Track Drilling

NMMM700

NMMM700

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Sep 29, 2005
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New Mexico
Has anyone drilled the track on their sled? If so, what pattern, what size hole? What type of drill bit was used? What are the positives and negatives? Does track drilling increase sled RPM's? This seems to be all the rave on mountain sleds and I am seriously considering doing it. Any feedback and opinions you guys out there have will be greatly appreciated.
 
1-1/4" holes, 3 in middle looks to be popular, some go 3-2-3-2 other use outside bands with 1 hole
try snowest.com there are tons of post on this subject, if I had a track just for mountain riding I would do it to it
 
Track holes

I first had a look at a drilled track in the Crazy Mountain Extreme's shop in Montana. In fact I picked up a drilled plug from a track he was working on. He was using a hole saw that he had ground the teeth off to make a knife edge. I built the tool but can't bring myself to do it.
 

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NMMM700 said:
ModMMax

Why the drill bit without the teeth? Does it cut easier through the track?
Click to expand...

A smooth cutting edge slices the fibers in the track rather than ripping and pulling them, leaving a smooth edge. Also some of the friction derived heat involved can help the rubber melt and bond with the exposed fibers to reduce the likelyhood of your track to come apart along the face of one of your drilled holes.

:Moon:
 
you guys gotta remember, this is for mountain applications. they arnt drilling holes to get alot of weight of sled parts themselves but, to evacuate the weight of the snow out of the track area of the suspension itself asap. meaning no snow in the track to lubricate slides. they have enough snow around them (powder) to get the lubrication to the slides. if you ride in subpar snow on hardpacked trails you'll have nothing to hold the snow in there, and slider, track and possibly rail failure can and will happen. somethings transpose over from mountain to trail riding, this one probably is not one of them. the choice is ultimately yours but if you dont have the time, money, or patience to do this mod then fix what fails on a regular basis, i wouldnt go hacking up that brand new track you have on your sleds. just my .02 and obervations. ski
 
Well guys I took the plunge and did it. I drilled my track in a 3-2-3-2 pattern with 1 1/4" holes. All the holes removed from the track weighed in at 1.74 pounds. 145 holes on a 151 track. Look foward to trying it out and seeing what difference they make.
 
Some guy's have reported more track stretch. Could be an issue if you run stock driver's. If I was going to do it, I would probably run anti-ratchet drivers.
 
I drilled my track. 3 - 1.25" hole pattern. It is amazing just how much easier the track turns when it is drilled. When I had about 2/3 of the track drilled and spun it by hand there is a very noticable difference between the drilled and non-drilled section of track. That alone makes it work it to me to drill it, efficiency is free horsepower. Also losing two pounds is free weight loss along with the loss of built up snow in your rear skid. Excessive track stretch seems to be only a problem with those people who drilled holes outside of the windows.

I built a template to ensure equal spacing, then drilled pilot holes. I semi-ground down the teeth on the bit. Be sure to drill in an open space unless you really get off on the smell of burning tires. Dont even try to use a cordless drill, it will suck the life out of batteries in a hurry, a half inch standard plug in drill works like a champ. Be sure to liberally apply WD-40 to the bit after each hole, it will smoke less, drill easier, and put less strain on your drill to not over heat it.
 
Yes, this mod seems like it would require less energy to pull the track around the drivers and the rear axle wheels, which would result in more power to the ground.

Let alone the reduction of unsprung weight, and rotating mass.
 
did my 151, three 1" holes, track ratchets terribly in deep powder. i think its stretching and ballooning as it never ratcheted before. doesnt do it on the hard pack, just deep powder. i would not recommend this
 
snowdad, dont mean to ask a silly question but did you tighten your track after you drilled your track? Are you running extroverts? Even before I piped my viper it would ratchet in deep snow under when the rear suspension was compressed.
 
Wow, after reading what snowdad had to say I am a little worried. There isnt any snow around here yet for me to try the sled after drilling the track. I do however run extroverts on my sled. I noticed though I have always had to run my track a little on the tight side even with extros. Maybe its a Yamaha thing. My buddies Cat's track has about 2" of play with 5lbs. of pressure. Hey ak ryda did you experience quite a bit of track stretch after drilling? How tight do you run your drilled track with extros?
 
I run my track with about 2" of sag when I gently pull down on it. I did have to tighten my track 3 turns after drilling it.
 
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