Engineering types... check my work!

Search "hoop stress".

"Phil, Squid-in-Training" <[email hidden]> wrote
in message news:[email hidden]...

Quoted message said:

So I pumped up the tires to 120 later that night, and within a few
minutes, psssssssss. The 3-mm slit the glass made in the tire tread
was too big for the tube. So I cut out some water bottle and used
duct tape for a boot. Works well.

tension from hoop stress is pr (lb/inch)
for a 7/8 inch wide tire at 120 psi this will be 120 x .44 = 53 lb/inch
for a 1/8 (3 mm) width the tension is 53/8 = ~ 7 lb

Phil H

Phil said:

I did a time trial with my college team this past weekend. The location is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to 30F/35R
that I realized I could have broken 20 minutes. Oh well.

So I pumped up the tires to 120 later that night, and within a few minutes,
psssssssss. The 3-mm slit the glass made in the tire tread was too big for
the tube. So I cut out some water bottle and used duct tape for a boot.
Works well.

Today in class I was mulling over whether I should repair it, not because
I'm worried about the tire failing in the future, but whether I could
actually sew the casing back together. Then I thought about the kind of
tension the thread would be under if I sewed it. I remembered that I have
some Kevlar thread from a digital camera fix a year ago, and it was rated at
25lbs. I did some calculations here:

http://plaza.ufl.edu/phillee/tireslit.jpg

and determined that I would need one thread to hold at least 14.5 lbs to
keep the tire closed, given a 3mm slit parallel to the direction of travel
in the center of the tread of a 23mm road tire at 120psi.

Ignoring gross uncertainties such as actual tire size, the fact that the
slit isn't so much parallel as diagonal to the tread, am I anywhere near a
correct answer?

Can't help you with the thread tension, but put in several stitches with
anything as strong as dental floss or stronger, and the threads won't
break. The bigger concern is whether they will pull out of the casing
cord. Make sure to engage several cords on both sides of the cut with
each stitch.

If you're using ultralight tubes, stick an inner tube patch over the
stitches to avoid abrading the tube (not sure if this is necessary, but
it won't hurt).

Have fun with your thread tension calculation.

Mark Janeba

Phil said:

So I pumped up the tires to 120 later that night, and within a few minutes,
psssssssss. The 3-mm slit the glass made in the tire tread was too big for
the tube. So I cut out some water bottle and used duct tape for a boot.
Works well.

It should. The thickness of a PET strip from a bottle is overkill.

What I thought about a while ago would be strips of Kapton with a really
good adhesive to glue into the inside of the tire. Kapton is a
lightweight, high strength plastic. It's expensive if you buy a pound
of it (waaay back in 1985 it cost $75/pound) but if you only have a few
strips of 2 or 5 mil Kapton, plus adhesive, it shouldn't be terribly
expensive.

Sewing up the slit in the tire should be belt-and-suspenders. Use silk
thread, maybe. It's really strong.

--
BMO

"Boyle M. Owl" <[email hidden]> wrote in message
news:R_JFd.26857$jn.2417@lakeread06...

Quoted message said:

Phil said:

So I pumped up the tires to 120 later that night, and within a few
minutes, psssssssss. The 3-mm slit the glass made in the tire tread was
too big for the tube. So I cut out some water bottle and used duct tape
for a boot. Works well.

It should. The thickness of a PET strip from a bottle is overkill.

What I thought about a while ago would be strips of Kapton with a really
good adhesive to glue into the inside of the tire. Kapton is a
lightweight, high strength plastic. It's expensive if you buy a pound of
it (waaay back in 1985 it cost $75/pound) but if you only have a few
strips of 2 or 5 mil Kapton, plus adhesive, it shouldn't be terribly
expensive.

Sewing up the slit in the tire should be belt-and-suspenders. Use silk
thread, maybe. It's really strong.

I used one of the really cheap house-brand plastic bottles that are much
thinner than bottles from Dasani, Zephyrhills, etc.

