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  1. #1
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    Reputation: crewcabrob's Avatar
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    Supersonic MKs or RKs over the UST version

    Hi all,

    This could have just as easily been directed at the Wheel tire section, but since my question is more about weight savings, I thought I would go the WW route instead.

    I currently have an 09 S-Works carbon StumpJumper FSR that weighs in at 24 pounds 6 ounces. Which is generally respectable for a 5" full suspension bike. The problem is I rode a good friends 09 S-works Epic for the weekend and thought it was fabulous and felt extreemly light. Since then, my WW tendencies have went into full action.

    Current build beyond the frame and Specialized Futureshock is:
    Canecreek headset with the 1 1/8 top and 1 1/2 bearings
    Thomson stem
    Specialized carbon riser bar
    Ritchie foam grips
    XO shifters
    XO Rear Der
    XTR Front Der
    XTR chain
    XTR cranks
    XTR cables
    XTR brakes F & R
    XTR cassette
    Wind cutter Rotors 160 F & R
    Ti bolts for the discs
    Ti bolts and barrels for the Thomson seatpost (cut down too)
    Rival SL saddle with ti rails 235g
    Mavic SL disc wheelset
    JL ti quick releases
    ti hardware for the brakes
    Kool Stop Al backed pads
    Specailized bolt through seatpost binder 19g
    No rim strips and running UST with 1 scoop of stans for thorns

    My tires are Conti UST Mountian Kings 2.4. One of them weighed in at 705g and the other at 710g. I kind of hit the lottery on these two tires as the came in under the weight by about 100gs each. I know there are other places to save additional weight on my bike, but this looks like a fairly easy painless upgrade. But is it worth giving up the reliability of a true UST tire which I already have?

    If I do swap out the tires, any recomendations on the Race kings or Mountian kings in the Supersonic or protection versions? I like the large volume tires for my applications. I had an MK UST 2.2 on the rear of my bike for a while and didn't like how small it looked or felt.

    Any idea how much I can loose with the simple tire swap?

    I'm going to replace the Rival SL with a Phenom SL for the 40gs I can save. But other than that, I have just about covered the rest of the bike.

    Thanks for your opinions on this matter.

    Rob

  2. #2
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    700g is respectful weight for UST, however MKs are very narrow. Try to run them for a while to see if you like them in first place.

    For the weight saving obviously you'll be looking for SS version but they are pain to get inflated unless you using rim strip. Also I would go for 2.4 version on MKs (it's same size as RK 2.2).

    Weights are about 480g for RKs 2.2 and 540g for MKs 2.4. I would put RK on the rear and MK on front for tad more traction. In my experience it was easier to install RKs on UST rim than MK. I just finished setting up MK on the Mavic XLs and I had to put a tube and inflate it first to get one side seated. I wasn't able to inflate it otherwise even using compressor.
    I have good experience with RK for XC riding with no burping and such. MKs I installed on the AM bike that I ride aggressively so it remains to be seen how the tire will hold.

    BTW, those carbon bars of Speshi are anchors unless they changed something (its above 200g for sure)
    I used to run tubes like you are, but then I got thorn in my wheel.

  3. #3
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    Reputation: millsm's Avatar
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    2.4 MK Supersonics

    I would go for the 2.4 MK SS. I have them on my '07 Titus Motolite and love them - extremely light for the size. I cannot say anything about tubeless (as i've never tried them nor intend to), but I run Panaracer Greenlite tubes (100g each), along with my 2.4 MK SS (550g each) and love the combo. I don't have any problems with thorn punctures up here, as I live in Alaska, but i've never gotten any flats up to this point. 650g will only save you 50g per wheel, so not sure if it's worth it or not. I weigh 150 and run 25 psi front/30 psi rear, and don't even come close to pinch-flatting - definitely love the ride quality.
    Hey, I didn't see that rock there."

  4. #4
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    Reputation: crewcabrob's Avatar
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    Thanks for the replies guys.

    I've been running the Mountian Kings for over a year and half and so far I'm not dissapointed in thier performance; at least in the 2.4 UST. They seem durable and grip most conditions well. I'm not sure they are the fastest rolling tire out there at low PSI. The lack of a center rib makes pavement riding a bit slow and noisy.

    I can't say I see the point in getting a SS MK or SS RK at this point. I would have to add 100g of sealant in them to make them work. Anyone have real world weights on them? Like I said with my MKs, I hit the lottery with such low weight for the UST version.

    I'm sure the bar is a bit heavy compared so some others out there. I guess I'm willing to pay the 50g weight penalty to have that nice of a bar to look at. I can only assume that Specialized over built it and that is why it is a bit of a pig.

    Thanks again Guys!

    Rob

  5. #5
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    Reputation: culturesponge's Avatar
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    weight saving on tires can be abit of a compromise in quality & often results in squirmy tires with risky über thin sidewalls compared to the MK UST tires your used to rolling.

    depending what trail conditions your riding, you might be happy with Race King Protection 2.2's which could save you approx 120g for the pr. - but tire weights vary so much between batches that's just a guessimate.

    .................edit to reduce blah....................

    Quote Originally Posted by crewcabrob
    My tires are Conti UST Mountian Kings 2.4. One of them weighed in at 705g and the other at 710g. I kind of hit the lottery on these two tires as the came in under the weight by about 100gs each. I know there are other places to save additional weight on my bike, but this looks like a fairly easy painless upgrade. But is it worth giving up the reliability of a true UST tire which I already have?

    If I do swap out the tires, any recomendations on the Race kings or Mountian kings in the Supersonic or protection versions? I like the large volume tires for my applications. I had an MK UST 2.2 on the rear of my bike for a while and didn't like how small it looked or felt.

    Any idea how much I can loose with the simple tire swap?
    Last edited by culturesponge; 07-02-2009 at 03:38 PM.

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