[PCinSC]

I'm trying to figure out these specs as precisely as possible before I make a move on components. Particularly the fork. So I have a few questions.

Does anyone know if the geometry of the 2001 and 2002 RFX's stayed the same? The reason I'm asking is because I've got a copy of the 2001 RFX specs in 5" mode...

...and I'm trying to decipher a few things. First off, is "fork length" referring to Axle to Crown length? If so, Turner was recommending that you run a fork with an A-C between 465mm and 485mm. That seems very short, almost equivalent to modern 4" travel forks (my Marz Dirt Jam is 488mm A-C w/100mm travel and my RS Reba is around the same with 115mm travel). I also realize that the forks from 5 years ago were quite different from what we have today.

The reason I ask is because if I can use what I currently own I will just build the bike up with what I've got (so at least I can ride it) and deal with upgrading later. It would seem (according to the above specs) that the HA would end up being just below 69* with a 19.1" (485mm a2c) fork. The specs also indicate a fairly low BB, but I'd be running a slightly taller fork than is indicated there and 2.4 tires rather than 2.1's. That should result in a slightly higher BB, probably around (I'm guessing here): 5 Spot territory (13.2" - 13.3"). What do ya' think, could this work?

And I know that several of you prefer to run longer (up to 538mm a2c) forks, even in 5" mode and I think that's probably the direction I want to go. This set-up would only be temporary until I get a chance to upgrade.

If 2001 and 2002 specs are not the same or "fork length" is not synonymous with a2c then set me straight and disregard all the preceding babble .

Sorry about starting another thread, I figure this question would get noticed more if it had it's own title. Thanks in advance for any info.

Patrick

 

[SSINGA]

Here is the 02 spec sheet. Fork length does = a-2-c.

 

[PCinSC]

Here is the 02 spec sheet

I've actually got that one also, but those specs are for 6" mode. And I believe the fork specs are utilizing some of the DC's from back in the day. I'd be speculating (well...guessing, really) if I tried to extrapolate the 5" travel geometry form the 6" specs.

Patrick

 

[SSINGA]

I've actually got that one also, but those specs are for 6" mode. And I believe the fork specs are utilizing some of the DC's from back in the day. I'd be speculating (well...guessing, really) if I tried to extrapolate the 5" travel geometry form the 6" specs.

Patrick

I did a post quite some time ago about my measured geo with the 66 at 5" (535mm a-2-c) and the 5" rockers. I don't remember what the numbers were but maybe you can find it in the search. Granted the 02 RFX and the 05 Pack might have not been identical but it should get you quite close.

 

[SSINGA]

Ok

I found some info. Remember these measurements were done with a construction angle finder and a measuring tape. There is a degree or 2 of error.

With the fork set at 130mm these are the geometry numbers I measured:

HTA - 68
STA - 71
BB - 13.75
SO - 31.5
WB - 42.5

 

[PCinSC]

I found some info. Remember these measurements were done with a construction angle finder and a measuring tape. There is a degree or 2 of error.

I found it also. A degree or two? That could be the difference between technical descent bliss and going OTB and smashing my face open!

With the fork set at 130mm these are the geometry numbers I measured:

HTA - 68
STA - 71
BB - 13.75
SO - 31.5
WB - 42.5

OK, we're talking bout the 66sl, right? Which has an a2c of 535mm @ 150mm travel. So at 130mm it's around 515mm a2c. If we drop that to about 485mm (the a2c of the forks I've got on hand) the HA would probably be 69* - 69.5*. That's a bit steep, but about what I'm currently running on my HT. So it may actually work.

Although, it's not an apples to apples comparison (as you said earlier) b/c you've got the 05 Front (which I believe has an inherently more slacked HA) and Rear (which has a slightly longer CS and maybe SS). So now I'm more confused than before. :madman:

I could always just build it up and see how it rides. But then again, that would cost me some $ b/c I haven't the skillz nor the toolz to do it myself. Oh, well. Thanks for the info.

Patrick

 

[cactuscorn]

i have all the #'s from my 5" and 6" modes here somewhere as i said in pm's but between the food poisoning and the work im back to doin on my biz plan before meetings the next 2 days, im way behind. if you can be patient, i think i can answer many of yer questions. dont get bummed pal. weve got ya covered.

