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Chinabomb Disc Brake Road Bike Build

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Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Chinabomb Disc Brake Road Bike Build

Old 03-30-17, 07:54 AM
  #101  
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Originally Posted by blazin View Post
Just guessing, but maybe he meant 25mm deep, not 25mm wide?
Oh, yeah. Just guessing, but I think you are right.
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Old 03-30-17, 07:57 AM
  #102  
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And thus was another BF blood feud avoided. Too bad...
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Old 03-30-17, 07:58 AM
  #103  
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Originally Posted by rpenmanparker View Post
Why would you run 23 mm tires on 25 mm tubular rims? There is no affect on the tire width by the width of a tubular rim like there is with clinchers. You might as well just save the weight and get narrower rims. The aero drag coefficient would be better. Or run 25 mm tires on the 25 mm rims if you want another approach to improved aero effect that provide wider tires. The one thing you don't want is to run smaller tires on wider tubular rims. They would be sitting in the middle of the rim, with some edge exposed. Besides aero I don't know what is wrong with that, but it must be something.
Current rims are 40mm deep (27mm wide) and ~405 grams. I have seen 25mm deep (~22mm wide) rims advertised at 260-280 grams. As you say, I would not use narrow tubulars on wide rims aside from briefly mounting a skinny spare to get home.
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Old 03-30-17, 07:58 AM
  #104  
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Originally Posted by blazin View Post
And thus was another BF blood feud avoided. Too bad...
Indeed.
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Old 03-30-17, 10:56 AM
  #105  
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You guys give up too easily ...

We just lost four pages of drama so you guys could act like rational adults.

I hope it's worth it to you.
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Old 03-30-17, 11:26 AM
  #106  
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Originally Posted by Maelochs View Post
That works. The curtains accent the gumwwalls.

Looks great .... but the amount of mechanical fiddling that went into it puts it beyond me. But it looks real good.
Thanks! Ironically, those 'curtains' are a photo backdrop that I was too lazy to pull out.

Most of the fiddling was my own doing. A Shimano group on the same frame would be very straightforward. Campy and TRP, not so much.

Originally Posted by zymphad View Post
That looks awesome. How is Chorus? Damn looks fast.
Thanks! I have about 0.1 miles on the bike so can't really comment on using Chorus other than shifting it on the stand. I agree it looks fast. I need to work on the engine to match.
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Old 03-30-17, 11:31 AM
  #107  
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Originally Posted by joejack951 View Post
Current rims are 40mm deep (27mm wide) and ~405 grams. I have seen 25mm deep (~22mm wide) rims advertised at 260-280 grams. As you say, I would not use narrow tubulars on wide rims aside from briefly mounting a skinny spare to get home.
Mine are 20 mm deep at that weight...I think.
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Old 03-30-17, 11:38 AM
  #108  
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Originally Posted by rpenmanparker View Post
Mine are 20 mm deep at that weight...I think.
There are a lot of options but here is one 25mm deep x 23mm wide quoted at 250 grams: 25mmx23mm tubular - Far Sports

The lack of a braking surface may be why they are lighter than yours even for a larger profile. Or the claim is just that and they really weigh 25 grams each more. Regardless, much lighter than my 40mm rims and good for half a pound off the bike.
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Old 03-31-17, 10:50 AM
  #109  
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Final build was as follows:


frame/fork: Hongfu FM-079-F w/ BB30
rims: Hongfu 40mm carbon tubular, 25mm wide, no brake track
tires: Vittoria Corsa G+ Isotech tubular, 25mm with Mastik One, Continental valve extenders
Brakes: TRP HY/RD Flat Mount, custom arms for Campagnolo levers
Rotors: Shimano ICE tech Freeza 160 front, 140 rear
front hub: Bitex BX106F centerlock 24H, 15mm thru, white!
front thru axle: Rock Shox Maxle, 15x100 (125mm overall length)
rear hub: Bitex BX106R Centerlock 28H 12mm thru, Campy, white!
Rear thru axle: Ibis Hexle Boost 148, 12mm x 171mm overall
Rear axle nut: Shimano e-thru nut (milled down a bit for more thread engagement)
Spokes: Sapim CX-Ray, black
Nipples: Sapim 12mm
Groupset: Campy Chorus, 50/34 crank, 12/29 cassette
Cable housing: Yokozuna Reaction, white
Pedals: Shimano Ultegra 6800
Saddle: Fizik Arione R1, white
Seatpost: Ritchey Superlogic UD Carbon
Handlebars: Ritchey WCS Streem II, 40cm
Stem: Ritchey WCS C260 110mm
Bar Tape: Fizik Classic, white

