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2012 AK sled build


The road to 399 lbs is going to be slow and tedious one. Tonight I made lightweight lower ski loop bolts.

Started with a piece of 1/4" .035 4130. I tapped one end for a 10-32 screw. .049 would have been the correct size to tap but since the screw is only there to keep the tube from sliding out, I don't see the shallower threads being a problem. For the other side, I drilled out a thin 10-32 nut to a 1/4" I.D. to fuse on the end of the tube. Lighter and smaller than using a 1/4" nut.


Fused the nut in 4 spots.


Ready to install with the hardware.


OEM ski loop bolt and my new tube for comparison.


I think the only way I could possibly make it any lighter would be to use aluminum washers but that's a matter of saving grams.

As for the weight difference: (keep in mind my scale is not intended for weights this small but I weighed each setup three times)

- The oem bolt, washer, and nut is .13 lbs
- My new tube bolt is .09 lbs

The upper 5/16" ski loop bolts will be replaced with aluminum bolts for additional weight savings.

I also picked up some 7/16" .035 tubing and thin 5/16" jam nuts for new ski runners since the .058 one I made was kind of on the heavy side.
 
Nikolai said:
I can look into that. I'd probably fuse the thin wear strips to the tube so there wouldn't really be any lip to start with, it'd be about 1/32" tall.

Since the sub 400 lb sled will have it's own home brew suspension, I wanted to start experimenting with spindles on my current ride to see if they'll hold up. The factory spindles are about 2.2 lbs each and I think I can make chromoly ones that are about half the weight. Right now I'm kind of leaning towards a single 1-1/4 .058 tube with tabs as pictured. I also may end up just copying Timbersleds old welded spindle design, I'm undecided.

Tomorrow I'm going to order the rod ends for my new a-arms. I've been looking at rod ends for a few months now and finally decided on some FK's. I was going to use some high misalignment chromoly ends from QA1 but the FK's are a 3 piece design and have higher load ratings, about the strongest rod ends I could find online. Misalignment is 21 degrees on the 1/2", and 19 degrees on the 5/8". They are quite a bit more than the QA1's at $45 ea. for the 5/8" and $35 ea. for the 1/2", but strength is a priority here.
FK high mis chromoly rod ends

I also have a set of Fox Float 3's on the way. Last year I weighed both skis, spindles, shocks, tie rods, all four a-arms, and mounting bolts and it came in at 40 lbs. I'm hoping I can get the complete front end down to 32-33 lbs.
Click to expand...

Caleb:
One thing I notice on the Nytro Skinz front end is the increased caster leads to increased steering effort.... like a chopper with really stretched forks. You've also got to be careful where the ski bolt is in relation to the center line of your a-arm heim joints: the further away, the greater the steering effort. The Nytro stock ski bolt is not in the same line as the heim joint bolts, which doesn't help. So its a double up of effort: a shallower caster angle (mine is 27 degrees which is way too much IMHO, and the bolt is not on in line with the a-arm pivots.

Something to think about when fabbing up those custom spindles.

I think I'm going to try the CR Racing 36" +3 a-arms next. Very close to stock geometry only pushed forward.

OTM
 
The CR front end is super nice, that's probably what I'd switch to as well if I were to buy another suspension.

The castor will be taken back to about 23 degrees with the new a-arms I'm building. I'm not following you on the ski-bolt though. The ski-bolt on my spindles in directly in line with the heim joint bolts, unless you are talking about being directly under the upper a-arm which would put the ski bolt behind the lower heim.
 
Exactly what I mean. The ski bolt is behind the lower heim joint. So with such a shallow caster, you are lifting a bit of the weight of the sled with every turn. Just adds up on my old arms after a while. Maybe I'm off base on that too.

A bit off topic, but I know you have had it apart: on the stock nytros, there is a lower pivot arm (the piece that your tie rods and steering link is attached to). What is that bearing inside of there? Assuming delrin or some similar plastic. No grease nipple, but seems to work better if you grease it top and bottom. Not enough miles on the sled to be worn out.

Now I know why you got rid of all that garbage...... ;)!

OTM
 
Interesting.....

