One of the major design points of a new ski-rubber is that it should be the full inside width of the area in the ski in which it sits... not skinny like the stockers.
Is chewing through rubber ski stops common?
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Personally, we've debated on this point time and time again over the past year. There seems to be two major arguments that can be made both ways. (Anyone, please chime in if you can offer up a scientific / physical reason for either argument)
Argument for full saddle width:
- More spindle bearing surface means overall the stress on both the stop and spindle itself are spread out along a greater surface area. In order to compensate for the increased bearing area, the stop material needs to be softer than OEM durometer value.
Argument against full saddle width:
- The biggest downside is weight. More sled weight. Many riders including myself are concerned with extra ounces. Wider stops also mean more material weight which equals higher cost. At $4 - $7 per ounce raw material cost on some of these high-performance elastomers, that extra weight adds up fast.
I'm curious what my friend from Ball comes back with, as his initial reaction when I told him that we were leaning towards a full saddle design was: "That could be a complete waste". His reasoning was that if the current OEM size in a new elastomer is adequate and does the job of providing a lifetime stop, then why go bigger?
My 2c.
Cat has a full saddle width (or at least mostly as I recall) and I went through a pile of those as well.
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Cat has a full saddle width (or at least mostly as I recall) and I went through a pile of those as well.
Sent from my iPhone using Tapatalk
I'm not really that worried with a small change in unsprung weight to have more surface area and more reliability in the field... .... also... with a lot of force on the skis during riding... keeping the spindle squarely planted on the rubber on the rubber as the load changes and there is some play in the pivot bushings and sleeves... keeps everything meshed well.
Polaris has played with this very balance that you've discussed... and they chose to focus on the weight measures rather than the durability and field issues for an item that is a "wear" item and not covered under warranty.
They've tried many different rubber compounds with the stock width, lighter weight, rubbers... and we still have the issues we are trying to solve here.
More contact area in the saddle and more contact area on the foot of the spindle, IMO, means a more reliable, better riding experience.
For me, not having to worry about the ski flopping up in heavy snow conditions is my top priority here !!
With the flex of the ski, I'm not sure how important the "fuse"-function of the rubber is??
Some people are more worried about grams than I am though.... and hey, that's fine too.
My 2¢
Good luck !
.
Polaris has played with this very balance that you've discussed... and they chose to focus on the weight measures rather than the durability and field issues for an item that is a "wear" item and not covered under warranty.
They've tried many different rubber compounds with the stock width, lighter weight, rubbers... and we still have the issues we are trying to solve here.
More contact area in the saddle and more contact area on the foot of the spindle, IMO, means a more reliable, better riding experience.
For me, not having to worry about the ski flopping up in heavy snow conditions is my top priority here !!
With the flex of the ski, I'm not sure how important the "fuse"-function of the rubber is??
Some people are more worried about grams than I am though.... and hey, that's fine too.
My 2¢
Good luck !
.
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Full width.
Jes sayin.
Jes sayin.
Yep, full width. The few ounces will be worth it.
Lol. Lemme be clear here. I wasn’t lobbying one way or the other. I’ll gladly pay you Tuesday for a full width ski dampener today!!!
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it sounds like you know a lot more about the compounds than I do! I thought a full bumper would be better in the long run...... but if you can make a smaller bumper that lasts the LIFE OF THE SKI!!! and save us some $$$ $h!t that is a no brainer ill take the lighter cheaper one that will out last the ski!! id be supper happy with that! but ether way you go my vote is to get a set that out lasts the ski.
one more thing I would like to ask you about is the engine mounts. is their a compound that is soft like stock {to adsorb vibration} but wont deform/sack out so easily?? it would be a another thing that would be well appreciated by the axys owners. thanks boondock
I don't know much about the stock mounts, so I can't say for sure. I'll check into it though after we get these ski stops finished. Thank you
Several of you have all asked for updates, so here is the latest:
One thing has led to another and yesterday evening into the wee hours of this morning, we ended up doing a CAD mock-up of the spindle, OEM stop, and ski saddle...and then running a finite element model.
