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  1. #1
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    How much does 4 pounds matter?

    Let's say to a really strong climber, how much does 4 pounds more weight matter? The reason I ask is because I'm still weighing that DWL Sultan vs DWL RFX decision. Being the big ol' bike geek that I am, I've got both builds all spreadsheeted out, and with both bikes built appropriately I get 28.75 for the Sultan and 32.75 for the RFX (with an educated guess on frame weight).

    I don't really notice switching from light tires to really heavy ones or having a couple of full water bottles on a bike or not. They all seem to climb just as well to me. So I don't think that the 4 pounds is going to make a world of difference to me climbing, and the DW rear might just be über-efficient enough, even in RFX guise that the extra travel won't slow me down either.

    I know some of you guys have had your Spots built up in both light and heavy configurations. Did the extra weight affect you a lot or not?

  2. #2
    Rolling
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    I think over several hours or riding (when you deplete your muscle glycogen) it will be noticed but on short rides no.

  3. #3
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    Quote Originally Posted by juan_speeder
    Let's say to a really strong climber, how much does 4 pounds more weight matter? The reason I ask is because I'm still weighing that DWL Sultan vs DWL RFX decision. Being the big ol' bike geek that I am, I've got both builds all spreadsheeted out, and with both bikes built appropriately I get 28.75 for the Sultan and 32.75 for the RFX (with an educated guess on frame weight).

    I don't really notice switching from light tires to really heavy ones or having a couple of full water bottles on a bike or not. They all seem to climb just as well to me. So I don't think that the 4 pounds is going to make a world of difference to me climbing, and the DW rear might just be über-efficient enough, even in RFX guise that the extra travel won't slow me down either.

    I know some of you guys have had your Spots built up in both light and heavy configurations. Did the extra weight affect you a lot or not?
    Obviously everyone will state that the placement of matter can make a bigger difference than absolute weight - IE adding weight to frame or hubs will matter a lot less than adding it to rims/tires/tubes.

    I agree.

    Although I've also found that the fit of the bike can make a bigger difference than this. If the bike is set up right, having a few extra pounds can be overcome. If the fit of the bike is all wrong, then it will be harder to climb.

    The Sultan and RFX are completely different bikes. The Sultan is going to climb better no matter what.
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  4. #4
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    Quote Originally Posted by lidarman
    I think over several hours or riding (when you deplete your muscle glycogen) it will be noticed but on short rides no.
    Excellent point, Lidarman. When I do rides longer than about 4 hours, I really start to notice the extra weight. When I've ridden my Sultan with my bigger/slower rolling tires (Rampages) it wears my legs out noticeably faster than with my lighter wheelset with Crossmarks.

    Also, the geometry differences are going to make the Sultan an inherently better climber. I think that with the way DT is describing the new RFX, it will climb plenty well.

  5. #5
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    Climbing is GHEY...

    [insert "Sulty" will win] dwl RFX doesn't exisit yet
    Just riding a muddy trail. . ..

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  6. #6
    how heavy are you ??
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    Ta

    Quote Originally Posted by trailadvent
    Climbing is GHEY...

    [insert "Sulty" will win] dwl RFX doesn't exisit yet
    WORD!
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  7. #7
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    Quote Originally Posted by iheartbicycles
    Obviously everyone will state that the placement of matter can make a bigger difference than absolute weight - IE adding weight to frame or hubs will matter a lot less than adding it to rims/tires/tubes.

    I agree.
    Adding weight to rims/tires/tubes, is commonly accepted as being extremely detrimental to performance.

    I disagree. I've added over 2.5 pounds in tires, with everything else being equal, and noticed little to zero performance degradation, just more traction. The weight at the periphery of the wheel is such a small percentage of the overall rider/bike package that I've never understood, or experienced, the claims of it making such a profound difference in performance.

    YMMV

    The Sultan and RFX are completely different bikes. The Sultan is going to climb better no matter what.
    I started a thread on this very subject a week or two ago. Amongst those who have actually owned both bikes, the results were 2 for Sultan, 2 for RFX, and 2 tied for better technical climbing prowess.

  8. #8
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    I was chatting about something along these lines yesterday with my buddy Paul;

    I'm a pretty agressive rider, I do kind of live for the downhills and technical stuff. The DW link bikes are hands down better than just about anything else. When you put the power down and accelerate, it's hard to think of anything that comes close. With that in mind, I think the firebird would be a great bike for me, although when the RFX comes out, it would also be in a good place to be the bike for me. The suspension is that much better IMO.

