I've been having a bit of a conversation with a SRAM rep for the past few weeks about 29ers, stay lengths and all the potential clearance issues that crop up. He directed me to this link which you can use to get all kinds of fun information about XX. http://www.sram.com/en/XX/products/front-derailleur.php. There's more than just front der info if you dig around.
SRAM XX specs
1 - 20 of 20 Posts
Joined
·
7,491 Posts
Some good specs in there.
I have some .pdfs of this set of specs and also the new SRAM Pressfit 30 BB standard (much better than BB30, IMO) info. If anyone wants it, drop me an email.
Kudos to SRAM - it seems they are making a real push to do some stuff with/for the small custom builders.
-Walt
I have some .pdfs of this set of specs and also the new SRAM Pressfit 30 BB standard (much better than BB30, IMO) info. If anyone wants it, drop me an email.
Kudos to SRAM - it seems they are making a real push to do some stuff with/for the small custom builders.
-Walt
Joined
·
2,675 Posts
Is anyone making steel shells for Press-Fit BB30 yet?
Joined
·
115 Posts
post weld machining?
Steven
I've kinda missed the boat a little with BB30 but these shells will still need post weld/braze machining though, right?Walt said:
Steven
Joined
·
7,491 Posts
Not sure.
The SRAM boys didn't explain it to me very well, but they seemed to be claiming that the answer is no. I can't see how that's possible, but who knows... the system is sort of like a headset, in that the bearings are held in plastic cups, which are pressed into the shell.
Drew at Engin has done one (http://www.engincycles.com/current-work/12-09/press-fit-30) but I haven't talked to him about it yet. Drew, if you're on the board, feel free to chime in.
The Moots boys have also apparently been building with the PF30 system, but once again, it's the holidays and I've not been interested in trying to chase people down to pick their brains before I leave for AZ.
I should have a sample BB and some shells when I get back, and I will keep everyone updated on what I find out.
-Walt
The SRAM boys didn't explain it to me very well, but they seemed to be claiming that the answer is no. I can't see how that's possible, but who knows... the system is sort of like a headset, in that the bearings are held in plastic cups, which are pressed into the shell.
Drew at Engin has done one (http://www.engincycles.com/current-work/12-09/press-fit-30) but I haven't talked to him about it yet. Drew, if you're on the board, feel free to chime in.
The Moots boys have also apparently been building with the PF30 system, but once again, it's the holidays and I've not been interested in trying to chase people down to pick their brains before I leave for AZ.
I should have a sample BB and some shells when I get back, and I will keep everyone updated on what I find out.
-Walt
shandcycles said:
Joined
·
34 Posts
I still don't see this whole "30" deviation thing as anything other than the big boys looking for an easier production BB joint. Why custom builders would want anything to do with such madness is beyond me...
Joined
·
7,491 Posts
SImple...
People will want it because it's a tiny bit lighter and "stiffer" (when was the last time you had a problem with crank flex, though?), and as long as it's not total crap, I'm happy to build them a frame that way and continue to pay my bills. Same story with tapered steerer tubes, direct mount front derailleurs (those actually pretty much rock for some stuff, IMO), and many other things. I don't think the benefits of the PF30 are very big, and there may be tradeoffs (there usually are) but if you don't try new things, you lose business.
Just IMO, as always.
-Walt
People will want it because it's a tiny bit lighter and "stiffer" (when was the last time you had a problem with crank flex, though?), and as long as it's not total crap, I'm happy to build them a frame that way and continue to pay my bills. Same story with tapered steerer tubes, direct mount front derailleurs (those actually pretty much rock for some stuff, IMO), and many other things. I don't think the benefits of the PF30 are very big, and there may be tradeoffs (there usually are) but if you don't try new things, you lose business.
Just IMO, as always.
-Walt
Arrak Thumrs said:
Joined
·
34 Posts
Is the same customer likely to accept a significant mark-up for this feature? I would be inclined to expect one. BB taps, Facers and all the other tooling a framebuilder is likely to have must be paid for even if sitting idle. In addition, the BB is the most consistently used feature which dictates frame alignment procedures. Even if you use an existing mill and boring head, it is a slow process. Add new adaptive tooling for aligment systems... and it just seems ridiculous from a one-off building perspective without a mark-up.
Yes, they still need to be machined post-weld. The rep I spoke with swears up and down that they don't and the simple fact is this - he's wrong.shandcycles said:
The tolerance on the PF30 is ± 0.0078 vs +0.001 -0 on a BB30 and for anyone doing a boring operation it'll be much easier to hit with much less risk of trashing the frame by going oversize or dealing with notchy bearings going undersize.
