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Discussion Starter · #1 ·
Hi 650b'ers

I have a 08 TNT RFX. I have 650b and 26" wheelsets and a Pike Uturn. I installed a 7.5 X 2" RP23 washered (home depot 3/8" 9.5 Nylon washer, split with wire cutter, fits perfectly) down with 4 washers (9/32" thick) to 1.72" with a 2.1 rear Neo and 2.3 Neo front. Also have a WTB 2.2 wolverine in the wings. I'm 230lbs and ride everthing from smooth single track, to very technical NE trails, with no jumping and only a 'safe' downhill.

My various ideas are:

1. full 650b. Rear seat and chain stays are good but only about 4mm clearance on the CS and about 6-7mm on the SS. Plenty of clearance on the '04 Factory Pushed Pike. Run the pike at 125-140. 67.2 degrees on the HA at 140mm and 67.8 degrees at 125mm. I checked that with my digital angle finder. Should have about 5" travel in the back based on this boards input. At 140 up front have a 14" BB at 125mm have a 13.75" BB.

2. 650b front, 26" rear. I could de-washer the 7.5 X 2 or buy a 7.875 X 2.25 RP23 and go back to the 6.3" travel rear. Maybe use a tall tire to come closer to a 650b OD. I would loose a little of the 650b feel, but gain travel, and a rotating weight savings.

3. full 650b, but go to a 7.785 X 2.25 RP23 and shim stroke down to where it won't hit the seat tube. I don't know if this will work or not. Anybody? The BB will probably be at 14.25??? unweighted. Any guesses on the travel?

4. Use the Wolverine 2.2 up front or in the rear? Or just buy another and do F & R? Would save some rotating weight, but performance??

So, any ideas / input?

Thanks
Bob
 

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noMAD man
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I'm partial to the 650B/26 setup on a longer travel trail bike...a Nomad in my case. I still like the acceleration and quickness of 26 in the rear. I've ridden a Stumpjumper with 650B front and rear and didn't like it quite as well as my 650B/26 Stumpy. For me, I'm even somewhat of a fan of 69'ers, but I'm not quite so fond of the loss of travel in the fork that's required. 650B in the front seems to be about right for max travel and bigger tire/wheel benefits.

People are different, however, and frankly you won't know the pros and cons until you try it all on the same exact bike that you'll be riding. I think a bigger wheel in front is pretty much accepted as a benfit under most all circumstances for trail riding, but you have to try it see how it suits you. Everything's a compromise, and mine is 650B/26 on my two bikes.
 

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I have done it all to my RFX. I started out 26,"s w/ a Pike Dual Air , 7.875 x 2.25 RP23, 2.4" Kendat Cortez tires - decided I would try a 650b up front. I don't think I terribly impressed as the steering felt sluggish with the Pike @ 140mm. I also felt the Neo-moto's tread compound was a little to hard. A few months later I decided I should try full 650b. Ran a 7.5 x 1.75 RP23 and Neo-moto's F&R. The bike steered fine and the travel was balanced. Blew my rear hub after a month and had to run a 26er in the rear. The tallest 26" tire I could find was a 2.5" still about 1/2" shy of the 650b. Ran the Pike @ 120mm BB height was low @ 13.25" - handled fine but had quite a bit of pedal smack. After my new rear wheel was built I went to a Roco TST coil and a Nevegal front / Wolverine rear - felt the best w/ a 13.75" BB height and 68* HA. Dual 650's balance out really well , running the 26" rear was either too low / too high depending on the shock length.
 

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noMAD man
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keen, something I've noticed on most all your feedback on your setups has been the headangle issue. Nothing at all wrong with your take on it, but this really shows that preference/riding style factor that can come into play. You seem to tend to want a steeper head angle by a small bit, and I like a slacker head angle by a small bit. Neither is right or wrong as some kind of absolute, but just points out that little bit of difference that's important to each of us. That's the part that almost requires the "must try it out" approach to really know what fits. Too bad there's not a magic formula...sure would save a lot of time and money.:lol: The good thing on your info here at least is that you have basically the same bike as the OP.
 

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TNC said:
keen, something I've noticed on most all your feedback on your setups has been the headangle issue. Nothing at all wrong with your take on it, but this really shows that preference/riding style factor that can come into play. You seem to tend to want a steeper head angle by a small bit, and I like a slacker head angle by a small bit. Neither is right or wrong as some kind of absolute, but just points out that little bit of difference that's important to each of us. That's the part that almost requires the "must try it out" approach to really know what fits. Too bad there's not a magic formula...sure would save a lot of time and money.:lol: The good thing on your info here at least is that you have basically the same bike as the OP.
Most of my first FS bikes had slack HA's as I always ran long travel forks on short travel frames - my 2001 Bullit had a 7,875 shock and a Shiver DC. I felt a steeper HA w/ a tall front end a sagged rear did the trick for me. I never feel twitching steering w/ a 67-68* HA on even my DH bike. So, in other words, I like a slack bike w/ a steeper HA.
 