I've split open a Park tire boot before... I didn't want to take any
chances.

--
Phil, Squid-in-Training

Squid-in-Training said:

Ignoring gross uncertainties such as actual tire size, the fact that the
slit isn't so much parallel as diagonal to the tread, am I anywhere near a
correct answer?

I can't say, but here's something to consider...

Some of the tubeless tire makers are recommending a variety of
cyanoacrylate adhesive as the repair method for punctures in their
products. By extrapolation, using the adhesive might be a reasonable
addition to the stitching. I have seen a couple of small cuts
stitched up in tires that were either expensive or hard to get under
the circumstances, with mixed results. The thread gets worn off on
the outside if the sewn area is in the tread region, breaking the
stitches in the process; the adhesive might help to keep the repair
together.

I suspect that while it may be possible to repair the tire well enough
to get it to work for some period of time, the chances are good that
any repair will fall short of an undamaged tire's durability. It's
just something to keep in mind when balancing effort versus cost and
results.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

"Werehatrack" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Squid-in-Training said:

Ignoring gross uncertainties such as actual tire size, the fact that the
slit isn't so much parallel as diagonal to the tread, am I anywhere near a
correct answer?

I can't say, but here's something to consider...

Some of the tubeless tire makers are recommending a variety of
cyanoacrylate adhesive as the repair method for punctures in their
products. By extrapolation, using the adhesive might be a reasonable
addition to the stitching. I have seen a couple of small cuts
stitched up in tires that were either expensive or hard to get under
the circumstances, with mixed results. The thread gets worn off on
the outside if the sewn area is in the tread region, breaking the
stitches in the process; the adhesive might help to keep the repair
together.

I thought CA was extremely brittle and would fracture under stress.

Quoted message said:

I suspect that while it may be possible to repair the tire well enough
to get it to work for some period of time, the chances are good that
any repair will fall short of an undamaged tire's durability. It's
just something to keep in mind when balancing effort versus cost and
results.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Quoted message said:

I suspect that while it may be possible to repair the tire well enough
to get it to work for some period of time, the chances are good that
any repair will fall short of an undamaged tire's durability. It's
just something to keep in mind when balancing effort versus cost and
results.

Sent post off too early:

This bike is my road racing bike and commuter bike. Old GT Edge with old
105 group. Handbuilt ME14A with spokes from a customer's tacoed wheel.
Cost me $250.

So yes, it's worth the effort 😉

--
Phil, Squid-in-Training

Phil said:

I thought CA was extremely brittle and would fracture under stress.

Yeah, but the weather's hard to beat.

Squid-in-Training said:

"Werehatrack" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Squid-in-Training said:

Ignoring gross uncertainties such as actual tire size, the fact that the
slit isn't so much parallel as diagonal to the tread, am I anywhere near a
correct answer?

I can't say, but here's something to consider...

Some of the tubeless tire makers are recommending a variety of
cyanoacrylate adhesive as the repair method for punctures in their
products. By extrapolation, using the adhesive might be a reasonable
addition to the stitching. I have seen a couple of small cuts
stitched up in tires that were either expensive or hard to get under
the circumstances, with mixed results. The thread gets worn off on
the outside if the sewn area is in the tread region, breaking the
stitches in the process; the adhesive might help to keep the repair
together.

I thought CA was extremely brittle and would fracture under stress.

Quoted message said:

I suspect that while it may be possible to repair the tire well enough
to get it to work for some period of time, the chances are good that
any repair will fall short of an undamaged tire's durability. It's
just something to keep in mind when balancing effort versus cost and
results.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Dear Phil,

Hmmm . . . the most common form of cyanoacrylate is super
glue.

Super glue can be used to stick fingers together--or even
the lips of wounds, though a medical version that reduces
all sorts of side effects is preferable.

