Dropping one in the front is the same as adding three in the rear. The only thing this does is shift the RPM band lower. You make power at lower RPMS, the only drawback is that you will lose a few MPH.
This will also throw your speedo off, so be prepared for that. They make devices that will make your speedo show the right speed though.
CHEF: Make sure you get the right sprocket. A lot of the online stores are listing the wrong sprocket for the 6r and 6rr. Call and double check before you order.
You can go either way and use the stock chain length.
Going down one in front is easiest and cheapest. You will get about a 7% change. Going to a smaller front sprocket might affect chain life slightly.
Going up two in the rear will give you about a 5% change. If you go with an aluminum sprocket you can also lose about 1 1/2 pounds of rotating and unsprung weight. The rear sprocket is more difficult to change and more expensive.
Im glad you think Im wrong considering you dont even have a front sprocket, and they are only $20 and are pretty easy to get. Here is why you CAN GAIN TOP END, odds are your bike will not be able to hit the rev limiter in 6th gear, it runs out of power before reaching it. When you drop one tooth on the front it changes your gear ratio. Now having the bike geared down now your bike will be able to take off quicker go through the gears faster getting you the same speed before but now that your geared lower so your bike can keep pulling a couple more thousand rpm allowing you to go a little faster. I know this is true with dropping 1 tooth, there is a point when gearing your bike down where you will start to lose top end. Also if your bike isnt tuned right you may not gain top end either because your air/fuel ratio or carb sync could be effecting top end. I have had many bikes including 2 6r's this year, and have setup several others, 1 tooth can make you have a higher top end.
Just got back from riding '03 ZX-6Rs at Texas World Speedway. They would hit 13,000 rpm on the start/finish straight in 6th. The max hp comes at 12,700 rpm according to their resident mechanic with the rev limiter set a 15,500, I believe he said. If you think they will do more top in by droping one in front you are on drugs.
You find me a front sprocket for 20 bucks for a 2003 zx-6r and I will buy it. The only one I found from Sprocket Specialists was the same price as the rear. They didn't even have a part number listed, I had to go by OEM part numbers to figure out which one would fit.
Second, I can see your point about the rev limiter and all but unfortunetely it doesn't work that way. Gearing the bike down means you are making power faster in the RPM band, which means you will run out of power sooner on the top end. Example: you change sprockets and now your max power is at 11,500 RPMS instead of the stock 12,500 RPMs. Which means from 11,600 RPMs to 15,500 you are losing power. So you are telling me that even though the bike is losing power for 1000 more RPMs it is going to go faster?
The only way this would work is on a rev-limted bike, where the bike hits the rev limiter way before running out of power. This isn't the case on 600s... try a liter bike maybe?
I dont know on the 03's, all the 02's and older I have messed with wouldnt. Every zx6r I geared down, went faster but I also messed with the carbs on all of them when I geared them down. Me and a friend rode our 01 6r's together everyday, our bikes were identical in speed. We geared his down and played with his carbs a little and with a 110lb passenger on his bike he would leave me on top end. We switched bikes and with me on his bike and the passenger with me I left him. Without a passenger he would leave me on top really bad with his bike. So I then dropped a tooth and messed with my carbs and our bikes were back to the same speed. Now all the bikes I have done also had slip on's, k&n, jet kits, and -1 tooth, and everyone of them gained top end. Im going by the shop Tues, I will see if they still have any sprockets, Im pretty sure they do, I saw 2 last week so they probly still have atleast one.
Well this is interesting conversation to say the least. I never really thought about it like you are stating, and it makes perfect sense I have just never heard of it. Personally though I could care less about the very top end. How often am I going 160 mph? Never have, probably never will.
Interested in the sprocket if you can beat 45 shipped. My local shops suck ass and the cheapest I have found online is 45 shipped for the front 14 toofer.
Asked a racer buddy of mine this same question (He rides an R6) and her's the answer I got: How much you change your gearing depends on the track you're on (Or the roads you ride). If you're not limiting fifth in the longest straight you could go down in gearing (Ideally you would hit the rev-limiter just befor breaking into the first curve after the longest/fastest staight) The only problems you encounter are (in lower gearings) a tendancy to wheelie out of corners due to the increased force applied at the rear wheel and the speedo issue. As long as you don't drop below 14 teeth on the front chain wear isn't such a problem. There was recently an article in Sport Rider covering this issue in some detail. (Not sure which issue but it was one of the last 4)
It will come up really easy with that gearing but it will be harder to ride wheelies. My stunt bike is -2 +5 and comes up in 1st-4th easy but it is so touchy in a wheelie because of the low gearing its hard to ride long distance's. I can a stock bike or one with -1 in the front till my arms get tired but I dont' think I could go a mile on my stunt bike. I havent tried any of the other guys bikies on the team that are geared really low but I havent seen any of them ride long wheelies since they geared them down, but some of there's are really low.
Despite changing your gearing, the power characteristics of an engine will still be the same. Peak power will still happen at the same time, it's just you'll reach that point quicker (or slower depending on which way you go with the gearing).
However, Minitryker does have a point in that some bikes in stock trim will have difficulty reaching peak power in 6th gear. The '03 636 doesn't... the tranny ratios are fairly tight, and enable the 636 to keep pulling even in top cog. The other point is that a 1-tooth front sprocket change has a fairly dramatic effect on overall gearing and would likely end up limiting top speed by a significant amount, although the trade off is that it will get to its limited top speed much quicker. For tighter tracks, it's a good move.
On a related note, anybody see that the '04 Honda CBR1000RR is going to have an interchangeable cassette tranny??? That's a pretty trick feature for a road bike. Racers will no doubt love that.
Yeah, the more I thought about it the more sense it made. I jsut knew it wasn't an issue for the 03 6r.
One question I had, is by going up three on the rear and down one on the front, how much WILL that affect my top end? Is there some way to determine how much I am going to lose? As long as I can still hit 120-130 then I am a happy camper. I just want the gearing for the mountains, when I get up there in the major altitude I want to be a bit quicker out of the corners.
Keep in mind altering (shortening) your gearing TOO much is gonna mean you're gonna go crazy shifting all the time. You'll be running out of each gear really quick if you do both ends like that. Unless you're into stunting only (MiniTryker might be better to answer this) in which case maybe that's a good sacrifice, but for real world riding, that'd be an awful chore in my books. Go with 1 on the front or up to three in the back or less, but you're talking TOO dramatic a change there.
Here's a thread that discusses gearing change. Check out Rob Lee's input on gear ratio towards the end of the thread, you might find it useful...
Thanks for the link. I guess I will just have to try different combinations to see which one I like better. I was told that just doing one or the other that small wouldn't make much difference which is why I went ahead and got both. We will see I guess. Thanks for the help.
Going down 1 and up 3 will change you gearing about 15%. So if you were doing 6,000 rpm at 80 mph in 6th you would now be doing almost 7,000. It will probably put you above the red line in top gear and close to the rev limiter. How much it will limit you top end is hard to say but a guess would be at least 10 mph because you will be developing peak hp at 136-140 mph.
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