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Help fine tuning a RS Domain

2042 Views 30 Replies 8 Participants Last post by  asw7576
So I have a 160mm U turn Domain that I have upgraded to a 318. I also swapped the stock med spring with a soft. I now have proper sag and the fork is much more responsive than with the med. spring. However, I also have more brake dive. I also noticed that when the MoCo is cranked all the way firm, the fork doesn't feel exceptionally stiff, but I'm 99% sure that I have enough oil in it.

what I was wanting to know is how would changing the weight of the oil affect the fork's handling? I would like to reduce the amount of brake dive W/O to many adverse affects.

and finally, how "locked out" should the fork be at 10 clicks of MoCo? standing on the pedals and bouncing ( not bunny hopping) on the bike, I still get about 2-3" if travel, that about normal?

TIA,
Max
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the_Alaskan said:
So I have a 160mm U turn Domain that I have upgraded to a 318. I also swapped the stock med spring with a soft. I now have proper sag and the fork is much more responsive than with the med. spring. However, I also have more brake dive. I also noticed that when the MoCo is cranked all the way firm, the fork doesn't feel exceptionally stiff, but I'm 99% sure that I have enough oil in it.

what I was wanting to know is how would changing the weight of the oil affect the fork's handling? I would like to reduce the amount of brake dive W/O to many adverse affects.

and finally, how "locked out" should the fork be at 10 clicks of MoCo? standing on the pedals and bouncing ( not bunny hopping) on the bike, I still get about 2-3" if travel, that about normal?

TIA,
Max
What do you consider "proper sag"? Are you checking sag in the attack position? How much do you weigh?

Standing on the pedals and bouncing isn't really a very good measure of a fork's performance... basically amounts to "the parking lot test"
proper sag for me is about 25%, so and 1 1/2" on the fork. I weigh 150... but with gear probably about 155-165, don;t know exactly cuz I haven't weighed myself w/ gear

yeah, I didn't think that pedal bounce was very accurate, but I thought it might help.
The Domain does not have a lockout by default, it is a low speed compression adjuster. 165 with gear may require you to be at the medium spring level (as delivered). Changing to a heavier weight oil will slow compression down. I'm 240, ride a 180mm Domain with a firm spring and also upgraded to the 318 Moco and the fork feels pretty good.
the_Alaskan said:
proper sag for me is about 25%, so and 1 1/2" on the fork. I weigh 150... but with gear probably about 155-165, don;t know exactly cuz I haven't weighed myself w/ gear

yeah, I didn't think that pedal bounce was very accurate, but I thought it might help.
Cool, you are in the right ballpark as far as spring rate goes. You could go with a medium spring, but first you should try experimenting with the low speed compression to get rid of brake dive with your current set-up. Personally, I like a very active set-up (with lsc backed off almost always) but others like a little more lsc or even tinker with it throughout aride.

A good starting point would be to find a place where you feel as if brake dive is hurting your performance. Run the section with no clicks, then again with five clicks, then again with ten clicks (make sure your rebound is pretty good first-if the fork is packing or pogoing, fix that first). Which one feels best to you? Try 2 clicks in either direction (well, only one direction if you are already maxed) and run the section again. Obviously the differences will be a little more subtle, but maybe you will find a sweet spot that takes care of your brake dive. Finally, try 1 click in either direction (if you can tell a difference-at this point, it may be more mental than anything else).

The key is to not just go one click at a time or to haphazardly try different settings on different trails (well, you can, but it isn't a very systematic way to find the sweet spot).

Once you know a good base setting to get rid of brake dive, don't be afraid to play with the clickers some more-you can always go back to that good setting once you know what it is.

And the fork shouldn't feel locked-out, just firmer with MoCo. It should still move a little with 10 clicks, but it should also be a noticeable difference from how much it moves at 0 clicks. If not, then you are low on oil and/or need a repair.

HTH
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@ uncle six pack
thanks for the advice. the trails are almost totally free of snow here, Can't wait to go and test out all my winter time tinkering. Been working on this over the winter to keep sane till spring

I was under the impression- from what I had read on other posts- that at 10 clicks, the fork should feel similar to being "locked out." But after reading what you said, and giving the matter a little more thought... I realized that the MoCo effects can't be felt in a parking lot test. So I won't be able to feel a huge difference until I get it out on the trails

Thanks for helping me get this figured out.
The MoCo isn't a lockout but the difference between 0 clicks and 10 clicks is huge and you should feel the difference in a parking lot test.
the_Alaskan said:
So I have a 160mm U turn Domain that I have upgraded to a 318. I also swapped the stock med spring with a soft. I now have proper sag and the fork is much more responsive than with the med. spring. However, I also have more brake dive. I also noticed that when the MoCo is cranked all the way firm, the fork doesn't feel exceptionally stiff, but I'm 99% sure that I have enough oil in it.

what I was wanting to know is how would changing the weight of the oil affect the fork's handling? I would like to reduce the amount of brake dive W/O to many adverse affects.

and finally, how "locked out" should the fork be at 10 clicks of MoCo? standing on the pedals and bouncing ( not bunny hopping) on the bike, I still get about 2-3" if travel, that about normal?

