I have a RC4 on its way to my sunday
- Thread starter saruti
- Start date
Assuming you have an 07/08/09 frame with the DHX compatible lower link, you will notice that there are two main cross-braces on the link. The forward one is pretty thin and needs to be removed completely, grind it back so it's smooth and flush (or close to flush) with the side of the link. The rear one needs a LOT of material taken out of it, to the point where you've removed about 75% of its cross sectional area. The only way to be sure is to take the spring off the shock, drop the pressure to zero and continually check clearance by cycling the shock through its travel. Just remember to remove MORE material if in doubt, because you won't be able to easily compress the bottom-out bumper without actually riding the thing (I found this out the hard way). I also had to take the LSC knob off mine.
As for basic setup, unless you're really heavy or really light - bottom out wound all the way in, high pressure (180-200psi) in the boost valve, rebound 5-6 clicks out from fully closed depending on your preferences, start with LSC and HSC at roughly 8 clicks back from fully closed and work on them from there. Remember also that you'll need to drop your spring rate about 50lbs from whatever the Fox spring calculator says you need (http://service.foxracingshox.com/consumers/Content/mtbspringratecalculator.htm - hope this link works).
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Plus show us some pictures of the link when you are done. If I run into some money I would like a little front and rear suspension upgrade on my Sunday for next year.
Hope this pic works -
Otherwise click here http://www.pinkbike.com/photo/4937211/
Shows the front brace removed, and how much I took out of the rear one, but really you need to take even more out of the rear brace. Yes it has the DHX back in it because this photo was from when I was selling the frame.
Man that's a lot of material, bigger balls than me! A mate tried to mod his and mullered it!
I doubt you'd ever break that lower link even with that 2nd brace completely removed, it'd just make the back of the bike a bit less stiff. BOS make a link for it but I don't know if it's RC4 compatible - I imagine it is but not sure.
Yeah I imagine the Bos link will fit nigh any shock going, I've got a Stoy on my Sunday and the link has barely any cross bracing at all.
You can just about make out the link if this pic works....
You can just about make out the link if this pic works....
A better way to mod the link is to remove it and the shock, mount the shock in the link using the lower pin (and hex pivots), and then rotate the link upwards until it hits the shock.
You should first work out how far the link has to pivot (i.e. how acute the angle is between the shock and lower link) by fully cycling the frame to bottom out point with no shock installed. At bottom out the cross brace between the uprights on the swingarm will *almost* contact the mainframe, and you will notice with the shock removed it will actually make contact, so this is a safe way to work out the correct link angle for bottom out.
You can then remove material until the piggyback allows the link to move far enough to obtain this angle, and avoid removing more material than you need to.
You should first work out how far the link has to pivot (i.e. how acute the angle is between the shock and lower link) by fully cycling the frame to bottom out point with no shock installed. At bottom out the cross brace between the uprights on the swingarm will *almost* contact the mainframe, and you will notice with the shock removed it will actually make contact, so this is a safe way to work out the correct link angle for bottom out.
You can then remove material until the piggyback allows the link to move far enough to obtain this angle, and avoid removing more material than you need to.
So you just chose to remove all braces or is yours a different link?
Agree I used the RM strength-o-meter which works on photos too and it looks equally strong
that's what I did to mine when I first got my RC4 about 2 years ago. I run 200psi in mine, 350lbs ti spring (i think)... i forget the rest. rebound all the way open.. i weight between 165-170
Havnt tried it myself but do remember DW saying awhile ago that it almost felt like the RC4 was made for the sunday it was that significant of an improvement.
The air spring effect of the RC4 is pretty substantial. You should be on a 250lbs/in spring at your weight - I'm 90kg and was pretty happy on a 300.Here are some pics of the link after some work...
The rear end of the sunday feel a little harder now, maybe its just because the shock is new....? I weight 72kg and using a 300 TI spring.
Sidenote, BETD makes links for "newer" fox shocks assuming they mean the RC4:
http://www.mountainbikecomponents.co.uk/items.asp?CategoryID=387&Name=IRON+HORSE+Linkages+and+spares
It's a bit steep tho: $200
http://www.mountainbikecomponents.co.uk/items.asp?CategoryID=387&Name=IRON+HORSE+Linkages+and+spares
It's a bit steep tho: $200
I wonder if it's worth pursuing the RC4, or if an Avy tuned DHX would be competitive? The price would end up being pretty similar...but no machining required.
hmmm...
hmmm...
it is interesting.
I use Vivid 5.1 and 300# seems quite good for me (i weigh 72kg)
rc4 is different, eh?