    Now, there aren't really any 29ers that compare IMO. Lenz may have a few models that compare travel-wise and in terms of geometry, but they'll bogg when you try to put the pedal down, nothing really suprising if you know what to expect, but not near the level of a DW-link bike. With that in mind, 29ers really haven't reached the development stage where we can compare them with bikes like the RFX IMO. They are still mainly XC bikes and the few examples that are a little more agressive lack the suspension performance that is currently at the forefront of other wheel-size bikes. With that in mind, as things stand right now I'd rather get the Firebird. If the RFX comes out I may think about that over the firebird if I feel it has some advantages. If someone has a decent 29er at that time with agressive angles AND decent suspension, I'd probably give that a go, but it does not exist right now and I don't know if it will by then.

    So the sultan isn't really much of a comparission IMO. If you want to rocket ahead on climbs and moderately technical rides, get the sultan. If you want a bike that can go down full-on DH runs/trails without feeling out of place, the RFX will suit the bill, and do pretty well in most other situations.
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  9. #9
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    for me, it was huge but remember im not what you would call a stong rider. the diff between my '02 rfx at 38lbs and the '07 at just under 33 was a substantial turning point in all areas. im skeered at what the dwl rfx may offer in terms of increased ridability but im ready for it. thats the direction id go in bein a big bike fan too.
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  10. #10
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    Allow me to say this; my strength to weight ratio is off the charts.

    I don't race too often, because it's not my cup of tea, but if I enter a Cat 1 race, road or mountain, I've got a 50% chance of winning, based on my record.

    I'm also not as good on the downhills as I'd like to be, and would like to purchase some "skills" , but technology and shock displacement will suffice.

  11. #11
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    Quote Originally Posted by juan_speeder
    Adding weight to rims/tires/tubes, is commonly accepted as being extremely detrimental to performance.

    I disagree. I've added over 2.5 pounds in tires, with everything else being equal, and noticed little to zero performance degradation, just more traction. The weight at the periphery of the wheel is such a small percentage of the overall rider/bike package that I've never understood, or experienced, the claims of it making such a profound difference in performance.

    YMMV



    I started a thread on this very subject a week or two ago. Amongst those who have actually owned both bikes, the results were 2 for Sultan, 2 for RFX, and 2 tied for better technical climbing prowess.
    I find rolling resistance has a lot more to do w/ it than weight. I.e. if I replace 750 gram fast rolling tires w/ 600 gram sticky tires the bike feels WAY slower, even though it's lighter.

  12. #12
    Natl. Champ DH Poser/Hack
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    yer like the porsche 917 of cycling! oh, wait, thats POWER to weight. that thing wouldnt hold up in a crash to save its own ass.
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  13. #13
    Moosehead
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    dood, if ur such a stud, then you gotta answer this for yourself. what has been your experience on a 29r vs 26r? have you demo'd the dwl anything yet? have you demo'd the dwl spot yet? i still think the dwl spot will be as much of a contender for you than the other two, er, ah one, as the dwl rfx aint available for some time.

    personally, yea 4 pounds matters on extended climbs, especially at elevation. speed, exertion, endurance, fatigue all are different. while my 30 lb spot climbs as well as my 26 lb flux, it does so with more output, and i notice it at the end of the ride.
    Last edited by moosehead; 01-19-2009 at 08:33 AM.

  14. #14
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    moose hit it on the head Mike. Demo the DW spot (if you can find one here). Unless you plan on doing some DH shuttles, Pajarito, or any other resort type riding, you will be disappointed in the RFX as a strictly trail/endurance mule. Seems you would be right at home with the DW spot (if it actually lives up to its hype). I have even seen one with a 66, which sounds just what I would be looking for. Take my RFX out for a day! I got some lighter rims/tires and we could throw the 55 back on it, and probably borrow one of the other homies air shock.

  15. #15
    Rolling
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    Quote Originally Posted by juan_speeder
    Allow me to say this; my strength to weight ratio is off the charts.

    I don't race too often, because it's not my cup of tea, but if I enter a Cat 1 race, road or mountain, I've got a 50% chance of winning, based on my record.

    I'm also not as good on the downhills as I'd like to be, and would like to purchase some "skills" , but technology and shock displacement will suffice.
    50% wins in cat 1! And you aren't pro?

    what a loss.

