Genesis Flyer Fixed chainline - an email from Madison

Hi all,

Those of you with Genesis Flyers may find this of interest. After chainline issues and many different opinions from different sources, here is the response to an email I sent to Madison, the parent company of Genesis.

Make of it what you will!

John

--

Hi John-

The fixed sprocket was included with the last batch of 07 models due to
an error at the factory - it is supplied as standard with the hub so
they included it in the box. We asked them to leave it out - a 3/32 18T
option wasn't available from the supplier. So the forum's aren't quite
correct, this won't affect chainline - it simply won't work, but we
didn't intend this part to be supplied with the bike. Apologies for any
confusion caused.

The chainline isn't perfect to the millimetre partly due to the chainset
supplied - a perfect chainline would mean fitting the ring to the
central position of the tabs on the Sugino chainset. For pricing reasons
we (and other manufacturers) use a double with a single ring attached,
but the 1-2mm this puts the ring out is no problem. The chain will only
be liable to unship if run too slack, a mm or so +/- won't cause this in
itself.
We have found the hub to be sensitive to differing fixed sprockets -
using the one mistakenly supplied puts the chainline out, but other
models such as Surly seem to give a better line, as if it is at the edge
of, rather than the middle of, the varying positions a fixed sprocket
sits (can vary by a few mm). The hub positions the sprockets differently
dependant on which side, I think this is to do with tolerances between
hub, freewheel and fixed sprockets.

What brand of fixed sprocket do you have fitted currently?

Regards,

James Olsen

Product Manager

-----Original Message-----
From: John Clare [mailto:john@johnclarephoto.co.uk]
Sent: 09 September 2007 14:12
To: Contact
Subject: Re: Ridgeback Message - Tue 29 May 07 - 16:24

Hi,

An update to this issue...

It seems that the Flyer is supplied with a 1/8 fixed cog, when the
rest of the drive train is 3/32. It seems a general consensus on
numerous bike forums that this could play a part in an imperfect
chainline with the Flyer.

I finally got my bike shop to fit a fixed sprocket (not the Genesis-
supplied one, as Evans didn't supply it due to above issue), and
indeed, the chainline is at least 4mm out, which is quite a lot, and
very noticeable. The chainwheel is further out than the sprocket.

Fixed riders have stressed the importance of a perfect chainline,
particularly when riding fixed, and I'm very disappointed with this
bike, seeing at it advertised as being fixed-ready.

As it is, I understand that the drive train will wear out much
quicker, and that the chain could even come off in some instances,
something that is very dangerous when riding fixed!

The chainline is perfect on the freewheel side, so I cannot
understand how such a basic requirement could have been overlooked on
the fixed side. Maybe the problem is the flip-flop hub?

I would appreciate a solution to this problem, and some form of
compensation for the time, money and effort spent in trying to
resolve this. The bike should work on both sides of the hub, as
advertised.

Regards,

John Clare