 

[SSINGA]

I found it also. A degree or two? That could be the difference between technical descent bliss and going OTB and smashing my face open!

OK, we're talking bout the 66sl, right? Which has an a2c of 535mm @ 150mm travel. So at 130mm it's around 515mm a2c. If we drop that to about 485mm (the a2c of the forks I've got on hand) the HA would probably be 69* - 69.5*. That's a bit steep, but about what I'm currently running on my HT. So it may actually work.

Although, it's not an apples to apples comparison (as you said earlier) b/c you've got the 05 Front (which I believe has an inherently more slacked HA) and Rear (which has a slightly longer CS and maybe SS). So now I'm more confused than before. :madman:

I could always just build it up and see how it rides. But then again, that would cost me some $ b/c I haven't the skillz nor the toolz to do it myself. Oh, well. Thanks for the info.

Patrick

My a-2-c is actually 4mm taller due to the tall crown race needed for downtube clearance.

Get the Zinn book out and build it up.

 

[airwreck]

Paul, get a 66sl and you'll be covered for both rocker sets and your weight, and you'll be able to fine tune the ride height.
Good deals are already showing up on them.

With the 5 inch rockers you'll be able to set it up with the same geo as a five spot.

Also, look through the Rfxiation thread, for lots of classic RFX info. You'll see my '02 RFX in there and I've tried many different fork and rocker combos. 5 inch rocker setup worked great with a 125 Vanilla and I've even tried a 150 Z1 with the 5's just to get a feel for that head angle. For my tastes the a2c of a 130 Marz (or 140 Pike) is perfect.

Things get more interesting with the six inch rockers...

 

[cactuscorn]

you want #'s? i got yer damn #'s!

i was in the middle of workin on my biz plan when my cpu overheat warning kicked and shut off my comp. im afraid to see what happened but i save continually so i think its not gonna be a big loss. so durrin the down time for the drive to cool down, i cooled off by cleanin up my desk and found my geo cheat sheet. here ya go!

1st, some ground rules: without a digi angle finder i did my best with good but old methods. no need for a tall lower race. and the followin:

g = ground
cl = centerline
wb = wheelbase
hta = head tube angle
sta = seat tube angle

6" mode of '02 rfx w/ '05 6 pack rear and rockers, '06 dhxc, '05 66 rc w/ fsa pig pro h/set, 2.5 kenda nev/bg tires, blahblahblah.

g to axle cl = 13 3/8"
g to b/bkt cl = 14 9/16"
a to c = 22 1/2"
w/b = 45 9/16"
hta = 67.5
sta 73

5" mode with same frame and h/set, '00 rfx "A" 5" rockers, '05 ava, '05 am sl, 2.35 maxxis minion dhf tires, yaddayaddayadda.

g to axle cl = 13 1/4"
g to b/bkt cl = 13 1/4"
a to c = 19 1/2"
w/b = 45 1/4"
hta = 68.5
sta 74

and if anyones really that interested, heres some rocker #'s. all measurements are done on bolt ceterline w/ a 7 1/2" shock i2i:

mp = main pivot
ss = seat stay
sm = shock mount

6" '05 6 pack rockers:
mp to ss = 7 1/2"
mp to sm = 3 1/16"
sm to ss = 9 15/16"

5" '00 rfx "A" rockers:
mp to ss = 5 13/16"
mp to sm = 3"
sm to ss = 8 3/8"

have fun workin out the triangulation. i dont have the mind nor the time today.

 

[airwreck]

very nice CC, only thing is Paul most likely has the 2002 6" rockers and stays which would mean a 14.75 BB height. I would suggest seeing if Turner can provide a six pack seat stay and rockers, they seem to be more open to this, a couple years ago when the six pack came out I asked if I could update my 02 rfx rear to bring the BB down and got a no for an answer...

 

[cactuscorn]

im sure yer right about his rockers and yer #'s. id have to compare his pic to my bike to confirm. good news is if he ever decides to make the update to a newer rear, hes golden. dont know why ya got the answer ya did. maybe their ideas have evolved along with our experimentation.

 

[PCinSC]

have fun workin out the triangulation. i dont have the mind nor the time today.

I hope you don't expect me to do any trigonometry?

