Are you running the correct tire pressure?

Cruzbike Chris

Well-Known Member
This cool new, free app could open your eyes a bit. I usually run 110-115 in my 25 mm GP II's body weight as of now 185+35lbs for bike, water, tools. This app says I should be running closer to 97 in each tire.

Prestacycle Bicycle Tire Pressure Calculator by David Finlayson
https://appsto.re/us/OCWYeb.i
 
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I didn't crash after a flat but I did have a slow leak from the valve. It was very difficult to control the bike and took all my effort to keep from leaning to the left and suffered from a death grip on the left handlebar. Since I was a very new rider at the time, I thought it had to do with my technique. I kept trying to improve my technique until I crashed and someone told me that my tire was flat. Fortunately, only a scratch on the front wheel.
 

Gary123

Zen MBB Master
I didn't crash after a flat but I did have a slow leak from the valve. It was very difficult to control the bike and took all my effort to keep from leaning to the left and suffered from a death grip on the left handlebar. Since I was a very new rider at the time, I thought it had to do with my technique. I kept trying to improve my technique until I crashed and someone told me that my tire was flat. Fortunately, only a scratch on the front wheel.
Yeah I scratched front rim and put a nasty road rash on my arm. I wonder why vendetta is nearly impossible to control after flat. I'm getting better on the bike but very nervous when I hit a bump. I fear flats and I cannot lie. This was on front, anyone have experience with rear flat?
 

ratz

Wielder of the Rubber Mallet
Yeah I scratched front rim and put a nasty road rash on my arm. I wonder why vendetta is nearly impossible to control after flat. I'm getting better on the bike but very nervous when I hit a bump. I fear flats and I cannot lie. This was on front, anyone have experience with rear flat?

Too low of pressure on the front can make the bike squirrelly because the front is both steering and pulling the bike. Completely flat is actually easier to control than say 60 psi. At 170lbs 85psi is about as low as I go; PluckyBlond I'll lower to 80psi. For aggressive riding I bring use both up to 95 for both speed, and handling without compromising grip in hard corners. Over 100psi , we just never have a surface worthy of that high of a pressure.

I've blow out front and rear and never had a real problem controlling the bike; but sitting up quickly is important if you expect it to behave like a DF bike does, you need more balance and you have to detatch your body motion from the bike seat so you and the bike and move independently of each other. I did blow the front tire completely off the rim at 25 mph (installation error on my part) and that we a quick ride to the ground.
 

Gary123

Zen MBB Master
Thanks
I didn't crash after a flat but I did have a slow leak from the valve. It was very difficult to control the bike and took all my effort to keep from leaning to the left and suffered from a death grip on the left handlebar. Since I was a very new rider at the time, I
Too low of pressure on the front can make the bike squirrelly because the front is both steering and pulling the bike. Completely flat is actually easier to control than say 60 psi. At 170lbs 85psi is about as low as I go; PluckyBlond I'll lower to 80psi. For aggressive riding I bring use both up to 95 for both speed, and handling without compromising grip in hard corners. Over 100psi , we just never have a surface worthy of that high of a pressure.

I've blow out front and rear and never had a real problem controlling the bike; but sitting up quickly is important if you expect it to behave like a DF bike does, you need more balance and you have to detatch your body motion from the bike seat so you and the bike and move independently of each other. I did blow the front tire completely off the rim at 25 mph (installation error on my part) and that we a quick ride to the ground.

thought it had to do with my technique. I kept trying to improve my technique until I crashed and someone told me that my tire was flat. Fortunately, only a scratch on the front wheel.
 

Gary123

Zen MBB Master
Thanks
I didn't crash after a flat but I did have a slow leak from the valve. It was very difficult to control the bike and took all my effort to keep from leaning to the left and suffered from a death grip on the left handlebar. Since I was a very new rider at the time, I
Too low of pressure on the front can make the bike squirrelly because the front is both steering and pulling the bike. Completely flat is actually easier to control than say 60 psi. At 170lbs 85psi is about as low as I go; PluckyBlond I'll lower to 80psi. For aggressive riding I bring use both up to 95 for both speed, and handling without compromising grip in hard corners. Over 100psi , we just never have a surface worthy of that high of a pressure.

I've blow out front and rear and never had a real problem controlling the bike; but sitting up quickly is important if you expect it to behave like a DF bike does, you need more balance and you have to detatch your body motion from the bike seat so you and the bike and move independently of each other. I did blow the front tire completely off the rim at 25 mph (installation error on my part) and that we a quick ride to the ground.

thought it had to do with my technique. I kept trying to improve my technique until I crashed and someone told me that my tire was flat. Fortunately, only a scratch on the front wheel.
 

BJ686

Well-Known Member
Thanks for the tips and info in this thread as this is an issue I had been thinking about. I have been running my 23c tires up near the max 140 psi pressure. Feels like I'm flying on perfectly paved roads (ie, new pavement), but I have noticed that there is a significant drop in speed even on a road in moderate to fair condition. On those roads, you can feel the bike constantly having very small "bounces" where I presume the highly inflated tires just cannot keep constant grip on the less than perfect road conditions. I had been thinking that I may need to switch to 25c tires as many are now doing to address this, but had not really thought about lowering the pressure that significantly in my current tires. I'll definitely give this a try.
 
