Very tight clearance between front derailleur and rear tyre

[pulseezar]

Hi all,

I noticed that the long cable arm on my Tiagra 4700 front derailluer is very close to fouling the rear tyre when in the large chainring. It works fine as is, but I'm concious that even a small wobble in the rear wheel could quickly destroy my tyre. See image which hopefully shows how close it is (apologies, not sure why the image is rotated incorrectly).

The bike was built up with a bit of a mix of components due to the shortages earlier this year. The levers are GRX 400 series, while the FD is this tiagra model on 50 & 34 tooth chainrings.

I'm looking for recommendations about how I might solve this problem, ideally without buying a new FD! Or am I over-thinking it?

Thanks

[Jdsk]

How wide is the tyre?

Where do you ride the bike?

Jonathan

[pulseezar]

How wide is the tyre?

Where do you ride the bike?

Jonathan

Hi Jonathan. The tyre fittted is 32c, and the frame is okay for up to 35c without mudguards. I ride mostly on tarmac with a small amount of gravel thrown in when needed. It's a technically a road bike but I do sometimes use it for light touring/bikepacking with a big saddlebag. I do lots of long (100km +) rides.

[Jdsk]

Thanks

Jonathan

[pwa]

I suppose the good news is that the mech is very smooth and rounded where it comes close to the tyre, so it is unlikely to shred the tyre wall. You would feel any rubbing before it did any real damage. Is the wheel properly dished. I.e., if you put the wheel in with the cogs on the wrong side, would the spacing between mech and tyre remain the same?

[tatanab]

I had a problem earlier this year with a similar derailleur. The modern design has a fore/aft parallelogram which gave me adjustment issues. I think the same, or similar, may be the problem here - the shape of the FD mech. I changed to an old style design without that parallelogram - like all front mechs used to be, and all was fine. i think it would help in your case because the actuating arm is further forwards. Whether such mech would play nicely with your gear lever I do not know.

[cycle tramp]

Hi all,

The bike was built up with a bit of a mix of components due to the shortages earlier this year. The levers are GRX 400 series, while the FD is this tiagra model on 50 & 34 tooth chainrings.

I'm looking for recommendations about how I might solve this problem, ideally without buying a new FD! Or am I over-thinking it?

Thanks
IMG_20210424_140246.jpg

How do you feel about running a single chainring instead of a double? Then you could do away with the front deraileur... failing that could you get away with using a bottom bracket with a narrower spindle - that would move the chainrings towards the seat tube which would mean that the front deraileur arm wouldn't have to swing back so much.

[cycle tramp]

The other solution might be to modify the mounting where the cable anchor bolt sits - so that the cable bolt anchor screws in from the front of the deraileur arm, and not the back.

[slowster]

What is the chainline of your chainset? That front derailleur is designed for a chainset with traditional road double chainline, i.e. 43.5mm.

[pulseezar]

What is the chainline of your chainset? That front derailleur is designed for a chainset with traditional road double chainline, i.e. 43.5mm.

Not sure exactly what you mean but the crankset is also a Tiagra one.

[rjb]

It looks like you have a bolt on front mech with a separate adapter. You may be able to rotate the clamp a few degrees which would then allow you to move your mech further away from the tyre. A mm or so but it all helps.

[jb]

You have the wrong FM for that frame am afraid.

[slowster]

What is the chainline of your chainset? That front derailleur is designed for a chainset with traditional road double chainline, i.e. 43.5mm.

Not sure exactly what you mean but the crankset is also a Tiagra one.

Explanation of chainline and how to measure it here:

https://www.sheldonbrown.com/chainline.html

What is the bottom bracket and what is the frame?

[Jamesh]

How about doing down to 28 or 30mm tyres?

l would hate to ride regularly on 32mm tyres did it tonight in fact in 35mm tyres and it was painful!!

Great on the canal towpath for first part of ride but a pain on the road (greater pressure would have helped!)

Cheers James

[Eyebrox]

Would wrapping the cable round the back of the anchor bolt allow the mech arm to come away slightly from the tyre while still providing precise shifting?