lets talk axle size

P

PeteL

Member
Is there any difference in performance etc with a 1 in axle v. 40 mm?
My kart has a thinner axle, and everyone else runs a 40 (at least) am I leaving any performance on the table, or can I compensate through gearing.
 
Handling would be the only difference .the actual speed would be the same with any gear on either axle .
Any improvement would be handling related .
What model and year chassis ?
 
flattop1 said:
Handling would be the only difference .the actual speed would be the same with any gear on either axle .
Any improvement would be handling related .
What model and year chassis ?
Click to expand...
I am just thinking out loud...I run a 2015 MGM chassis. At the moment, after a half year of racing in the Senior heavy class (390 lbs) I am about 3 seconds per lap off the pace. So I am grasping at straws and looking at all angles (inluding talent) to find a second or two.
 
Sprint or oval handling is a big key . Sprint even more so . 206 briggs class ?
Ther must be some issue that stands out .
 
YEa, there is a big difference in handling between a 1" and 40mm axle in sprint racing. You want a 40. You probably want to be close to 55" overall width. If your pushing, you want about 44-43% front weight. If your stuck, move it back to about 59-60% rear.
 
PeteL said:
I am just thinking out loud...I run a 2015 MGM chassis. At the moment, after a half year of racing in the Senior heavy class (390 lbs) I am about 3 seconds per lap off the pace. So I am grasping at straws and looking at all angles (inluding talent) to find a second or two.
Click to expand...
3seconds is a huge margin. Have you had the motor dyno'd to make sure its in the ballpark on power? Next obvious thing is driver, have someone about the same size that runs up front take it out and see if they have the same times.
 
I think you have a 1 1/4 inch axle not a 1"
I'm not criticizing flattop but
I would talk to Paul Rice at MGM. I'm very sure he can help better than any one else.
He's a great guy an often posts on here so do a search or call him.
I'm sure he will ask the same question flattop asked.
However, I'm curious what the total weight is when you go across the scales?
 
Jimbo said:
I think you have a 1 1/4 inch axle not a 1"
I'm not criticizing flattop but
I would talk to Paul Rice at MGM. I'm very sure he can help better than any one else.
He's a great guy an often posts on here so do a search or call him.
I'm sure he will ask the same question flattop asked.
However, I'm curious what the total weight is when you go across the scales?
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Correct on the axle. I have spoken to Paul a few times, but not about handling. My total weight is usually 393-395. (390 minimum).
 
racinnut15xm said:
3seconds is a huge margin. Have you had the motor dyno'd to make sure its in the ballpark on power? Next obvious thing is driver, have someone about the same size that runs up front take it out and see if they have the same times.
Click to expand...
The margin is huge. And I know i am new and practicing every chance I get. The motor is new. Replaced the old motor just before this weekend's practice. Was hoping for some improvement, but was running about the same times. We played with tire pressure and front alignment and had marginal improvments. I have not had anyone else drive my kart yet. I just watch everyone pull away from me during races.
 
First of all this isn't as easy as it looks. It take lots and lots of seat time to become good at this!
As a starting point for this discussion you need to tell us if the kart is loose or pushing?
 
Jimbo said:
First of all this isn't as easy as it looks. It take lots and lots of seat time to become good at this!
As a starting point for this discussion you need to tell us if the kart is loose or pushing?
Click to expand...
Definitely not pushing. Turn in is sharp. I know the biggest problem is the loose nut behind the wheel, and the lack of relative experience. The question at hand for this discussion, all of which is helpful, was the relative performance/handling difference between my thin 1.25" axle v. the more prevalent 40mm axle and what can be done to offset that difference (if anything). It seems to be the largest difference between my current setup and what everyone else is running.
 
Loose is a very general term. I tend to follow up with loose at turn in, loose before apex, loose after apex.

It is not uncommon for a newbie on a sprint track to be 2-3 seconds off the pace. Usually, a good coach can knock 1-2 seconds off with a couple of coaching sessions (3-4 hours track time)
 
Thanks for all the responses thus far. I know I am new, and learning tons thus far. The last three seconds between me and the field are going to be the toughest. Trying to eliminate most non-driver variables. I think I am loose after apex, if Ihad to guess.
 
First thing I would check is that you are running the same or close to the gear ratio everyone else is running.
As little as 2 teeth or more/less is enough that even with a perfect setup will lose a lot of ground based on that alone.
 
Mac_49 said:
First thing I would check is that you are running the same or close to the gear ratio everyone else is running.
As little as 2 teeth or more/less is enough that even with a perfect setup will lose a lot of ground based on that alone.
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One of the first things I did was to check ratios with the other drivers. I am close
 
Close on the gear ? How close exactly ?
On the axle is it a thin axle ?
When you call mgm have a pencil and paper in hand for notes .
 
flattop1 said:
Close on the gear ? How close exactly ?
On the axle is it a thin axle ?
When you call mgm have a pencil and paper in hand for notes .
Click to expand...
Within a tooth on the ratio with the same driver. Don't know whether the axle is thin or not. Copy on pen and paper.
 
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