oblique 

Fellow pedallers,

I just bought my first 'real' road bike - a Felt F75 with Mavic CXP22 rims with eyelets and aluminum nipples. After bringing it home I gave it a close inspection and realized that there were bumps on the inside face of the rim right at the eyelet as if the nipple wanted to pull out. They were most pronounced on the eyelets leading to the spokes connecting to the drive side of the rear rim (whose spokes were quite taught) but I could see smaller humps on the other side of the rim and and even some on the front wheel.

I took it back to the shop and the techs took their meter and measured the drive side spokes as '80' and said it was normal. I was in disbelief. They checked other bikes in the store (the ones with the same rims I presume) and said they looked similar - they had the same bumps in the rim.

I made a stink and their rep is going to check out the issue. I imagine it would be hard for him to admit any issue so Im turning to you guys for help - is there an issue at the factory? Are these rims just not meant to take 'normal' tension and are giving way? am I nuts?

Frankgt2

picture?? There are some mavic wheels that come with like ''bumps'' in the rim where the nipples are but just part of the design just like kysriums

well biked

I just checked two different model bikes we have in our shop that come stock with CXP-22 rims, and the rims are perfectly smooth between the nipples, no bumps. I've not seen your bike in person, so I won't make a judgement on what's going on with it, but there should be no raised area on the rim around the nipples, it should be smooth.

Btw, if there is a problem with your wheels related to the bumps you describe, it's most likely too much spoke tension and not a defect in the rims themselves. CXP-22's are not high end rims, but they've been around for a long time, are reliable, and are indeed capable of withstanding "normal" spoke tension.

mrrabbit 

My Mavic CXP-33s show a slight hint of this this at only 110 kgf.

Also Velocity Aeroheads and A23s will do this as well at only 110 kgf.

A very slight bulging effect around the sides of the holes seems to be common with lighter weight rims with aero profiles.

=8-)

well biked

The OP's rims are CXP-22's, a heavier rim than the CXP-33's.

mrrabbit 

It'll even show on some DeepV's...not often...and when it does - faintly.

The worst are Star Cricles from China and copies often found on Virtue bikes...

=8-)

FBinNY 

The seriousness of the bumps as an indicator of excess tension depends on the wall thickness of the rim along the spoke line, and the ductility of the metal. I ride very light (310gr) tubular rims, and these will begin so distort at the spoke holes at very low tensions, yet because they're fairly ductile they can do this without danger of stress cracking.

Other rims, especially hard anodized rims, and some of higher strength alloys, aren't so ductile and the distortion can be a prelude to future stress cracking. I can't speak for these wheels, not having seen them, and not having enough experience with the particular rims to know how they'll handle the distortion. So this may be a case where only time will tell.

What the OP might seek as a compromise is a warranty against failure by stress crack at the spokes for a mutually agreeable time period. Obviously this won't be a blanket warranty, since wheels can fail for any number of reasons, just a bet that that they won't fail for the one reason stipulated.

oblique 

As a structural engineer Ive seen steel failures as a result of fatigue and while we dont work with structural aluminum, its properties are not confidence-inspiring. There is less elasticity in aluminum than in steel and when that threshold has been breached (the bulging is a permanent deformation) the material capacity to resist tension is compromised.

Right now I feel like this is a safety risk and cant see myself enjoying riding my new bicycle. Whether a manufacturing defect of the rim or an assembly error I cant swallow this as acceptable.

canam73

What were they measuring the tension with? '80' would sounds low for the drive side if that's kgf, but I you could have a heavier straight gage spoke and I don't know what is normal for those.

mrrabbit 

Not a safety risk...

It a a hole cracks...you'll get a slight wobble that drag the brakes...you'll stop...b*&*%, moan, grumble, do a sailor and stuff...

Wonder what their "80" meant...

=8-)

well biked

I'd guess it was kgf on the rear drive side with air in the tire, which would probably be about right.

