Gearing for the track - 08 1KRR

2094 Views 23 Replies 11 Participants Last post by pdfruth, Apr 21, 2009

pdfruth

Discussion Starter · Apr 12, 2009 (Edited)

Question for those who run around a track.

I'm excited to get some seat time on the new track, here in Denver (HPR).
Since there hasn't been many to do so yet, I'm finding little/no intel about what gearing works best on the 08 CBR1K, on this track.

I know it's very track specific. Good gearing choice on one track may not be good for another track. But I'm wondering what you track addicts out there use. I have an assortment of sprockets, and will certainly be bringing them to the track with me. But, I'm just looking for a good starting point. Do you go -1 up front, and then take an assortment of rears with you to the track (as I plan to do)? What do you start with? 15/42, 15/43, 15/44? Or do you start with stock gearing, and go from there?

LosPer, In searching a few threads, I came across your build thread (man thats a long read). Appears you're using stock gearing on the track? Is that still the case?

Jet City, what gearing do you tend to use on the track?

Any/all input very much appreciated.

1 - 20 of 24 Posts

lhintze

· #2 · Apr 12, 2009

I am interested as well...someone speak up please.

Silvy

· #3 · Apr 12, 2009

Losper is using stock gearing for now.

IMO, a change to -1/+2 is a great all around gearset. Unless the track has some really long (175mph+) straights, you'll be fine with that setup.

Silvy

· #4 · Apr 12, 2009

There's no telling what JCR is running. He's loco

LosPer

· #5 · Apr 12, 2009

The bike is currently a 520 conversion with stock gearing. I have purchased sprockets for -1 +2, and plan to install them this spring.

I think LDH has the best writeup on this, and is where I got my advice and direction.

pdfruth

Discussion Starter · #6 · Apr 12, 2009

LosPer said:
The bike is currently a 520 conversion with stock gearing. I have purchased sprockets for -1 +2, and plan to install them this spring.

I think LDH has the best writeup on this, and is where I got my advice and direction.

Excellent stuff. Thank you sir.

joema

· #7 · Apr 12, 2009

pdfruth said:
Question for those who run around a track...just looking for a good starting point. Do you go -1 up front, and then take an assortment of rears with you to the track?...

I've done many track days, but next week will be my first on the CBR1k.

I already went -1 on the front sprocket. Acceleration is better, bike is more responsive. It's easier to start in 1st gear -- less slipping the clutch (important in traffic). So far no big drawbacks.

-1 on the front reduces top speed a little, but the bike should still do at least 160, maybe more. Highway cruise rpms go up a little but it's not bad. Highway gas mileage seems almost unchanged.

According to Gearing Commander (a great site), with -1 it will do 173 mph at redline. http://www.gearingcommander.com/

For a pure track bike you can do pretty much whatever you want. But for a street or combined street/track bike, I'd recommend just doing -1 front as a 1st step. Then evaluate whether you want to change the rear sprocket.

But there are various other related factors. If you have a 55-series rear tire, that numerically lowers the drive ratio, thus a bigger gearing change might be required to achieve the same result.

Also related is whether you have the Bazzaz Z-Bomb or Power Commander's Ignition Retard Controller (IRC). Without these the power peak on the bike is around 10,500 rpm. With them power peak moves up to around 12k rpm, and the peak is broader. This can affect gearing choice.

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Jet City Racer

· #8 · Apr 13, 2009

Silvy said:
There's no telling what JCR is running. He's loco

Damn, is it that obvious??? :thefinger:

Anyways, while I've only ridden my CBR on one track so far, I was happy with 16-44 as we apex turn 1 at about 175 which puts me right about 11k on the smaller part off the tire. The CBR has plenty of torque, som it's OK to be a little tall on the gearing. I could go a bit lower, but if I do that I might be too short on many of the other turns. I prefer to match the gearing for the majority of the track as long as I'm not bouncing of the rev limiter in 6th on the front straight.

crotchrocket71

· #9 · Apr 13, 2009

gearing always different to each others ride butremember when you gear set your sag and suspension up again since itll change

dracus

· #10 · Apr 14, 2009

Hey cool! I live in Denver and had no idea a new track had gone up. I'm not up for taking my Blade out onto the track yet, but I wouldn't mind tagging along and watching a fellow 1kRR'er do some laps. Let me know when you plan on going and maybe we can meet up!

