gearing question

[mdabyo]

Haven never actually ridden my Rc yet lol. i have a gearing question. This is a 100% race only bike. my track is very technical, lots of turns and only short straight aways. any recommendation for gearing? some have said to leave it stock? I want to get a new rear sprocket to go with an aluminum one when i install a new chain, so thought i would ask for recommendations!

thanks!

-Jason

 

[isaac_]

*lurking*

Curious to know what track you ride?


Sent from my iPhone using Tapatalk

 

[mdabyo]

I am on the east coast of Canada, track is called Atlantic Motorsport park.

Track – Atlantic Motorsport Park

I have also ridden New Hampshire motor speedway and it seemed similar but our straights are shorter.

 

[Trae327]

Cant go wrong going up a tooth. especially on a tight track. Youll notice a little more get up and that could be beneficial.

Haven never actually ridden my Rc yet lol. i have a gearing question. This is a 100% race only bike. my track is very technical, lots of turns and only short straight aways. any recommendation for gearing? some have said to leave it stock? I want to get a new rear sprocket to go with an aluminum one when i install a new chain, so thought i would ask for recommendations!

thanks!

-Jason

 

[Maddog Reynolds]

My stock 2015 road bike will rev to 9,500 (and more with my head down) in top quite easily, so I guess it all depends on how far you have between bends

You'll tend to get better chain & sprocket life with an odd number of teeth, but I know it doesn't always work out that way on the track.

I've just *dropped* two teeth at the rear to 43, because mine is a road bike and it would rev over the speed for max power (depending on who you believe, stock bike makes max power at 8,600 or 9,300 rpm, from memory) and mine was getting close to 10,000, the limiter).

It's more relaxed now and just as quick on open roads

 

[green_bread]

Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator is your friend.

If it were me, Id invest in a 14T front sprocket (its going to be the cheapest and easiest to swap quickly) but leave the gearing stock. Go to your track and ride the bike, as is. If you feel like youre lacking power coming out of the corners or if you are finding yourself having to shift up in to the next gear for very short amounts of time to turn around and shift right back down, try throwing on the 14T and see how things go after that. This should give you a much better idea of where you need to be with your gearing and you can buy rear sprockets to better "fine tune" the gearing, if needed.

Keep in mind that dropping a tooth on the front sprocket will have much more of an effect on your gearing than adding a tooth in the rear.

 

[snaggletooth77x]

I practice at what looks like a similar track, I would invest in a 46T rear and try it out. If your bouncing off the rev limiter at the end of the longest straight then drop back down to the stock gearing. This is how I typically gear for any track.

 

[Mike91]

I have the opposite problem, most of my tracks (Florida) I am hitting the rev limiter half way down the back straight. Plan to try a 16T counter shaft sprocket next race.

 

[snaggletooth77x]

My main local track has a straightaway that is almost a full mile long. I use a 41T rear sprocket there.

 

[green_bread]

I have the opposite problem, most of my tracks (Florida) I am hitting the rev limiter half way down the back straight. Plan to try a 16T counter shaft sprocket next race.

16T was the key for me at NCM with its long straights. I didnt lose that much drive coming out of the corners, either. I think youll be surprised like I was.

 

[parillaguy]

I race my RC390 at a track that is flat and tight except for one long straight. I went down to a 43 on the rear and put on a new lighter weight DID race chain. Gearing isn't just about top speed. It will change the gear you are in for some corners. I went smaller on the rear to gain some top speed. But sometimes you change to a different rear sprocket to avoid having to over rev the motor in 1st gear on a real tight corner (as an example). I suggest you talk to some of the other racers who ride lightweights (CBR250,Yam R3 and Ninja 300) at AMP and see if they went up or down from stock. They are geared similar to the KTM from new and will be the best guide. parillaguy

PS the 'roller coast' section at AMP is the most fun of any track I have ridden.

 

[psych0hans]

One easy way to get slightly taller gearing and better turn in, at the same time, is to switch to a 140/70 rear tire. I did this and the effect was immediately noticeable.

 

[mdabyo]

Thanks everyone! i always ran a -1+2 on my R6 for my track and think a +1 will likely be what i am looking for. Sprockets are cheep so i will grab a +1 when i mount my new chain and go from there. worst case i will easily be able to drop back to stock.

And you are right parillaguy, AMP is a hell of fun track to race!

 

[mdabyo]

So i went with a +1 gearing and all was good. except i am having issues with one corner. I either bounce off the limiter in 4th for a few seconds or grab 5th before a hard braking zone that is downhill and off camber so not a good spot to drop it back into 4th if i do take the gear (upsets the bike way to much). The problem i am having is if i shift up to 5th i am really low in the revs after the corner and lacking power heading onto the back straight. so it kills my drive. but if i stay if 4th i am loosing out on drive i could be getting and bounching off the limiter for a while which i dont like.

Thinking about either.
- putting on a -1 tooth sprocket on the rear. that should allow me to not bounce off the limiter.
- Put on a +2 rear sprocket, force me to shift earlier and hopefully still have power after the conrner
- put on a +1 front sprocket (then i can use the +1 rear to fine tune)

I wish i just had a bag full of sprockets to play with. LOL

 

[mdabyo]

it should be noted i am nowhere near the rev limiter on the back straight, so maybe up gearing is better than down.

 

[Fangfactor]

Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator is your friend.

If it were me, Id invest in a 14T front sprocket (its going to be the cheapest and easiest to swap quickly) but leave the gearing stock. Go to your track and ride the bike, as is. If you feel like youre lacking power coming out of the corners or if you are finding yourself having to shift up in to the next gear for very short amounts of time to turn around and shift right back down, try throwing on the 14T and see how things go after that. This should give you a much better idea of where you need to be with your gearing and you can buy rear sprockets to better "fine tune" the gearing, if needed.

Keep in mind that dropping a tooth on the front sprocket will have much more of an effect on your gearing than adding a tooth in the rear.

Thats good advice.
1 tooth on the front equals approx 3 on the back

 

[CDN Duke]

Low mileage 43T Superlite sprocket FS here: FS: Last Try Parts! - KTM Duke 390 Forum

 

[CDN Duke]

I'm very pleased with 16T front for street use. Not consistent enough at the local track to gear for it yet...

 

[Fangfactor]

it should be noted i am nowhere near the rev limiter on the back straight, so maybe up gearing is better than down.

If you go to the 14 front. you will be closer to hitting the limiter on the main straight and you will be changing up earlier into 5th for your problem corner and it may give you enough drive out of that corner with the lower gearing. If not you at least get a little squirt in 5th before changing back down to fourth on entry.