Technical FAQ: Drilling holes in CO frames and more

May 5, 2015 - photo frame

  • By Lennard Zinn
  • Published 2 hours ago
The usually holes in a support should be a ones drilled by a manufacturer. Photo: Logan VonBokel |

Drilling holes in a CO frame

Dear Lennard,
Can we cavalcade holes in a down tube of my CO towering bike support though negatively impacting a constructional integrity?

The behind story: Rather than regulating a trek for my hydration bladder, we place it in a support bag, that eliminates a weight on my behind and is many some-more comfortable. On a new ride, we satisfied that a sincerely large down tube on my bike (a CO Silverback 29er), offers poignant capacity; utilizing it would lessen a need for even a support bag. My thought is to cavalcade a 3/8″ in. hole on a top side of a down tube nearby a conduct tube, and another 3/8″ hole on a bottom of a down tube nearby a BB. we would afterwards sanitize a inside of a tube with food-grade chemicals, block a bottom hole with a threaded rubber stopper, fill a down tube with water, and insert a suitable length of 3/8″ OD surgical tubing into a top hole, affixing a bit valve finish on a bars.

Again, we am wondering if drilling holes of this inlet would significantly revoke a constructional firmness of a frame. (By a way, we hereby recompense we from any and all ramifications of me drilling holes in my frame.) This might seem like a reticent doubt (“Of march it’ll screw adult a frame!”) but, for example, a fifth pattern in a VeloNews print letter on a new Trek CO IsoSpeed frame clearly shows a hole for a “rivet or a port” on a bottom side of a down tube. To make a prolonged line of logic short, if Trek can do it, because can’t I?
— Jeff

Dear Jeff,
That’s a really bad idea. It’s not a good thought to cavalcade a hole, quite that large of a hole, even in a steel frame. But during slightest on a steel frame, you’re not slicing by fibers as we are on a CO frame.

Below are some responses we should compensate courtesy to.
― Lennard

From Specialized:
Drilling holes in a down tube is a bad idea. The holes will emanate highlight concentrations where cracks could form, compromising a constructional firmness of his frame. If we meant for holes to be drilled in those locations we would have reinforced a tube walls in those area. (Needless to contend this would blank a bike’s warranty). Most of a holes in a frames are drilled, though we have specific reinforcements in those areas to forestall constructional issues and a drilling routine is really tranquil and repeatable.
— Luc Callahan
Engineering Manager- Road
Specialized Bicycle Components

From Trek:
There is no business where a hole can/should be drilled in a CO support by anyone other than a manufacturer. The reason we can cavalcade holes in frames is that we privately pattern areas with bolster for post-molding machining processes. We make perplexing and accurate fixtures that can take advantage of those areas with a suitable slicing tools. There is positively no business where we would feel gentle with anyone outward of Trek drilling a hole in a CO frame.
— Ben Coates
Trek Road Product Manager

More on Trek’s skewer recall

Dear Lennard,
I don’t know if we should be promulgation this email to we or to “Legally Speaking,” but here we go.

I gamble Mr. Tullio Campagnolo is branch in his grave. Between a counsel lips and this recall, he contingency be saying, “it’s a elementary device, people, though we keep anticipating ways to screw it up.”

So a video shows a automechanic putting a push on the side with a hoop brake. Is there a law opposite putting it on a non-brake side?

He describes a unfolding were a push “just opens up.” I’m guessing that this happens because the skewer is not parsimonious adequate and/or indicating forwards. So Trek’s “solution” is to reinstate it with a shorter lever. Sure, it prevents a push from throwing in a disk, though it does not solve a tangible problem of not adequate tension. In fact a shorter push will make it harder to tighten.

So here is my doubt for Professor Zinn: Are there any skewers on a marketplace that let a supplement know that skewer is parsimonious enough? Anything that ensures correct alignment, i.e., not indicating forward?

I do comprehend that a tangible resolution is to learn new riders a correct way. Each year on a gift float that we do, we indicate this out to during slightest one rider. One man even said, “That’s how a emporium told me to do it.”
— John

Dear John,
I know of no skewers that tell we when they are parsimonious enough, or that they are oriented in an authorized instruction …

I have always put my push on any disc-brake front circle on a non-brake side, though we am vacant during a ridicule we spasmodic get from people who find it unsightly to have a skewer push on a expostulate side.

I trust that carrying a push on a non-drive side is positively a approach to go to forestall removing greasy fingers on a front and to forestall inadvertently tortuous a front by pulling on it with a fingers when pulling a push over with a heel of a hand. That said, given we can’t forestall people from branch it around a other way. Trek simply training a shops to put a skewer push on a expostulate side is substantially deficient to residence this issue, that for 3 people was really serious.