We believe that one of the main reasons that Polaris chose a cheap soft rubber, was because the front spindle tap is under a tremendous amount of stress when the ski is flexed upward a decent amount. It wouldn't surprise me if there are people out there who have snapped the tab off messing with any sort of mod and/or aftermarket stop. Widen the stop from OEM spec or widen / narrow your ski stance, and the stress on the tab is even greater. I speculate that cost, and perhaps weight are most likely what drove these type of design decisions.
It's imperative that stress on the spindle tab is taken into account in the overall chemistry and geometry of the stop.
We also discovered that the radius of the OEM stop does not match up inline with the axis of the spindle. Although not much, this is most likely contributing to the wallowing out of the ski bolt (bushing) holes since the stop is constantly rotating along the incorrect axis in relation to the spindle. We should be able to help alleviate a bit of this problem also with our stop. Two birds with one stone as the saying goes.
Having said all this, I don't like to criticize anther's work. Therefore, instead I'll offer a word of caution: Personally, I would be hesitant to run any sort of mod or non-OEM stop if the designers haven't taken into account these stresses on the spindle. I think it's safe to assume that if the part doesn't have properly aligned parting lines or hasn't been fully degassed, then most likely the designer didn't do a finite analysis.
I think we are still on schedule; this week we should have a finalized design and 3D prototype for molding.
You all have a great weekend and talk to you soon,
Ryan
One thing has led to another and yesterday evening into the wee hours of this morning, we ended up doing a CAD mock-up of the spindle, OEM stop, and ski saddle...and then running a finite element model.
We believe that one of the main reasons that Polaris chose a cheap soft rubber, was because the front spindle tap is under a tremendous amount of stress when the ski is flexed upward a decent amount. It wouldn't surprise me if there are people out there who have snapped the tab off messing with any sort of mod and/or aftermarket stop. Widen the stop from OEM spec or widen / narrow your ski stance, and the stress on the tab is even greater. I speculate that cost, and perhaps weight are most likely what drove these type of design decisions.
It's imperative that stress on the spindle tab is taken into account in the overall chemistry and geometry of the stop.
We also discovered that the radius of the OEM stop does not match up inline with the axis of the spindle. Although not much, this is most likely contributing to the wallowing out of the ski bolt (bushing) holes since the stop is constantly rotating along the incorrect axis in relation to the spindle. We should be able to help alleviate a bit of this problem also with our stop. Two birds with one stone as the saying goes.
Having said all this, I don't like to criticize anther's work. Therefore, instead I'll offer a word of caution: Personally, I would be hesitant to run any sort of mod or non-OEM stop if the designers haven't taken into account these stresses on the spindle. I think it's safe to assume that if the part doesn't have properly aligned parting lines or hasn't been fully degassed, then most likely the designer didn't do a finite analysis.
I think we are still on schedule; this week we should have a finalized design and 3D prototype for molding.
You all have a great weekend and talk to you soon,
Ryan
I have broken a spindle “nose” off.
But it was because i had two layers of cut up drive belt underneath the spindle. (And i bailed off my sled as it went off a cliff in early season snow with no base)
I think even with the polyurethane at full width there isn’t a danger of breaking that nose off. (But that’s just based on a full season of thrashing a set of the poly bumpers)
Zero FEA or cad time.
Something worth pondering... The aftermarket skis have different bushings, Slydog/CA-Pro/SLP etc...
They have a wide, stiff ski-rubber... no rash of breakage.
I have seen the 'foot' of the spindle cracked off on one or two of the stock spindles/ski/rubber.... in photos around the internet... not an epidemic by any means though.
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They have a wide, stiff ski-rubber... no rash of breakage.
I have seen the 'foot' of the spindle cracked off on one or two of the stock spindles/ski/rubber.... in photos around the internet... not an epidemic by any means though.
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Update
Good morning and Happy Thanksgiving everyone! As you can see, my username has changed from "boondockdawg" to "DuraPro", in order to now reflect the trademarked name and logo of the elastomer product line we will soon be revealing. Only one product as of now with the Gripper ski stop, but we have several other ideas that we'll be revealing over the next few weeks.
Several brilliant colleagues and friends have contributed to this project and we believe that we've come up with a design that addresses the numerous problems with the current OEM ski stop, all the while improving ski response and ride quality!