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Hey,

Spongebob said:
Hi 650b'ers

I have a 08 TNT RFX. I have 650b and 26" wheelsets and a Pike Uturn. I installed a 7.5 X 2" RP23 washered (home depot 3/8" 9.5 Nylon washer, split with wire cutter, fits perfectly) down with 4 washers (9/32" thick) to 1.72" with a 2.1 rear Neo and 2.3 Neo front. Also have a WTB 2.2 wolverine in the wings. I'm 230lbs and ride everthing from smooth single track, to very technical NE trails, with no jumping and only a 'safe' downhill.

My various ideas are:

1. full 650b. Rear seat and chain stays are good but only about 4mm clearance on the CS and about 6-7mm on the SS. Plenty of clearance on the '04 Factory Pushed Pike. Run the pike at 125-140. 67.2 degrees on the HA at 140mm and 67.8 degrees at 125mm. I checked that with my digital angle finder. Should have about 5" travel in the back based on this boards input. At 140 up front have a 14" BB at 125mm have a 13.75" BB.

2. 650b front, 26" rear. I could de-washer the 7.5 X 2 or buy a 7.875 X 2.25 RP23 and go back to the 6.3" travel rear. Maybe use a tall tire to come closer to a 650b OD. I would loose a little of the 650b feel, but gain travel, and a rotating weight savings.

3. full 650b, but go to a 7.785 X 2.25 RP23 and shim stroke down to where it won't hit the seat tube. I don't know if this will work or not. Anybody? The BB will probably be at 14.25??? unweighted. Any guesses on the travel?

4. Use the Wolverine 2.2 up front or in the rear? Or just buy another and do F & R? Would save some rotating weight, but performance??

So, any ideas / input?

Thanks
Bob
So far ive only ridden both of my conversions as full 650bs. The current set up is the 06' 5 spot using 08' chainstays, 06' seatstays and the 5.3 rockers. I tired some 5.5 rockers but the rockers additional length over the 5.3s made the 2.25 RR buzz the seatstays so i went back to the 5.3 rockers. I have a WTB 2.2 wolverine on its way. Im hoping for better fitment. Ive also thought about mod'ing the 06' stays or buying some 08' stays which are 3mm longer.

i went with a TALAS 140 up front. ive always liked the TALAS when i rode 26' bikes and the tire clearance is great even with a nev 2.35. Id like to push it sooner or later. This combo results in a static BB height of somewhere between 13.75 and 14"s and i retain the HA and SAs which i really like. Im running about 18mm sag in back and around 12mm up front.

Ive messed around with tires a bit Ive got back and forth between the 2.35 neo and the 2.35 nev up front. I foudn a tradeoff between the two. The nev rolled slow but was perfect when it was rolled over whereas the neo rolled fast but squirmed a bit when rolled on its side. Oh well. The RR 2.25 in back has proved to be a great dry tire but it really gives it up fast in the wet. I really am looking forward to trying the WTB in back with the neo or nev up front.
 

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650 front only here

I researched for ever (bugged some of you on this board a ton too!) and tried a ton of different things. In the end, bought a 2010 trance X - then swapped the stock 120 fork for a Float 140 and a 650b Neve 2.35. Running a conti diesel in the back.

Head angle is around 67 unsagged, BB is 13.6. I like slack bikes and got a perfect balance. BB height -yes its on the low side, but the maestro rear doesn't wallow in its sag much so I really don't get pedal strikes.....and it rails corners.

Simply blown away by this bike. carvy and fun fun on smooth stuff and I've never had more fun on big chunky stuff (up and down) on anything else. Haven't ridden my 29er since I built it up and for the first time ever don't want anything else than what I've got.
 

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try #2, the faster spinup, lighter weight, and lower gearing are all noticeable plusses in the rear, while the front benefits from the larger size where it counts most. best of both worlds, it's not a surprise why motox are setup this way.
 

