A few wheel tech questions

Couple questions for those in the know:

Is the PF formula of the Bowlriders and Bombers the same as the SPF formula? I've tried researching this, but can't find a yes or no answer, just some nuanced, ambiguous language.

Also, would the wider contact patch of the 60mm Bombers make them grippier than the SPF 60's (which I alread ride)?

Thanks for clearing this up for me.


  • first question is no because spf is skatepark formula and pf is a pool formula so they are 2 different things
  • I never knew that was the case. So what's the difference between the two? I know nobody wants to quote durometers, but (pardon the pun) throw me a bone here.
  • the PF is our Powell version of the SPF. we use different terms to differentiate between the two brands, Powell and BONES.
  • I've got both the 64mm PF Bowl Bombers & 62 mm SPF's, and would swear
    that the SPF's are both harder & faster (on smooth concrete) - Maybe it has
    something to do w/the wheels' profiles, but I'd swear that the PF Bombers
    are grippier, but slower (not just in accelerating due to their bigger size but
    in top end as well). I'd definitely like to see if some 64mm SPFs would be the
    ultimate in carving speed...
  • ok here is the answer your looking for.the older PF formula wheels are of the same formula as the SPF's but the PF's came out to be maybe 2 points softer. that is most likely what your feeling while riding. the newer PF wheels will be the same as the SPF's. sorry it took a while to get the correct answer.
  • Cool - I'll definitely be into picking up a newer set of 64mms;
    Also, I'm beyond stoked to see the return of the orange/red flames
    graphic on the hot rod models, will most certainly be stocking up on
    a few of 'em when they come in - It sure is nice to know that there's
    a company out there like Powell, whose stuff isn't just 7.5 -8" wide,
    or, only over 42" in length either. There's a whole lotta in between
    both extremes,& thankfully, Powell's got it (& me) covered!
  • In what ways are the DTF wheels different? are they just a softer version of the SPF? how many "points" would you say?

    Is "natural" a different formula all together?

    should I have started a whole new thread?
  • DTF is a derivative of the SPF and STF formulas but has many different characters in the overall formulation. As for the natural formula...it is a completely different material all together. SPF, DTF. and STF are all forms of TDI urethanes and our natural formula is an MDI urethane
  • thanks SOC.

    If you were to compare the DTF to other wheels with a durometer rating, what hardness does DTF resemble the most? 95a? 97a? 99a?
  • when your riding the DTF's the sound of the wheel is that of a softer wheel (quieter) yet they are fast like a 95-97 dero wheel with out the noise. i would say a mid 90's hardness
  • so would it be safe to say then, that if bones wheels were compared to durometer ratings, it would roughly look like this?
    DTF - 97ish
    STF - 99ish
    SPF - 101ish
  • I skated the 60mm DTF at a local cement park, and to me they felt like my 95A(60mm) Bowl Riders.
  • DTF's are 95a, STF and SPF wheels are harder than can be accurately measured by the A scale, but this is the only scale that skaters have ever gotten “calibrated” on and understand, so we had a choice of calling them 104A as we have in the past, or taking a different direction and stating what they were designed for, street or park. Getting into how we came up with the number 104A is an interesting story, and part of the Bones legacy, but perhaps more technical than most skaters care about. Also, I think if the kid reads the wheel as 104, he’s gonna think it’s too hard. But the urethane that we use—it needs to be that hard to ride the way it does. So we just use STF Street Tech Formula and SPF Skatepark Formula as the hardness. I think what we need to do is educate the kids on the B scale so that they understand it. It’s gonna take some time, but if everyone gets into it, we can have a way more accurate reading on wheels. My 101A wheel could be completely different from somebody else’s 101A wheel just because of the urethanes they use and because it is a guesstimate. There’s too many variables involved there.
  • Duro differences are definitely noticeable when it comes to different wheel co.'s... My 95a 64mm Bowl Bombers are waaay faster & a bit harder than some Skaterbuilt 63mm 99 duro Pool favors I got flowed - different profile too makes a difference, especially when it comes to steel lips vs pool coping. I also got
    a replaced a set of Sector9's "Goddess of Speed" wheels (73mm 80a = big & slow) on my downhill longboard w/68mm 85a Bombers - a helluva difference in both speed & responsiveness. Haven't tried either STF or DTF yet, but can honestly say that the best wheels for parks/bowls are the SPFs, & the 64mm Bowl Bombers
    (95a for rougher crete, PF for bigger trannies). There's alot to be said for Powell's in-house production/ R&D as opposed to just slapping some graphics on another urethane manufacturers' molds, and calling it your own (worse, hyping it in an ad as "new improved formula). Too many companies out there get away w/shortchanging their customers, even loyal ones. (Just look at Spitfire's up & down record, among others).
    As far as the Natural formula goes though, the previously mentioned 68mm 85a Bombers dust the Surf1 68mm 85a Bombers, no contest. Same duro/size numbers, but different formulas means big difference. They're nowhere near each other when it comes to speed pure & simple, not even close.
  • so can we talk about the "b" scale?

    if we need to learn what it is, tell us all about it :)
  • edited June 2007
    I just put on some DTF 58s. very nice wheel. feels like a 95, but sounds like an 85.

    grip for miles, but slides when you want it to.

    it'd be great if they came in a "97ish" hardness as well - I'd be all over it.
  • I would also like to learn about the B scale.
  • I own the Powell all terrain 65mm / 80a wheels. I want to keep the wheel size the same but switch to a wheel somewhere in the 62mm-63mm range with a duro of 90a-92a. I also need a width of 40mm. Which is the best?
  • we do have a few wheels to choose from but nothing as specific as what your looking for.
    here are some options;

    the Bowlriders are a 60x37 95a
    the Skull and Swords 58x37 90a
    and the Bomber 60x40 85a

    if i was looking to get a new wheel with those dimensions i would personally try the SPF 62x40. they are harder than what your looking for but hold the shape that your requesting. we all skate different terrain so its hard for me to say what would be best for you. good luck with whatever you choose.
  • durometer conversion chart:

    Soc - what formula urethane do you use for the street series?
  • its a special urethane that we have developed here but thats information that can not be leaked. sorry
  • ok. so are, those 97 rippers just a harder DTF?
  • no, they are a different formula.
  • edited January 2008
    do you think they're of a lesser quality urethane?

    please try to be honest.
  • Living up here in Nor-Cal I like riding the DTF (62)on those cold mornings becouse they grip but remain fast and as the cement harms up like summer Bommers and SPF 62 and super six bearings are like stepping on wet glass.
This discussion has been closed.