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 Post subject: shimano parallogram V's
PostPosted: Thu Apr 18, 2013 9:29 pm 
Old School Hero
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Hi folks. Can anyone tell me if it's possible to set up M750 XT parallogram V brakes without them squealing. For reasons best known to myself I have a full set of them, despite never successfully setting them up not to squeal. Believe me i've tried, on several frames and forks since I got them. My guess is that all the pivots wear, and cause the pad to rattle when the brakes are applied. They'd really suit my new old Cinder Cone frame, but not if they drive me nuts whenever I brake.

Regards

Marge


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PostPosted: Thu Apr 18, 2013 9:41 pm 
Old School Grand Master
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The very first thing I'd check would be the 'toe in' on the brake blocks, as this is probably the most common cause of brake squeal.

The leading edge of each brake block (ie. the end which points towards the front of the bike) should be ever so slightly closer to the rim than the trailing edge (the end pointing towards the back of the bike). The leading edge then comes into contact with the rim first when the brake is applied, and this prevents the pad etc. from vibrating and causing the squeal.

A simple way to create toe-in is to put a thin strip of card behind the brake block to create the toe-in angle, and then tightening the brake block up.

Hope this helps a bit :D


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PostPosted: Thu Apr 18, 2013 10:16 pm 
Retro Guru

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Great tip with the card board :)


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PostPosted: Thu Apr 18, 2013 10:27 pm 
Old School Hero
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Indeed it is. Sadly, i've been using the cardboard trick for quite a few years, but to no avail with the M750's. Tried various degrees of toe too. Thanks for the reply though Barney. Perhaps the best thing for them is ebay.

Marge


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PostPosted: Fri Apr 19, 2013 7:37 am 
Old School Grand Master
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marge602 wrote:
Indeed it is. Sadly, i've been using the cardboard trick for quite a few years, but to no avail with the M750's. Tried various degrees of toe too. Thanks for the reply though Barney. Perhaps the best thing for them is ebay.

Marge


Ah, ok..

In that case, before you ditch the brakes, try giving the rims and brake blocks a thorough clean. Sometimes a bit of grime on either can be the cause of the problem.

Clean the rims with methylated spirit, and remove any grime from the blocks by sanding them down a little.

And if that doesn't work, get some new brakes! :lol:


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PostPosted: Fri Apr 19, 2013 8:05 am 
Gold Trader
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I had this problem. I did what Mr Ballbags suggests, but also swapped the pads over for some Ashima grey/orange soft ones - no squealing now.


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PostPosted: Fri Apr 19, 2013 8:07 am 
retrobike rider
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If you've never set them up and they were new then it's not wear 'n' tear on the pivots, this design apparently not like the m739 with it's problems.

You'll know if the pivots have gone though.

Have you tried more race targeted brake blocks? These are softer so wear faster but because of that they shouldn't squeal.

If not it must just be 'you' as other people have managed :lol:


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PostPosted: Fri Apr 19, 2013 8:36 am 
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Location: The land of Lea & Perrins
I've heard that some pad/rim combos hate each other, so as others have said it might be worth changing your brake blocks :D

Also, as FluffyChicken says, it was the M737 and to a lesser extent M739 V Brakes which had the squeal issues. I haven't heard of the problem with M750s. I've had a couple of sets myself and they've been fine :)


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PostPosted: Fri Apr 19, 2013 6:42 pm 
Old School Hero
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Location: Little Scotland
Thanks for all the advice. I don't think I can have used them enough to wear the pivots out, so it must be the pad/rim combo. I'm gonna build some new wheels anyway, and one set of the M750's don't have pads(for some reason) so will replace with new all round. Sounds like I just have to choose wisely.

Thanks again

Marge


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PostPosted: Sat Apr 20, 2013 5:07 pm 
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Location: Somerset
Rebuild kit's are available for the pad holder pivot.


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