to get a true top speed, they just use the peek horsepower rpm. and as someone else stated you'll be able to pull closer to the rev limit in 6th gear with lower gearing

curt248 · 05-15-2008, 10:43 PM

I'd like to try the sprocket. How much gravy?

More difference than a full exhaust. Wow. That's saying a lot. Too bad I just ordered a full exhaust to get a little more pull from my 929.

I did just pick up a usb powercommander III locally from a guy for $120.

I'm hoping it'll smooth out the power delivery. I saw a guy on an 08 fireblade going about 40mph and effortlessly pull up the front with what looked to be just a twist of the throttle. I remember thinking that he must have a super smooth and strong powerband.

flea954rr · 05-16-2008, 9:31 AM

to put things in perspective kurt, a gearing change is easily the best bang for the buck. being is that its a maintenence item, changing gearing can be looked at as that. highly recommend doing the 520 conv. at the same time. one thing to remember is you will need the "best" chain any of the mfg. carry to maintain strength, i like the DID ERV3 or RK GXW which is what i'm running now. do a search, very popular mod.

954WRECKER · 05-16-2008, 5:29 PM

After 15K miles with the stock 530 at 16/43 I just recently did the switch 3 months ago to a 520 with 15/45. Huge difference, the biggest I've noticed compared to pipes and powercommanders without a doubt. I'm kicking myself for not having switched the chain and sprockets sooner (I waited 4 1/2 years!). It really does pull harder and I like the gearing and new shifting. After going on a 300 mile ride the first weekend I checked my buddies odometer and mine was about 10-11 percent higher than his. My most recent idea was to try a 14 tooth front and see what happens, I found one for $30 and I'm definitely curious what it feels like. -1 in the front is very close to +3 in the rear, I'd go to a 48 in the rear and leave the front at 15 but theres no way my new chain can handle the 3 extra teeth right now after just under 1K miles from when I installed it. My kit was from sumofallparts.net and it was the best $150 I've ever spent, no problems with the vortex sprockets or the RK GXW chain yet.

954WRECKER · 05-16-2008, 5:34 PM

Gearing commander is a great site I found it right before I switched my gears and its dead on for my setup. I like how in 3rd gear now I can just watch the rpm's and not pay attention to the crazy speedometer since they are almost exactly matched with my actual speed (3rd gear is the only one but its my most common gear so it works out pretty well)

curt248 · 05-16-2008, 5:34 PM

Wow that's a pretty big jump down in gearing. -1/+2. Are you saying that this gave harder acceleration than putting on a full pipe and powercommander?

I would think it should. I just bought a full exhaust and powercommander and am very excited to see what sort of difference it makes.

954WRECKER · 05-16-2008, 5:41 PM

Never pulled the trigger on a full system, trust me I thought about it for a very very long time. But I went through a ton of bolt on pipes that saved some weight and definitely sounded better than the silent stock exhaust. I even tried a powercommander but never noticed a real difference I think the 954 stock mapping is pretty good even without the powercommander. A full system and powercommander plus the lighter 520 with the new gearing should be pretty fun for you.

954WRECKER · 05-16-2008, 5:50 PM

flea if your chain can handle the extra size you should without a doubt go to a 45, as long as its not completely 100% brand new I'm sure your chain will be just fine.

flea954rr · 05-18-2008, 3:11 PM

wrecker, i'm due for a new 520 set up, and think i'm sold on going from -1 in frt. only to the -1/+1 this time, keeping in mind in my daily commuter, in other words 2/3 highway during the week, so seems like a good trade off.

also, had full exhaust and pcIIIr pre 520 conv. easilly the bigest difference of all the mods from SOP dyno.

curt248 · 05-18-2008, 4:52 PM

Flea. The 520 conv made the biggest impact on the dyno?

954WRECKER · 05-18-2008, 9:08 PM

Yeah if your on the freeway all the time it makes sense to keep the ratio a little bit lower to keep the rpms down a bit. But I cruise just fine in 6th gear on the highway here in Cali and its not too bad. I admit I'm not on the highway nearly as much as you are though. Good luck, I'm sure that gearing will feel great compared to stock.