General question:

The rear tire of my mtb runs too close to the chainstays. If the trail is even remotely muddy, the mud buildup on the chainstay clogs the front derailleur and the chain begins to skip/drop. What can I do to remedy the situation, preferrabli without going to skinnier tires.

More details on the problem:

This is a custom build of Bontager XR4 2.35 tires on Mach1 MAD 25C rims, mounted on a Dartmoor Hornet frame. The problem is that the seat stays are WIDER than the chain stays. Consequently, any accumulated mud instead of getting scraped off harmlessly by the seat stays and falling to the side, gets trapped onto the chainstays and into the front derailleur.

PS: Please refrain from comments on not riding muddy trails - I know I would errode them! My riding is XC marathon type, with a few muddy sections around a lake and some streams.

  • I was not sure about tags, if you find any suitable, pelase add. Also, creating tag mud. If not needed, feel free to remove it. – Vorac Jun 3 '15 at 11:59
  • Lizard Skins sells (sold?) a product called "Grunge Guard" for this. – Batman Jun 3 '15 at 21:45
  • @Batman, that's nice, but wouldn`t work. The mud builds up in the way of the chain and derails it to the outside! – Vorac Jun 4 '15 at 6:37
  • My Cyclocross also gets completly clogged (abload.de/img/imgp1682m4dha.jpg) but I never had any FD shifting problems. Are you sure it’s properly adjusted? Maybe a chain catcher would help? – Michael Jul 4 '15 at 6:31
  • Find anything for this yet? – BPugh Sep 1 '15 at 19:38

How about a DIY route by making a tire scraper mounted to the seat stays? Use a old milk jug or some other sturdy plastic cut to fill the space between the seat stays. Put a notch (with some gap obviously) in it to slide down around the tire. Zip tie it in place and go.

The milk jug plastic probably won't hold up by itself (but maybe layers or a zip tie running between the stays for a brace), but it is a starting point (or a good template). Plastic may get too brittle when cold, but you could try some cheap washable plastic plates (dollar store fine dining, not the throw away kind). Maybe those "for sale" signs (paint it or turn it around face down, don't want to get bugged). Just about any flat piece of it that will lay on the stays, and easy to shape.

I thought about a metal solution but I'm not a fan of sharp edges, and it may weigh more. I'm not a metal worker so I couldn't tell you if filing would work well enough. An old license plate (with painted numbers instead of raised), some discarded duct work, cookie/popcorn gift tin (ah, they do have a purpose!).

Make a note how far the wheel comes up the seat stays (mark with some painters tape), then take it off. Take some heavy paper and template it out. Shape it to lay on the stays without sticking out too far (or fit between them, your choice) and have it go past the wheel mark. Mark out the space the wheel will need. Take it to your material and cut it out, drill out some holes for zip ties, and attach. I bet it wouldn't take more than an hour to get a good enough solution.

This is a close idea to what I'm thinking. Here is a photo search of the bridge between the blades of a front suspension fork. In these the tire is really close to it. Now imagine creating this and putting on the back tire.

  • I was thinking in these lines. Some questions: 1. wouldn't the plastic of the jug just bend in the way of the sticky mud? 2. Do you have any link to a picture of something similar, along with the seps to construct it and the pitfalls to avoud? – Vorac Jun 3 '15 at 12:54
  • @vorac I updated my answer to address your questions. This is an idea I had pop in my head and it sounds like it is a simple, cheap, and easy thing to try. Feel free to edit my answer with photos of what you did. – BPugh Jun 3 '15 at 16:14

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