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Old 09-13-09, 12:53 PM   #1
Anthony2
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Tire Keeps Becoming Untrued

Bike: Jamis Coda
Wheels: From Alex Rim DC19 to the "upgraded" Alex Rim R450 (which, from what I've been told, has 4 more spokes).

Okay, I don't get it. I've barely had a decent time riding this year because the tire situation. It happened several times with the older wheel and now (after only about 3 or 4 rides) has happened twice with the new wheel. I don't know if it's the slight over-inflating (very slightly above the 120 PSI it calls for), my weight (250-260), combination of both, or "other." So this is what I want to know:

Why in the world does this keep happening? Is it normal? This never happened to me the first year I bought the bike (which was last year).

And finally, are Alex Rim wheels just not "good?" Would buying another wheel solve this problem?

I actually bought a spoke wrench and tried to fix it myself so that I wouldn't have to go back to my LBS yet -again-, but couldn't figure out which one to turn, which way to turn it, etc. So......I'm stuck!
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Old 09-13-09, 01:40 PM   #2
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First off, at your weight you want to be careful about hitting any type of road hazard. If you must hit something (railroad track for example) you'll want to unload the wheels as much as possible as you go over the bump.

Second, lots of machine built wheels are not properly tensioned and stress relieved. If you ride these wheels for long, you'll have spokes coming loose and the wheel will quickly go out of true. I would find a mechanic skilled at wheel building and have him go through your wheels completely. With all the spokes evenly tensioned, you'll have the best shot at the rims staying true.

If you continue to have issues, I would highly recommending getting a set of hand built wheels with 36 spokes. Something along the lines of a touring bike wheel would be perfect for you. Peter White seems to be highly recommended for building such a wheelset though I have no experience with him.

If you wanted to learn to work on your own wheels (something that you should at least have some knowledge about) read up here for starters: http://sheldonbrown.com/wheelbuild.html
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Old 09-13-09, 02:48 PM   #3
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Peter White gets my recommendation - his wheels are great. Never seen one that went out of true:

http://www.peterwhitecycles.com/

He can suggest good wheels for your needs. The other solution is, as above, finding a competent wheelbuilder at a bike-shop and have him basically rebuild your wheels.
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Old 09-13-09, 04:24 PM   #4
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Quote:
Originally Posted by Anthony2 View Post
Bike: Jamis Coda
Wheels: From Alex Rim DC19 to the "upgraded" Alex Rim R450 (which, from what I've been told, has 4 more spokes).

Okay, I don't get it. I've barely had a decent time riding this year because the tire situation. It happened several times with the older wheel and now (after only about 3 or 4 rides) has happened twice with the new wheel. I don't know if it's the slight over-inflating (very slightly above the 120 PSI it calls for), my weight (250-260), combination of both, or "other." So this is what I want to know:

Why in the world does this keep happening? Is it normal? This never happened to me the first year I bought the bike (which was last year).

And finally, are Alex Rim wheels just not "good?" Would buying another wheel solve this problem?

I actually bought a spoke wrench and tried to fix it myself so that I wouldn't have to go back to my LBS yet -again-, but couldn't figure out which one to turn, which way to turn it, etc. So......I'm stuck!
What do you mean the 'rims' were upgraded? Were the whole wheels rebuilt with new spokes, old hub with the new r450's? Handbuilt? Or some other stock wheelset? Alex makes some good rims and some bad rims.

Good rims include the Da22/28 and the R450. Good doesn't mean you can start slapping 2 ton weight riders doing 10 ft drops on them though - even a good wheelbuild won't stand up to abuse it was never designed to handle.

Also, are you inflating to 120psi on the STOCK tyres? Those aren't 23c's - they're much wider than that. You shouldn't need to pump them up that high (this doesn't really have much to do with your wheels going untrue).
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Old 09-13-09, 05:25 PM   #5
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You shouldn't need to pump them up that high (this doesn't really have much to do with your wheels going untrue).
Hmm, that may not be 100% true. With that kind of pressure a lot less shock load is being absorbed by the tire and going directly to the wheel. I agree that that's probably too much PSI.
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Old 09-13-09, 07:45 PM   #6
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finding a competent wheelbuilder at a bike-shop and have him basically rebuild your wheels.
I'd agree with this 100% if you took the re, out of rebuild in your post. The codas come with garbage formula hubs. If you're going to be building a solid, robust wheelset for a heavy rider, high quality all the way (at least deore lx hubs).
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Old 09-13-09, 09:59 PM   #7
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I'd have to see it to make that decision. But you are likely right. Crappy wheels seems to be what the decade of 2000 has been about.
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Old 09-13-09, 10:23 PM   #8
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Originally Posted by joejack951 View Post
First off, at your weight you want to be careful about hitting any type of road hazard. If you must hit something (railroad track for example) you'll want to unload the wheels as much as possible as you go over the bump.
I do that. I actually get up off of my seat every time I get near any kind of bump. I s'pose I'll try to steer clear of any bumps from now on and when if there's any I can't avoid, I'll simply slow down.