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I ran a similar set up to jrm - 05 spot w/5.1 rocker was best wrt to bb ht. which was 13.75 I also used push rockers bb ht was 14.25. jrm's particular set up is probably best. The HL rear was super tight at seat stay -- sometimes rubbed. Also tried 26 rear which was ok, messed geo a bit and lost some slow speed rollover. The 06 rears (particularly the seat stay) had better clearance. 2007 and 2008's shared the same seat stay which gave great tire clearance but jacked up the rear and bb ht. So from my experience the 2006 spot is the best bet for full 650b. I tried the 08 spot rear and bb ht was a hair over 14inch. All of the above is from memory -- I wrote the actual numbers somewhere... Eventually the seat tube snapped on the old spot and I went dw spot with full 650b. On the dw, the 2.3 neo rubbed a few nobs when climbing. 2.1 nevegal back there now and no rub. gearing was best solved with
shimano 12-36 cassette. With RS pike at 140 and 2.1 in rear bb ht = 14. Clears seat stay by 3mm and lower stay by 1mm. Yes, I did drink the dw kool aid -- and it tastes real good.
 

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Mr.650b - Mr.27-5
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DBAD said:
I ran a similar set up to jrm - 05 spot w/5.1 rocker was best wrt to bb ht. which was 13.75 I also used push rockers bb ht was 14.25. jrm's particular set up is probably best. The HL rear was super tight at seat stay -- sometimes rubbed. Also tried 26 rear which was ok, messed geo a bit and lost some slow speed rollover. The 06 rears (particularly the seat stay) had better clearance. 2007 and 2008's shared the same seat stay which gave great tire clearance but jacked up the rear and bb ht. So from my experience the 2006 spot is the best bet for full 650b. I tried the 08 spot rear and bb ht was a hair over 14inch. All of the above is from memory -- I wrote the actual numbers somewhere... Eventually the seat tube snapped on the old spot and I went dw spot with full 650b. On the dw, the 2.3 neo rubbed a few nobs when climbing. 2.1 nevegal back there now and no rub. gearing was best solved with
shimano 12-36 cassette. With RS pike at 140 and 2.1 in rear bb ht = 14. Clears seat stay by 3mm and lower stay by 1mm. Yes, I did drink the dw kool aid -- and it tastes real good.
PICTURES!
 

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Beer swillin' rabble ridr
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[ it's not a surprise why motox are setup this way.[/QUOTE]
Respectfully disagree -- spinup difference is minimal (in my opinion anyway). Also, outer diameter of motocross tires front and rear is pretty close, rims sizes are way different though. Rear being wider, beefier and tire itself is much taller in rear (cush!)
 

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Discussion Starter · #12 ·
What if .........

Spongebob said:
Hi 650b'ers

I have a 08 TNT RFX. I have 650b and 26" wheelsets and a Pike Uturn. I installed a 7.5 X 2" RP23 washered (home depot 3/8" 9.5 Nylon washer, split with wire cutter, fits perfectly) down with 4 washers (9/32" thick) to 1.72" with a 2.1 rear Neo and 2.3 Neo front. Also have a WTB 2.2 wolverine in the wings. I'm 230lbs and ride everthing from smooth single track, to very technical NE trails, with no jumping and only a 'safe' downhill.

My various ideas are:

1. full 650b. Rear seat and chain stays are good but only about 4mm clearance on the CS and about 6-7mm on the SS. Plenty of clearance on the '04 Factory Pushed Pike. Run the pike at 125-140. 67.2 degrees on the HA at 140mm and 67.8 degrees at 125mm. I checked that with my digital angle finder. Should have about 5" travel in the back based on this boards input. At 140 up front have a 14" BB at 125mm have a 13.75" BB.

2. 650b front, 26" rear. I could de-washer the 7.5 X 2 or buy a 7.875 X 2.25 RP23 and go back to the 6.3" travel rear. Maybe use a tall tire to come closer to a 650b OD. I would loose a little of the 650b feel, but gain travel, and a rotating weight savings.

3. full 650b, but go to a 7.785 X 2.25 RP23 and shim stroke down to where it won't hit the seat tube. I don't know if this will work or not. Anybody? The BB will probably be at 14.25??? unweighted. Any guesses on the travel?

4. Use the Wolverine 2.2 up front or in the rear? Or just buy another and do F & R? Would save some rotating weight, but performance??

So, any ideas / input?

Thanks
Bob
.......I went to a 7.875 X 2 rear shock? It would raise the BB to about what? 14.25? And would I get a 2 or 2.25" stroke? I'm guessing that 2" would be OK either straight away or nylon washered down. I wonder what rear travel I would get? Anybody lend a educated guess?
Thanks
PS. Took the RFX out for a 1st test ride in the neighborhood and left the PIKE at 140mm. Didn't feel sluggish at all. Weighed 28.96 lbs with Pacetti 2.1 and 2.3 and a very heavy seatpost. Will post some pics as soon as I get some time.
 
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