TIA,
Max
so you went from a 160mm u-turn domain to a 180mm? I am trying to go the opposite way, what parts did you change? what are you doing with them? wanna sell those?
no, he upgraded his domain 302 to 318 spec by installing a motion control damper/knob and put a softer spring in.
what he did didn't effect total travel.
to do this (and i plan on upgrading my 302 with the moco damper) you'll need to use this:

http://www.ride-this.com/index.php/rock-shox-mocois-nr-damper-07-domain.html?source=googleps

and this:

http://bike.com/rock-shox-motioncon...uct&utm_medium=CSE&utm_campaign=GoogleProduct

and of course the med spring if you intend to go softer.
Just sharing info

I have Domain 302 standard ( no adjustments at all on top, only rebound adjustment at lower bottom ). So there are nothing interesting inside the oil damper tube ( only oil and piston rod ).

I filled up the tube with more oil up to 1cm below the threads. I know this is more than recommended oil capacity by SRAM ( 200mm ), but If I look at the oil level inside the tube, the oil level is way too low. So what the heck... I topped it off. Remember 1cm below the threads.

The result : Very nice man !! ..... it feels like air spring ...... The plushnesss is still there, and now... it has some kind of progressiveness when the fork is compress very deep. I'm going to test further.
what did you use for oil? brand? viscosity?
Mobil 1 5W-50 full synthetic motor oil.

I also give15ml of Mobil 1 to coil spring tube and both lower bottom.

Seriously, my domain have more plush :thumbsup: than my Fox Float 36 180 and Boxxer World Cup.
i'll have to try that...but i'll likely just use the sram shock fluid.

i just measured the travel on my 302's. 4.75" with all my body weight on it...so just barely over 120mm. this is advertised as a 160mm travel fork. bullcrap.
istandalone said:
i'll have to try that...but i'll likely just use the sram shock fluid.

i just measured the travel on my 302's. 4.75" with all my body weight on it...so just barely over 120mm. this is advertised as a 160mm travel fork. bullcrap.
When leaning on fork or jumping etc.?
How much sag do you get?
Maybe spring is not correct for you or damper oil has gone to lowers.

I have cca 30% sag and get almost full travel on usual rides.
i get about 29mm of sag when sitting on it (i weigh about 176lbs with all my gear on).

the 120mm of travel is with my full body weight compressing it with a little bit of bounce thrown in. measuring the stanchions, there is just about 165mm of steel showing at rest.

my bike being an 09 leftover i would not doubt that the oil has migrated to the lower fork area. i think i'm going to install a motion control damper, so when i do that i'm going to fill it to the proper level with oil.
istandalone said:
i get about 29mm of sag when sitting on it (i weigh about 176lbs with all my gear on).

the 120mm of travel is with my full body weight compressing it with a little bit of bounce thrown in. measuring the stanchions, there is just about 165mm of steel showing at rest.

my bike being an 09 leftover i would not doubt that the oil has migrated to the lower fork area. i think i'm going to install a motion control damper, so when i do that i'm going to fill it to the proper level with oil.
Maybe you have firm spring? I'm also around your weight with default (medium) spring and it seams to be spot on, not sure exactly, but I get around 40-50 mm sag, around 30% as said before.
If you have oil in lowers, be sure to replace o-rings on rebound damper as well when you do the service.
also i'm thinking they need to bed in some. it's a new bike (although 2+ years old) and has very very little ride time on it.
@asw7576

thanks for the info. I'll have to try that sometime. for right now, seeing as it's the only fork I have right now, I'll stay with factory specs. but who's to say? I may get the bug to tinker and void warranties :)
istandalone said:
i'll have to try that...but i'll likely just use the sram shock fluid.

i just measured the travel on my 302's. 4.75" with all my body weight on it...so just barely over 120mm. this is advertised as a 160mm travel fork. bullcrap.
I can't even bottom out my 100mm XC fork by leaning on it and bouncing. On my domain I get about 120mm travel if I lean and bounce but it definitely gets full travel when I land a jump flat or get pounded going through a rock garden.
asw7576 said:
Just sharing info

I have Domain 302 standard ( no adjustments at all on top, only rebound adjustment at lower bottom ). So there are nothing interesting inside the oil damper tube ( only oil and piston rod ).

I filled up the tube with more oil up to 1cm below the threads. I know this is more than recommended oil capacity by SRAM ( 200mm ), but If I look at the oil level inside the tube, the oil level is way too low. So what the heck... I topped it off. Remember 1cm below the threads.

The result : Very nice man !! ..... it feels like air spring ...... The plushnesss is still there, and now... it has some kind of progressiveness when the fork is compress very deep. I'm going to test further.
Can you still get full travel with that much oil in the damper side? I am thinking that as the fork moves through its travel the volume of the rebound piston shaft is going to cause a hydraulic lock and prevent full travel.
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