Stupid close tire [fixed]

I know I know I know - this tire is entirely too close to the frame. I’ll explain. We are looking at a Nimbus II 24" frame with two different tires. The smaller tire is stock, and the larger is a 24x2.5" Hookworm. Honestly, I’ve been riding it like this, and doing a lot of learning on it. The tire doesn’t actually touch the frame, and there is no friction. But, of course, it’s stupid close.

I loved having the larger tire so much that I went and grabbed a 27.5" Nimbus MUni, thanks to all of your advice. But I still ride the 24" and use it for learning purposes, etc. While the larger tire works, of course if I go through a mud puddle sometimes I get some build-up that then will cause friction.

It got me to thinking. Lets say I want to use this tire for a good long while; is there any reason to not file just a bit of the lower part of that frame? Making sure to not file into the welds, sticking only to the vertical tube extending below the joints.

Picture 1: The hash marks would represent what might be able to be filed away without risking the integrity of the structure too much.

Picture 2: Stupid close, but it works in the absence of mud haha.

Final product!:

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I’ve got a similar situation on a Nimbus 20” with a Duro something or other tire 2.4” wide. It can’t be inflated more than about 45 psi or it hits the frame. I haven’t gotten around to it yet, but next time the tire is out of the frame I’m going to do the filing that you are also thinking of doing. Just be sure to paint where you file so it doesn’t rust.

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Just, like, Rustoleum spray paint?

And thanks for the note!

Well, that would work but it will be a pain to mask the whole frame to paint a little spot. I would take some metal paint and primer two in one stuff from Rustoleum and spray it on a brush then just brush it on the exposed parts, at least that is what I do on similar applications as I don’t have any other paint suitable for metal that’s not in a spray can.

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I’ve done this on an old uni, just like you described it. Do not file down the welds and you should be fine.

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Thank you. I might Frankenstein this thing out and just burst spray the spot with something bright haha :smiley:

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So just my 2 cents as well but the hookworm doesn’t have a lot of tread. My understanding of stuff sticking to the tire is the more aggressive tread bites the ground for traction and the snow or mud packs between the frame and wheel. Because your tire is a skinny it won’t have as much issue for mud. So I’d say file away with the precautions mentioned above and stop when you get enough room for the tire

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Good note. Yeah, and most other alternate tires (skinny or not) are below the 2.5 width (for this diameter).

Pretty much, and realistically I find riding in mud and snow (at least with my 27.5" wheel) to be hard and not the most fun. I’d usually walk those sections and move faster. Or if the trails are really that muddy chances are you shouldn’t be in them and wait for them to dry.

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Use clear coat, forget painting the whole or part of the frame. I don’t paint my frames at all. Just spray protect it and ride.

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“Don’t file the welds” is a little naive. The material beyond the welds is also part of the strength. What is proposed to be removed will weaken the frame but probably not enough to matter that much.

Does the excess pipe below the fork help with structural stability? Maybe. We don’t need to get out the trigonometry and engineering textbooks for this one, I don’t think. Is the whole thing gonna crumple with me on it because the excess pipe is missing below the fork? Probably not. And if it does, we’ll have a funny picture and story haha.

My main reason for asking was mostly to see if there were any other unexpected repercussions. Sounds like its a fairly safe endeavor as long as I don’t get seriously overzealous with filing.

Thanks everyone :smiley:

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Overzealous filing sounds like a good name for a band.

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What I found with my Quax RGB and a 3.25” tire was that it would rub during hard climbs and it had much more clearance than your frame does. I will say that the steel Nimbus frames are built much stronger than the Quax RGB frames however. So perhaps that won’t be an issue for you.

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Not really. Every bit sticking out below the welds is dead material that does not receive a significant amount of stress.

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That was my thoughts. Or at least from first principles from college. The maybe was to leave room for any engineer armchair philosophy lol.

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This is the frame I filed down years ago for the tire in the background. We use it for our training group. Skinny tire for track & field, knobby tire for muni. I went really high in the middle, as the mid-knobs of the tire (I think it’s a Schwalbe Smart Sam) are protruding really high. Used no paint and no clear coat, still no problems.

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Thats awesome to hear. I just filed mine about an hour ago. I did give it a blast with Rustoleum (paint and primer in one). It’s not pretty, but it should be functional. I’ll share a picture when its together tomorrow.

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Here is the filed final product. I did use some Rustoleum spray that you can see. Wasn’t pretty, but I didn’t intend it to be:

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Looks good from here.

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