How Can I Stop My Front Derailleur Rubbing? | The GCN Tech Clinic

How Can I Stop My Front Derailleur Rubbing? | The GCN Tech Clinic


– Right, well welcome back
to the GCN Tech Clinic where together with you, we’re gonna help solve a lucky, or unlucky, depending on which way
you look at it, member of the GCN Tech community’s bike problem. Last week, we opened up the clinic door and we put to you a very simple question. And that was, “How to stop handlebar end plugs falling out.” We had loads and loads of replies. Some of them weird,
some of them wonderful. I’m just going to read out a couple of them to you quickly. We had one from Nick B: “Let’s have Jon “open up a bottle of shampers” champagne, “down it”, presumably in one, “and then attempt to shove “the cork up the bar end.” He’d buy that for a dollar. Sorry, Nick, not going to go there. Probably going to make too much mess, for me anyway. Rob King, he suggested chewing gum in the bar end plug. “Shove it in. “It won’t be pleasant, but it will stick.” Yeah, that’s kind of a bodge, really. I wouldn’t advise that one either. However, the winning solution for me was actually Nathan Green. I’ll read out Nathan’s quickly. “The best way to solve
a loose bar end plug “is to use some masking or painter’s tape. “Yes, electrical tape is the saviour “of the cycling world, “but for loose bar end plugs, “electrical tape is too slick. “Masking tape is more grip “and will hold the plug more securely.” I 100% agree with you on that one, Nathan. I use that method myself
and I have to say, I have found it more successful than using electrical tape. So masking tape or
painter’s tape, do that. Definitely. Right, onto the main subject. We’ve had lots come in. We’ve been scrolling through and we found this one from Mark Sato which is probably quite a common problem, judging by the responses. And we’re going to try and tackle that one today. So, the problem is: “My front derailleur “often rubs on my chain
and sometimes it makes “it hard to change from the big chain ring “to the small one and vise versa. “This problem occurs more when sprinting. “Why?” Okay, right. First up, I wouldn’t actually recommend trying to change chain rings while sprinting. Reason being, the cadence difference is going to be pretty huge and that’s not potentially even that safe. So try and avoid that. Also, try and use your cadence actually as a clutch mechanism. That will help shift the chain, but I do understand your problem and that you want to have all your gears working all the time. I’m exactly the same, perfectionist, and you just want that to be spot-on. So, let’s have a look in the comments and let’s see the solutions. Right, well without knowing exactly what bike you’ve got, Mark, it’s hard to give you a perfect solution. But that’s part of the challenge and fun of this, right? So first solution is from Daniel Czirjak, who thinks you’ve got chain ring wobble. What’s chain ring wobble? I hear you ask. Well, providing your
chain ring’s not bent, and when your pedalling
it’s when your outer chain ring just moves
slightly off of line. What you can do is use
your derailleur cage as a guide to actually monitor that. So pedal around and see where it’s moving. Then, if you’ve got a square tapered bottom bracket, so again Mark, don’t know
what bike you’ve got, but if you do have a square-tapered bottom bracket, remove your right-hand chain set and then just rotate it 90 degrees. Re-fit onto the bottom bracket axle and then check again using the derailleur cage as a guide. If it’s not running smooth or straight, then move it another 90 degrees, recheck, and then you’ve got final 90 degrees where you can see. Hopefully, that solved it. If not, we’ve got another
solution coming up. Hmm, still not solved though, Mark. Well, John Downey thinks that you need a new bottom bracket, that your bearings are worn. How are you going to check for that? Simple, grab each side of the chain set and rock it from side to side. If there’s any play or movement there, new bottom bracket time. That could well be the solution. Still not solved that problem, have we Mark? Well, Lop Three thinks
they’ve got a solution. They actually fitted a narrower chain because they have the same problem as you. What did they do? They fitted a Shram chain because it was not point one millimetres narrower than the Shimano one that they had. So I’ve actually just measured some 11-speed chains. So if you’re using
11-speed, listen carefully. I measured Shram and that was 5.54 millimetres across. Shimano and KMC, 5.58. And Campagnolo, 5.46 millimetres. So the Campagnolo was the narrowest. Of course, those measurements are from one plate to the
other on the outside. So maybe, that’s your
solution, a narrower chain. Now I’ve actually used all three of those chains across
all three group sets. So Shimano, Shram, and Campagnolo and they’ve worked. So maybe that is your solution. Well Mark, the most common response to your question was actually that the front derailleur itself needs some looking at. So, my advice to you. Un-clamp the cable and start afresh. So, re-clamp it and then play around with the screws. Of course, don’t actually
play around with them. We’ve got a link in the description below for a video on how to adjust your front derailleur, or just up here. And hopefully, yep hopefully, that’ll be your problem solved.
(bike clicking) And soon, your front derailleur will be working like that again. However, I still don’t
advise trying to change from one chain ring to
another while sprinting. The load you’re going
to be putting through it and the change in cadence, if your chain was to derail, the consequences aren’t necessarily going
to be in your favour. Right, Mark, I hope your problem solved. If not, I’ve got one final tip, or one final little
thing for you to check. Make sure that your chain rings are actually fitted
the correct way around. Now with most modern-day chain rings, it’s pretty obvious because of the way that they’re designed. Inside chain rings, though, sometimes they can be a little pain. I once had a bike that I was looking at and someone had swapped
the chain ring around and it was just a little bit too big a gap for the derailleur to cope with well. So just make sure to check that one. Now, remember, you can
submit your problems for us down below in the comments. And I want everybody else to have a look through there and try and solve someone else’s. That way, we can try and solve, or even definitely
solve, someone’s problem. Now remember, like and share this video with your friends and subscribe to the GCN Tech Channel, click just here. And for two more great videos, how about down here: “How
to Level Your Levers” and down here: the latest GCN Tech Show. (upbeat music)