K2 / Proflex Riders Group
General => Tech Forum => Topic started by: numbnuts on June 22, 2004, 02:25:24 am
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I am thinking of ditching my big ring and fitting a rock ring and guide. My first choice is the Evil but it is a bit spendy and the MRP LRP can be had for a more reasonable amount. Does anyone have any experience with these ? I think fitting should be no-hassle but do they work with all BB's and is there any problem? I do find that I drop my chain a lot at present which is annoying.
Also is there any rule of thumb regarding the chain length, presumably a shorter chain can be used if the big ring is not used ?
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NN,
I've been wanting to do the exact same thing... Both my local bike shops think it's nuts (numb) to eliminate the front derailleur.
But here's the deal - I haven't used the FD in over a year and am getting tired of dragging the extra machinery through the woods!
If I can talk my buddy into selling me back my old Proflex - or if I can snag another from ebay - I plan to build a belt drive unit with no derailleurs at all. If I can pull it off, it will probably need a Nexus 7 speed to be very useful.
A key benefit of the Proflex design is the chain (or belt) doesn't have to enter the rear triangle. Kind of opens up a lot of drivetrain options...
Anyhow, try looking at BMX chainring setups and/or the eccentric BB setup. The BMX route offers some pretty bulletproof alternatives.
There are also eccentric rear hubs for single speeds, but that seems a little too complex.
Good luck
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For those of you who only ride uphill, yes, you can eliminate the big ring...
Can't imagine not having a big ring myself, but then, I use the big ring as my chain tensioner! (Just put it in the big ring and voila! You've got a tight chain that rarely even slaps, let alone comes off (which has NEVER happened in my big ring). On top of that, when I'm riding downhill at speed, I find it disconcerting to be in a gear that requires a cadence of over 130 rpms.
However, my brother had an MRP on his (mostly) downhill rig, and it worked perfectly. Of course, he was always complaining that he needed a front derailleur... Also, I've considered a bash guard a few times - basically every time I bend a tooth on my big gear! Personally, my goal is to eliminate my granny gear. I figure it's only for wimps, which unfortunately, I am. However, someday, I think it would be cool to be able to say that I can ride all the same climbs without going below my middle ring...
Take everything I say with a grain of salt. It's all just biased opinion...
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The LRP works great on the EVO, I had one on mine (see pic). I believe the only thing special I needed was an e-type bottom bracket.
(http://idriders.com/proflex/galleries/RED5/OldRide.jpg)
Another choice if you don't want to lose the big ring would be to get a Heim Guide (pic) ( http://montaramtb.com/Products/3Guide/3Guide.htm ). I've used one on my Big Hit and it worked great. Good luck.
(http://montaramtb.com/Assets/3Guide.jpg)
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RED5, thanks, the link didn't work but I'll search for the Heim guide
Matno, I have been unsure about dropping the big ring also but I only use it occasionally, mostly on road rides. It seems that most of my rides now consist of steep or technical downhills that involve a lot of brakes and hardly any pedalliing. In fact I am thinking of upgrading to 8" rotors. I have thought of losing the front der completely, a friend did it and manages well with just a 34t up front. My bike is pretty heavy so although i try to complete most rides without using granny, I do use it at times and don't think i want to lose it. We are constantly searching for new trails and one we are looking at seems like it has a long gradual double/single track, we've only seen it from a distance but if it works I probably will keep the big ring, otherwise I'll just use my hardtail for road rides. [smiley=nod.gif]
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well I have the HEIM for three rings, and is great! besides I also have a ROCK RING, that I installed intead of the big ring once, for a 'freeride' kind of ride, but I like it so much that I never went back to the big ring!! but I still have the HEIM , in case I wanna go triple again..........