Weight as pictured above: 16.65 lbs./7.57 kg
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Old 04-03-17, 01:27 PM
  #110  
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Standard drive side shot (yes, I know, my cranks moved a bit):



Aero handlebars and those shiny white hubs:



Business end. Derailleur housing runs all the way to the bottom bracket cable guide. Hongfu provided a short noodle which looked like it might have allowed me to only use housing from the dropout exit point to the derailleur but I didn't trust what the cable might be rubbing on internally. Hongfu provided a crappy fitting grommet to use at the dropout exit point in lieu of the noodle which I needed to trim to fit even close to nicely (ugliness hidden in this pic):



Front TRP HY/RD Flat Mount caliper with custom arm sort of showing awkward housing entry into caliper:



Campy stuff is P R E T T Y pretty



Front TRP HY/RD Flat Mount caliper with custom arm again sort of showing awkward housing entry into caliper, also Rockshox Maxle:



Rear TRP HY/RD Flat Mount caliper with custom arm sort of showing awkward housing entry into caliper, also Ibis Hexle:



Flush cut fork with custom steerer reinforcement piece, no top cap:

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Old 04-03-17, 01:46 PM
  #111  
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Yup.
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Old 04-05-17, 08:01 AM
  #112  
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Originally Posted by rpenmanparker View Post
Why would you run 23 mm tires on 25 mm tubular rims? There is no affect on the tire width by the width of a tubular rim like there is with clinchers. You might as well just save the weight and get narrower rims. The aero drag coefficient would be better. Or run 25 mm tires on the 25 mm rims if you want another approach to improved aero effect that provide wider tires. The one thing you don't want is to run smaller tires on wider tubular rims. They would be sitting in the middle of the rim, with some edge exposed. Besides aero I don't know what is wrong with that, but it must be something.
Wide rims are more aero than narrow rims (at least in some conditions), but wide tires are most definitely not more aero than narrow tires, even when used on wide rims. For best aerodynamics, you want the brake tracks to be wider than the tire. This is why Zipp recommends using a 23 mm tire with their Firecrest rims for best aero performance.

The numerous other reasons for not having narrow tires on wide rims still stand, of course.
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Old 04-05-17, 10:31 AM
  #113  
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Eh... If I had a 25mm wide rims, I'd use 25mm tires. The aero difference for my riding ability would be negligible, but the ride feel and comfort would not be.
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Old 04-05-17, 01:35 PM
  #114  
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The bike pictured has 25mm tires and these rims (tubular version):

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Old 04-05-17, 03:21 PM
  #115  
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Originally Posted by zymphad View Post
Eh... If I had a 25mm wide rims, I'd use 25mm tires. The aero difference for my riding ability would be negligible, but the ride feel and comfort would not be.
We've pretty well established he meant 25 mm deep, not wide.
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Old 04-05-17, 03:59 PM
  #116  
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Originally Posted by rpenmanparker View Post
We've pretty well established he meant 25 mm deep, not wide.
I thought he clarified it's 40mm deep, 25mm wide.
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Old 04-05-17, 04:07 PM
  #117  
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Originally Posted by zymphad View Post
I thought he clarified it's 40mm deep, 25mm wide.
Whoops. I missed that. Sorry.
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Old 04-05-17, 04:08 PM
  #118  
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Originally Posted by joejack951 View Post
Standard drive side shot (yes, I know, my cranks moved a bit):



Aero handlebars and those shiny white hubs:



