Front/rear flat ratio

[me]

Is it everyone's experience that rear road tires get flats while riding more
often than front ones? It sure is mine, and I wonder why. Seems like the
front should go flat more since it's the first to encounter the sharp
objects. Anyone care to theorize?

Not that I mind the ratio...I'd much rather have a rear than a front tire go
flat on me.

Cal

[Brian Huntley]

Not if you're fixing it yourself in the rain.

But it's very close to 2:1 rear:front for me. The theory is the front
wheel throws up things that had been lying flat.

[Phil, Squid-in-Training]

me wrote:
> Is it everyone's experience that rear road tires get flats while
> riding more often than front ones? It sure is mine, and I wonder
> why. Seems like the front should go flat more since it's the first
> to encounter the sharp objects. Anyone care to theorize?
>
> Not that I mind the ratio...I'd much rather have a rear than a front
> tire go flat on me.

Jobst says it's because the front wheel kicks up the penetrating agent right
before the rear wheel runs over it. Envision a nail on its side, spun about
with angular velocity omega. If it is kicked up just right, the nail will
spin 90 or 270 degrees around orthogonal to the plane of the road, and say
hi to the rear tire. That's an instant goner. With glass, it becomes
embedded until a few revolutions later when it's forced past the tire casing
and into the tube. SSSssSSSssSSsssSSssSSssSSss goes the tube.

--
Phil, Squid-in-Training

[Sorni]

me wrote:
> Is it everyone's experience that rear road tires get flats while
> riding more often than front ones? It sure is mine, and I wonder
> why. Seems like the front should go flat more since it's the first
> to encounter the sharp objects. Anyone care to theorize?

It's because the rear wheel is a bit bigger PITA to remove. (That's also
why more drive-side spokes break than non-d-s.)

HTH, Realist Bill

[Werehatrack]

On Sat, 18 Mar 2006 20:30:47 -0800, "me" > wrote:

>Is it everyone's experience that rear road tires get flats while riding more
>often than front ones? It sure is mine, and I wonder why. Seems like the
>front should go flat more since it's the first to encounter the sharp
>objects. Anyone care to theorize?
>
>Not that I mind the ratio...I'd much rather have a rear than a front tire go
>flat on me.

Unless you're on the brakes, the rear tire has more weight on it;
that's the important factor in my opinion.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

[Ron Ruff]

Whatever the reason my ratio has been at least 5:1... maybe 10:1... I
seem to always get a flat in the rear tire. Front tire kicks stuff up
that then gets embedded in the back one, more weight on the back...
plus it may be related to fact that I wear out rear tires at least 3
times as fast as the fronts... driving and squirming forces may also
help embed sharp objects.

[John Forrest Tomlinson]

On Sat, 18 Mar 2006 20:30:47 -0800, "me" > wrote:

>Is it everyone's experience that rear road tires get flats while riding more
>often than front ones? It sure is mine, and I wonder why. Seems like the
>front should go flat more since it's the first to encounter the sharp
>objects. Anyone care to theorize?

More weight on the rear tire.

JT

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[(PeteCresswell)]

Per me:
>Is it everyone's experience that rear road tires get flats while riding more
>often than front ones? It sure is mine, and I wonder why. Seems like the
>front should go flat more since it's the first to encounter the sharp
>objects. Anyone care to theorize?

Based on MTB experience, I think it's the added weight.

The idea about the front wheel throwing the object so that it penetrates the
rear wheel sounds logical for a road situation, but most of my MTB punctures are
from thorns...so the "throwing" effect is not there and my rear tire flats
noticeably more often than the front.

When I rode on the road a lot, many of my flats were shards of glass that worked
their way deep enough into the tire to finally puncture the tube. Seems like
that process is accelerated by lots of weight on the tire...
--
PeteCresswell

[Sorni]

(PeteCresswell) wrote:
> Per me:
>> Is it everyone's experience that rear road tires get flats while
>> riding more often than front ones? It sure is mine, and I wonder
>> why. Seems like the front should go flat more since it's the first
>> to encounter the sharp objects. Anyone care to theorize?
>
> Based on MTB experience, I think it's the added weight.