  16. #16
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    Quote Originally Posted by juan_speeder
    Allow me to say this; my strength to weight ratio is off the charts.

    I don't race too often, because it's not my cup of tea, but if I enter a Cat 1 race, road or mountain, I've got a 50% chance of winning, based on my record.

    I'm also not as good on the downhills as I'd like to be, and would like to purchase some "skills" , but technology and shock displacement will suffice.
    can you sign my breast?

  17. #17
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    Read thru these posts and still see an apple to orange comparison. OP do you want an XC trail bike or AM + bike ??? If you don't care about tire weight hell anything will work short of a 8" DH rig. Personally tires make a huge difference in my overall riding experience - i'd rather XC a Highline w/ 2.3 Kevlar tires / tubes (2050g) than a Spot w/ 2.5 DH tubes n tires(3400g).
    Last edited by keen; 01-18-2009 at 11:54 PM.

  18. #18
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    juan_speeder: i'd be interested to know how you came up with such a big weight difference (4 lbs) between the new sultan and new RFX. from the turner site the frames come in at about the same weight (7+change pounds) and the difference for a fox fork 29er 120 and a fox 160 is about a pound. if they both have equivalent rims, hubs and tires, the 26er wheels should be a bit lighter. so in the end i expect the new RFX to be a bit heavier than the sultan v.2 in comparable builds. did i miss something? thanx!

  19. #19
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    I run a 35lb '02 RFX and a 24lb Ti hardtail. I have a pretty good power to weight ratio, but all that means is that I don't have much weight or much power!

    "Just riding along" there's not all that much difference - even uphill, until it gets *really* gnarly, sure it's a bit leaden, but the increase in traction makes up for the weight. Where I really suffer is in hard acceleration, whether it's coming out of corners on singletrack or trying to keep the bike rolling on rubbly DHs that just aren't quite steep enough for the bike to carry it's own momentum, and at that point the weight is very noticeable, and often the hardtail will be faster as I can spend more time "riding" and less time mashing the pedals whilst the black spots flash before my eyes.

    One of the jobs for '09 is to increase my power output...

  20. #20
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    Quote Originally Posted by Jon Edwards
    I run a 35lb '02 RFX and a 24lb Ti hardtail. I have a pretty good power to weight ratio, but all that means is that I don't have much weight or much power!

    "Just riding along" there's not all that much difference - even uphill, until it gets *really* gnarly, sure it's a bit leaden, but the increase in traction makes up for the weight. Where I really suffer is in hard acceleration, whether it's coming out of corners on singletrack or trying to keep the bike rolling on rubbly DHs that just aren't quite steep enough for the bike to carry it's own momentum, and at that point the weight is very noticeable, and often the hardtail will be faster as I can spend more time "riding" and less time mashing the pedals whilst the black spots flash before my eyes.

    One of the jobs for '09 is to increase my power output...
    My sentiments exactly. Sprinting in the flats or even on moderate climbs is a chore. I also have a LW hardtail SS and racing around the FH's trails on my RFX compared to the SS is very noticeable. On the long FR climbs where there are steep sections integrated with the sustained climbing, is quite a chore as well....but the DH sure is fun! If you are into ball busting climbs to get to the DH then you will like the RFX in those particular situations. Have you been motoring to ride or do you still ride your bike to the TH these days? There is not much around here (immediate vicinity) except a few shuttle runs during the summer, and couple of choice spots at Cedro/Otero and E. Mtns. Getting that bike to the TH is something else to consider. I can't imagine commuting on my RFX every day.

    Edit: Let me add this. I am pretty sure that you know Chris over at REI and Jeffe. Both commute on their bikes, and both have done so on bigger bikes. Chris on his moment and Jeff on a big, burely DH hardtail. Talk to them and get a perspective. Of course neither have anything close to your endurance, but might help to tip your decision one way or another.

  21. #21
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    Let's look at the maths

    Alright, lets look at the maths first.

    Not sure how much you weigh, but you're fast, so let's call it 150 lb. Keeping things light, we'll add in 5 lb for kit, so you and bike have a rolling weight of either 184 or 188 lb - about 2% difference.

    If we think about acceleration first, taking a very simple approach and ignoring air, rolling resistance, and rotational acceleration of the wheels - i.e. only considering the power needed to linearly accelerate your mass - according to my back of the envelope calculations the distance covered u in time t when accelerating from rest with a constant power output is proportional to mass m to the power of -1/2. Therefore, you cover about 1% less distance with the heavier bike.

