What's the best ALL AROUND RX-1 Mountain gearing?

[Frostbite]

I still have my 03 RX-1M.

I do a bunch of different types of riding with my sled. I trail ride 50% of the time not because I like trail riding that much but because of the dense forests in the Pacific Northwest.

I boondock (where and when I can) I'd guess 25% of the time, hill climb 15% of the time and drag race on back country airstrips about 10% of the time.

I still have the stock gearing in my sled. Is it 21 x40?

I would think there may be an advanctage to going to slightly lower gearing.

I may be picky but I want gearing where I can still pull the same top end speeds AND still use my existing chain?

I remember a 2.0 gear ratio was about the highest one would want in the mountains and closer to 1.5 is where the serious climbers migrate. Maybe a 1.75 could be the best of both worlds for a guy like me?

I haven't looked into this subject at all just yet so what are the options?

 

[givemeaboost]

Most people I know gear down for the mountains which is numericaly higher number. 21/40 is 1.90 ratio and to get it to pull at higher elevation you need to go to 21/42 or lower yet. The higher you go the more hp you lose which is why you need to gear down not up , Ken.

 

[Trxster]

I run at 20/42, others run at 19/43 for mountains. For your application I would say 20/40 (stock vector mountain) would work well. Lower but not too low.


Rt

 

[Frostbite]

Thanks guys.

20 x 40 huh?

So, I'd be I'd have to go even smaller on the top sprocket. Hum....
Right now the chain is so long it darn near touches the other side when I tighten the tightener finger tight. That can't be a good use of H.P.

Maybe I could go to a shorter chain with the gear change (68 link). What is the stock pitch? 70 right?

I just pulled out the 2003 technical update book and it says yes they lower sprocket is a 40 tooth. The upper changes with elevation. For my elevation 4-6500 feet it says i should have a 22 tooth upper gear. Only for 8-10,000 feet do they go tho the 21 tooth upper gear.

I have to believe Yamaha must have corrected their chart in the later years.

Frosty

 

[Trxster]

Sorry frosty, I just meant that was a good in between ratio.....with a 70 chain you could go 21/42 and it would be the same.



Rt

 

[Frostbite]

How big of a bottom sprocket will fit in the chain case?

Yup, a 21 x 42 or 21 x 43 would be right in the ball park.

Does anybody have a 68 link chain, a 20 tooth sprocket or a 42 tooth sprocket laying around?

Frosty

 

[Trxster]

Call MPI (mountainperformance.com) or check their website. They have the gears available for about $35 (they are Polaris Hyvo gears and work well) and they also have the gearing chart that shows what combinations you can use for your length of chain on the website. You don't want to buy a new chain as they are like $100 or something. Good luck man and say hi to all the team 509ers that are over your way that I got to party with last weekend at Puyallup.


Rt

 

[rx1tom]

Frosty,

I run a 23/40 combination which gets you to a 1.74, my 05 RX 1 Mtn came with a 21/40. 1.90 ratio from the factory. The type of riding I do is similar to what you are doing and it works fine, I typically ride in upper michigan and we do get some very deep snow and I have had no issues at all. For $35 dollars a gear is fairly cheap and if you wanted you could also try the 22 tooth gear for a final drive of 1.82. You will have to re clutch, I could easily pull 11,000 rpms with the stock clutching and the 23/40 gears, but the 23/40 combo will get you about 106mph at 10400rpms. It is a good all around set up, and works well for me. You also can reuse your 70 link chain.

Tom

 

[Trxster]

23/40 would be good in MI but as soon as you hit some of our mountains in our snow you would drop RPM's like a rock. Just my $.02

 

[Rx1M5]

I run 19 40 now because of reverse but if I had my druthers on a non-turbo sled I'd run 19 42 in the mountains. I ran 19 42 prior to reverse and it rocks. 19 40 is a good all around gearing as well but doesn't climb as well as the 19 42. Now that I'll be turboed I think the 19 40 will be fine. For your application 19 40 would probably be pretty good. 1 gearing never works for all riding but it especially sucks if you are over geared when boondocking or climbing. I'm always willing to give up some top end for better climbing and low speed power. The caluculated ratio for 19 42 is 2.21:1 20/40 is 2.0/:1 etc etc. I think you want to target around 2.0:1 ratio using any combination of gears and chain that works for that ratio.

Rx1M5

 

[Frostbite]

RX1M5, Thanks for the information. I called my parts guy today and learned a few things.

For anything under 21/40 a 68 link chain is suggested.

The ratios are:

21/40 = 1.90
20/40 = 2.00
19/40 = 2.11
18/40 = 2.22

Thanks again for all the help guys.

Frosty

 

[Frostbite]

Oh yeah, one more thing I forgot to ask.

My parts guy says the lower sprocket is available in 37-40 tooth versions.

So is there a "Yamaha" 42 tooth available that he didn't see on his listing or does one have to use an aftermarket or Polaris sprocket?

Frosty

 

[Trxster]

Polaris Hyvo gears work. $35 from MPI.


Rt

 

[Rx1M5]

Yamaha makes a 42 tooth. Don't use an 18 top too much bend in the chain.

 

[Jonny Rocket]

Frosty,

I have a 42 tooth in my garage if you want to use it.

J.