Business end. Derailleur housing runs all the way to the bottom bracket cable guide. Hongfu provided a short noodle which looked like it might have allowed me to only use housing from the dropout exit point to the derailleur but I didn't trust what the cable might be rubbing on internally. Hongfu provided a crappy fitting grommet to use at the dropout exit point in lieu of the noodle which I needed to trim to fit even close to nicely (ugliness hidden in this pic):



Front TRP HY/RD Flat Mount caliper with custom arm sort of showing awkward housing entry into caliper:



Campy stuff is P R E T T Y pretty



Front TRP HY/RD Flat Mount caliper with custom arm again sort of showing awkward housing entry into caliper, also Rockshox Maxle:



Rear TRP HY/RD Flat Mount caliper with custom arm sort of showing awkward housing entry into caliper, also Ibis Hexle:



Flush cut fork with custom steerer reinforcement piece, no top cap:

Why do you need that custom steerer piece? Why not just remove the cap after the stem is tightened.
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Old 04-05-17, 04:41 PM
  #119  
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What's up with that steerer-tube reinforcement? Is it simply a XF tube wedged down the steerer to reinforce it> I like the idea a lot. (Rathe,r I hated the weight of an expander, but the only one which didn't weigh a ton was pretty pricey on a gram/dollar scale.)
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Old 04-05-17, 06:59 PM
  #120  
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Originally Posted by zymphad View Post
I thought he clarified it's 40mm deep, 25mm wide.
Currently, yes. When I mentioned using '25mm' rims as a weight savings measure down the road (which was the comment initially misunderstood by Robert), I was referring to 25mm deep rims. Just so we're all clear, not that it matters.
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Old 04-05-17, 07:29 PM
  #121  
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Originally Posted by rpenmanparker View Post
Why do you need that custom steerer piece? Why not just remove the cap after the stem is tightened.
Need? Maybe not, but maybe. Hongfu provided a compression device with my fork that fits a full 38mm into the steerer tube. The impression that gave me is that they intend for the steerer tube to be fully supported in the clamp zone of the stem. It seems nearly every carbon fiber fork manufacturer expects a compression device to be used, too, so the idea of not using anything in the ID, or even one of the minimali$$$t expanders didn't sit well with me. But, the provided device weighs a ton (60 grams, or nearly 60% of the weight of the stem on my bike!) and I'm not guaranteed that it won't slip.

It's also an idea I've been kicking around in my head for years after two bad experiences with expanders, both of which had to be torqued just right not to slip but not too much so that they deformed the steerer tube. I won't lie that I got the idea from Aplha Q (I believe) who used to provide a simple sleeve and star nut with their forks, where the sleeve would be epoxied to the fork ID and the star nut driven in like it would be on a metal steerer.

Originally Posted by Maelochs View Post
What's up with that steerer-tube reinforcement? Is it simply a XF tube wedged down the steerer to reinforce it> I like the idea a lot. (Rathe,r I hated the weight of an expander, but the only one which didn't weigh a ton was pretty pricey on a gram/dollar scale.)
Not sure what a 'XF tube' is but it is a custom piece sized for a tight slip fit in the steerer tube and bonded in place with Loctite 648, not something I found that happened to fit. Here's a cross section of the part:


Nominal wall is 1mm to keep the weight down (18 grams on my scale) and there are M6 threads in the thick section to work with your typical headset cap.

My initial design goals of this piece were:

1. provide a non-slip means of adjusting bearing preload
2. reinforce stem clamping zone
3. further reinforce steerer tube at the upper headset bearing (hence the 60mm total length, enough to get below the upper bearing with my slammed stem)
4. simple installation (hence the lip at the top to prevent pushing it in too far)

I didn't initially intend to run this part without a top cap (I would have made some changes, and plan to in the future, for a cleaner final appearance assuming there is interest and I make more) but figured why not. I think it looks good enough as-is and I saw no reason to leave any protruding steerer tube above the stem given this solid reinforcement. I have the tapped hole plugged with a short plastic screw to keep water out.
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Old 04-05-17, 07:38 PM
  #122  
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Originally Posted by joejack951 View Post
Not sure what a 'XF tube' is but it is a custom piece sized for a tight slip fit in the steerer tube and bonded in place with Loctite 648, not something I found that happened to fit. Here's a cross section of the part:


Nominal wall is 1mm to keep the weight down (18 grams on my scale) and there are M6 threads in the thick section to work with your typical headset cap.
Machined it out of what?