I'm sure that a needle bearing wouldn't benefit from grease LOL!

One massive job to get it out of there to properly lube.... :o|

Many thanks.
 
Ordered Fox Float 3's from Anchorage Yamaha which I picked up yesterday. My Ohlins are 16.5" and I wanted a hair longer shock, so I ordered Floats for the Arctic Cat F series/Z1. They are 16.8" and I measured the travel at the ski bolt yesterday and got 8" which is what a stock Nytro is. I need to make a couple spacers since the bushings are too narrow for the Nytro but I'll get them mounted up Tuesday or Wednesday. They are almost exactly 3 lbs lighter for the pair.


I started on the .035 ski runners tonight, I got one tacked up so I could weigh it. The stock carbide is .81 lbs with washers and nuts. I went to the hardware store today and got aluminum nuts and washers. The .035 runner with aluminum hardware is .31 lbs right now. It will gain a little weight from the wear strip I'll add but still should come in under .35 lbs. I also got some 5/16" aluminum bolts to replace the steel bolts at the upper ski loop mount. Hoping to lose a pound total between both skis.


New aluminum hardware with the oem ski loop bolt. I'll order some nicer 7075 hardware in the future for the 399 sled, this was the only aluminum hardware available in town.



I will be carrying most of the factory hardware in my backpack for the first couple rides until I know the aluminum will hold up.
 
Nice work !
really interesting to see you chase every oz.

You need to mount that Cat master cylinder, should be some weight savings there.
 
Might seem like a dumb idea, but has anyone ever tried making CF skis? The difference in weight compared to plastic might not be significant enough to be worth the effort or expense, but putting that aside I'm wondering if a CF ski has ever been tried for a sledding application and if so, how well do they hold up?

I've seen CF waterskis made for jumping, which are substantially lighter than other composites (even those that are honeycomb cored) and they're subjected to fairly substantial abuse when you consider what jumpers put them through ... repeatedly hitting a ramp at speeds approaching 65-70mph... and still they seem to hold up fairly well.
see: Goode skis
 
OVR4D said:
Might seem like a dumb idea, but has anyone ever tried making CF skis? The difference in weight compared to plastic might not be significant enough to be worth the effort or expense, but putting that aside I'm wondering if a CF ski has ever been tried for a sledding application and if so, how well do they hold up?

I've seen CF waterskis made for jumping, which are substantially lighter than other composites (even those that are honeycomb cored) and they're subjected to fairly substantial abuse when you consider what jumpers put them through ... repeatedly hitting a ramp at speeds approaching 65-70mph... and still they seem to hold up fairly well.
see: Goode skis
Click to expand...

I do remember seeing carbon fiber skis way back in the day that were made by Tison Performance for the their TMK sled. They were tested but I don't believe they were ever available to purchase. I think not too long after that Tison Performance kind of just dwindled away. I want to guess that this was back around 2000 or 2001. I don't recall what the ski weights were.

Freekin cool, glad you back at it.
Click to expand...
Thanks!
 
Finished the ski runners today. Got them welded up and then cut 1/4" wide wear strips out of .040 4130 plate.


Getting them ready to weld.


100% done with the ends capped as well.


Factory hardware for both skis next to the new hardware.


Since my scale is not super accurate and sometimes varies by an ounce or two, I reweighed everything tonight.
Both factory carbides without hardware are 1.5 lbs
Both of mine without hardware are .68 lbs
Weight loss: .82 lbs

The factory hardware for both skis is .36 lbs
My hardware for both skis is .20 lbs
Weight loss .16 lbs

Total combined weight loss from the skis so far: .98 lbs

Thursday evening I'm going to do a mild "Carl's Cycle" cut to each ski to see if it improves sidehilling as much as everyone claims. I'll post complete ski weights once they're cut.
 
I'm not sure about the ski bolts, Ti. bolts are about $35 a piece for a minimal loss. I may try to make 3/8" 4130 tubular bolts like I did for the ski loops.

Here's a couple pics with the skis cut. Once I get a few rides on them I'll report back on any performance gain/loss. Complete ski weight excluding the ski rubber is 4.99 lbs.


 
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