    Now instead thinking about climbing, you can play around with calculators such as this: http://bikecalculator.com/veloUS.html or http://www.kreuzotter.de/english/espeed.htm. Using the former, taking an 8% grade for a 7 mile/3000 ft climb and a decent 350 W of power (since you say you're fast), then on the lighter bike you're looking at about one minute longer on the heavier bike for a 46-odd minute climb.

    Aerodynamics, rolling resistance and moment of inertia of the wheels will all play less certain roles. Taking the latter, for instance, tyre carcass size and rim cross-sectional area will typically be larger on the RFX. However, the larger diameter of the Sultan wheels mean, if you instead consider identical rims and tyre styles, it will have proportionately heavier rim and tyres, and the moment of inertia increases as the square of the diameter. Factor both of these in, and there is actually a cube relationship of wheel moment to rim diameter. Hmm, more detail is needed to make a comparative calculation. Just to emphasize, moment of inertia ("rotating weight") only makes a greater difference to performance than changes in mass elsewhere on the bike when you are accelerating. If you are climbing a constant grade on a smooth surface at a constant speed, then changing "rotating weight" is no more important than weight elsewhere.

    So, you can see that, on paper, the 4 lb in mass do not have a great import on your speed. However, the Sultan and RFX are not the same beasts. Rider position, weight distribution, suspension travel are very different, and these have a big impact on how they will ride. I went from a 05 Spot to a 07 RFX; overall, there was not a great weight difference between the builds, but the RFX lacks "motricity" in the comparison. Although I have been perfectly happy climbing a few thousand feet on the RFX, it cannot be made to hustle on flat or rolling terrain in the way the Spot could. On the other hand, in the rough and on the downs the RFX has a very different level of ability - much greater margin of error, significantly more confidence inspiring, and will accelerate through bumps in a way the Spot would not. For me, this is a worthy trade off, but it's a matter of rider taste and requirement.

  22. #22
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    boredwitless: i can see the relationship between head tube angle, fork and suspension travel in most bike companies offerings. the XCs are lighter 70+ degrees HA with 4 to 5 inch travel machines while the AMs are burlier 67-68 degrees with 5.5 to 6.5 inch travel machines. just a matter for my own education or maybe just a stupid question, but is it possible/feasible to take that old spot of yours and engineer it to have much slacker HA without adding the extra travel and extra frame weight so it will take the downs more or less like your RFX does today? thanx!

  23. #23
    Roy
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    You'll notice it when you switch back to back rides with a lighter (or heavier) bike. If it's your only ride, you will get used to it shortly and won't remember the difference.

  24. #24
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    I've been riding a long time, so I've been working on curing my weight bias for several years now and I'm beginning to embrace the fact that it's not that bad to have a bike that is over 25lbs. I have a steep, but smooth 30 minute climb out my back door and I did some timing awhile back to see how my 32.5lb RFX did against my 20lb +/- CX bike. Interestingly, the average time difference worked out to be consistently less than 2 minutes in favor of the CX, which is surprising since I run 80psi air pressure on the 700c wheels, nearly half the weight, etc. Now 2 minutes in 30 is almost 7% though, so I'm not saying it isn't significant, especially when you consider 2+ hour climbs (8.5 minutes if the 7% stays consistent, which it likely wouldn't as the glycogen levels decrease as mentioned above).

    Anyway, that's my input.

  25. #25
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    Quote Originally Posted by starre
    boredwitless: i can see the relationship between head tube angle, fork and suspension travel in most bike companies offerings. the XCs are lighter 70+ degrees HA with 4 to 5 inch travel machines while the AMs are burlier 67-68 degrees with 5.5 to 6.5 inch travel machines. just a matter for my own education or maybe just a stupid question, but is it possible/feasible to take that old spot of yours and engineer it to have much slacker HA without adding the extra travel and extra frame weight so it will take the downs more or less like your RFX does today? thanx!
    Rode a number of 4-5.5" travel bikes originally spec'd around 130mm fork. Installed a range of forks from 140mm - 170mm - not a one could come close to a 160mm plus rear suspended bike when the trail pointed downhill. My 08' RFX has that "sit in the travel" feel where my 02' Enduro w/ a Super T dual crown still felt like a XC high chair. Even though riders tweak their rides all day long the manufacture usually has an intended use for each frame.

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