I agree, the tube is designed to keep the stem from crushing the fork, and is needed---which is why I went with the disgustingly heavy compression cap, rather than collapsing my steerer while trying to turn.
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Old 04-05-17, 07:48 PM
  #123  
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Originally Posted by Maelochs View Post
Machined it out of what?
6061-T6 aluminum, anodized black.

Originally Posted by Maelochs View Post
I agree, the tube is designed to keep the stem from crushing the fork, and is needed---which is why I went with the disgustingly heavy compression cap, rather than collapsing my steerer while trying to turn.
I'm more concerned about repeated stress from me pulling/pushing on the handlebars and, less so, the annoyance of having headset play develop, but the result of a fork failure for any reason would be similarly bad.
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Old 04-05-17, 09:20 PM
  #124  
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Originally Posted by joejack951 View Post
Need? Maybe not, but maybe. Hongfu provided a compression device with my fork that fits a full 38mm into the steerer tube. The impression that gave me is that they intend for the steerer tube to be fully supported in the clamp zone of the stem. It seems nearly every carbon fiber fork manufacturer expects a compression device to be used, too, so the idea of not using anything in the ID, or even one of the minimali$$$t expanders didn't sit well with me. But, the provided device weighs a ton (60 grams, or nearly 60% of the weight of the stem on my bike!) and I'm not guaranteed that it won't slip.

It's also an idea I've been kicking around in my head for years after two bad experiences with expanders, both of which had to be torqued just right not to slip but not too much so that they deformed the steerer tube. I won't lie that I got the idea from Aplha Q (I believe) who used to provide a simple sleeve and star nut with their forks, where the sleeve would be epoxied to the fork ID and the star nut driven in like it would be on a metal steerer.



Not sure what a 'XF tube' is but it is a custom piece sized for a tight slip fit in the steerer tube and bonded in place with Loctite 648, not something I found that happened to fit. Here's a cross section of the part:


Nominal wall is 1mm to keep the weight down (18 grams on my scale) and there are M6 threads in the thick section to work with your typical headset cap.

My initial design goals of this piece were:

1. provide a non-slip means of adjusting bearing preload
2. reinforce stem clamping zone
3. further reinforce steerer tube at the upper headset bearing (hence the 60mm total length, enough to get below the upper bearing with my slammed stem)
4. simple installation (hence the lip at the top to prevent pushing it in too far)

I didn't initially intend to run this part without a top cap (I would have made some changes, and plan to in the future, for a cleaner final appearance assuming there is interest and I make more) but figured why not. I think it looks good enough as-is and I saw no reason to leave any protruding steerer tube above the stem given this solid reinforcement. I have the tapped hole plugged with a short plastic screw to keep water out.
I'm completely satisfied with my Carbon-Ti expander that weighs 14 g. Support for the steerer seems to be fine. I still don't understand why you don't use a cap. How does a screw keep the water out?
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Old 04-05-17, 10:03 PM
  #125  
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Originally Posted by rpenmanparker View Post
I'm completely satisfied with my Carbon-Ti expander that weighs 14 g. Support for the steerer seems to be fine. I still don't understand why you don't use a cap. How does a screw keep the water out?
If I reduce the height of my part down to 40mm from 60 to only support just the stem clamp area (which is more support than the Carbon-Ti unit offers) it would weigh 14 grams, too.

I don't use a cap because 1. I don't need one and 2. 4 grams is 4 grams and 3. I'm so vane that any benefits of using a cap are negated instantly by how ugly my stem area would look with the added height of a spacer and cap.

The screw/plug keeps water from getting down into the fork. Water can still collect in the depression in the top of my part. Had I originally planned to not use a cap I would have made that whole top surface flush, and will do so on any additional parts I produce.
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