20 posts • Page 1 of 1
I am considering experimenting with getting a custom chinese titanium frame built up but have a few questions to those who have gone through the process or know of someone who has. Specifically interested in people who had tweaked the standard frame options not just geometry wise but in feature spec. Has anyone gone for a tapered internal headtube, internal cable routing, BB30 or pressfit? Made any changes to the overall style of the frame? Such as moving the seat stays, brake location, etc etc.
If so how did it work out? I have done a search and from the looks of most examples its a pretty standard frame, I haven't seen any with any of the options they can offer apart from the internal routing. I have a donor bike hence wanting the tapered headtube and BB30 but am worried about quality after reading about some issues with headsets fitting correctly.
I have an idea of the geometry and overal look but it is quite different from what they typically produce, hopefully they are up to the task. From the few drawings they have sent through it seems as if they can pull it off, but there is a long way between a drawing and a working frame.
Also if anyone has any advice about the process as well I would gladly appreciate it.
There are a number of discussions about these bikes in this forum and have moved your thread to the Generic Carbon section.
BNA have looked into doing reviews and asked with a number of suppliers though all to avail.
$3207 Raised from $5000 in my Adelaide to Darwin charity ride: TourXOz Details and Fundraising
Everything you state is possible, just remember if you make a mistake they will make it exactly like that, and they may not even bring it up. YOU have to know what YOU are doing and how to read the CAD.
If in doubt, simply copy the geometry of an existing production frame that is similar to what you want.
Send me the CAD if you want for a 2nd look. I'm working on my 3rd frame now. My previous two frames have been great, however some have been unlucky.
Generic carbon, custom titanium... really the same thing?
Other than geometry and tubing specs, the only thing I specified differently on my XACD road frame was the disc brake mount on the chainstay.
They had a "stock" dropout to do this, but I must say, it's a fairly agricultural lump of metal. But it certainly does the job.
I also had to decide on cable routing and stop locations, but that's fairly trivial.
My (rather long) head tube does have the dreaded bend in it (if you hold a straight edge up to it), but it was counter-bored straight and parallel for headset insertion. Very tight headset insertion. I noticed that I had a cup misaligned (rotated with the logo facing the wrong direction ) after I'd pressed it in, but there's no way I'm ever going to get that thing out again without destroying it or the frame.
I would wonder how they make tapered headtubes, and expect that it would be very (comparatively) costly. I expect they machine it down from a very thick straight piece of tube (or solid) - and you pay $/gram titanium price for all the swarf that ends up on the floor, and also for the tool bits they wear out in the process.
Would it be worth getting the frame made with a straight 1.5"-capable (49mm ID?) head tube and using a reducing / tapered headset? Such things exist... I'm running a straight 1.125" fork in a 49mm head tube on my MTB. A standard 1.5" bottom cup and a reducer top cup would fit your tapered fork just fine, and I know some manufacturers sell such things pre-mixed.
Not much difference between tapered and 1 1/8" headtubes - $30
The two people I know personally who have XACD frames have had problems with them which required them to be sent back at their own expense. Not sure exactly what. Heavy too - 1.8kg for a size 56 with (fake) S&S couplers for one of the above. This seems to be consistent with the t'interwebs view on them.
YMMV of course.
The above was enough to consider it too expensive an experiment for me, not least because at the time Van Nicholas had a Euros (complete bicycle - Campy Veloce + Mavic Ksyrium Equipe) in my size going for a similar price that a XACD + similar bits would have cost. No S&S though, but have kid now so no travelling bike for me anyway.
Then again I know people who have had problems with bikes of all flavours, no-name to well respected brands. You pays your money and you hopes.
S&S couplers run at about 150g per unit, so using them (or copies) will add 300g to a frame straight away.
So, an equivalent 1500g frame. That's not in the same realm as the latest <1000g pro-spec carbon bikes, but it's quite reasonable for a one-off metal frame. There might be places on the frame that could get away with less metal to save weight, but you'd be brave to go there without doing any testing at all... which is really not an option unless you're putting the design into series production. On a one-off frame, it's wise to be a bit conservative.
Mine weighed 1600g, for a 54x50cm disc-brake road frame, made of straight-gauge tubing to save some cost. Not ridiculously light, but there are plenty of production frames heavier than that. If you can find me a lighter custom frame (in any material) for $1k delivered, I'll buy a couple of them.
If you fit on a series-production frame, then of course, you're probably going to get a better developed frame for your money. I'm not quite sure why you would get a one-off frame built to "standard" geometry.
Any idea where your Van Nicholas frame was built? I'd make a pretty confident guess that they come out of either XACD or Titan Product.
Couplers can be added to any frame, after manufacture, so that's not really a case for or against. Especially for an unpainted Ti frame.
I'm sure I got my money's worth out of XACD. I paid $1k for a 1600g frame built to fit my odd-ball proportions, with quirky features of my own choosing (disc brake, rack and fender mounts, clearance for fat tyres). You could easily pay that for a 1600g production frame with somebody else's geometry and features.
Not with a branded series-production ti frame in my experience. They all seem to be more expensive than XACD.
