BUMP STEER IMPROVEMENT

[00-NUKE]

From the specifications, the '09 spindles are supposed to have a caster angle about 4 degrees more slack (laid back) from the '08. I've not mounted the '09 spindle on my sled to check the difference with my angle finder.

Now that you bring this up, the reduced caster angle could have been the reason why they raised the mounting tabs for the tie rod? I should get a chance to play around with my sled later this week and start taking some measurements. I also have a spliter for the laser level that turns the beam into a "plus" sign so I'll easily be able to see the change in camber since the spliter has a level built into it.

That would make sense, although wouldn't the caster angle depend on the angle from the upper to lower A-arm mounting points or would the base of the spindle be different? If it's based on the a-arms, then my theory of adding 08' spindles to 09 A-arms would be even more likely to work. Hmmmmm.

 

[AKrider]

I compared the spindles again and it appears the ball joint mounting holes are in ever so slightly different locations. It is hard to see it with the naked eye however. But this would be the only way for Yamaha to decrease the caster angle without changing either the a-arms or a-arm mounts. I was always under the impression that the only difference in the upper '09 a-arms was the length, not angles. I was also under the impression that Yamaha did no changes to the subframe geometry in each of the generations of subframes they've come out with.

The base of the spindles are different as the '09 has more trail built into it.

 

[00-NUKE]

I compared the spindles again and it appears the ball joint mounting holes are in ever so slightly different locations. It is hard to see it with the naked eye however. But this would be the only way for Yamaha to decrease the caster angle without changing either the a-arms or a-arm mounts. I was always under the impression that the only difference in the upper '09 a-arms was the length, not angles. I was also under the impression that Yamaha did no changes to the subframe geometry in each of the generations of subframes they've come out with.

The base of the spindles are different as the '09 has more trail built into it.

Thanks for the 411! That's all good to know. I'll stick with my current mod and see how it does. If I have time I'll take some more photo's of the finished product. It's a lot like the most rescent photo's only I added longer SS bolts and cotter pins to the upper A-arm mount and the tie rod mount on the spindle for safety measures.
I am constantly impressed by this site and it's users. This thread helped me gain a lot of understanding on the Nytro geometry and how much it can snowball on you with 1 single change. I hope my calculations = Performance.

Off topic - WTF is the deal with dancing deodorant?

 

[raginyamaha]

I compared the spindles again and it appears the ball joint mounting holes are in ever so slightly different locations. It is hard to see it with the naked eye however. But this would be the only way for Yamaha to decrease the caster angle without changing either the a-arms or a-arm mounts. I was always under the impression that the only difference in the upper '09 a-arms was the length, not angles. I was also under the impression that Yamaha did no changes to the subframe geometry in each of the generations of subframes they've come out with.

The base of the spindles are different as the '09 has more trail built into it.

Thanks for the 411! That's all good to know. I'll stick with my current mod and see how it does. If I have time I'll take some more photo's of the finished product. It's a lot like the most rescent photo's only I added longer SS bolts and cotter pins to the upper A-arm mount and the tie rod mount on the spindle for safety measures.
I am constantly impressed by this site and it's users. This thread helped me gain a lot of understanding on the Nytro geometry and how much it can snowball on you with 1 single change. I hope my calculations = Performance.

Off topic - WTF is the deal with dancing deodorant?

who cares thats pretty funny lol

 

[AKrider]

LOL to recommend banning somebody.

 

[AKrider]

 

[00-NUKE]

Update... I spent a little bit of time cycling the suspension using the flipped '08 spindle and I'm experiencing toe in. I need to align the front end and as I think I've got my tie rod set too long. That would give me toe in as the a-arm compresses. I think there is potential here but I've got to dig further into the sled to loosen the inner jamb nut on my toe rod and I've not had the time or ambition.

I've not tired my '09 spindle as I've got much higher quality aftermarket lower ball joints and the '09 spindle will need to be drilled out to accept a larger mounting bolt.

Reason I think I'm onto something with the flipped '08 spindle is because the line the laser plots is much straighter than what I recorded before. it appears that it also requires my ground down outer ball joint and to be shimmed with flat washers. There is no reason this won't work as grinding off the edges of the spindle for a-arm clearance will be a simple exercise.

I was starting to loose ambition towards the end as well. For every change I made, it affects 3 others. For a while it seemed like an endless battle. If nothing else, I'm sure your lack of ambition will all get fixed when the snow flies!
So I'm guessing that you gave up on the Rev Spindles?

 

[AKrider]

Yeah, the Rev spindles would take some machining work that I can't personally do. They'd need custom spacer sleeves or the stock Yamaha a-arms would need to be modifed to accept the Ski-doo ball joints.

Not worth the effort or cost for me to do as an experiment.

 

[00-NUKE]

FINAL RESULT

Here is the final result of my bumpsteer improvement. Not the prettyist, but I think she'll do!

 

[AKrider]

 

[rlcofmn]

Sad to see your signature change

I've got a SPG box sitting at the post office waiting for me, I'll have to bring the sled with next trip down.

 

[AKrider]

I know! After this year's Mayor's Cup and getting passed by so many people I decided if you can't beat'em, join them. I can still keep my Nytro and will be experimenting with the front end but it finally dawned on me that it will never be as competitive as the other brands of sleds. Plus, I started off on Polaris and always liked their stable handling and feeling at high speed.

Looking forward to receiving some snow in the next two months to put some of these theories to practice in the real world.

 

[ruffryder]

Isn't yamaha getting back into cross country racing? I thought I heard that they have made suspension improvements on their sleds..

 

[AKrider]

They are but it is a limited effort and they are picking up where they left off last time they quit.

The main problem with Yamaha is they don't support grass roots racers nor do they seem to take racing seriously. In my opinion, this latest effort is more about marketing than it is results. They don't have enough racers on blue sleds figure out what works and what doesn't. In addition, they don't seem to understand that you'll greatly increase your odds of getting on the podium if you have a bunch or guys out there running blue sleds.

Then you have the fact that the Nytro is now dated and has not received any major updates since '09. I have a feeling the real reason Yamaha decided to get back into racing is due to Cat coming out with the F1100. The F1100 was offered on the Cat race program this year and it is legal to race in the Iron Dog.

 

[00-NUKE]

They are but it is a limited effort and they are picking up where they left off last time they quit.

The main problem with Yamaha is they don't support grass roots racers nor do they seem to take racing seriously. In my opinion, this latest effort is more about marketing than it is results. They don't have enough racers on blue sleds figure out what works and what doesn't. In addition, they don't seem to understand that you'll greatly increase your odds of getting on the podium if you have a bunch or guys out there running blue sleds.

Then you have the fact that the Nytro is now dated and has not received any major updates since '09. I have a feeling the real reason Yamaha decided to get back into racing is due to Cat coming out with the F1100. The F1100 was offered on the Cat race program this year and it is legal to race in the Iron Dog.

I think you'll like the IQR. I've spent some time on Polaris's new rear suspension, and with the right settings, it's pretty good. My only problem is that the rear suspension doesn't have a happy medium setting for those of us that like to go from trails to ditches. I would be constantly be adjusting on the IQR. It seems as though the racers like them though.