Ask a Mechanic | Rotating Road Tires & Clunking Forks

Welcome to our Ask a Mechanic column where our expert mechanic Daniel Slusser answers your bike maintenance questions. If you have a question for Daniel, please post it on our Facebook Wall or e-mail Daniel directly at daniel.slusser@artscyclery.com. Today’s column discusses whether or not you should rotate your road tires and diagnosing the cause of a clunk in a Fox fork.

Question

Should I rotate my road tires or wait for the rear to wear out and replace just that one? From: Kelly

Answer

To rotate or not to rotate? That is the question: Whether ’tis nobler in the mind to suffer the glass and thorns of outrageous fortune or to take arms against a road of troubles and by opposing end them: to die, to sleep no more; and by a sleep, to say we end the heartache, and the thousand natural shocks that flesh is heir to?

While one could wax philosophical about this question, I prefer to be more pragmatic. Since the control of your bike is handled primarily by the front tire, safety dictates that you want a tire up front that will resist flats well and offer predictable cornering. So, I recommend only replacing the rear tire when it inevitably wears out long before the front. If you really want to be fastidious, you can move your used front tire to the back and replace the front tire with a new one so you will always have the greatest safety and performance possible.

Question

My Fox 40 has clunk to it that I only feel at high speed through rock gardens or when I compress it really fast. I just replaced the lowers with new ones so I don’t think the problem is bushing slop. I’ve never had this problem before and it didn’t start until a few rides after I replaced the lowers. Any ideas on what the problem might be? From: Dane

Answer

I agree that it doesn’t sound like you have bushing slop issues, although there is still a possibility that it could be the problem. Just think back to when you swapped your lowers and whether there was excessive wear on the stanchions such as deep scratches or patches where the anodizing or Kashima coat has worn off. If you have this type of damage, then bushing slop is the problem and your stanchions will need to be replaced.

However, I think you most likely have a problem with the damper. That clunk is probably being casued by a brief moment in the fork’s travel at high speed that is undamped either due to damage within the damper or because the oil level is low and/or the damper has air trapped inside it that is causing inconsistent damping performance. You should also check to make sure that the damper rods were properly torqued when you installed the new lowers as this could cause a similar feeling.

If torquing the damper rods doesn’t debunk the clunk, then you will need to have the fork sent to Fox Racing Shox to repair the damper. This will require the assistance of an authorized Fox Racing Shox dealer. Either take the fork to your local Fox dealer or give us a call at 800-626-3440 and we can get a return authorization (RA) number for you and you can then ship it directly to Fox. We will then email a prepaid 2-day air shipping label to you that will have Fox’s shipping address printed on it and our return address. This is because Fox will only ship the fork to the dealer that established the RA number and will not work directly with customers for repair work.

After Fox evaluates the fork they will call us with an estimate and we will then call you for approval. After the repair is complete, Fox will ship the fork to us, we will inspect it, run your credit card to cover the cost of the repair and shipping, and then ship the fork to you the same day we receive it. If you wanted to order any other products from us while the fork is being repaired we can ship them to you with your fork to save you money on shipping. You will be back on the trail faster than you could ever be dealing with your local bike shop.

Daniel Slusser is a professional bicycle mechanic with over ten years of experience. He holds a bachelor’s degree in business administration from HSU and a master’s degree in history from Cal Poly University. When he is not riding, wrenching, or writing he enjoys spending time with his wife and two children.

2014-03-05T16:08:19-08:00