# Grinding when pedaling in higher gears



## offmainstreet (Aug 26, 2013)

I owned a rigid mid-90s Trek 800 for well over a decade before I finally upgraded. That bike was the most solid, reliable vehicle I've ever owned in my life. I barely did anything as far as maintenance or care other than to occasionally hose it down, and I rode it hard over the course of it's lifespan and even took it on a couple very long trips. It took everything I dished out like a champ. And because of that, I became a believer in the reliability and quality of Trek bikes.

I just recently upgraded to a full suspension Trek EX5. It's got 3x10 gearing, as opposed to the 3x7 on my old 800, and I notice that I get a fair amount of noise (grinding?) coming from the chain when pedaling in a number of the gears, typically when I'm in one of the higher (smaller) gears on the rear cassette. I haven't noticed any real problems with it other than the sound. It doesn't shift randomly or drop the chain, but the noise is unnerving. I also just bought my wife a Trek Lush 29, also with a 3x10, and hers is doing almost exactly the same thing. It's less noticeable when I'm not pedaling hard, and it's primarily in the highest three gears on the rear, and doesn't seem to be affected much at all when I select a different front chain ring (cross-chaining was a thought I had). I have only had my bike a bit over a month or so, and I am getting ready to take it in for it's "30 day" once-over at the LBS, and I'm not sure if this is a normal thing or if it's something I should bring up.

Is this fairly normal, perhaps when reaching for those smallest cogs on these 10-gear cassettes, for the chain to perhaps not mesh as smoothly with the teeth as it does in the middle gears? If so, I won't put too much thought into it, and I will continue to go on loving my Trek bikes. But it's just a bit unnerving to drop close to 4K on two brand new bikes, and have them both make grinding noises in ANY gear, never mind several of them.


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## A DuB (Jul 9, 2013)

Most LBS's offer a 1 year service deal with the purchase of a new bike. If the noise concerns you, you should bring it up to the shop and have them adjust it if its necessary.


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## citiznkain (Jun 11, 2012)

sounds like the chain is rubbing the front derailleur. should just need a little bit of adjustment as most bikes do from time to time.


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## cobba (Apr 5, 2007)




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## offmainstreet (Aug 26, 2013)

citiznkain said:


> sounds like the chain is rubbing the front derailleur. should just need a little bit of adjustment as most bikes do from time to time.


Good call. I flipped my bike over and hand-pedaled as I ran through the gears. It is definitely rubbing on the front derailleur in the three smallest gears. I could understand this if I was in the smallest gear up front, but I spend most of my time in the middle gear. I'm going to ask if there is an adjustment they could make so that I can at least reach gears number 8 and 9 from the middle chainring without rubbing. Thanks.


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## lotusdriver (Sep 15, 2013)

Also make sure the parts are all well oiled, I fitted a brand new XT rear cassette to replace the budget standard fit one on my (also brand new) Cube hardtail, and the grinding noise when pedalling was really bad, I thought it must be out of alignment or something, but a good spray with mountain bike chain oil on the cassette silenced it. Strangely the noise did not occur with the original cassette, I can only assume the new cassette was dry of any oil.


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## Brockwan (Aug 6, 2013)

offmainstreet said:


> Good call. I flipped my bike over and hand-pedaled as I ran through the gears. It is definitely rubbing on the front derailleur in the three smallest gears. I could understand this if I was in the smallest gear up front, but I spend most of my time in the middle gear. I'm going to ask if there is an adjustment they could make so that I can at least reach gears number 8 and 9 from the middle chainring without rubbing. Thanks.


its easy to do yourself. just go to you tube and become enlightened. its literally loosening a screw, moving the derailleur position and tightening the screw again.


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