But don't you tend to pinch-flat the front at least as often as the rear due
to bashing into rock edges and stuff? I can minimize that if I /see/ the
obstacle in time to unweight the front wheel, but on some trails it's
practically unavoidable (at least for my ham-footed skills). You're right,
though, then the REAR tire often takes the hit, and pssssssttt...

> The idea about the front wheel throwing the object so that it
> penetrates the rear wheel sounds logical for a road situation, but
> most of my MTB punctures are from thorns...so the "throwing" effect
> is not there and my rear tire flats noticeably more often than the
> front.

Same here. I often can steer around a thorny patch or whatever, but the
rear wheel rolls right through it.

> When I rode on the road a lot, many of my flats were shards of glass
> that worked their way deep enough into the tire to finally puncture
> the tube. Seems like that process is accelerated by lots of weight
> on the tire...

Yup.

Bill "hit a nasty glass field other day, but Pro Races ain't flat (yet)" S.

[(PeteCresswell)]

Per Sorni:
>But don't you tend to pinch-flat the front at least as often as the rear due
>to bashing into rock edges and stuff?

I've only pinch flatted once so far. I'm about 220#, run my tires at 35-40
PSI; but I use fairly high-volume tires (WTB Mutano Raptors size 55/55).

OTOH, my skill level is somewhere between beginner and pathetic and if there's a
choice between a technical route and an easy route I'll take the easy route
every time... so there may not be as many challenges to the tires as with
somebody else.
--
PeteCresswell

[Neil Brooks]

On Sun, 19 Mar 2006 00:55:29 -0500, "Phil, Squid-in-Training"
> wrote:

>me wrote:
>> Is it everyone's experience that rear road tires get flats while
>> riding more often than front ones? It sure is mine, and I wonder
>> why. Seems like the front should go flat more since it's the first
>> to encounter the sharp objects. Anyone care to theorize?
>>
>> Not that I mind the ratio...I'd much rather have a rear than a front
>> tire go flat on me.
>
>Jobst says it's because the front wheel kicks up the penetrating agent right
>before the rear wheel runs over it. Envision a nail on its side, spun about
>with angular velocity omega. If it is kicked up just right, the nail will
>spin 90 or 270 degrees around orthogonal to the plane of the road, and say
>hi to the rear tire. That's an instant goner. With glass, it becomes
>embedded until a few revolutions later when it's forced past the tire casing
>and into the tube. SSSssSSSssSSsssSSssSSssSSss goes the tube.

I totally subscribe to--but hate--that theory.

A few months ago, riding straight line on a city street, I had a rear
blowout. Turns out, I hit a difficult-to-see replacement blade for a
utility knife--one of those trapezoidal-shaped deals.

It must have been laying flat, but the front tire set it up on some
measure of acute angle just enough to slice perfectly perpendicularly
through the rear tire. Game over.

Luckily, I knew of an LBS about two blocks away ... though I *did* ask
them if this was their little marketing scheme ;-)

[Zog The Undeniable]

Sorni wrote:

> It's because the rear wheel is a bit bigger PITA to remove. (That's also
> why more drive-side spokes break than non-d-s.)

I was going to post "Sod's Law", but you beat me to it ;-)

[Phil, Squid-in-Training]

Sorni wrote:
> (PeteCresswell) wrote:
>> Per me:
>>> Is it everyone's experience that rear road tires get flats while
>>> riding more often than front ones? It sure is mine, and I wonder
>>> why. Seems like the front should go flat more since it's the first
>>> to encounter the sharp objects. Anyone care to theorize?
>>
>> Based on MTB experience, I think it's the added weight.
>
> But don't you tend to pinch-flat the front at least as often as the
> rear due to bashing into rock edges and stuff? I can minimize that
> if I /see/ the obstacle in time to unweight the front wheel, but on
> some trails it's practically unavoidable (at least for my ham-footed
> skills). You're right, though, then the REAR tire often takes the
> hit, and pssssssttt...

I ran 15psi during a flattish MTB race with 2.0 tires and dented my rim
slightly on a root, but didn't pinch the ultralight tube, probably because
I'm 135lb. This was on a full rigid SS. It was sweet though because I got
4th out of 8 in the men's collegiate Bs, but that's only because the course
was flat and somewhat technical. If there are any long, straight uphills,
I'm out. Plus, it was an easy bike to hop due to the 19lb weight.