You need a solvent to get your glued fingers apart--you
can't just roll them back and forth and crack the thin bond
between them.

So while it may sound brittle, I suspect that it's tougher
than we might think at first. The usual description is that
it "dries to a hard, tough adhesive"--we tend to think of
hard as brittle, but it's actually "tough" in this case.

Carl Fogel

Werehatrack said:

I have seen a couple of small cuts
stitched up in tires that were either expensive or hard to get under
the circumstances, with mixed results. The thread gets worn off on
the outside if the sewn area is in the tread region, breaking the
stitches in the process;

The trick is to push the needle between the casing and the tread - that
is, sewing from inside the casing, push the needle deep enough to get
near the tread but not far enough to be exposed on the outside of the tire.

This is easier said than done, but with a little practice it's do-able.
Waxing your needle and using a thimble to push the needle and pliers
to pull it can make the job a little less difficult.

On sidewall cuts, it's much easier as exposed stiches won't hurt.

Mark Janeba

Phil said:

I thought CA was extremely brittle and would fracture under stress.

Not really, not if you've ever glued your fingertips together. The more
stress you're under, the longer it takes for the acetone to dissolve the
superglue.

*rimshot* I'm here all night. Try the veal. Thank you.

CA is not resistant to *shock*, however. Glue two pieces of steel
together with cyanoacrylate and you'll have a tough time pulling them
apart, but a tap with a 1oz hammer will separate them instantly with the
totality of glue on one of the pieces and none on the other.

Here's an interesting bit about cyanoacrylate (superglues):

If you have ever read the MSDS sheet, you'll notice that surgery is an
absolute LAST resort for an eye glued shut. Indeed, the instructions
are to put a patch over the affected eye and let MomNature do her bit by
sloughing off protiens from the cornea.

--
BMO - Brittle under stress.

Phil said:

I did a time trial with my college team this past weekend. The location is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to 30F/35R
that I realized I could have broken 20 minutes. Oh well.

How did you place in that TT? And where's that school?

Because 20:19 over 7 miles is ~20.7 mph.

--Blair
"Maybe I could matriculate and start
stacking up the bling."

"Blair P. Houghton" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Phil said:

I did a time trial with my college team this past weekend. The location
is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the
TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a
lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to
30F/35R
that I realized I could have broken 20 minutes. Oh well.

How did you place in that TT? And where's that school?

I placed 16th out of 20. Here were the results:

Name Sex 1/8/05 Average Fastest
1. M 16:12 15:55 14:59
2. M 16:13 17:30 16:13
3. F 17:05 17:30 16:40
4. M 17:20 17:20 17:20
5. M 17:28 17:15 15:51
6. M 17:40 17:52 17:40
7. M 17:41 17:57 17:29
8. M 18:10 19:15 18:10
9. M 18:24 18:24 18:24
10. M 18:27 18:27 18:27
11. M 18:28 18:54 18:04
12. M 18:40 18:40 18:40
13. M 18:43 19:20 18:43
14. M 19:03 19:15 19:03
15. M 19:50 20:02 19:50
16. M 20:19 21:07 20:19
17. M 20:20 20:49 20:20
18. M 20:52 21:54 20:52
19. M 21:40 22:30 21:40
20. M 22:02 22:12 21:04

The fastest ever solo time (the team coach) was 14:59, and the fastest ever
group time is a min or two faster.

Quoted message said:

Because 20:19 over 7 miles is ~20.7 mph.

I'm not sure if you mean that's slow or fast. It's definitely slow amongst
us Team Florida Cycling (University of Florida) members. I'm an
urban/mountain biker anyways and riding road is fun sometimes.

--
Phil, Squid-in-Training

"Blair P. Houghton" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Phil said:

I did a time trial with my college team this past weekend. The location
is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the
TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a
lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to
30F/35R
that I realized I could have broken 20 minutes. Oh well.

How did you place in that TT? And where's that school?

