New rear wheel, rear derailleur fouling spokes

[Yellow Saddle]

Cheers, I've ordered the Park Tools alignment tool, considering my other bike just came back from the LBS for hanger alignment I think it’s about time I invested in the hanger tool. I'm not in the habit of having mechanics look at things unless I'm stumped! Watch this space!

Good move. Here's a general rule for diagnosing a bent hanger. Gears will shift across a limited number of gears only, For instance, you can get it to shift from 9 to 8 and then it gets progressively worse after that. Fiddling with it can get it to shift from 1 to 2 and 3 but then it gets worse after that again.
If in your case the gears shift perfectly across the range, up and down, something else is amiss but I don't know what. My guess is that the hanger is bent but perfectly in-plane or the actual derailer cage is bent, not the hanger. Your new ParkTool truth machine will reveal it all, I hope.

 

[confusedcyclist]

Thanks for the tips, I just adjusted the low screw, and by around 3-4 mm and happy with the clearance. Is there a minimum recommended clearance from the spokes? I recently removed the plastic spoke guard as the teeth that connected to the freehub were damaged resulting in clicking against the old wheel's spokes. Presumably this is a result of the time I dropped it but the issue didn't surface until I got the last rear wheel trued following a spoke breakage (odd, maybe LBS just broke it instead?). Now I'm wondering if it was that impact that caused the misalignment but somehow got away with it on the old wheel due to different spoke lacing on new wheels.

However the good news, its working fine now with perfect shifting up and down gear range, just need to be confident the rear mech ins't going to get chewed up! So minimum clearance for rear mech?

 

[wajc]

I had a similar issue where the rear mech was just touching the spokes and like you had a look at the mech hanger and couldn't see any particular issue.

I found the following advice whilst trawling the net and it enables you to check the mech alignment without any special tool - just use a spare rear wheel.

It involves removing the quick release mechanism in the spare wheel and the rear derailleur from the bike. Then screwing the wheel axle directly in to the rear mech hanger (making sure the surface of the hanger is clean). it is conveniently the same thread size

You then have two wheels fixed in a parallel position at the rear end and can gauge the relative distance between the wheels at various positions around the rim. (Make sure that the original bike wheel is sat correctly in the dropouts)

I did this and used pieces of dowel of different lengths as gauges. Rotated the wheels so that the valve stems were in line and looked to see the gaps between the wheels at the 3,6,9,12 o'clock position (rotating the wheels each time so the valve stems lined up to discount any error due to wheels being out of true).

I found that there was at least an inch difference between the wheels at the 6 and 12 o'clock positions. It was unnervingly easy to apply a bit of pressure to the spare wheel which effectively bent the mech hanger back where required to get this sorted.

Once happy that I had got a consistent gap all-round I removed the spare wheel and refitted the rear mech. First thing I checked was how close the mech could get to the spokes and it is now at least 10mm rather than the hairs width it was before.

It also cured the annoying clicking/rumbling noise I had been getting from the drivetrain for the last couple of months which was what prompted me to look in to this in the first place.

 

[confusedcyclist]

I had a similar issue where the rear mech was just touching the spokes and like you had a look at the mech hanger and couldn't see any particular issue.

I found the following advice whilst trawling the net and it enables you to check the mech alignment without any special tool - just use a spare rear wheel.

It involves removing the quick release mechanism in the spare wheel and the rear derailleur from the bike. Then screwing the wheel axle directly in to the rear mech hanger (making sure the surface of the hanger is clean). it is conveniently the same thread size

You then have two wheels fixed in a parallel position at the rear end and can gauge the relative distance between the wheels at various positions around the rim. (Make sure that the original bike wheel is sat correctly in the dropouts)

I did this and used pieces of dowel of different lengths as gauges. Rotated the wheels so that the valve stems were in line and looked to see the gaps between the wheels at the 3,6,9,12 o'clock position (rotating the wheels each time so the valve stems lined up to discount any error due to wheels being out of true).

I found that there was at least an inch difference between the wheels at the 6 and 12 o'clock positions. It was unnervingly easy to apply a bit of pressure to the spare wheel which effectively bent the mech hanger back where required to get this sorted.

Once happy that I had got a consistent gap all-round I removed the spare wheel and refitted the rear mech. First thing I checked was how close the mech could get to the spokes and it is now at least 10mm rather than the hairs width it was before.

It also cured the annoying clicking/rumbling noise I had been getting from the drivetrain for the last couple of months which was what prompted me to look in to this in the first place.

Great tip, sadly my new wheelset didn't come with QR levers/skewer. Will definitely check alignment though as 3-4mm clearance is making me nervous!

 

[PpPete]

Easy enough to fabricate something. Just needs a fine thread (M10x1.0) bolt to go in the hanger.
Don't whatever you do thry to force a regular M10 bolt in.