What is Gear Bound??

bsg29

New member
I was reading another thread and seen a few people talk about gear bound, how will you know if you are gear bound? I have now raced 6 races but have not gotten the karts up to the recommended RPMs about 500 off running the recommended gears.. Flat footing it the whole time.. I changed tires for the main that had no outside prep and was about 10 points harder to try and get more RPMs.. The kart was a lot more free but the RPMs still never got up more than 100 more than previous. In a clone do you have to hold the break a little to keep it up to RPMs instead of just flat footing it?? I use to run Flat heads back in 2005 and we just burped the throttle.. sorry for all the crazy questions..

Thanks for help and information
 

Dover Power

Member
Even though you can flat foot it,,, not as important as one would think.. Theirs a lot to be said for the BURKing the throttle.. It helps the engine remain strong especially in the later part of the race.. I promise ya won't loose any speed,, matter fact overall time of race will go down for your kart..

GEAR BOUND is a tough problem to describe..
Facts its happening is when you add gear to rear axle the RPM's never change.. I have witnessed going down on gear actually raised the RPM's,, that was due to being gear bound..

I too would like for someone to tell us all exactly the answer to what Gear Bound actually is?
I'd like to further help my customers when this situation happens..
 

bsg29

New member
Thanks you Dover... Racing Promoter.. The track is Patriot Speedway.. Not sure the exact size.. I was running 18-60. Thank y'all for the help its been aggravating just try to get the RPMs up.. I went to hard tires just to show myself it's not tires.
 

racing promotor

Moderator
In my hillbilly terms I look at gear bound as simply, if you yourself ran around the race track and choose to start sprinting out of turn 2 say picked up speed UNTIL half way down the back stretch then leveled out and stayed consistent the second half because your tongue was hanging out, That's your motor when gear bound, so if your on a flatfoot track it's worse because the consistent is a lot longer.
Bottom line to tall rear gears motor peaks way to soon ( quits pulling ) and it's tongue is hanging out lol !! Lower RPM drops than normal is a good sign of gear bound.
 

racing promotor

Moderator
Thanks you Dover... Racing Promoter.. The track is Patriot Speedway.. Not sure the exact size.. I was running 18-60. Thank y'all for the help its been aggravating just try to get the RPMs up.. I went to hard tires just to show myself it's not tires.

18-60 sounds reasonable on a clone, that would be ball park for a fifth mile, if it's a fifth or bigger most likely you needed taller rear gear, did you notice your RPM drops on your tack ? if so were they a lot less than normal. ?
 
My bet is that it's like when I first began racing 4-strokes, the first thought is to keep adding teeth to the sprocket, but when it doesn't seem to help, and then, later , when you remove teeth and it goes faster, you were, "Gear-Bound".
 

Bob Evans

Administrator
Just a point.
In hot rod terms, a "tall" or "high" ratio is numerically lower than a "low" ratio. A 3 to 1 ratio would be considered "taller" or "higher" than a 4 to 1 ratio. Maybe because of theoretical top speed, I don't know.
It's been my understanding over the years, if you were running a 3 to 1 ratio when the track and class called for a 4 to 1, and you were unable to get your motor into the sweet spot, rpmwise, then you would be gear bound. And if adding teeth to the rear increases rpm AND lowers lap times, you were gear bound.
To my way of thinking being "bound" applies to the corners, and means something that would slow you down.
 

paulkish

old fart
Same as what others have said, but how I like to think about it.

You need to use your engine up from the start of acceleration, to the end of the straight. If you use it up too soon your gear bound.

You can become gear bound if you learn to get around the corners better. If you improve your corner speed you'll start your acceleration at a higher rpm and use up your engine before the end of the straight. That's what leads to, get around the corners better, take gear off and go faster.

edit: I'd better add in maybe.
 

Bob Evans

Administrator
It may be nit picking, Paul-- but to be "bound" means you are being held back. And in my pea brain, that means you are geared too high to reach your target rpm, which can and will vary from motor to motor.
It's obvious from this thread that it means different things to different people, which makes me doubt it's relevance.
 

paulkish

old fart
click... I see it differently now Bob.

I was pretty much going with what I thought was the flow, figuring I had it right. Now I see it differently and see I wrote about something other then gear bound.

Your not nit picking at all, but pointing out I was wrong and explaining why. That's how we learn. thank you
 

racing promotor

Moderator
18-60 sounds reasonable on a clone, that would be ball park for a fifth mile, if it's a fifth or bigger most likely you needed taller rear gear, did you notice your RPM drops on your tack ? if so were they a lot less than normal. ?

Good point, I should of just worded my intent as higher number on rear gear, I never looked at it Bob as you are saying, I can see how to some it would apply as well, what it means to me you I feel the kart is being held back ( Slower ) so bound applies as well, but ya great point !!
 

KKania17

Member
x2, I've also had as Jerry said, RPM increase with gear taken off. I've gone up a whole clutch driver a time or two and still gained RPM and speed.
 

alvin l nunley

Site Supporter
x2, I've also had as Jerry said, RPM increase with gear taken off. I've gone up a whole clutch driver a time or two and still gained RPM and speed.
That's really surprising to hear!!, considering that one tooth on the driver is the same as taking 4 teeth off the axle. It's certainly not something I would expect to see, but if it works, it works. Good information to keep in the box.
 
My bet is that it's like when I first began racing 4-strokes, the first thought is to keep adding teeth to the sprocket, but when it doesn't seem to help, and then, later , when you remove teeth and it goes faster, you were, "Gear-Bound".

I agree with that ^^ and with "to me gear bound is when you can take teeth off of the rear and your lap times go down but your rpm stays the same"

But this isn't the reason you can't get up to the target RPM you want. With too much gear (gear bound) you get to your rpm target, but are going slower than you should be. Yes, taking away sprocket teeth will then make you faster at the same RPM, but I;ve never seen the RPM's actually go up by taking gear out of it.

To get more RPM you one or more of: More gear or More power or More speed
 

racing promotor

Moderator
I agree with that ^^ and with "to me gear bound is when you can take teeth off of the rear and your lap times go down but your rpm stays the same"

But this isn't the reason you can't get up to the target RPM you want. With too much gear (gear bound) you get to your rpm target, but are going slower than you should be. Yes, taking away sprocket teeth will then make you faster at the same RPM, but I;ve never seen the RPM's actually go up by taking gear out of it.

To get more RPM you one or more of: More gear or More power or More speed

I agree with you, but I have had guy's pull as many as 4 teeth on rear and Gain over 100 Rpm's.
 
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