No. I agree. The difference is that Van Nic deal with the quality control rather than me.
I am sure you did get your monies worth - "YMMV of course". I know two people who I think did not.
barefoot, can you post a pic of your road rear dropout/disc brake mount?
Haven't got any close-ups, but they can be seen pretty clearly in these:
I can take a crop out of a high-res image if you want more detail.
Sorry for this late response, it took me a while to find the thread again. I also agree its a weird place to put a thread about a custom Titanium frame, but I guess there are not many other places for it to go.
Thank you to all the replies, I think I have it relatively sorted in terms of geometry but for those that would like a gander I have attempted to attach the supplied plan. I am having trouble (with the language barrier) getting the seat tube length right but hopefully that will get sorted in the near future. It just needs to be a bit shorter no biggie at this stage.
I went with some similar numbers to what I am riding now, just made the rear end a little shorter and have made some changes for aesthetic reasons. Apart from speccing stuff around the build kit of the existing bike, which sadly is out of commission right now I wanted to break away from the norm and get something that I would like to ride. Hence a lot of my decisions are really just personal preference, such as the internal routing but I feel that will be a bit of a gamble, some say it works well, others hate it. It really is the headtube I am most worried about, especially being an internal, tapered design. Thanks for the suggestion of a straight 1.5, that might be the way to go.
One thing I would be keen to try out, only because I like the look of it is placing the rear brake on the chain stays, ala time trial and the Trek Madone. Just not sure if they have the know how to make it work, but it sure does look nice.
Anyway again thanks for the discussion it is very helpful.
*edit gave up trying to attach, if anyone would like to see it I'm more than happy to email.*
Barefoot - the more I look at your dropouts the more they remind me of a cheese knife. Do you notice any flex through the rear end, especially where the chainstay joins the dropout plate?
Merry xmas barefoot
Would have a hard time cutting cheese with an 8mm thick slab of titanium, but I see where you're coming from.
I don't notice flex, but I get what you're saying. It looks almost like a point contact that would be very prone to flex. I'll have a closer look when I get home. At least according to my memory, the "plate" is pretty well embedded in the chainstay, and welded all 'round, so it should be reasonably stiff.
Chainstays are usually made to be pretty chunky, for reasons of stiffness. On the other hand, seat stays are being made more and more slender to allow a bit of controlled flex.
If the chainstay/BB cluster area is stiff enough, it's almost certainly strong enough to support braking load. Especially if the whispy seatstay assembly on a mainstream bike is strong enough.
If you're confident you can get the physical geometry right - the bridge position, hole angle, cable routing and cable stop position - I'd say go for it. Little details like that make the custom bike process more fun.
I reduced the diameter of my seatstays from their original drawing, and got them S-bent instead of straight, because I figured I could get away with it because the seatstays aren't supporting any brake forces. My chainstays are nice and fat for stiffness... and strong as a by-product of that.
If you want to email your drawing to me (bna at timpaton dot net), I'll chuck it up on my server and post it here. Or use any of the free hosting services like the one Crawf mentioned.
So I am back and finally recovered from the 3 Peaks ride - was a brutal day out with the heat. I have attached the CAD drawing and would love to hear some feedback, the measurements will have me running a 120mm stem (6degree drop), with the stem slammed and the seat post needs to be slightly shorter but we are getting there.
As for the rear brake, I think it would be a good experiment to place it on the chainstays but am worried about getting the measurements and placement correct. I have asked them to do this so we will see what happens. I would also like to get a hold of some forks off a Ridley Noah or the new Stork Scenario to get the integrated front brake look but I don't think that will happen.
Again thanks for the responses, much appreciated
-Race bike? Worth beefing up the seatstays from 0.9 to 1.2mm? The seat stays don't see as much stress but something to think about.
-How will the ISP work? Is that dialed in with your measurements, is there a margin for change, cleat/stack height etc...
-Inner cable routing - I find their port hole 'caps' crap. And opt for just plain holes now, so you may want to reduce the hole size if going the latter.
Drool over these for some nice ideas.
Crawf - thanks for the tips. Haven't had any experience in Ti at all and actually specced the smaller diameter seat stays to aid in a bit more comfort due to the compact rear end. Easy enough to up the diamtater if this could potentially cause problems with durability. The internal routing actually looks much better with just holes, is that something that is easy to request? As they automatically specced the "caps" when I requested internal routing.
Its going to be a race/training bike so really comfort is not the main concern.
Stick with the 0.9 then, durability shouldn't be an issue on seat-stays really.
If you just want holes then just tell Porter, or cross them off on the CAD to get your message across and specify a smaller hole length (18-20mm?), otherwise those holes will be will be quite gaping if not re spec'd. (I find pics the easiest way to communicate with him).
But also remember the holes will be more prone to water ingress depending on the location, running full cable outers isn't a bad idea if your not a weight weenie worrier.
Anyone happen to have spare seatpost clamp for an FM098?
I was foolishly not specific enough in telling Denfu that I would need one of their aero seatpost clamps to fit their aero seatpost.
20 posts • Page 1 of 1
Who is online
Users browsing this forum: No registered users