Tech Mailbag #2: Drip-on wax chain lube prep and bedding-in new disc pads

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Welcome to the CyclingTips Mailbag column, where you send us your tech questions, and our team of nerds gives you answers. Got a question about wheel and tire standards? Want to know how to diagnose that weird shifting issue? Wondering where that darn ticking sound is coming from?! Send your questions our way at tech@cyclingtips.com to be featured in an upcoming CT Mailbag column.

In this second edition, Dave Rome addresses the commonly asked question about prepping a new chain for drip-on wax chain lube, how to run Di2 on a frame that previously had mechanical shifting, and whether new disc brake pads need bedding-in in a previously bedded-in brake system. 


When preparing a brand new chain for a drip on wax lube (I just picked up a bottle of Squirt), how thoroughly do I need to remove the factory grease? I really can’t be bothered to get a jar of mineral spirits and do several flushes to remove the factory goo, but have gone over it with several baby wipes, which seems to have worked for the surface of the chain. I get that you really want to remove the grease from inside the rollers and wherever the baby wipe doesn’t reach.

Have I done enough? Can I apply lube and ride my bike now, or do I absolutely need to go the extra mile?

The chain is an XT 12-speed. I have several for both road and mountain bikes, so would rather not need to do a million extra steps each time I put on a new chain. Paging Dave Rome for this one. The internet seems to give me conflicting advice.

 — Rob Stein 

Hey Rob, 

You need to get the factory oil out from the inside of the chain before you can use a wax-based lube like Squirt. It’s what’s on the inside of the chain that actually matters, and so with the factory oil in place, the wax-based lube won’t adhere and will effectively be repelled away. The cleaner you get that chain to start with, the better a wax-based lube will perform. I have two suggested paths in this scenario.

Option one is to save the wax lube and just ride the factory oiled/greased chain until it breaks down, becomes obviously dirty and begins to wear off. At this point, you can degrease the chain while it’s still on the bike and then start using the intended wax lube. However, do note that with this method you’ll almost certainly attract more dirt into the chain early on and in turn cause wear on at least the chain coating and also progress into the chain elongation lifespan (in other words, you’ll cause an increased rate of chain wear versus if you were to use the wax lube from the start). 

Option two is to degrease the chain before first use and begin using Squirt straight away – this is absolutely what the likes of Zero Friction Cycling would suggest. You don’t need to get that chain sterile clean as if you were doing a submersion melt-on wax treatment, but you do need it far cleaner than what’s possible with baby wipes. You want to clean the chain until the chain rollers are floppy with no oil or grease acting as a damper. So for this, you could put the fresh chain on the bike, clean it with a really good degreaser, and then repeat once or twice until most of the stubborn factory oil is gone. This won’t remove all of the factory lube, but it’ll be good enough.

That all said, leaving the new and yet-to-be-installed chain to soak in a jar of mineral spirits or metal-safe degreaser overnight arguably remains the most effective and low-effort method. Just be careful of the hydrogen embrittlement that common household products such as regular Simple Green can cause in chains.

Cheers,

– Dave.

Hey CT tech crew,

Proud VeloClub member here! Do you actually have to bed in new brake pads, or just new rotors? My understanding is the purpose is to distribute brake pad material onto the rotor, and thus as long as you keep with the same material when replacing worn pads, all should be well (and in fact you should use dedicated rotors for metallic versus organic pads if I am not mistaken).

 — Clark Smithson

Hi Clark, 

You’re correct about the purpose of bedding in disc brakes and also that brake manufacturers officially recommend that you change rotors if changing to a different pad material. Unfortunately new rotors or not, it doesn’t change the need to bed in the new brake pad material. You can see an example of this through the loss of initial braking power when first installing a fresh set of pads on your old rotors. 

My process for installing new disc brake pads is to reset the braking system in order to greatly reduce the chance of contaminating the new pads from anything that may be on the rotor. I also treat pad replacement as a chance to do some strongly recommended preventive maintenance for the caliper seals. 

After removing the wheel, I’ll remove the old pads and clean out the caliper as best as possible. A tiny bottle brush and a bit of isopropyl alcohol are perfect for this, but even just flossing a clean rag through the caliper and between the pistons will suffice. 

I’ll then use a flat-shaped plastic tyre lever (Pedro’s is my pick for this) to carefully and slowly push the now-clean pistons back into the caliper bores. Pay close attention to keeping those pistons straight/square and not loading on an edge. On Shimano brakes with ceramic pistons (such as most road models), I’ll actually crack open the bleed port at the lever to ensure there’s no pressure against the delicate pistons. 

Before installing the new brake pads, I’ll drip a bit of clean water on them and rub them together. At first, you’ll feel they are quite slippery and then soon become grippier. Once there is a bit of resistance between the two pads, I’ll drip some more clean water on them to clear away the muck that has formed. This is a process I learned from a Downhill World Cup mechanic and the intention is to prime the surface of the pads in a way that reduces the bed-in time required. 

Now, clean the rotor with isopropyl alcohol (ensure the rag is clean) and install everything. If the caliper isn’t centred, I’ll re-align it while giving the lever a few squeezes as the pistons progress out to meet the rotor. 

Now, go ride and complete the bed-in procedure.  

And sorry that my suggestion has likely caused you more work, the exact opposite of your question’s intention!

– Dave.

Hi CT Tech team,

I recently upgraded my Canyon Endurace’s mechanical Ultegra to Di2. First, Canyon’s VCLS seatpost can’t fit the Di2 battery and the frames sold as mechanical don’t have the battery holder Canyon designed to mount near the bottom bracket, so I wrapped the battery in a bunch of bubble wrap and stored it in the down tube. So far it’s been quiet, but are there any issues I should be aware of in terms of moisture or rattling that would damage the battery?

Secondly, none of the mechanical grommets fit with the Di2 cables, so I left them out. That means there’s some holes in the frame where it looks like water could enter. Again, are there any problems that could develop with the BB (a Hambini press fit) or other components?

Thanks for your help!

 — Terence Patrick

Hey Terence,

You’re right that your version of the Canyon Endurace doesn’t offer the same battery holding facility as the Di2 version. While there are ways to mount the battery outside the frame, your chosen approach is likely the same path I would have taken as it’s the cleanest-looking option. However, there are a few things I’d watch for.

First, make sure the wrapped battery can’t bounce around inside the down tube. You shouldn’t be able to hear or feel it when shaking the bike. Second, I’d pay close attention to how the Di2 wire exits the battery to ensure that it’s not getting pinched against anything and that it’s not banging against the central press-fit bottom bracket sleeve. If it’s touching, I’d look to fashion a housing that reinforces the Di2 plug section and further protects the Di2 wire – this would be easy to fashion with a 3D printer but could also be achieved with some closed-cell foam. 

I wouldn’t be too stressed about moisture or vibrations as neither of those will be worse for the battery than the usual concealed positions. However, I would suggest looking at your handiwork after a truly wet ride or bike wash to ensure your method of padding isn’t holding onto or trapping excess moisture – that could be a problem long-term. 

As for the second part of your question, my advice would be to try to conceal those holes. Jagwire (also sold under SRAM branding) now offers a fairly extensive range of rubber frame plugs for this very purpose. You’ll need to measure the holes you’re trying to plug, but something like the 2.5 mm e-shift to 8 mm port plugs should be pretty close to what you need. Shimano also offers similar Di2 frame plugs but in a far more limited size range. 

– Dave.

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