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-   -   Would Switching to Slime Tubes Prevent Pinch Flats? (http://www.bikeforums.net/clydesdales-athenas-200-lb-91-kg/276022-would-switching-slime-tubes-prevent-pinch-flats.html)

dydst 03-09-07 08:43 AM

Would Switching to Slime Tubes Prevent Pinch Flats?
 
Since switching to 700c x 25 tires a few weeks ago, I've been plagued with pinch flats. I'm 6'2-6'3 and about 240 lbs. Some people on this forum suggested pumping my tires to the maximum pressure each morning, and this has been very successful at preventing flats. Unfortunately, I got another pinch flat this morning. The roads I ride on aren't the best, but I didn't strike any large potholes or anthing like that.

My question is this: would slime tubes go a long way towards fixing my problem? The pinch flats I get are so small, and I'm thinking that slime tubes would be just the thing to seal them up.

What does everyone think? Would switching from standard tubes to slimes solve my problems, or is it not that easy?

Weaklink 03-09-07 09:38 AM

Are you sure it's snake bite?
 
I have ridden 20mm tires at 200+ and never had any problems. If you are hitting large pot-holes or sharp-edges surfaces, then yes, I could see a problem. At 200+ you can't hit square-edges objects hard.

Things I would check:
- air pressure. Is your gauge reliable? Are your tires rock-hard to thumb pressure at 100+ psi?
- Are your tubes fresh?
- Is your rim-strip covering the nipples holes?
- do you have any debris embedded in your tire?
- are you orientating your tires on the rim in the exact same spot so you can tell if the hole is coming from the exact same spot in regard to the rim/tire each time?

I don't think that Slime is really the solution to your problem, only a band-aid to mask it.

hard to say....

andymac 03-09-07 09:55 AM

The slime would likely seal the holes in the tube but at the rate you appear to be getting flats you would shortly have a tire full of that nasty green goo as you are not preventing the pinch flats you are just sealing them as they happen. When the tube finally gives out you will not enjoy the task of cleaning all that stuff out.

I would suggest that the last response by Little Darwin to your original thread is the correct identification of your problem. The Giant Cypress comes equipped with wide rim and either 38 or 40 tires. These rims are most likely too wide for a 25 tire. By putting the 700 * 25 on this wide rim you end up with a very low profile tire as the sidewalls are spread out more than they were intended to be. As the sidewalls move out the profile is reduced, the lower the sidewall is the more likely you are to compress the sidewall enough to pinch the tube. This also increases the chances that the rim is actually going to be dented by whatever obstacle it is that you are running over.

Find out what sort of rim you have on that bike then try to find the interior width, it is quite likely 19mm considering that the current model of the bike comes stock with a 700 * 40. If that is the case then the narrowest tire that should be used on that rim is a 28 and even that may be pushing it.

Velo Dog 03-09-07 10:12 AM

We're the same weight, and I haven't had a pinch flat in at least 15 years, even though I ride on some really bad roads and often take my Atlantis on fire roads and gravel. Grant Petersen, who founded Rivendell Bicycle Works and designs its bikes, says nobody over about 175 pounds has any business on skinny tires, and it's been true in my case. I do nearly all my riding on 700x35 Panaracer Paselas (best all-around tires I've ever used), and my "skinny" tires for fast rides are 700x32s. I run the 35s at 75-80psi and the 32s at 90-100, and I've had NO pinch flats in probably 25,000 miles.
Don't worry about them slowing you down. There's a convincing argument that very hard tires are SLOWER than fatter ones at a lower pressure, and I believe it. I've ridden the same 25-mile round-trip commute regularly since 1979, on tires from 21mm to 41mm, and there's no correlation between tire size and the time. How long it takes me to get to work depends much more on traffic, stop lights and what I had for breakfast than it does on the size of my tires.

dydst 03-09-07 10:39 AM

Quote:

Originally Posted by andymac
These rims are most likely too wide for a 25 tire. By putting the 700 * 25 on this wide rim you end up with a very low profile tire as the sidewalls are spread out more than they were intended to be. As the sidewalls move out the profile is reduced, the lower the sidewall is the more likely you are to compress the sidewall enough to pinch the tube. This also increases the chances that the rim is actually going to be dented by whatever obstacle it is that you are running over.

A-ha! I never thought of that . . . Thanks!

CastIron 03-09-07 04:17 PM

Same answer as your other post.

thebankman 03-10-07 06:30 PM

Slime tubes probably were the cause of my floor pump breaking today. I'm beginning to believe that they're more trouble than they're worth and making sure every other factor is working in your favor is the first step to take to reduce flats before trying slime.

FarHorizon 03-10-07 06:46 PM

I DESPISE slime tubes. They've burst on me, showering me and my home with green snot that won't come off the walls & ceiling. They are NO MORE flat resistant than ordinary tubes. They make it impossible to depressure a tube or air up a tube without getting slime everywhere. DON'T BUY SLIME TUBES!

If you want to prevent punctures, buy "thorn-proof" tubes. They're heavier, but they (unlike slime tubes) actually resist punctures.

If you want to prevent pinch-flats, run higher tire pressures.

I must respectfully disagree with the poster who said that larger profile tires are more likely to cause pinch-flats. My experience is that a generous tire size combined with adequate air pressure is the best remedy for pinches. Both factors are important - the tire size provides more cushion before the rim hits the tire and adequate air pressure lets one use that cushion.

ONE IMPORTANT CAVEAT! Don't use a significantly wider tire than the rim manufacturer recommends (particularly on %&*^$(*&^ Mavics!). Rims have failed (mine included) because of wide tires on a narrow rim. It isn't pretty...

Cheers!

teamcompi 03-10-07 06:58 PM

Something is wrong, I weigh more, ride really bad roads and do not get pinch flats even when I nail things really hard. Something stinks here????? are you using a wide rim with your narrow tires? Even though they will fit you widen the profile at the bead and functionally reduce the road to rim distance.

I have a set of go fast wheels that I add to my t-2000 touring bike. My easton circuits with 23's and a small block are a fast fun ride. I do not think I would put my Pro-max tires on my touring rims. Check your rim width.

dydst 03-11-07 06:29 AM

Quote:

Originally Posted by teamcompi
Something is wrong, I weigh more, ride really bad roads and do not get pinch flats even when I nail things really hard. Something stinks here????? are you using a wide rim with your narrow tires? Even though they will fit you widen the profile at the bead and functionally reduce the road to rim distance.

I have a set of go fast wheels that I add to my t-2000 touring bike. My easton circuits with 23's and a small block are a fast fun ride. I do not think I would put my Pro-max tires on my touring rims. Check your rim width.

yes teamcompi, I'm pretty certain that my rims are too wide to be running 700 x 25's. I'm switching back to my fat stock tires until I can buy a set of tires that are still thin, but more compatible with my rims.

Thanks for the responses, everyone!

Wogster 03-11-07 07:12 AM

Quote:

Originally Posted by dydst
yes teamcompi, I'm pretty certain that my rims are too wide to be running 700 x 25's. I'm switching back to my fat stock tires until I can buy a set of tires that are still thin, but more compatible with my rims.

Thanks for the responses, everyone!

You should check out what Sheldon Brown has to say about tire sizing. The article shows what measurement is needed, it's a diagram, then a chart at the bottom shows what width tires will work. Another problem can be that your running too low a tire pressure.


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