Handling with 35 mm rear / 23 mm front tire combo

[Anthony DeLorenzo]

Would running a rear tire that is much wider than the front cause any
handling issues?

By way of explanation, I am thinking about entering a time trial this
week on my fixed gear commuter. (I have a choice between that or my
singlespeed mountain bike.) It's a short event consisting of a 3.5 km
course where the first 2.0 km is a long downhill.

In order to have any chance of surviving the downhill, I plan to gear
up from 60 to 90 inches on my fixed. (36x16 to 50x15). However, I'm
not totally confident in the rear wheel standing up to me trying to
push that big a gear. I'm 6'6" 250+ lbs and can really power the
pedals when I try to. I am planning to build a new rear wheel but at
the moment I just use an old touring wheel converted with a Surly
Fixxer.

My MTB rims use a flip-flop hub, so I was thinking of throwing a cog
on that wheel and swapping on a slick tire. However, it's a very wide
rim and the best road tire I have available would be a 35 mm.

I know that mixing tire widths is common, but I would like to know if
this large difference would cause any issues with bike handling,
particularly at speed when I am trying to furiously spin a fixed gear.
The last thing I want to do is crash at 50 km/h. Any thoughts or
experience welcome.

Regards,
Anthony

[catzz66]

Anthony DeLorenzo wrote:
> Would running a rear tire that is much wider than the front cause any
> handling issues?
>
>

Sounds interesting. Please post some photos somewhere if you do it.

[Chalo]

Anthony DeLorenzo wrote:
>
> Would running a rear tire that is much wider than the front cause any
> handling issues?
>
> By way of explanation, I am thinking about entering a time trial this
> week on my fixed gear commuter. (I have a choice between that or my
> singlespeed mountain bike.) It's a short event consisting of a 3.5 km
> course where the first 2.0 km is a long downhill.
>
> In order to have any chance of surviving the downhill, I plan to gear
> up from 60 to 90 inches on my fixed. (36x16 to 50x15). However, I'm
> not totally confident in the rear wheel standing up to me trying to
> push that big a gear. I'm 6'6" 250+ lbs and can really power the
> pedals when I try to. I am planning to build a new rear wheel but at
> the moment I just use an old touring wheel converted with a Surly
> Fixxer.
>
> My MTB rims use a flip-flop hub, so I was thinking of throwing a cog
> on that wheel and swapping on a slick tire. However, it's a very wide
> rim and the best road tire I have available would be a 35 mm.
>
> I know that mixing tire widths is common, but I would like to know if
> this large difference would cause any issues with bike handling,
> particularly at speed when I am trying to furiously spin a fixed gear.
> The last thing I want to do is crash at 50 km/h.

My first inclination is to observe that any wheel that holds up for
you on the street, will hold up in a race. _You_ can feel your
muscular effort imposing stresses on the bike, but the biggest forces
on the bike are probably not from your pedaling. If you are planning
on thrashing the bike way over from side to side while stomping on the
pedals, just don't do that. (I don't assume that's necessarily what
you had in mind.) A smooth, well-controlled riding style that keeps
your wheels pointed in the same direction is faster, even if it
doesn't feel like you're working as hard.

Second, I want to be clear that you are talking about a 29" MTB wheel
and not a smaller wheel size. You _can_ put a smaller sized wheel on
the rear of a fixie, but that's generally not a good idea. A smaller
diameter rear wheel will cause steering flop at anything other than
very high speeds, and the lowered bottom bracket may contribute to
pedal strike.

If you are using the same rim diameter for the wider rear wheel, then
the 10mm or so axle height difference between a 700x23 and a 700x35
should not cause ill effects on handling (though there might be a
noticeable difference in feel at the bars).

Chalo

[Anthony DeLorenzo]

On Jul 25, 6:35 pm, Chalo <chalo.col...@gmail.com> wrote:

> My first inclination is to observe that any wheel that holds up for
> you on the street, will hold up in a race....

I have been re-thinking it over the last couple of days and I think
I'm leaning that way. I've been trying to push the bike a bit while I
am riding around town and it seems to handle it OK, so I may just
stick with the current wheel.

> Second, I want to be clear that you are talking about a 29" MTB wheel
> and not a smaller wheel size. You _can_ put a smaller sized wheel on
> the rear of a fixie, but that's generally not a good idea.

Definitely, I run 700C on both road and mountain bikes. I try to use
the same components as much as possible across both so I can share
parts easily.

Regards,
Anthony