Some random build questions

[BigPoser]

All,
The gears have been turning in my head for a while now and I've got some random build questions for those who know. I apologize in advance if these seems like silly questions, but I'd really like to know.

1. With a road bike disc build, which is better for rear spacing, 135mm or 142mm? What kind of complications should be considered? (I really want to build an endurance frame with disc)
2. With a tapered head tube, what is the best way to miter the DT? Is it strictly a hand file job, do you use a hole saw, or a combination of both?
3. With a integrated headset, how exactly do you shape the head tube to accept the upper and lower bearings? Do you have a machine shop do it? If you do it yourself, what tools do you use?
4. For mounting the rear brake on the CS (mounting through the CS), I assume there are threaded inserts that are brazed into the CS for the brake to mount?

Thanks in advance.

Brandon

[steve garro]

1. With a road bike disc build, which is better for rear spacing, 135mm or 142mm?

Brandon

They are the same thing spacing wise

- Garro.

[Amaro Bikes]

All,
The gears have been turning in my head for a while now and I've got some random build questions for those who know. I apologize in advance if these seems like silly questions, but I'd really like to know.

1. With a road bike disc build, which is better for rear spacing, 135mm or 142mm? What kind of complications should be considered? (I really want to build an endurance frame with disc)
2. With a tapered head tube, what is the best way to miter the DT? Is it strictly a hand file job, do you use a hole saw, or a combination of both?
3. With a integrated headset, how exactly do you shape the head tube to accept the upper and lower bearings? Do you have a machine shop do it? If you do it yourself, what tools do you use?
4. For mounting the rear brake on the CS (mounting through the CS), I assume there are threaded inserts that are brazed into the CS for the brake to mount?

Thanks in advance.

Brandon

Hello Brandon:
1. As almost any other possible question, it depends... as Steve said, it's basically the same spacing, just variates upon the type of axle, so would you like to use quick release classic releases or thru axle ones? If you go on the thru axle option, 142x12 is the way to go, if you want to stick on to classic quick releases, 135x9mm is the choice, and as somehow a middle game, you could go with 135x10 thru bolt TA from DTSwiss, which uses the same "open" structure dropout as classic 135x9 axles, but using a wider 10mm axle following similar ideas as on thru axles (stiffer structure). IF you ask for personal thoughts, considering what the actual market is evolving into, I would probably recommend the 142x12 option for a road disc frame, combined with Flat Mount disc insertion, so you'll get the widest options to chose from (most wheelsets, most road disc groupsets, etc). Personally I think 135x9/10 is stiff enough for a road disc bike (and rigid mtb as well), but think about what the future is going to offer you on components before making any final decission.
2.Hand miter is always the way, for about everything, unless you're a pure professiona builder with enough orders as to keep you that busy to need some faster production times, any machined mitering process is completely nonsense. I might not be the best sample to be objective about this matter, but honestly handmiter is as precise as any machine, it's just not as fast and continuously consistent, but for certain jobs not even machines can handle what your eye-hands work can achieve. Measure twice, cut once, practice first with a scrap tube to understand the hidden tricks of any new mitering shape, and you'll soon see how amazingly accurate human machines can be.
3.Not sure about what you mean, but if you ask about reaming, you just get the right reaming cutters/tool, depending on the headtube you're using, you might need to braze the cups as a separate part to be reamed afterwards, other cases you'll be reaming the headtube itself.
4.Again, not 100% sure about the question, but related with question 1, if you're looking for the CS mount, your best call is Flatmount, specially for road frames, it comes in different flavours, you can get integrated dropout systems which include it all at the right dimensions, so all you have to do is weld the dropout to the chainstay, you can get the half-integrated option where you have both holes integrated in one plate to be welded to the dropout and chainstay, and there's a final option where you get both "holes" independently to be welded directly to the chainstay. Any of them easily available at Paragon Machine Works which can offer you the best options for your own needs with fully working and tested tolerances. If you ask me, go for either option 1 or 2, so the braking forces are managed by the dropouts+chainstay+caliper structure, rather than just chainstay+caliper. My favourite one is the semi-integrated "plate" as gives both clean aesthetics and strong structure, although the fully integrated dropout option will make your life easier on mitering/welding. It also depends a lot on your welding technique, I'm talking TIG, where wright styled dropouts are best to my experience, but brazing is a different world of specifications and integrated dropout might get your best ticket.

Hope it helps

Cheers