Quote:
Originally Posted by joejack951 View Post
If you continue to have issues, I would highly recommending getting a set of hand built wheels with 36 spokes. Something along the lines of a touring bike wheel would be perfect for you. Peter White seems to be highly recommended for building such a wheelset though I have no experience with him.
Thanks, I'll look into it.

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What do you mean the 'rims' were upgraded?
Well, I was told the R450 was "better" than the one I had and thus why I used the word "upgraded."

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Good doesn't mean you can start slapping 2 ton weight riders doing 10 ft drops on them though - even a good wheelbuild won't stand up to abuse it was never designed to handle.
No, I know. I just wasn't sure if the R450 was a crap wheel or not.

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Also, are you inflating to 120psi on the STOCK tyres?
Not real knowledgeable about bikes, I was 1.) told to do that and 2.) believe that is what's stated on the tire itself.

--------------

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Hmm, that may not be 100% true. With that kind of pressure a lot less shock load is being absorbed by the tire and going directly to the wheel. I agree that that's probably too much PSI.
How is one to know how much air to use exactly?

--------------

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I'd agree with this 100% if you took the re, out of rebuild in your post. The codas come with garbage formula hubs. If you're going to be building a solid, robust wheelset for a heavy rider, high quality all the way (at least deore lx hubs).
I'm willing to spend some money to upgrade this bike. Can I get a pair of really good hubs for $50-$100? If so, can you recommend a few, please?

--------------
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Old 09-13-09, 10:36 PM   #9
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New hubs wouldn't do you any good unless they were laced in good rims with a reasonable spoke-count.

On the sidewall of the tires there should be a Max. Pressure listed - either in PSI or in Bars (1 Bar = 14.5 psi).
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Old 09-13-09, 10:42 PM   #10
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You still didn't answer my question. Your use of the term "ugpraded" is ambiguous. A new rim could mean a *completely* new wheel featuring said r450 rim, or your old hub relaced to the R450. Quite different.

I also recommended hubs in my last post. Please read carefully.
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Old 09-13-09, 10:59 PM   #11
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Upgraded: "The term upgrade refers to the replacement of a product with a newer version of that same product."

I was given an entirely new rim.

p.s. I seen your recommendations, checked the price and asked for recommendations on higher quality/priced hubs.
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Old 09-13-09, 11:27 PM   #12
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How is one to know how much air to use exactly?
The label on the tyre only has a maximum pressure rating. It's typically set at 50% of the pressure required to blow the tyre off the rim. In actual use, tyre-pressure has to be selected based upon the tyre-size and the rider's weight. Common suggestions is to pick a pressure that results in a 15% sink/compression amount. For your weight, you'd want to use 110-130psi with 700x25c tyres. Or 100-120psi with 700x28c tyres. I wouldn't bother with anything smaller than 700x25c as the higher pressures required would transmit way too much shock to your wheels, not to mention your bum. Higher pressures also makes the tyre more susceptible to punctures as well.
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Old 09-14-09, 01:42 PM   #13
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The label on the tyre only has a maximum pressure rating. It's typically set at 50% of the pressure required to blow the tyre off the rim. In actual use, tyre-pressure has to be selected based upon the tyre-size and the rider's weight. Common suggestions is to pick a pressure that results in a 15% sink/compression amount. For your weight, you'd want to use 110-130psi with 700x25c tyres. Or 100-120psi with 700x28c tyres. I wouldn't bother with anything smaller than 700x25c as the higher pressures required would transmit way too much shock to your wheels, not to mention your bum. Higher pressures also makes the tyre more susceptible to punctures as well.
I appreciate the info - thank you!
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