Technical FAQ: Sealing CX tubulars, through axle loosening, wire flats, Road Link

This article originally appeared on Velo News

Have a question for Lennard? Please email us veloqna@comcast.net to be included in Technical FAQ.

Dear Lennard,

I have a few pairs of Challenge Pro and Team Edition tubulars taped to rims using Effetto Mariposa Carogna. Last season, work and family obligations cut into my pre-season preparation time, and I didn't use tent seal on the sidewalls. A couple of the tires with light cream sidewalls seemed pretreated, but the darker tan versions didn't.

After a lot of mud and power washing in the pits last year, a couple of our tires are showing faint lines of desiccation in the sidewalls. They're holding air and seem structurally sound, so I'd like to use them for a second season since tubular tires are in short supply right now. Any reason not to treat the sidewalls now, in year two? I'm thinking of using a Gear Aid product called Seam Grip. Any other tips for extending the life of tubulars tires in their second year of use?

Eric

Also read: Tested: The fastest bicycle inner-tubes

Dear Eric,

Yay! Cyclocross season is again nigh, and I love questions about it. Here is the response from Cyclocrossworld founder Stu Thorne, who has run Team Cannondale/Cyclocrossworld for years and is as well-versed as anybody anywhere in sealing CX tire sidewalls:

"We never had much luck putting sealant on a used tire. I felt it was a bit of bandaid at that point, and trying to get another year out of a tire was not something we did very often, as we used fresh glue each year. Sealing a tire was always done when new and actually never done on a Challenge, as they used more latex on the sidewalls. The Dugasts we used years ago absolutely had to have sealant. So, I'd say try it if you want, and maybe it will prolong the life of the tire a bit, but I wouldn't expect much."

-- Lennard

Dear Lennard,

I read your articles from August 1st on thru axles coming loose. I have had this problem on two bikes, both have cam style thru axles. I believe I finally figured out why this is occurring. On both of the cam style thru axles, when the cam is fully open, the handle and the thru axle are locked, meaning if you turn the handle the thru axle rotates (of course a requirement for you to tighten the thru axle), however when the cam is closed the thru axle can rotate freely (I’m assuming it is designed this way to allow a person to close the thru axle then rotate the handle to their desired location).

Also, the knurled nut that the cam tightens against is not part of the thru axle. So, once the thru axle is tightened and locked, the actual thru axle can rotate while the cam lock and knurled nut stay in place. The thru axle off my Devinci gravel bike has some light groove worn into the right side of it. So, my theory is the freehub bearings may be developing some drag, and when I’m pedaling are causing the thru axle to loosen. Anyway, I’m curious if this sounds correct to you or do you think something else is causing the issue.

Tom

Dear Tom,
I had not thought of that before, and your reasoning makes sense. On a front axle, unless the hub bearings seized up, I can't see how this could result in the through axle loosening up. On the rear, though, I can see how the scenario you propose could result in the axle coming loose.

-- Lennard

Dear Lennard,

I can totally backup your response Mark’s question about flats from bits of wire . When I was commuting on a regular basis, I would get one of these flats at least once a year. My route passed through some industrial areas. The flats were never blow-outs but slow leaks. I had to use needle nose pliers to pull out the wires. The wire was never perpendicular but at an “almost tangent”.

I think these wires are “everywhere” and I think they get stuck on a tire and work themselves in.

Geoff

Dear Lennard,

I also have the misfortune of getting flats which are caused by thin metal wires. I believe these wires are nearly always the remnants of shredded car and truck tires. As such, they are typically steel/magnetic, so could their orientation on the road be vertical due to static charge? Just a thought, thank you for reading.

Stuart

Dear Stuart,

That's an intriguing thought. They're probably generally well-grounded on the road, thus dissipating the charge. In low humidity on concrete or asphalt, I imagine it's possible for there to be static charge standing them up after a dry tire passes over them.
-- Lennard

Dear Lennard,

My favorite thing about Technical FAQ is how an obscure random topic can draw more comments from readers and additional thoughtful analysis from you. While reading the latest question and answer on flat-causing steel wires (8/30/22), I was reminded of something I saw back in the early days of online cycling forums (Usenet newsgroups). The late Jobst Brandt was a presence there, both for writing authoritative explanatory posts and for not suffering fools gladly. He wrote that steel wires are more likely to cause rear flats, as the wire (or other sharp debris) can be kicked up by the front tire and then puncture the rear. (Source) I wanted to share that and see if this reasoning makes sense to you.

Keith

Dear Keith,
Cool! I have always gotten far more flats on the rear than on the front. I generally associated it with the higher load on the rear tire and often the higher level of tread wear on that tire. This is an interesting concept that the front tire might be flipping the sharp objects up for the rear tire to be impaled upon. Too bad Jobst is no longer with us to come up with pearls like this.

-- Lennard

Dear Lennard,

I read your piece today with great interest on the application of the Wolf Tooth Road Link to get greater gear capacity

I have a pair of 2015 ish road bikes with SRAM Red ETAP (not AXS). One is short cage with a 52/36-11-28, the other WIFLI with a 52/36-11/32. I’d love to get greater climbing ranges on the one (Shenandoah is right here…!) without sacrificing the 52-11 for those critical sprints. I know I can spend $700 to get an upgraded derailleur but that’s a lot of coin. Will the Wolf Tooth Road Link do that for me? Is there another alternative?

Don

Dear Don,

Yes, the Road Link will allow you to use a larger rear cog. Of course, the further you move the rear derailleur away from the cogs, the less crisply it will shift across the small cogs, so your shifting up during "those critical sprints" might suffer.

Other solutions? Well, you can often get your rear derailleur to accept another tooth or two on the largest cog by turning the b-screw in further. That, too, results in less snappy shifting across the small cogs due to the upper jockey wheel being further away from the cogs.

-- Lennard

Lennard Zinn (https://www.velonews.com/byline/lennard-zinn) , our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder and purveyor of non-custom huge bikes , a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”
He holds a bachelor's in physics from Colorado College.

Follow @lennardzinn

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