Yeti/RMS 137SS

[tillbuilt]

Yesterday was testing day for the 10” wide Yeti/RMS 137SS. The snow was deep. The bikes were trenching and getting stuck regularly. Even the big 12 inch wide 137’s we’re getting stuck.

The two bikes were a 2018 YZ450F with a big bore, ECM and pipe, on a 2019 Yeti 129SS with a rider weighing 190lbs. The second bike was a 2020 KTM 350XC with a slip on muffler and a 2019 Yeti/RMS 137SS with a rider weighing 230lbs.

Throughout the day we had four or five good stuck’s and they were both trenching way down after breaking through the crust, especially when we were climbing and hit jack pines on the hillsides. When climbing they were almost side-by-side with the 137 sometimes showing a slight advantage, but the real tale tale was at the end of the day when we switch bikes and 190 pound rider got on the 137. He could not believe the track speed and the flotation differences. The weight difference on the 137 really showed he could climb things, with a higher track speed than he ever could on the 129. There was not any hard snow to feel the handling difference between the two but in the deep powder they felt very similar in handling.

The 137 Yeti/RMS is a real eTicket for that rider who is wanting more flotation but high track speed out of a 10 inch wide system. We are very pleased with this build.

Sent from my iPhone using Tapatalk

 

[Chadx]

Love it, toby. You are always working on something! Ha. Was this a custom build for a customer or a custom build for your shop bikes and to compare for the season?
Curious why a 137ss would have higher track speed than a 129ss? I can see more traction and faster ground speed, but how track speed? Due to the different bikes?

 

[tillbuilt]

Thank you.

Yes, this is a shop build.

The 137SS does carry more track speed when you get to the climb and start loading it, due to the increased footprint. It is not spinning and trenching in, it is moving the bike and getting up on top. The 10" track spins and chainsaws in at low speed clutch drop situations, but the 137SS comes out of that quicker then the 129SS. Once it is on top it motivates. This is in deep powder situations. 10" of fresh on top of 2 day old 3' dump that had a day of 38deg. bake. It had fresh, then 3" crust layer, then bottomless to the ground kind of snow.

Love it, toby. You are always working on something! Ha. Was this a custom build for a customer or a custom build for your shop bikes and to compare for the season?
Curious why a 137ss would have higher track speed than a 129ss? I can see more traction and faster ground speed, but how track speed? Due to the different bikes?

 

[Chadx]

...
The 137SS does carry more track speed when you get to the climb and start loading it, due to the increased footprint. It is not spinning and trenching in, it is moving the bike and getting up on top. The 10" track spins and chainsaws in at low speed clutch drop situations, but the 137SS comes out of that quicker then the 129SS. Once it is on top it motivates. This is in deep powder situations. 10" of fresh on top of 2 day old 3' dump that had a day of 38deg. bake. It had fresh, then 3" crust layer, then bottomless to the ground kind of snow.

Thanks Toby. I define track speed as the speed (rpm) the track is spinning which, of course doesn't necessary translate into faster ground speed. Plus, track speed (track rotation) would be very hard to measure since we don't have a track or driver-connected speedometer. What your describing I've always understood as ground speed; the machine is moving across the ground, or up the hill, faster. Read "GPS speed". Which I have no doubt the long track would have faster ground speed in this comparison. Your comment that the longer track is not spinning as much and has more traction also points to faster ground speed; but not faster track speed. Similar to sleds, isn't it correct that, all things being equal, a longer track with more traction, and more friction and weight, will always have a slower track speed? Though, yes, in many situations a faster ground speed? It's my understanding that more traction and more rotating mass and friction can never result in faster track speed. Just trying to ensure our definitions match up and that I'm not misunderstanding the results of your comparison. Thanks.

 

[chumbilly1]

So my question is, how does 137ss compare to new 129fr? Both in ground speed, rolling resistance, and manuverability? And weight I guess

 

[byeatts]

So my question is, how does 137ss compare to new 129fr? Both in ground speed, rolling resistance, and manuverability? And weight I guess

137 SS RPMs and track speed are faster than the FR and far more nimble, the overall footprint is less however cutting a path through the powder is far more efficient on a narrow track vs wide , it Frees up RPM and ground speed.