Thanks for posting what you have. The HA in 5" mode is pretty steep, 72*, am I reading that right? I'm hoping that I get different #'s than you, b/c I sure don't want it to be that steep (that's 3* steeper than my HT ). The 6" mode looks pretty good, but IIRC the '05 66RC is really tall, so that would result in a slacker HA and higher BB height than the current crop of 66's.

My feeling is that my rear and rockers are different enough from your that direct comparisons may not be reasonable. Although it gives me a good idea of what to expect in terms of "geometric tendencies". Thanks again for taking the time to post.

Patrick

 

[PCinSC]

very nice CC, only thing is Paul most likely has the 2002 6" rockers and stays which would mean a 14.75 BB height. I would suggest seeing if Turner can provide a six pack seat stay and rockers, they seem to be more open to this, a couple years ago when the six pack came out I asked if I could update my 02 rfx rear to bring the BB down and got a no for an answer...

Who is this Paul fella you keep talking about?

My wife's name is Paula, but if that's who you're referring to, "Whachu talkin' 'bout my wife fo'?"

I don't plan on experimenting with the 6" rockers anytime soon. I'm gonna set the bike up first to perform well as a trail bike that can take hits (whatever that means ). I'm going to have to get some "counseling" from suspension experts (Push or Avy) if I plan on running a 3:1 leverage ratio (with 6" travel) at my bodyweight. It remains to be seen if I will like the BB that high or not.

Patrick

 

[airwreck]

sorry I keep getting confused with Paul who is setting up the 5 pack.:blush:

 

[cactuscorn]

I hope you don't expect me to do any trigonometry?

Thanks for posting what you have. The HA in 5" mode is pretty steep, 72*, am I reading that right? I'm hoping that I get different #'s than you, b/c I sure don't want it to be that steep (that's 3* steeper than my HT ). The 6" mode looks pretty good, but IIRC the '05 66RC is really tall, so that would result in a slacker HA and higher BB height than the current crop of 66's.

re edit!: ya caught me tryin to fool ya. acctually i dorked it up. its really 68.5. sorry for the bad fingers and eyes. and yeah, that rc is a friggin skyscraper and will be for sale. too much for me and what i ride. makes a great dh fork im sure which was the original intent before i found colorado and our d/h series got cut.

 

[cactuscorn]

check my #'s again pete, or whoever the hell ya really are. i think i have em down now that ive reread my copious notes and remeasured the 5" bike. i got myself all turned around and i suck. sorry for all the confusion. chalk it up to feelin half human and seein double today. fockin food poisoning and spreadsheets. which will kill me 1st?

 

[PCinSC]

fockin food poisoning and spreadsheets. which will kill me 1st?

Spreadsheets.

The numbers look good, I like 'em. The 5" numbers are almost "Spot-like" which is fine with me. You know, you can take care of your bizness before you get back to me, I can wait.

I hope ur tummy feels better.

Patrick

 

[cactuscorn]

no sh!t! just finished a few more pages. (thud!)

its cool man. i gotta take a break now and again. today i started at 9:30am and at 11:30pm just finished my part. when candycorn gets home soon, its her turn to massage the bastages to reflect totals. i told myself i woudnt work this long but i lost 2 days in bed and had little choice with a deadline looming tomorrow am. thanx for givin me reason to divert my eyes from a page of numbers with yer.... oh. nevermind. maybe that explains why i had such a brain fart gettin those angles right.

 

[PCinSC]

You know, I don't think anyone knows the true answer to my original question. Which was: are the 2001 and 2002 RFX specs the same?

Because if they are, I should be able to put my RS Reba (which has a 19.1" a2c when set at 115mm travel) on the RFX in 5" mode and get a 69* HA, 73.5* STA and a BB of ~13.2". Basically, those are Spot geometry #'s. In fact, they are exactly the same as the Spot. Which is just fine with me.

Does anyone have an opinion on whether this will work are not? Am I missing something here and screwing these number up somehow?

BTW, here are the recommended fork choices (in 2001) for the 2001 RFX in 5" mode:

• Manitou, SuperNova
• Marzocchi, Z-1 MCR 130mm, QR20 Plus,
• RockShox, Psylo XC, Psylo SL, both are available with Tulio thru axle.
• White Bros FR-3.

Does anyone have any info about any of these forks. A-C heights, amount of travel, etc.? I'd just like to be able to compare their specs to modern forks, including the ones that I own. Thanks, guys, for responding if you've got info to share.

Patrick