Yeah I scratched front rim and put a nasty road rash on my arm. I wonder why vendetta is nearly impossible to control after flat. I'm getting better on the bike but very nervous when I hit a bump. I fear flats and I cannot lie. This was on front, anyone have experience with rear flat?
You may want to look at tires with a kevlar belt to prevent flats. Some brands are Continental Gran Prix 4000 S and specialized Turbo pro. This will decrease floating form punctures but not pinch flats. I am very careful to avoid pinch flats by carefully pumping up my tire pressure and then deflating it. Then I go around the rim of the tire and pull it away from the wheel rim. Then I re inflate the tire. It is probably over kill when replacing a new inner tube but I have not had any pinch flats since I started doing this.
 

Gary123

Zen MBB Master
You may want to look at tires with a kevlar belt to prevent flats. Some brands are Continental Gran Prix 4000 S and specialized Turbo pro. This will decrease floating form punctures but not pinch flats. I am very careful to avoid pinch flats by carefully pumping up my tire pressure and then deflating it. Then I go around the rim of the tire and pull it away from the wheel rim. Then I re inflate the tire. It is probably over kill when replacing a new inner tube but I have not had any pinch flats since I started doing this.
 

Gary123

Zen MBB Master
I'm referring to pinch flat from road impact. I'm much more careful watching for potholes and debris now . I'm running conti 4000s at about 100 psi. I'm a long time df rider and have ridden bacchetta strada off and on for three years. Never had much of a problem controlling bikes after flat until the vendetta. I went down very fast after flatting. I'm not giving up. I only have a few hundred miles on vendetta and about the same on a quest. I can feel advantage on climbs but crashes are not a good thing.
 

MrSteve

Zen MBB Master
I'm referring to pinch flat from road impact. I'm much more careful watching for potholes and debris now . I'm running conti 4000s at about 100 psi. I'm a long time df rider and have ridden bacchetta strada off and on for three years. Never had much of a problem controlling bikes after flat until the vendetta. I went down very fast after flatting. I'm not giving up. I only have a few hundred miles on vendetta and about the same on a quest. I can feel advantage on climbs but crashes are not a good thing.

If you keep it up, your crashes might improve.

The only way I know, for sure, that my tire is flat is if I can see that the tire is actually flat.
For example, I was riding my Sofrider up a long, long hill and it was getting more and more difficult to pedal.
The speed was probably originally 12mph and slowed to about 4mph.
Looking down at the front, I was shocked to see that the front tire was flat.
A flake of beer bottle glass cut the tube.

A few weeks ago, I got my first flat on the Vendetta.
I'd hit the sharp edge of a small new pot hole at about 24mph.
After two miles and a turn, the transmission felt funny... like it was dragging.
Looking down, I was surprised to see that the front tire was flat.
Snake bite.

My guess is that lots of time on the MBB makes emergencies easier to deal with.

-----

Tire pressures, hmm, I run 100 p.s.i. on the V and about 65-80 p.s.i. on the Sofrider.
 

trapdoor2

Zen MBB Master
All of my flats have happened at low speed, I've not gone "down" due to a flat...yet. :cool: I haven't had a flat on my V20 but I had one on my V2/K. Like Steve, it took a while for me to notice something was "not right". I got off and the front was flat. I was in 'meandering' mode, so...

I'm running a comfy 95psi in the 700cX28 "Thick Slicks". Being a 'Clydsdale', I easily exceed the calculated limits. Meh.
 

ratz

Wielder of the Rubber Mallet
I only have a few hundred miles on vendetta and about the same on a quest.
I can see a front flat being a bit scary sub 500 miles if you are still not relaxed on the bike; tension on top of tension can be a bad thing. Broken record guy would point out that slow speed drills help... I was talking with Ken about his silvio in IA; and I made the point that do 10minutes in a nearby parking lot; then go on your long ride; then finish with 5 at the end; those 15minutes add up really fast.

FWIW I've never found Conti 4000 to be graceful in a crash they do have a habit of coming off the RIM more than most. I like a tire that is hard to get on the RIM as they tend to stay on the rim if you don't notice you have a flat right away. You can use tubless sealant on the bead to improve it's tendency to stay on the rim; it won't keep the air in; but it might keep the tire mounted long enough for you to stop.
 

Gary123

Zen MBB Master
To be fair I am a raw beginner in the vendetta, but I can average 20 mph for a ride and feel reasonably confident in traffic. When the front tire flatted it felt like I hit an ice patch, instant asphalt bath. Tire didn't roll off of rim but it felt like it did, no control. I'm doing fig 8s and slow speed and trying not to lose my confidence but I don't think vendetta handles like softrider after a flat. Maybe I should deflate and go for a ride. Thanks for all the help. I'll keep working.
 

Gary123

Zen MBB Master
Sorry Mr Steve I misread and did not realize you flatted on vendetta and did not know it. I'm sure I need more time on bike and maybe flats won't be so scary if I can stay upright after one. Don't mind a battle scar but I'm not looking for more
 
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