>> The idea about the front wheel throwing the object so that it
>> penetrates the rear wheel sounds logical for a road situation, but
>> most of my MTB punctures are from thorns...so the "throwing" effect
>> is not there and my rear tire flats noticeably more often than the
>> front.
>
> Same here. I often can steer around a thorny patch or whatever, but
> the rear wheel rolls right through it.
>
>> When I rode on the road a lot, many of my flats were shards of glass
>> that worked their way deep enough into the tire to finally puncture
>> the tube. Seems like that process is accelerated by lots of weight
>> on the tire...
>
> Yup.
>
> Bill "hit a nasty glass field other day, but Pro Races ain't flat
> (yet)" S.

--
Phil, Squid-in-Training

[G.T.]

Ron Ruff wrote:
> Whatever the reason my ratio has been at least 5:1... maybe 10:1... I
> seem to always get a flat in the rear tire. Front tire kicks stuff up
> that then gets embedded in the back one, more weight on the back...
> plus it may be related to fact that I wear out rear tires at least 3
> times as fast as the fronts... driving and squirming forces may also
> help embed sharp objects.
>

I get pinch flats on the rear (which hasn't happened in years) and
puncture flats on the front. The front tire never seems to kick stuff
up, whatever it runs over seems to stick in it. So at this point I get
probably 20 front flats to 1 rear flat.

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

[Ron Ruff]

G.T. wrote:
> I get pinch flats on the rear (which hasn't happened in years) and
> puncture flats on the front. The front tire never seems to kick stuff
> up, whatever it runs over seems to stick in it. So at this point I get
> probably 20 front flats to 1 rear flat.

I haven't gotten a pinch flat in a long time... I guess I know where
all the potholes are by now. Still, I get all the flats on the rear...
including one yesterday. I ride through a lot of glass and debris...
when the alternative is playing chicken with 18 wheelers...

[Werehatrack]

On Sun, 19 Mar 2006 08:03:41 GMT, "Sorni" >
wrote:

>me wrote:
>> Is it everyone's experience that rear road tires get flats while
>> riding more often than front ones? It sure is mine, and I wonder
>> why. Seems like the front should go flat more since it's the first
>> to encounter the sharp objects. Anyone care to theorize?
>
>It's because the rear wheel is a bit bigger PITA to remove. (That's also
>why more drive-side spokes break than non-d-s.)

Note also the number of bikes built with a QR on the front but not the
back. And, last night, a special award to the rear brake with the
nearly frozen cable that made the whole process just that much more
special.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

[Michael Press]

In article >,
"(PeteCresswell)" > wrote:

> Per me:
> >Is it everyone's experience that rear road tires get flats while riding more
> >often than front ones? It sure is mine, and I wonder why. Seems like the
> >front should go flat more since it's the first to encounter the sharp
> >objects. Anyone care to theorize?
>
> Based on MTB experience, I think it's the added weight.
>
> The idea about the front wheel throwing the object so that it penetrates the
> rear wheel sounds logical for a road situation, but most of my MTB punctures are
> from thorns...so the "throwing" effect is not there and my rear tire flats
> noticeably more often than the front.

Why is the throwing effect not active for off-road riding?

[...]

--
Michael Press

[Phil, Squid-in-Training]

Michael Press wrote:
> In article >,
> "(PeteCresswell)" > wrote:
>
>> Per me:
>>> Is it everyone's experience that rear road tires get flats while
>>> riding more often than front ones? It sure is mine, and I wonder
>>> why. Seems like the front should go flat more since it's the first
>>> to encounter the sharp objects. Anyone care to theorize?
>>
>> Based on MTB experience, I think it's the added weight.
>>
>> The idea about the front wheel throwing the object so that it
>> penetrates the rear wheel sounds logical for a road situation, but
>> most of my MTB punctures are from thorns...so the "throwing" effect
>> is not there and my rear tire flats noticeably more often than the
>> front.
>
> Why is the throwing effect not active for off-road riding?

If Pete is referring to thorns still on a branch or bush, then the branch or
bush wouldn't get thrown around from the front tire running over it. A
single detached thorn, maybe, but not the whole branch.