I placed 16th out of 20. Here were the results:

Name Sex 1/8/05 Average Fastest
1. M 16:12 15:55 14:59
2. M 16:13 17:30 16:13
3. F 17:05 17:30 16:40
4. M 17:20 17:20 17:20
5. M 17:28 17:15 15:51
6. M 17:40 17:52 17:40
7. M 17:41 17:57 17:29
8. M 18:10 19:15 18:10
9. M 18:24 18:24 18:24
10. M 18:27 18:27 18:27
11. M 18:28 18:54 18:04
12. M 18:40 18:40 18:40
13. M 18:43 19:20 18:43
14. M 19:03 19:15 19:03
15. M 19:50 20:02 19:50
16. M 20:19 21:07 20:19
17. M 20:20 20:49 20:20
18. M 20:52 21:54 20:52
19. M 21:40 22:30 21:40
20. M 22:02 22:12 21:04

The fastest ever solo time (the team coach) was 14:59, and the fastest ever
group time is a min or two faster.

Quoted message said:

Because 20:19 over 7 miles is ~20.7 mph.

I'm not sure if you mean that's slow or fast. It's definitely slow amongst
us Team Florida Cycling (University of Florida) members. I'm an
urban/mountain biker anyways and riding road is fun sometimes.

--
Phil, Squid-in-Training

"Blair P. Houghton" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Phil said:

I did a time trial with my college team this past weekend. The location
is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the
TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a
lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to
30F/35R
that I realized I could have broken 20 minutes. Oh well.

How did you place in that TT? And where's that school?

I placed 16th out of 20. Here were the results:

Name Sex 1/8/05 Average Fastest
1. M 16:12 15:55 14:59
2. M 16:13 17:30 16:13
3. F 17:05 17:30 16:40
4. M 17:20 17:20 17:20
5. M 17:28 17:15 15:51
6. M 17:40 17:52 17:40
7. M 17:41 17:57 17:29
8. M 18:10 19:15 18:10
9. M 18:24 18:24 18:24
10. M 18:27 18:27 18:27
11. M 18:28 18:54 18:04
12. M 18:40 18:40 18:40
13. M 18:43 19:20 18:43
14. M 19:03 19:15 19:03
15. M 19:50 20:02 19:50
16. M 20:19 21:07 20:19
17. M 20:20 20:49 20:20
18. M 20:52 21:54 20:52
19. M 21:40 22:30 21:40
20. M 22:02 22:12 21:04

The fastest ever solo time (the team coach) was 14:59, and the fastest ever
group time is a min or two faster.

Quoted message said:

Because 20:19 over 7 miles is ~20.7 mph.

I'm not sure if you mean that's slow or fast. It's definitely slow amongst
us Team Florida Cycling (University of Florida) members. I'm an
urban/mountain biker anyways and riding road is fun sometimes.

--
Phil, Squid-in-Training

"Blair P. Houghton" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Phil said:

I did a time trial with my college team this past weekend. The location
is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the
TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a
lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to
30F/35R
that I realized I could have broken 20 minutes. Oh well.

How did you place in that TT? And where's that school?

I placed 16th out of 20. Here were the results:

Name Sex 1/8/05 Average Fastest
1. M 16:12 15:55 14:59
2. M 16:13 17:30 16:13
3. F 17:05 17:30 16:40
4. M 17:20 17:20 17:20
5. M 17:28 17:15 15:51
6. M 17:40 17:52 17:40
7. M 17:41 17:57 17:29
8. M 18:10 19:15 18:10
9. M 18:24 18:24 18:24
10. M 18:27 18:27 18:27
11. M 18:28 18:54 18:04
12. M 18:40 18:40 18:40
13. M 18:43 19:20 18:43
14. M 19:03 19:15 19:03
15. M 19:50 20:02 19:50
16. M 20:19 21:07 20:19
17. M 20:20 20:49 20:20
18. M 20:52 21:54 20:52
19. M 21:40 22:30 21:40
20. M 22:02 22:12 21:04

The fastest ever solo time (the team coach) was 14:59, and the fastest ever
group time is a min or two faster.