I truly appreciate our patience over the past couple of weeks with everything, but believe that the wait will be worth it! As soon as I have a go-ahead from the examiner (still checking into patent options), I will post pictures, a description of the product highlights and problems they address, and finalized pricing (which we expect to be around $70 per set). With the holiday upon us, I expect this to happen at the beginning of the week.
My original estimate of being able to ship the first week of December remains realistic, as our proprietary mix is being manufactured for us and should be in our hands a week from today. We will immediately start injection molding and fulfilling orders thereafter on a first-come first-serve basis beginning with those who have already expressed interest through PM / email.
I'm excited and hope that you are too! Running off to parties, but I'll continue to be in touch!
Kind regards,
Ryan
Good morning and Happy Thanksgiving everyone! As you can see, my username has changed from "boondockdawg" to "DuraPro", in order to now reflect the trademarked name and logo of the elastomer product line we will soon be revealing. Only one product as of now with the Gripper ski stop, but we have several other ideas that we'll be revealing over the next few weeks.
Several brilliant colleagues and friends have contributed to this project and we believe that we've come up with a design that addresses the numerous problems with the current OEM ski stop, all the while improving ski response and ride quality!
I truly appreciate our patience over the past couple of weeks with everything, but believe that the wait will be worth it! As soon as I have a go-ahead from the examiner (still checking into patent options), I will post pictures, a description of the product highlights and problems they address, and finalized pricing (which we expect to be around $70 per set). With the holiday upon us, I expect this to happen at the beginning of the week.
My original estimate of being able to ship the first week of December remains realistic, as our proprietary mix is being manufactured for us and should be in our hands a week from today. We will immediately start injection molding and fulfilling orders thereafter on a first-come first-serve basis beginning with those who have already expressed interest through PM / email.
I'm excited and hope that you are too! Running off to parties, but I'll continue to be in touch!
Kind regards,
Ryan
thanks for the update 70$ a pair is a bit more than gulfi's sets but probably about the same when shipping to our house is factored in! thanks for all your hard work to get us a top quality product! and look forward to seeing what else you have in mind...
PS: don't forget to make time to enjoy the products that you worked so hard on...may the snow gods dump 10ft on you...as soon as your done
PS: don't forget to make time to enjoy the products that you worked so hard on...may the snow gods dump 10ft on you...as soon as your done
thanks for the update 70$ a pair is a bit more than gulfi's sets but probably about the same when shipping to our house is factored in! thanks for all your hard work to get us a top quality product! and look forward to seeing what else you have in mind...
PS: don't forget to make time to enjoy the products that you worked so hard on...may the snow gods dump 10ft on you...as soon as your done
I have $60 per set in the 7 sets i got from gulfi.
Fwiw
You guys are comparing a Cadillac to a Pinto.
I'm assuming you didn't have any any Customs charges on only 7 sets, whereas you will have Customs charges on 40+ sets (If the package's honest value is being declared).
Furthermore, the others don't address a couple of the secondary problems with the OEM stop. If the stop isn't properly designed, it can actually exacerbate those already existing problems (e.g. wallowing out of the ski bushings holes).
Just want to make sure that this new stop is receiving a fair comparison. We want to keep the price reasonable, but if comparing to others out there, a set's worth much more than $70.
Thanks for your guys' interest and feedback.
You guys are comparing a Cadillac to a Pinto.
I'm assuming you didn't have any any Customs charges on only 7 sets, whereas you will have Customs charges on 40+ sets (If the package's honest value is being declared).
Furthermore, the others don't address a couple of the secondary problems with the OEM stop. If the stop isn't properly designed, it can actually exacerbate those already existing problems (e.g. wallowing out of the ski bushings holes).
Just want to make sure that this new stop is receiving a fair comparison. We want to keep the price reasonable, but if comparing to others out there, a set's worth much more than $70.
Thanks for your guys' interest and feedback.
It’s not cadillac vs pinto...........
Comparing an excellent working prototype thats in my hand.
Against a pretty bird in the trees.
Prove me wrong! Lol
Touché! Haha, what I should have said is that the OEM one is a Pinto (at best), the one you have in your hand is a Cadillac, and the one on my desk is a Nasa Space Shuttle. LOL
well it is looking like tomorrows ride to Cantwell might be the last ride on the new rubbers I got this season so im desperate to get a set and not waste my $$$ on another POS set keep me posted I need some BAD!!!
