Hi all,

I have a Carbon Roadie with a frame that's about 4 weeks old. Ive noticed that the rear wheel appears to be misaligned. The wheel is slightly (1-2mm) closer to the chain stay and seat stay on one side. Ive installed two different wheel sets so am confident its the frame - not wheel dish. GOne through all the necessary steps to ensure ive installed wheel properly. The manufacturer has confirmed before that the chainstays are suppose to be symmetrical.

When I received the bike with new frame the wheel appeared aligned so something may have changed since new.

Not going to name the Bike manufacturer - but ive had 6 warranty frame swaps for various issues over the last 2 years. I could probably go them again for this but cant be arsed. I have 28mm tyre clearance on chainstays so don't think ill get tyre rub.

My questions - would the misalignment have a material impact on the performance of the bike? Should I be concerned from a safety point of view? I'm a 90kg big dude. Frame is 860kg's maybe I'm the problem.

cheers,

j

First question I ask is can the rider feel the issue when riding? Does the bike track straight while riding? Another words, is there a performance issue at all? If not then just ride the bike and be happy, remembering that bikes, like spouses, are not perfect but can still give years of happy partnership.

Every manufacturer will have some sort of tolerance of this or that aspect of frame alignment. Not that one will ever see in print said tolerances. The consumer discussion about this (with their dealer or manufacturer's rep) is usually vailed in non specific terms. So the bottom line is how does the bike ride and function. If the misalignment can be measured but not felt when riding then it likely won't qualify as a warranty, excepting a customer satisfaction one.

Still if the bike were in the shop I work at we would do a series of assessments. Measure and document the alignment of the various aspects of the frame and the wheel. Test ride and by experience and skills determine the handling aspect of any misalignment. Then we would have a talk with the manufacturer and review our findings and relate best possible the customer's view and expectations.

Warranties are a gray area and things get done for different reasons that other times might not be agreed to.

But this all starts with the retail dealer. If that dealer is an on line one this gets far more problematic for the communications and assessments to happen. But the process is still much the same.

As to the safety or integrity of the frame over the future- I strongly doubt any problems exist due to any slight misalignment. Very strongly doubt it. I see dozens (hundreds?) of carbon (as well as other frames using other materials) every year with slight wheel placement "errors". Some of these are new yet to be sold, others are used with tens of thousands of miles on them. And the bikes track straight and make their owners happy. The frame issues we see are impact or fatigue related most all the time. I can't say I have seen a frame alignment issue grow into a crack or failure. (Not to say that an impact that created a misalignment wouldn't cause a crack or failure. But that puts the cart behind the horse).

Are you the problem? Maybe if the bike otherwise rides well and straight yet you can't let go of this "issue". Then you do become the problem. Andy.

That's not much of a test. Maybe try reversing the same wheel and compare careful measurements.

Just FYI, no measured quantity can be perfect. The universe works that way.

Before getting worked up over what may be nothing, keep in mind that there's no rule that says that chainstays have to be symmetrical where the tire passes. The right stay often needs to be modified to improve chainring clearance, and this can throw off symmetry.

If you're concerned, the right way to measure is with respect to the frame's true center plane. Here's one way.

Get a straight edge of some kind (a broomstick may be OK if it rolls smoothly).
place it against the seat tube where the tire is closest, and some reference on the head or downtube, and extending out past the rim Measure from rim to gauge. Repeat on the opposite side using the same references.
Compare -- they should be equal.

Note that it's important that the straight edge be placed against the same references because the tubes aren't usually the same diameter, so changing positions will cahse angle changes and error. Also, you can leave the tire mounted, but be sure to measure to the rim because that's more accurate.

If it passes, all is OK and you can go back to enjoying the bike, but if not, all is not lost because there are other possibilities such as incorrect wheel dish.

Lastly maintain some perspective. This is a bicycle, not a space ship. There are working tolerances, so some variance is both normal and acceptable. The key isn't how a bike measures, but how it rides. If the bicycle tracks true, rides no hands without pulling to either side (consistently), and doesn't have handling issues at high speed, then it's OK regardless of what the ruler says.

To add to Francis's post (which says much of what I had before) I have seen bikes where the frame AND FORK (as it's wrong to take one out of context from the other) both had misalignments where they canceled each other out and the bike rode straight. Andy.

Thanks all for the replys - will do the no hands trick a few times to check tracking. My thoughts in regards to effecting performance was more around increased rolling resistance??? You guys saying that this would be neglible?

Good call I will switch the wheel around to check dish in case both wheels are out - unlikely but should rule that out.

In regards to the centre plane test - should I be measuring the distance between the straight edge and the front rim or the rear rim?

Given the issues ive had with this bike its hard to maintain perspective and these issues are getting in to my head. Slowly gaining it back though....

In order.

The effect on rolling resistance won't be negligible, it'll be ZERO. So no sweat there.

Since it's the rear wheel we're talking about, you measure to that one. Anyway you can't measure to the front since that one turns (steers).
Also, don't forget that ride trumps measurements, so if it rides right, then it's OK.

Sorry to hear about your problems, hopefully they're all behind you now.