Quoted message said:

Because 20:19 over 7 miles is ~20.7 mph.

I'm not sure if you mean that's slow or fast. It's definitely slow amongst
us Team Florida Cycling (University of Florida) members. I'm an
urban/mountain biker anyways and riding road is fun sometimes.

--
Phil, Squid-in-Training

"Blair P. Houghton" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Phil said:

I did a time trial with my college team this past weekend. The location
is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the
TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a
lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to
30F/35R
that I realized I could have broken 20 minutes. Oh well.

How did you place in that TT? And where's that school?

I placed 16th out of 20. Here were the results:

Name Sex 1/8/05 Average Fastest
1. M 16:12 15:55 14:59
2. M 16:13 17:30 16:13
3. F 17:05 17:30 16:40
4. M 17:20 17:20 17:20
5. M 17:28 17:15 15:51
6. M 17:40 17:52 17:40
7. M 17:41 17:57 17:29
8. M 18:10 19:15 18:10
9. M 18:24 18:24 18:24
10. M 18:27 18:27 18:27
11. M 18:28 18:54 18:04
12. M 18:40 18:40 18:40
13. M 18:43 19:20 18:43
14. M 19:03 19:15 19:03
15. M 19:50 20:02 19:50
16. M 20:19 21:07 20:19
17. M 20:20 20:49 20:20
18. M 20:52 21:54 20:52
19. M 21:40 22:30 21:40
20. M 22:02 22:12 21:04

The fastest ever solo time (the team coach) was 14:59, and the fastest ever
group time is a min or two faster.

Quoted message said:

Because 20:19 over 7 miles is ~20.7 mph.

I'm not sure if you mean that's slow or fast. It's definitely slow amongst
us Team Florida Cycling (University of Florida) members. I'm an
urban/mountain biker anyways and riding road is fun sometimes.

--
Phil, Squid-in-Training

"Blair P. Houghton" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Phil said:

I did a time trial with my college team this past weekend. The location
is
11 miles away, and during the ride there, I got 2 flats! I managed to get
enough air in the two wheels, and managed to get there in time to do the
TT
before everyone left. I ran a 20:19 for the 7-mile course, which was a
lot
better than the 22:00 I had gotten the last time I tried it. It wasn't
until I got home and discovered that my tires were only inflated to
30F/35R
that I realized I could have broken 20 minutes. Oh well.

How did you place in that TT? And where's that school?

I placed 16th out of 20. Here were the results:

Name Sex 1/8/05 Average Fastest
1. M 16:12 15:55 14:59
2. M 16:13 17:30 16:13
3. F 17:05 17:30 16:40
4. M 17:20 17:20 17:20
5. M 17:28 17:15 15:51
6. M 17:40 17:52 17:40
7. M 17:41 17:57 17:29
8. M 18:10 19:15 18:10
9. M 18:24 18:24 18:24
10. M 18:27 18:27 18:27
11. M 18:28 18:54 18:04
12. M 18:40 18:40 18:40
13. M 18:43 19:20 18:43
14. M 19:03 19:15 19:03
15. M 19:50 20:02 19:50
16. M 20:19 21:07 20:19
17. M 20:20 20:49 20:20
18. M 20:52 21:54 20:52
19. M 21:40 22:30 21:40
20. M 22:02 22:12 21:04

The fastest ever solo time (the team coach) was 14:59, and the fastest ever
group time is a min or two faster.

Quoted message said:

Because 20:19 over 7 miles is ~20.7 mph.

I'm not sure if you mean that's slow or fast. It's definitely slow amongst
us Team Florida Cycling (University of Florida) members. I'm an
urban/mountain biker anyways and riding road is fun sometimes.

--
Phil, Squid-in-Training