650B for more mud clearance? and mud problems.

The spirit of Grav-lo-cross. No but seriously, cyclocross and gravel go here!

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PoorCyclist
Posts: 783
Joined: Wed Dec 07, 2011 1:26 am
Location: California's country side

by PoorCyclist

Winter is here and it is a little muddy, I noticed a big limitation of "Gravel" bike.

It is a 700x40mm tire and I can barely put a 4mm wire or hex key between the tire and driveside chainstay. The non-drive side have more clearance. It is a aluminum frame multiple pieces welded at the chainstay, I wasn't sure if I got a bad frame or not, shop told me it's asymmetrical chainstays, but the chainring have more than enough space everywhere. Could not find another same bike to compare.

About every 20 pedal strokes I had to dismount an pick the mud out of there or it will grind the frame, so basically it is un-ridable?
Asking for mercy if transition from mud to tiny gravel, the wheel look like a sprinkle donut and except the spinkle are rocks and ouch, the frame. I actually just lifted the bike back.

If I get a 650B wheels, it is 1.5" smaller, so it would put the rim about 0.75" back. Mine actually have a weld back there, But it would be hard to say without an actual test fit. The other thing is 650B of that tire is usually a bit wider, like 42 or 46mm.
Would I make it double safe to go with 650bx38mm tires? Since the whole tire has a layer of mud on it, the style of tire almost doesn't matter.

The other consideration is lowering the BB by 0.75" as the gravel bike is already low to the ground. It does not sound like a good thing.

Also intersted in 650b for easier climb. Sticky mud doesn't seem to have traction problem but it is very hard to climb.

Do you know of other tricks? Lower tire pressure so the tire is smaller? Put grease on the side of tire and chainstay? Get a MTB?

Karvalo
Posts: 3444
Joined: Fri Aug 10, 2018 6:40 pm

by Karvalo

PoorCyclist wrote:
Sun Nov 07, 2021 12:46 am
Winter is here and it is a little muddy, I noticed a big limitation of "Gravel" bike.
That's a limitation of "your" gravel bike. There are plenty of others that have much bigger clearances there.

Instead of going to a 650 wheel and smaller tyre with all the bb/pedal issues that come with that, why not put a 33mm mud CX tyre on your current wheels? If it's sticky enough mud it will still build up enough to fill the space eventually but you won't be grinding the frame. Similarly any size tyre in the same mud will become a sprinkle donut when you go back onto the gravel, so all those stones flying off and hitting your bike is just something you'll need to deal with if you ride that route in the winter, unless you fit full mudguards.

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PoorCyclist
Posts: 783
Joined: Wed Dec 07, 2011 1:26 am
Location: California's country side

by PoorCyclist

That's what I am leaning towards 700x33 mud.
I measured the current tires and they are 42 actual mm and going to 33 will have 35mm actual and that will free up 3.5mm each side and from what I saw will clear the chain stay with that clearance.

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