I have a broken DHX at home who would like to know too. I do think if the choice was between a new RC4 and my old DHX avy tuned I would rather have a brand new shock. That damn DHX has always started leaking right after I got it back from service.
Yes, the RC is different.
I actually run an old Manitou Swinger 6way I got from Iron Horse that they had tested on the Sunday. 72kg/158lbs and run a 250 spring on the Swinger if that means anything.
What are your thoughts on that spring rate for your weight?
I'm 71kg (no clothes/gear/shoes) so about the same as you and run a 250 as well (on a bos) but I feel like it's too soft.. the bike just sits too low on anything really rough and it's a pain having to worry about clipping stuff so much. Getting like 38% sag when I would be happy with ~34.
I was thinking about trying a 300 but am worried it'll be too hard, and maybe make the bike harsher over bumps and steeper in the HA. Trying to avoid the drama of sourcing a 275 ti spring (don't want to deal with obtainium)..
I wiegh 75 kilograms without gear and ran a 400 lbs on my dhx with the sunday, at about 130 psi pressure (I think cant remembr the pressure all that well). The bike felt solid and could handle anything I threw at it. I tried with a 350 which was on the softer side, but would bottom out waaay to often.
I weigh 195 and run a 400lb spring on my DHX. 350 was was too plush and blew through travel. 400 feels pretty great...I use full travel but don't bottom out too often. I think I run about 150psi, and could probably use more compression.
With the DHX I ran a 300 spring. I used that spring on the Swinger but did not get full travel. The 250 spring is perfect for the Swinger and the shock actually works pretty good. I have never felt it bottom out. It only feels a little slow reacting when multiple fast hits.
It should be a perfect shock for the bike as the Sunday was build around a platform shock.
Just got back from a great day on the mountains
Still using a 300 TI spring
But changed the compression settings a bit
hs - 2 clicks
ls - 5 clicks
140 psi
r - 4/5 clicks (still not sure what feel better)
This shock is great
Hasn’t bottom it yes in places where I used to bottom the DHX5
And it tracks great and really feels great on rocks and everything
UDI. try the 300. you will still have 30-35% of sag.
Still using a 300 TI spring
But changed the compression settings a bit
hs - 2 clicks
ls - 5 clicks
140 psi
r - 4/5 clicks (still not sure what feel better)
This shock is great
Hasn’t bottom it yes in places where I used to bottom the DHX5
And it tracks great and really feels great on rocks and everything
UDI. try the 300. you will still have 30-35% of sag.
Yes, isn't the what the platform/SPV/5th Element shocks all were/are?
Don't drop the reservoir pressure below 75psi or air could get into the oil and the shock will have to be bled. This is straight from Fox. This pressure is low enough that you can still cycle the shock all the way.
Hi mate. I writing you from Bulgaria and my english level is not excellent. I want to ask you, can i mount a stock Fox RC4 on my sunday, without ant special tuning. Now i run Progressive 5th element shock on my frame and they are running smooth, but i want to put any newer shock. Does any one reply to my questions. Thanks in advance. Cheers!
Nope you cant without modyfying the linkage.
You can mount a stock RC4 fine, the shock itself does not require special tuning. However, to make the shock fit, you must modify the lower link of the frame, as you can see in the photos in this thread.
Also your English is very good!
I've ordered an RC4 for my sunday but just got an RC2 to borrow in the meantime (thanks buckoW!) so I'll tell you my settings when I get a chance to try it out, probably this weekend!
HS isn't adjustable (set at 8 clicks) and neither is bottom out, but I changed the IFP depth to roughly be the same as bottom out all in on an RC4.
I'm also on a 300 Ti and weigh maybe 74kg.
HS isn't adjustable (set at 8 clicks) and neither is bottom out, but I changed the IFP depth to roughly be the same as bottom out all in on an RC4.
I'm also on a 300 Ti and weigh maybe 74kg.
I'm not on a Sunday, but on a Legend Mk1 with similar leverage curve. I'm running similar settings. Differences: 175 psi, and only 1 click HS. I play with the LS depending on the track...it is not as sensitive as the LS on CCDB. I've tried the full range of LS without too much impact on the feel of the bike.
I would have done this. Linkage mod looks iffy
http://www.pushindustries.com/2009/index.php?menu_id=31&type=products&title=FOX DHX 3.0/4.0/5.0&product_id=16
http://www.pushindustries.com/2009/index.php?menu_id=31&type=products&title=FOX DHX 3.0/4.0/5.0&product_id=16