Walt, I spoke with Butch @ Moots at great length a few weeks ago. The're boring the shells out with a boring head on a mill.Walt said:
The PF30 bearing assemblies locate via the I.D. of the shell AND the outer face. If you only bore the shell, you can probably get away with not pressing in the cups tightly if you want to go that route. Personally, I'll be modifying a tool so I can face the shells after the boring operation.
dude, tapered steerer tubes rock for long travel forks. Seriously. Pair it up with a QR15 or 20mm axle and it's a game changer for sure.Walt said:
I agree that BB30/PF30 may not have many tangible benefits in the real world, but for me, PF30 is what my customers are going to get if they want a 30mm BB axle based solely on the fact that the tolerance window isn't 0.001"
Joined
·
7,491 Posts
Did I say they didn't?
I was just listing new stuff, not trying to make any value judgements about what's worth doing or not. I agree that for long travel (meaning a lot of XC 29er forks too) the tapered steerers will be a nice upgrade.
I generally won't ride suspension forks without through axles.
Getting head tubes made in steel for taper is going to suck, though.
Thanks for the PF30 info. That's kind of what I figured. Be nice if someone made a tool, but I guess I can chuck up the boring head and go at it. That tolerance should be pretty easy to hit.
-W
I was just listing new stuff, not trying to make any value judgements about what's worth doing or not. I agree that for long travel (meaning a lot of XC 29er forks too) the tapered steerers will be a nice upgrade.
I generally won't ride suspension forks without through axles.
Getting head tubes made in steel for taper is going to suck, though.
Thanks for the PF30 info. That's kind of what I figured. Be nice if someone made a tool, but I guess I can chuck up the boring head and go at it. That tolerance should be pretty easy to hit.
-W
smudge said:
I can't argue with that. Making them out of ti sucks.Walt said:
I should start a new thread for this. I'm toying with the idea of having some lower cups made that fit into "InSet" head tubes but house 1.5" bearings in a standard cup. This would allow us to avoid having to make tapered head tubes or using something huge as would be necessary with a 1.5 standard cup. If people are interested, PM me and I'll get a list going. I'm finalizing the design and have yet to get mfg quotes.
Better yet, bug King or Cane Creek about it so I don't have to do it.
Joined
·
7,491 Posts
I'm in
I assume you mean a pretty substantial "cup" (including enough taper to clear the steerer) in steel or ti that would be fusion welded or brazed into the upper 1 1/8" standard head tube, right? So a 2-piece head tube, essentially?
Anyway, email me or something. I have next to zero pull with any of the folks (ie King, Cane Creek, etc) that could easily make this happen, but I'm happy to help bug them and/or put my name on the list of interested folks.
I'm thinking that a year or two from now this (tapered steerers) is something that all mountain bike builders will need to have in their quiver of capabilities. Certainly more so than the PF30/BB30/whatever - I just don't see people noticing a huge difference vs external bearing setups that will run with current shells. Of course, I could be wrong.
-Walt
I assume you mean a pretty substantial "cup" (including enough taper to clear the steerer) in steel or ti that would be fusion welded or brazed into the upper 1 1/8" standard head tube, right? So a 2-piece head tube, essentially?
Anyway, email me or something. I have next to zero pull with any of the folks (ie King, Cane Creek, etc) that could easily make this happen, but I'm happy to help bug them and/or put my name on the list of interested folks.
I'm thinking that a year or two from now this (tapered steerers) is something that all mountain bike builders will need to have in their quiver of capabilities. Certainly more so than the PF30/BB30/whatever - I just don't see people noticing a huge difference vs external bearing setups that will run with current shells. Of course, I could be wrong.
-Walt
smudge said:
I'm talking about "normal looking" 1.5 lower bearing cup with a 44mm cup skirt instead of a 49.6mm cup skirt. The HT would have an external lower bearing and an internal upper.
I know we've covered this before, but you can make "inset spec" head tubes out of 1.5" sched 40 seamless pipe assuming you have a lathe. The pipe isn't quite as large on the O.D. as the Inset or Cane Creek equivalent but Carl Strong made the suggestion a few weeks ago that we ask Paragon to make rings that can be brazed, welded on to match the diameter. I spoke with Mark on Tuesday and he's interested, so I'm going to work up a design to send him.
Once I make the time to work out the solid models, I'll send emails. Anyone who wants in, PM me. If it's OK with the powers that be at MTBR, we can use this forum as a collaborative space or I can set up something else.
.
I know we've covered this before, but you can make "inset spec" head tubes out of 1.5" sched 40 seamless pipe assuming you have a lathe. The pipe isn't quite as large on the O.D. as the Inset or Cane Creek equivalent but Carl Strong made the suggestion a few weeks ago that we ask Paragon to make rings that can be brazed, welded on to match the diameter. I spoke with Mark on Tuesday and he's interested, so I'm going to work up a design to send him.
Once I make the time to work out the solid models, I'll send emails. Anyone who wants in, PM me. If it's OK with the powers that be at MTBR, we can use this forum as a collaborative space or I can set up something else.
.
1 - 20 of 20 Posts
Join the discussion
