The bottom bracket and the downtube of my bicycle (these parts are very wide on E-bike, to accommodate the battery and the engine) get dirty much faster than the rest of the frame and, unlike tires, they do not self-clean. In the place where I park the bicycle, this is for me a problem, I need to wash it often. I have a non-tarmac section on my way of commuting I cannot easily navigate around.

The solutions I am currently using are:

  • Fenders, front and rear. These arrived with the bicycle and look reasonably serious.
  • Flexible fender extender on the front. It helps but it gets very dirty itself, and is very visible.

Is it possible to take any more action against the sticking dirt, like maybe some chemical repellent or basically anything?

5 Answers 5


In short: Yes.

Just like for cars there are many cleaning/detailing products like waxes/polishes that peel off water more easily and make dirt less sticky.

However, there are limits to these products and even with the best nano-coating you can't expect your bike to be immune to dirt. Especially in the areas around the downtube/BB and rear triangle where dirt gets thrown up from the tires, stuff usually sticks the most because of the rotational forces from the wheel...

You probably have to try one of these products and see if it makes a difference. I can only speak of products for drivetrain cleaning/lubrication and depending on your typical riding conditions, the right product makes a huge difference (with all its advantages and disadvantages, indeed).

  • In reply to the other user calling this "optimistic".... the right product will make water peel off more easily and that probably helps with light pieces of dirt sticking to the frame less likely too, but if your problem is that you have to bring your bike into a "clean" space right after riding in bad conditions, you'll still have water drops coming off, even if reduced amounts and leaving less watermarks or dirt stains when using water-repellant products. So, it not as if you're getting a bike that stays 100 percent clean and dry from bad conditions with any product, I'm afraid....
    – DoNuT
    Commented May 24, 2023 at 6:25
  • 1
    Perhaps I should add: If you just need to make sure that dirt and water from your bike doesn't drip to the floor in the place it is regularly parked, a good old towel or some other old cloth to wipe off excess dirt might be the pragmatic solution. I don't do it for that purpose, but I keep a cloth around to wipe the chain dry when riding in wet conditions.
    – DoNuT
    Commented May 24, 2023 at 7:24
  • I see many products that are marketed more for the chain but it is written "creates water and dirt repelling wax cover". On small area of the black frame, may even not be important if adds some tint of its own. Will try.
    – nightrider
    Commented May 24, 2023 at 7:55
  • @nightrider I just noticed that you have an e-bike, so some part of the BB will actually be the motor's plastic cover, so make sure that whatever product you are using isn't damaging the material, some stuff might not stick on a rough plastic cover. I wouldn't waste too much money on a set of products, maybe a patch of something like 3M Protective tape (I think it is called "helicopter tape") in the right areas might also help and probably doesn't even stand out if applied properly, especially in hidden areas like the downtube/BB.
    – DoNuT
    Commented May 24, 2023 at 8:12
  • And finally just dumping some related YT videos Ceramic coating @ GCN: youtube.com/watch?v=LiRE4A855dY 3M tape hack: youtube.com/watch?v=P2Lehw-SaB4
    – DoNuT
    Commented May 24, 2023 at 8:15

All be it not so much for a commuter, but have had some success with just a simple can of silicone spray. After cleaning my bikes, I spray it on a clean cloth, then simply wipe the down tube down. Not perfect, but do notice the difference when I'm too lazy.


For non-regular rides, some pre-planning by wrapping the downtube in plastic wrap might be a workable solution. Just peel off the wrap at your destination. However, this would take up your time (not to mention the environmental aspects) for daily commuting. In that case, an automotive paint protection treatment would help. You can get wipe-on or spray-on products which leave a dirt-repelling film.


I'm afraid there's not so much more that what you are currently doing that can be done, if your goal is that your bike doesn't look dirty.

Fenders are the only mean to prevent the mud from getting there at the first place, having properly fitted fenders with sufficient coverage can improve the situation. While the fender/extension is covered by the question, fender fit doesn't seem to be addressed. I had a look at your questions history and it looks like a suboptimal fender fit may "aggravate" the problem in your case: while your bike (Winora Yucatan Pro?) is fitted with high quality fenders (Curana Apollo), the pictures suggest that they are not optimally dimensionned: your bike is fitted with 27.5" wheels, and the fenders look like they are designed for 29" wheels (and do not cover enough of the front wheel). Having better fitted fenders won't improve dramatically the situation but can definitely be an improvement - especially if they go lower than what you have. Unfortunately, it's very hard properly fitted fenders for 27.5" wheels, especially with wide tires (the only bike I've seen that would match my definition of good fenders with 27.5"in wheels is the 2023 Canyon Pathlite:ON, but Canyon doesn't sell these fenders separately.

A DIY solution can also be to mount "ass savers" as fender extensions, if no extension is proposed by the fender manufacturer, as proposed by GCN.

There's the option to fit protective (hydrophobic) film on the painted parts of the frame, to avoid that the dirt sticks directly on the pain, but that doesn't really help in the context of commuting, as you would need to clean the bike when you arrive at work to avoid that the mud dries. The motor wouldn't be covered as well.

  • What are ass saver fensder extensions?
    – gerrit
    Commented May 24, 2023 at 8:07
  • @gerrit: ass savers are thick plastic sheets usually mounted on saddles or seat post to avoid direct projections from the wheel on the ass/back. The proposition of GCN is to mount them on fenders as prolongation.
    – Rеnаud
    Commented May 24, 2023 at 8:11
  • @Renaud I also thought of the GCN hack (or is it a "bodge" by their own terms?^^) but I wouldn't drill holes in my original fenders, however, the concept makes sense ... fenders usually end at the 9 o'clock position and that leaves some space for spray. Only some radonneur-style bikes seem to have wider fenders just for that purpose, but maybe there is a intermediate solution with neutral ass-saver colors and using a rubber band or just tape them on with double-sided tape....
    – DoNuT
    Commented May 24, 2023 at 8:54
  • @DoNuT in the original ones, I would not do it as well, but on a aftermarket ones why not (although I would rather directly buy randonneur style ones to start with, if it's possible). I would not however rely on glue on this area of the bike, it's on of the muddiest ones, and more subject to vibration than a (partially) suspended frame for instance.
    – Rеnаud
    Commented May 24, 2023 at 9:24

The accepted answer seems a bit optimistic, it is better to get down to earth. I mean literally, have a look at the ground, pollution from car exhausts that slowly deposits on the road, dust release by the tyres the occasional drop of lubricant. All of this makes an oily soot that can be quite sticky. Hydrophobic repellents repulse water, but they might mix happily with the oily soot coming from the ground.

  • 3
    This sounds more like a comment to me, or are you proposing a alternative answer here somewhere?
    – Hursey
    Commented May 23, 2023 at 20:48
  • I would like to add that I did indeed keep it pretty generic but generally, that's the OPs only option. Did mention any of the plenty GCN cleaning videos where they get excited about nano-coating and didn't even suggest any of the obvious Muc-Off products, just a generic answer leading into the right direction, not having the time for any specific recommendations because the staff at his LBS etc. could definitely give better advice on specific products. I clearly mentioned that there are limits, so a bit of nano magic won't make everything peel off nicely, but it helps.
    – DoNuT
    Commented May 24, 2023 at 6:19
  • @Hursey The reasonable alternative is: do not believe marketing.
    – FluidCode
    Commented May 28, 2023 at 7:41

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