I've seen a little bit of distortion on certain rims like everyone is mentioning, but what makes me think something's off here is that I checked the bikes I mentioned in post #3, and there is absolutely no raised area around the spoke nipples on the pre-built wheels with CXP-22's in our shop. None, completely flat. Which makes sense, because they're heavy rims. I think you'd have to really overtension the spokes to get very noticeable "bumps" around the nipples like the OP is describing on these rims, or maybe have a batch of defective rims, I don't know. But again, there is absolutely no bump around the nipples on the wheels with CXP-22's in our shop.

FBinNY 

As a structural engineer you also know that fatigue is the result of movement or flex, not static load per se. In use the rim doesn't flex much, so other than this initial set, it shouldn't fatigue any faster than otherwise.

In any case it's certainly not a safety issue, spokes have been breaking for decades and I doubt anyone has ever been injured as a result. There's plenty of redundancy in a wheel so the loss of a single spoke, whether through spoke failure or through a rim failing at the spoke hole won't lead to anything worse than inconvenience. In any, while spokes break without warning, your rim will announce impending failure with visible stress cracks, weeks or months in advance of letting go.

There's not enough info here to know if this is normal build distortion or an indicator of a over-tightened wheel (or too much spoke for the rim) but all of that doesn't matter, even if it isn't a safety issue.

It's a brand new bike, and assuming you haven't ridden it, you don't have to accept delivery of anything that displeases you. if you have ridden it, either reconcile yourself to the "issue" or do your best to negotiate a swap or credit.

well biked

One other note: oblique, you've mentioned that there are eyelets on your rims. CXP-22 rims are available with or without eyelets, and the CXP-22's in our shop, on the bikes I've mentioned, don't have eyelets. So there is a difference at the spoke holes between your rims and the rims I looked at. FWIW.

A good, clear pic of the bumps around the spoke holes you're talking about would be helpful.

canam73

My drive side tension goes down maybe 5 kgf when I put a tire on starting from 125-130. That's with a 28 spoke rear laced 3x with DT comps. What kind of numbers are you working with? That's a clincher, from what I understand tubulars are affected more.

well biked

I usually see about a 15-20% drop in measured spoke tension, I think, when measuring spoke tension with a fully inflated clincher road tire vs. measuring with no tire mounted. Maybe I'm off a bit, but the difference isn't as minor as you say IME. Then again, I don't measure a lot of spoke tensions with inflated tires on the rims, either. ............But anyway, I don't think it would be too far off to say that if they measured the rear drive side tension with a fully inflated tire and got 80 kgf, the actual tension (without a tire mounted) would be somewhere in the 90-100 kgf range. Which would be a little on the low side but not too far off. Of course, that would be the opposite of what we would expect with the distorted rims.

Again, pics of the rims we're discussing would help-

FBinNY 

Whatever the tension drop tire inflation causes is moot. Yes, the tension drops somewhat, but that's factored into the published recommended tension specs. As long as the tension is in the working range (above a minimum level) added tension doesn't make a wheel stiffer or longer lasting. On the contrary, excess tension and/or overly stiff spokes can cause rim stress cracking.

Other than low spoke count wheels, 80kpf or more is well sufficient. The real issue for rear wheels is left side tension which is always much lower. I try to keep that at 60kpf minimum, bringing the right side as high as needed to achieve that.

well biked

My head's kind of spinning (no pun intended)...... as often happens we're going into a lot of things that have no bearing on the OP's question . The main questions are whether or not the spokes are over-tensioned to the point that they have damaged these 500+ gram rims, or perhaps the rims are defective, or maybe the OP is simply over-reacting and making much ado about nothing.

A sidebar question was posed "I wonder what the '80' they mentioned is referring to?" I made a guess as to what the '80' referred to. My apologies to the OP for going off topic, hopefully this thread won't get too sidetracked and we can stay focused on the origional question(s).

And to the OP.....pics or it didn't happen.

FBinNY 

We tried to answer the OPs question, and I for one tried to offer reassurance that it probably wasn't a problem, and for sure wasn't a safety issue. There's insufficient info to offer the OP a better answer because, there were no pictures, and no clarification of whether the 80 was the direct reading on a tension meter (and which brand it was) or a converted actual tension in kpf or whatever.

