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 Post subject: Chainring Help Needed
PostPosted: Mon Nov 23, 2009 2:31 pm 
Retro Guru

Joined: Thu Sep 17, 2009 11:41 pm
Posts: 829
Location: Ramsgate, Kent, UK
Hi All,

First of all - Mod if you think this is in the wrong place please move.

I'd like a small favour from the forum with regards to chainrings.

I am playing around with different chainring sizes and I'd like to try a 52t outer and 40t middle for triple.

I was wondering if I could borrow a 52t & 40t 110mm BCD/PCD chainrings to see if they will fit the frame, bottom bracket and front mech that I am using. At present I am just re-building and setting up the bike so I wouldn't be using the ring on a ride. I'd like to check fit and clearances before buying my own if all OK as I'd be a bit miffed if I shelled out for rings and they didn't fit and work.

If you are able to help I'd be very grateful so pleass let me know - I am more than happy to re-imburse any postage costs and I wouldn't need the rings for more than a few of days.

Looking forward to hearing from you.

With thanks

Jules


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 Post subject:
PostPosted: Mon Nov 23, 2009 9:15 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8221
Location: New Forest, UK
In my experience you usually only encounter problems with the granny ring hitting the chainstay, not the middle.


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 Post subject:
PostPosted: Mon Nov 23, 2009 11:19 pm 
Retro Guru

Joined: Thu Sep 17, 2009 11:41 pm
Posts: 829
Location: Ramsgate, Kent, UK
Hi,

Thanks for the heads up about the granny ring - got a 30t on route so will be able to check fairly soon.

The issue I have is that I'm not using a road frame - I'm setting up an MTB frame for use on the road (I have a modern bike for the off road stuff) so there isn't as much clearance for the rings as there would be on a road frame.

I'm looking to increase the clearance between the outside of the front mech cage and the back of the crank as I am using a CQP crankset and clearance is a bit of an issue with these cranks and there are essentially 2 ways to do this;

i) get the file out (and this is a common fix) or ii) fit larger chainrings.

With a 50t chainring I get a bit of clearance but I'm fairly tight on the chainstay so I'd like to see how a 52t chainring fits without buying one as if it doesn't fit I'll end up with a chainring that will be of no use to me.

So if anyone can help I'd be very grateful.

Jules


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 Post subject:
PostPosted: Tue Nov 24, 2009 10:25 am 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8221
Location: New Forest, UK
Got it - are you using a road front mech or MTB?

Sorry I can't help with the rings - they are fairly unusual sizes.


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 Post subject:
PostPosted: Tue Nov 24, 2009 10:54 am 
Retro Guru

Joined: Thu Sep 17, 2009 11:41 pm
Posts: 829
Location: Ramsgate, Kent, UK
Hi,

Am going to be using an MTB front mech - it'll be either a XTR M901 or M953 as I have both available.

I know "newer" versions of MTB front mechs aren't designed to work with larger sized chainrings, but I do know that you can get 52t XTR M952 chainrings (just seen one for sale of eBay) so I am hopeful that the front mechs I have should be OK.

Both seemed to work alright with the 50t chainring I have.

Hopeful someone will have the rings as they are available although not as common as the 130mm BCD size.

A note to all who may have a ring - I'd be happy to pay a holding deposit if you were at all worried that I wouldn't return the ring. I brought a few things via the forum recently and have had no negative feedback / comments.

If anyone can help I'd be very grateful.

Thanks

Jules


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 Post subject:
PostPosted: Tue Nov 24, 2009 12:18 pm 
Retro Guru

Joined: Wed Dec 10, 2008 9:19 am
Posts: 2096
Location: Sheffield, top city
cant help, but would ask you to let us khow you get on. My next project is to Roadify (if thats a word) a MTB with a chorus square taper 30/42/53 chainset using a shimano top pull front mech that was designed to work with and old style 28/38/48 MTB chainset.


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 Post subject:
PostPosted: Tue Nov 24, 2009 12:39 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8221
Location: New Forest, UK
I ran a Veloce 52/42 with a SRAM front MTB triple on a Kona Cindercone.
I never bothered with a triple though.


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 Post subject:
PostPosted: Wed Nov 25, 2009 1:19 am 
Retro Guru

Joined: Thu Sep 17, 2009 11:41 pm
Posts: 829
Location: Ramsgate, Kent, UK
Hi all,

A partial update....

With the current width BB (122.5mm) a 52t chainring will not fit - with a 51t chainring (have one a fitted it) I only get a couple of mm clearance on the rear stay so fitting anything larger isn't an option unless I fit a longer BB.

I will still see how the operation of the front mech goes and report back.

Jules


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