Unlike a front, we can’t retreat a skewer on a back so a push is on a expostulate side, given a push would be in a approach of a derailleur. While a locked-up back front would not be as inauspicious as one on a front, it is still not something you’d wish to have happen. Trek flattering many had to residence this emanate in a approach that it has.

The remember replaces a skewers with ones that don’t flip open past 180 degrees.

It seems doubtful that other manufacturers of disc-brake bikes aren’t also offered skewers that flip open past 180 degrees; we consternation how many other bicycle brands will follow Trek’s lead.
― Lennard

More on disc-brake hubs on bikes

Dear Lennard,
You stated, “You aren’t good to find disc-brake hubs with fewer than 32 holes to insert them to.”

Small detail, though I’d like to indicate out that DT Swiss offers highway front hubs in hole depends of 20, 24, 28, and 32, in Classic flange, and 24 and 28 in Straight Pull prong hubs. Of course, a low spoke count front circle is not for each rider, though we do make a options accessible to wheelbuilders.
— Steven Sperling
Tech Manager
DT Swiss, Inc.

Dear Lennard,
In a new column, “Technical FAQ: Disc brakes in highway racing,” Mark commented that given kinetic appetite is proportional to a block of speed, braking appetite (and therefore feverishness generation) was proportional to a block of speed. This isn’t particularly true. If we are braking to come to a stop, we remove all of your kinetic energy, that is proportional to a block of a initial speed, as Mark states. However, when braking on a descent, we aren’t typically losing kinetic energy, though rather preventing gravitational intensity appetite from augmenting it. The rate of detriment of intensity appetite is proportional to highway class times speed, so if we stop to say speed on a prolonged descent, a rate of feverishness era will be approximately proportional to a speed, not a block of speed. So forward a 20 percent class during 30 kph would outcome in twice a rate of feverishness era as forward a 20 percent class during 15 kph. Total feverishness era depends usually on a intensity appetite lost, so speed doesn’t matter for sum heat, that determines limit feverishness boost on really brief descents. Although, if a feverishness penetrate (in this box a rotor) is losing feverishness to a air, afterwards a rise feverishness will be roughly proportional to a rate of feverishness era on prolonged descents where “steady state” is reached. This all of march ignores appetite dissolute to breeze resistance, rolling resistance, etc. But a pivotal indicate is poignant kinetic appetite is not being mislaid when speed is approximately constant, and there’s no reason to design heating proportional to a block of speed.
— Dan

Dear Lennard,
Just review your Tech FAQ on front brakes. Although we determine that it substantially doesn’t make clarity to modify edge stop rims to disc, folks are not singular to 32-hole hubs. I’ve run dual front stop bikes for over 3 years now. we live in Seattle and get many of my training in around prolonged invert rides year-round. Prior to going to front brakes, we went by a edge a winter notwithstanding clever and unchanging cleaning of a stop track. we wanted a go-fast, year-round bike. TiCycles built me a tradition highway competition geometry support with front brakes (not a converted sand or cyclocross). This bike was creatively built with Ultegra 10-speed Di2 and Avid BB7s. we upgraded it to Dura-Ace 11-speed and Shimano hydro about a year ago (as an aside, no problems with stop blur even on 95+ grade days on prolonged towering pass descents). we also have one of their sand front frames that got a Ultegra Di2 and BB7s as hand-me-downs.

At any rate, we have 4 sets of wheels, all front brake. On my highway bike, we run 28 hole, three-cross for both wheelsets. For dry weather, a set of 28-hole DT Swiss 240 centerlock hubs laced with DT Aerolite spokes to Reynolds Competition 46 rims (DT Swiss temperament usually make it one winter deteriorate for me, so we cruise them junk for soppy continue riding). For soppy weather, we run 28-hole Chris King R45 front hubs laced with Sapim CX-Ray spokes to Hed Belgium+ front rims. we import about 163 pounds and float with a follower bag for about 75 percent of my miles. Both of these wheelsets have seen a lot of violence and are holding adult really well. On my sand bike, we do run 32-hole hubs (both Chris King ISO discs with Sapim CX-Ray spokes to Belgium+ front rims for my quick tires and Sapim Force spokes to Stan’s Grail rims for my sand tires).
— Joel

FILED UNDER: Bikes and Tech / Technical FAQ

Lennard Zinn

Lennard Zinn

Our longtime technical author assimilated VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and a Art of Mountain Bike Maintenance and Zinn and a Art of Road Bike Maintenance, as good as Zinn and a Art of Triathlon Bikes and Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He binds a Bachelor’s grade in production from Colorado College. Readers can send brief technical questions to Ask LZ.

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