Then, as so often happens on the forum the thread drifted into tangents.

FastJake

+100

This entire thread is 100% guessing without pictures of your actual wheel. What may look like a defect to some may not to others.

FBinNY 

yes, pictures might help, but we'd still be guessing, and putting our "knowledge" against that of the wheel builders at felt.



....realized that there were bumps on the inside face of the rim right at the eyelet as if the nipple wanted to pull out. They were most pronounced on the eyelets leading to the spokes connecting to the drive side of the rear rim (whose spokes were quite taught) but I could see smaller humps on the other side of the rim and and even some on the front wheel.

I took it back to the shop and the techs took their meter and measured the drive side spokes as '80' and said it was normal. I was in disbelief. They checked other bikes in the store (the ones with the same rims I presume) and said they looked similar - they had the same bumps in the rim.

I made a stink and their rep is going to check out the issue. I imagine it would be hard for him to admit any issue so Im turning to you guys for help - is there an issue at the factory? Are these rims just not meant to take 'normal' tension and are giving way? am I nuts?[/QUOTE]

If I read the OP correctly, both his rims and others on the same model bike in stock had the same distortion, so a rim defect isn't likely. It comes down to two questions.

1- are the folks at felt generally over-tightening their wheels? In which case knowing what the "80" figure given referred to might be a guide.

2- is there a safety issue, in which case the answer is clearly no. The rim may eventually stress crack, but that isn't anything at all likely to cause an accident.

Even with pictures, I wouldn't speculate and accuse both the shop staff and the builders at Felt of total ignorance. To do that I'd need to compare the actual tension to Mavic's guidelines for that rim.

Now the OP has a problem in that he lacks confidence in the wheels, and the integrity of the shop staff, who reassured him that all was OK (which in all likelihood is true). It's up to him to determine the extent of the non confidence. If it's high I suggest he consider returning the (unridden) bike. Not because there's anything actually wrong, but because seeds of doubt usually take root and sprout, and that will color his judgement if and when anything else is wrong, or goes wrong in the near future. I know I couldn't enjoy a bike I didn't have confidence in and I assume the OP is the same.

bradtx

oblique, If your wheels are showing a pattern similar to this:

then that is a sign of over tensioning. These wheels were way over tensioned, but I didn't know that until I noticed the unusual pattern on the braking surface (Maybe hard to see in the photo, look on the rim where a spoke is.). I don't remember how tight they were, but retensioning made a more uniform pattern. There was no damage to the rim as it's still in use at least 15 years later.

Brad

ultraman6970

The marks in that rim are because the rim is not machined to start with. Old rims were not machined and always have those marks in the braking area, doesnt matter if the spokes are over tensioned or not. If the rim is not machine will get like in the picture, spoke tension has nothing to do with it, that rim is simply old and the bike is not like a super bicycle to put it as example either

If the rim hole and eyelets gives up then is clear u have over tension, besides that the next thing is that spokes start snapping out of the blue. As for the OPs wheel, well... doesn't surprise me at all and yes sure the spokes were over tensioned. Some iterations of those rims came up better than other batches, that's why doesnt surprise me at all the problem.

Wake

I doubt the alloy used in cx22's would deform without cracks showing externally. I replaced some Alex rims with CX22's (no eyelets) on my SS sputnik with high-flange hubs 3-cross. I tensioned them pretty tight (I judge by "pinging", not a tension gauge). They ride very rough compared to the previous setup. I don't notice any bulging.

3alarmer 

The obvious answer here is that the OP's rim labels are either
facing the wrong way or applied asymmetrically.

I'm surprised no one has suggested it.

mrrabbit 

1. Put down the pipe.
2. Hit the back button of your browser...mouse, not your fist.
3. Refresh forum list...that's mouse again, not a stiff drink.
4. Find and click on correct thread...that's mouse again, not the sound stuff...

=8-)