--
Phil, Squid-in-Training

[(PeteCresswell)]

Per Phil, Squid-in-Training:
>If Pete is referring to thorns still on a branch or bush, then the branch or
>bush wouldn't get thrown around from the front tire running over it. A
>single detached thorn, maybe, but not the whole branch.

Typically old dried-up raspberry fronds laying out of sight under a thin
covering of other stuff...
--
PeteCresswell

[me]

"Neil Brooks" > wrote in message
...
> I totally subscribe to--but hate--that theory.
>
> A few months ago, riding straight line on a city street, I had a rear
> blowout. Turns out, I hit a difficult-to-see replacement blade for a
> utility knife--one of those trapezoidal-shaped deals.
>
> It must have been laying flat, but the front tire set it up on some
> measure of acute angle just enough to slice perfectly perpendicularly
> through the rear tire. Game over.
>
> Luckily, I knew of an LBS about two blocks away ... though I *did* ask
> them if this was their little marketing scheme ;-)

Responses have been interesting so far - most are having many more rear
flats than front ones. The only front "blow-out" I can recall involved
riding over an unseen car wheel weight. It was apparently lying
perpendicular to my direction of travel with the steel tab that crimps it
onto the wheel rim sticking up - cut through my tire and tube like a knife.
Had a spare tire and tube on me though, so I was rolling again in 15 min.

Cal

[Sorni]

me wrote:
> Responses have been interesting so far - most are having many more
> rear flats than front ones. The only front "blow-out" I can recall
> involved riding over an unseen car wheel weight. It was apparently
> lying perpendicular to my direction of travel with the steel tab that
> crimps it onto the wheel rim sticking up - cut through my tire and
> tube like a knife. Had a spare tire and tube on me though, so I was
> rolling again in 15 min.

Do you always (or even usually) carry a spare tire, or was this on a tour or
something?

Anyway, good planning!

Bill "I'd've been screwed" S.

[RonSonic]

On Sun, 19 Mar 2006 20:45:55 GMT, Michael Press > wrote:

>In article >,
> "(PeteCresswell)" > wrote:
>
>> Per me:
>> >Is it everyone's experience that rear road tires get flats while riding more
>> >often than front ones? It sure is mine, and I wonder why. Seems like the
>> >front should go flat more since it's the first to encounter the sharp
>> >objects. Anyone care to theorize?
>>
>> Based on MTB experience, I think it's the added weight.
>>
>> The idea about the front wheel throwing the object so that it penetrates the
>> rear wheel sounds logical for a road situation, but most of my MTB punctures are
>> from thorns...so the "throwing" effect is not there and my rear tire flats
>> noticeably more often than the front.
>
>Why is the throwing effect not active for off-road riding?

Because off road that doesn't cause flats so much as kill spokes and rear
derailleurs. Branches get flipped up and back. If it causes a flat it's by
knocking the valve stem off - something I watched happen to the bike in front of
me last winter.

Ron

[me]

> Bill:
> Do you always (or even usually) carry a spare tire, or was this on a tour
> or something?
>

Yes, one folding tire is always in my pack. I've decided to put it on in
other cases where a boot could have been okay, but this time even a boot
wouldn't have worked.

Cal

[E Goforth]

In all the years I've been riding, I can only recall one flat front tire
on my road bike. My ratio must be at least 20 to 1.

-Eric

Sorni wrote:
> me wrote:
>> Responses have been interesting so far - most are having many more
>> rear flats than front ones. The only front "blow-out" I can recall
>> involved riding over an unseen car wheel weight. It was apparently
>> lying perpendicular to my direction of travel with the steel tab that
>> crimps it onto the wheel rim sticking up - cut through my tire and
>> tube like a knife. Had a spare tire and tube on me though, so I was
>> rolling again in 15 min.
>
> Do you always (or even usually) carry a spare tire, or was this on a tour or
> something?
>
> Anyway, good planning!
>
> Bill "I'd've been screwed" S.
>
>

[G.T.]

"E Goforth" > wrote in message
...
> In all the years I've been riding, I can only recall one flat front tire
> on my road bike. My ratio must be at least 20 to 1.
>

I've never had a rear flat tire on my road bike, only on my mtn bikes.

Greg