Silvy

· #11 · Apr 14, 2009

Do a -1/+2 and be done with it.

it'll do 170+

that's plenty

TrackHo

· #12 · Apr 14, 2009

15/44 (-1/+2) Seems to work fine at most tracks. I am going to try 15/45 in a few weeks at Inf.

Just beware--If you do a 520 conversion the only sprocket combos that will work with the chain length are 15 on the front and 43, 44, 45, 46 on the rear. If you want to run a 42 on the rear..you will run out of chain adjustment. I have NO idea why anyone would want to run a 42 or a 43

pdfruth

Discussion Starter · #13 · Apr 15, 2009

dracus said:
....but I wouldn't mind tagging along and watching a fellow 1kRR'er do some laps. Let me know when you plan on going and maybe we can meet up!

I'm planning to be out at HPR all day next Monday (4/20)... Weather permitting. Would love to see ya, and say hi. Look for an old guy, with a red 08, pitted next to a silver 05 Pathfinder.

Jet City Racer

· #14 · Apr 15, 2009

TrackHo said:
I have NO idea why anyone would want to run a 42 or a 43

You've obviously never been to Spokane. The front straight is soooooo long, you can eat lunch and take a nap before braking for turn 1. On my Aprilia I ran 17-42 there. (At Thunderhill I ran 16-46)

opcorn2:

Chris Sarbora @ Spokane Raceways

TrackHo

· #15 · Apr 15, 2009

Jet City Racer said:
You've obviously never been to Spokane. The front straight is soooooo long, you can eat lunch and take a nap before braking for turn 1. On my Aprilia I ran 17-42 there. (At Thunderhill I ran 16-46) opcorn2:

Well if you are redlining in 6th gear, by all means--use higher gearing--BUT my point was, if you want the chain to fit--you better use a 16T in the front. Cory Call has been radared at T-Hill at 163mph on a GSXR1K at T-Hill, with a (-1/+2). So if you can redline a non-tractor I4 at T-Hill by all means run taller gearing--but you would be the first to exceed 165 down the straight and live.

What kind of lap times were you running at T-Hill?

pdfruth

Discussion Starter · #16 · Apr 15, 2009

Jet City Racer said:
You've obviously never been to Spokane. The front straight is soooooo long, you can eat lunch and take a nap before braking for turn 1. On my Aprilia I ran 17-42 there. (At Thunderhill I ran 16-46) opcorn2:

Holly cow... You could land a plane on that front straight.
Kinda like the front straight at Peublo, which doubles as a drag strip (as seen in the first few seconds of this vid).

pdfruth

Discussion Starter · #17 · Apr 15, 2009

Thanks to all for the input. I really appreciate the help.

I'll be starting with -1/+1, and will bring an assortment of rears with me. I've got an extra sprocket carrier (aka. cush drive), so sprocket changes will only take a few minutes. It'll be fun to experiment

Jet City Racer

· #18 · Apr 16, 2009 (Edited)

TrackHo said:
What kind of lap times were you running at T-Hill?

I haven't been to Thill since I was a novice on the old pavement but got down to 2:02. I never really got the hang of that track for some reason. it just doesn't fit me.

I was just looking for a chance to post the Spokane front straight. It goes on forever. :sleep006:

rustytrombone

· #19 · Apr 16, 2009

can't you remove a link for a 42?

dracus

· #20 · Apr 16, 2009

pdfruth said:
I'm planning to be out at HPR all day next Monday (4/20)... Weather permitting. Would love to see ya, and say hi. Look for an old guy, with a red 08, pitted next to a silver 05 Pathfinder.

Cool, I'll try to make it out, also weather permitting.

1 - 20 of 24 Posts

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