Stupid tire clearance question

[cribbit]

https://imgur.com/03Lx8mH.png

This is with a tire that matches the rear. 700c wheel, 35c tire (38 as inflated). The fork is already a smidge larger than it's supposed to be, putting a bigger tire as is would jack it up even more.

If I put a 650b wheel on the wheel radius goes down 38mm - 622 -> 584. That should be able to be made up by a 19mm larger tire.

If I do something stupid like putting a 650b wheel with a 55-60c tire do you think I'll have good results? Or would that be really dumb?

For reference, the rear clearance: https://imgur.com/a/4rpypn4

[marciero]

Are you saying that the fork axle-to-crown is greater than what was spec'ed, and you want to put a 650b wheel only on the front in part to offset the front being higher than it was designed to be? Would be more of a hack than a proper way to mitigate this issue.
I would just get the proper fork, or ride as is.

[cribbit]

Are you saying that the fork axle-to-crown is greater than what was spec'ed, and you want to put a 650b wheel only on the front in part to offset the front being higher than it was designed to be? Would be more of a hack than a proper way to mitigate this issue.
I would just get the proper fork, or ride as is.

Sorry, should've been more clear.

I hate the aesthetics of having much more clearance available than used. I also really like big tires. Since the geo is already slightly adjusted I don't want to skew it further. Is a smaller wheel with a bigger tire a really dumb, sort of dumb or not actually that dumb way of dealing with this?

[R3awak3n]

Personally Id just ride it like that, cant see gap while you ride it. You could put a big tire in the front but probably not great on pavement compared to what you have now. However big tire in front and smaller in back would work great for some gnarly gravel. Front tire more important in the loose stuff.

Personally noy a fan of big 650s on the road. They ride fine but prefer 709

[skouri]

Add fender 😀 seriously tho I think it will look fine once on the bike and hopefully you won't be looking at it while riding (unless flying over the bars) even for a BAAW cafe shot it really shouldn't be obvious. I would leave it personall

[happycampyer]

Given that 650B x 42mm is roughly the same diameter as 700C x 23mm, then I think all you will have is a tire that is roughly the same OD as the current wheel, but with less clearance to the fork legs. I too vote to ride it as is—proper geometry and ride characteristics should trump aesthetics. Out of curiosity, if the current tire is already bigger than what was spec’ed, why was the bike spec’ed with a fork with so much clearance?

[Brian Smith]

Sorry, should've been more clear.

I hate the aesthetics of having much more clearance available than used. I also really like big tires. Since the geo is already slightly adjusted I don't want to skew it further. Is a smaller wheel with a bigger tire a really dumb, sort of dumb or not actually that dumb way of dealing with this?

It's like you're thinking...if not exactly as you've written. Don't get confused in your math when alternating between radius and diameter. You can get your larger tire on a 650b rim in there with the same overall diameter, and although your head tube will remain in a different location from the bike's original design, as it would still have the longer fork, and you will still have your detested clearance between the top of the tire and the crown of the fork, the chunky tire would however make the whole assembly including the gap look "better" or at least a bit more traditional.

If you're not concerned about how the whole assembly looks, and you really just want to fixate on the space between the tire and the fork crown, you've got no other choice than to fill that space up with tire, which means sticking with 622 or going to 630, either of which further affects your geometry. If you really want to fix all of that while eliminating your detested gap, you could instead get an even larger diameter 584 tire and a shorter fork, and with proper selections you can even get your head tube back where it was originally supposed to be. Your trail will still be changed from the original design, but perhaps you can, in more than one sense, own that.

[cribbit]

It's like you're thinking...if not exactly as you've written. Don't get confused in your math when alternating between radius and diameter. You can get your larger tire on a 650b rim in there with the same overall diameter, and although your head tube will remain in a different location from the bike's original design, as it would still have the longer fork, and you will still have your detested clearance between the top of the tire and the crown of the fork, the chunky tire would however make the whole assembly including the gap look "better" or at least a bit more traditional.

If you're not concerned about how the whole assembly looks, and you really just want to fixate on the space between the tire and the fork crown, you've got no other choice than to fill that space up with tire, which means sticking with 622 or going to 630, either of which further affects your geometry. If you really want to fix all of that while eliminating your detested gap, you could instead get an even larger diameter 584 tire and a shorter fork, and with proper selections you can even get your head tube back where it was originally supposed to be. Your trail will still be changed from the original design, but perhaps you can, in more than one sense, own that.

Thanks for the tips.

I'm not as worried about crown space, just side to side space.