You are hereForums / By Discipline / Mountain (off road) / MTB Gear / Tune options on Fox RP23??
Tune options on Fox RP23??
NB: Originally posted elsewhere on the Global Riders Network and appears via syndication.
I'm thinking of upgrading the rear shock on my bike to a Fox RP23. Do these come in different compression tunes like the Rockshox Monarchs? Also the shock size on the bike is 7.5 x 1.75. the new one would be 7.5 x 2 so the stroke is 5mm more. would this make any difference?
Thanks
Alan
- Login to post comments
- Bookmark & share
Tags
The extra stroke could make a big difference depending on how much clearance is built into the system.
Let the air out of your current shock and compress it fully to double check how much room you have at full compression. If it looks like you have a bit of room there you should be ok but repeat the process with the new shock just in case.
YOu are looking for anywhere where things might foul up. ie tyre bottoming out on seat tube/seat/frame, linkages topping out on lugs or even front deraileur, etc
The RP23 gives a few different tune options that are factory set depending on the pressure/sag you run.
First you have the major switch of ride platform on or off. then with the RP on you have 3 choices of hard, medium or soft which you can select depending on suspension system and riding preference.
With my GT Marathon RP was pretty much always off. with my Blur I normally have it on soft.
HOpe that helps
Thanks for the reply Flynny. I know with the Monarch, you can order the shock in different compression tunes from the factory to suit the type of bike and weight of the rider. Is that the same for the RP23?
No, the RP23 comes with standard setting but the pressure you run (therefore the tune) is dependent on the bike, rider weight and style
RP23 does come in different factory tunes (low, med, high or 1, 2, 3 depending on the year) for compression, which also affects the 3 propedal levels, and rebound to match the frame's suspension setup. It also comes with different boost valve pressures.
The only time I bought a new shock, I had to provide brand, model and year of my frame in order to get the correct tunes and also mounting hardware.
My DW link bike for example came with a low compression, low rebound tunes and 225 psi for the boost valve.
RP23's definately come in 3 tune settings. I think it has more to to with the leverage ratio of the frame than anything else. Both my Roscoe and now my Remedy came with the middle setting. There is a little label on the shock with one of the 3 bars coloured red to indicate the tune. It's actuallya compression tune IIRC.
My understanding is the RP2 and RP23 both come with a range of compression and rebound settings, indicated with bars on the air can down near the seal with the shock body. For example, my Rize is fitted with a medium.
In addition to soft, medium and firm damping tunes, the new RP23's come with "adaptive logic" - instead of having a choice of three pro-pedal settings, you now have only the one pro-pedal and three different "open" compression settings, which I reckon makes a lot more sense.
Increasing to 2.0" is 15% more travel. Hmm... I wouldn't change the shock stroke unless I had tested and confirmed it's not going to result in suspension or tyre contact with frame at the end of the stroke. What's the warranty situation - is it a new or secondhand bike? Knowing what distributors are like, changing the shock stroke would provide them with a happy excuse to deny a warranty claim.
If the new shock has 5mm more travel, it might actually be longer than your current shock. Which in turn might mean that it will either:
- not fit in the frame without you compressing it to get it in there
- might foul the frame when the rear wheel is weightless (jumping, drops, yumps, cafe etc)
- your rear ride height will be higher by more than 5mm (suspension leverages the shock to turn 2inches of travel into 4,5,6+)
- your headstem angle will change so bike steering might feel quicker but less stable (more nervous)
You could fix ride height issue by reducing air pressure but then your rear end (and pardon me) will be squishy.
You can figure out leverage by comparing your bike's rear end travel to the rear shock's stroke; eg 4" travel bike with 1.75" shock = 2.29:1.
With a 2.29:1 ratio, 5mm extra at the shock = 11.4mm at the rear wheel.
If it isn't longer but has 5mm extra (sweet!), then as Flynny said, check you have the space for (possibly) 11.4mm extra travel.
So, looking for your vernier callipers and calculator yet?
You may want to check really carefully what you have and are getting, because I cant find any evidence that 2 sizes exist for that measurement- id guess the the 1.75 is actually a 7.25 length.
Thanks for the help guys. 1.75 is the stroke of my current shock. I would be looking to replace it with one that's 7.5 x 2. Reason being that no one makes the size shock i need (big thanks to specialized for that one!!). I could get the stroke reduced but looks like its going to cost some coin. Read in MTBR that some people changed it to the longer stroke without problems but it makes me nervous.
Other option is a 7.25 x 1.75 so the stroke is correct but the i2i is 0.25 inches shorter. Would this option be better?
Having a look online none of the websites state what tune RP23s they are actually selling. So I guess i have to contact them before purchase.
Actually, on reflection you could "very" easily insert a 6mm spacer inside the air chamber behind the bump rubber - that would probably do the trick with reducing the travel
What bike is it? Most spec' fsr bikes need a medium/high comp and medium rebound.
I looked into fitting a longer stroke and eye to eye on my stumpy. It's very doable.
Only problem was that I got sent the wrong shock. In the end I bought a new bike.
Bike is a FSR XC 2009. would the same stroke but smaller (by 0.25 inches) i2i work ok?
I saw that on the stumpy 2009 the shock size is 7.25 x 1.75. I thought essentially the stumpy and the XC is the same frame bar the materials used so maybe i can use the 7.25 x 1.75 but would this affect the geometry of the bike?
My past experience is with the stumpjumper. Personally I would not go the shorter stumpy shock as the eye to eye is not right. It does look like people have put the longer stroke shock on the the fsr xc with mixed comments. Some say that it fits and others say it does not. I think you need to measure up as in the above posts and see if there is room. Any doubt and give it a miss, or keep looking on the web until you find a definate answer.
Worse case if you pick up a cheap rp23 and it does not fit then you can have it made to the required lenght and tune.