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Old 06-06-10, 08:13 AM   #1
Mr Gnome
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New Tires & Tubes

I have a Sun x3-sx trike. I just put on new tires and tubes. On the rear are Odyssey 120psi 20" x 1.85 and on the front is a Kenda Kwest 100psi 16x1.50. I could tell a big difference in performance over the 65psi Kenda Kwest tires they replaced!

One of the rear tubes it was defective and blew destroying the rim. I only ran the new tires 2 days and on the 3rd one of them blew. The LBS strongly suggested putting in Sunlite thorn resistant 20x1.50-1.95 tubes on the rears, so I did. Unbelievable, but they are about as heavy as the tires!

To me they feel like I've lost the performance gain I got from going to the higher psi tires...in fact, they feel more sluggish than the 65psi tires. Is it me, or are they really holding back the performance gain?

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Old 06-06-10, 08:46 AM   #2
cny-bikeman 
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The tube DID NOT blow out because it was defective. Tubes do not blow until they escape from the tire through a hole or under the bead. If the tires are working ok now the problem was that the one that blew out was not mounted correctly. Putting in thorn resistant tubes will "work," because it's hard to miss an incorrect mounting and they will not blow out under all but extreme circumstances. but it's the wrong fix. If you mounted the tires you need to learn proper mounting procedure - lots of guidance online. It's best to see the process rather than just read it, but many discussions on this forum.

If the bike shop mounted the tire you might talk to them about some compensation for the problem. Either way learn to visually inspect your mounted tire to head off problems.
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Old 06-06-10, 11:18 AM   #3
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I mounted the tire. The bike shop owner and the manufacture have already replaced the wheel because the tube was defective, as per them after looking it over!

Thanks for the info and concern, but that wasn't my question. It was about loss in performance using the thorn resistance tubes? These things must be at least 1/4" thick on the outside diameter and half that on the inside diameter.

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Mr Gnome
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Old 06-06-10, 11:23 AM   #4
kwoodbury
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thorn resistance tubes suck. get a better tire.
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Old 06-06-10, 11:43 AM   #5
cny-bikeman 
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Quote:
Originally Posted by Mr Gnome View Post
I mounted the tire. The bike shop owner and the manufacture have already replaced the wheel because the tube was defective, as per them after looking it over!

Thanks for the info and concern, but that wasn't my question. It was about loss in performance using the thorn resistance tubes? These things must be at least 1/4" thick on the outside diameter and half that on the inside diameter.

Thanks,
Mr Gnome
Yes, I realize I did not directly respond to your question. However, my intent was in part to let you know that the thorn resistant tubes were not necessary to avoid a blowout. The shop was simply wrong in diagnosing a defective tube from a blowout, and they did you no favors by neglecting to advise you as to the actual cause.

To answer your question: Yes, the loss in performance with thorn resistant tubes is very large - the tire can't respond as well to the road and you are adding weight in the worst possible place - the outermost rotating portion of the wheel.
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Old 06-06-10, 11:56 AM   #6
bjoerges
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It's possible that the shop wanted to get rid of some of the thorn resistant tubes. I only recommended them when it was appropriate to do so, but my shop hated carrying them because they were so hard to sell.

Besides that, if it WAS a defective tube, a non-defective standard tube should have been a sufficient replacement. There is a significant performance penalty in using thicker tubes. They do not deform as smoothly as a standard tube for easy rolling nor do they leave as large of volume of air for cushioning impacts.

If you value performance over puncture resistance you went the wrong route.
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Old 06-06-10, 12:28 PM   #7
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Thanks all on letting me know that it's not my imagination there is a big loss in performance using those tubes. When I first changed from the 65psi to the higher psi I swear it was like I added a motor assist and quicker off the line!

I'm putting back in the non-thorn ones I have.

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Mr Gnome
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