Re: [CR]Suntour Vista VGT and working chainlenght


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Date: Thu, 5 Feb 2004 13:40:15 -0500
To: "heddarr" <heddarr@indianaconnect.com>, "Classic Rendez-vous" <classicrendezvous@bikelist.org>
From: "Sheldon Brown" <CaptBike@sheldonbrown.com>
Subject: Re: [CR]Suntour Vista VGT and working chainlenght


Howard Darr wrote:
>
>Is anyone familiar with this model of Suntour rear derailleur? It looks
>like a 70's VGT only has VISTA on the Body plate. It has "all alloy VGT" on
>the pulley arms.

Yes, that's the immortal VGT, only with Vista branding. These were also seen with Raleigh branding. It was arguably the greatest derailer of the 1970s, and probably did more to create acceptance of Japanese parts than any other single component.
>Lastly, as usual I have chosen a chainlength that is too short to go big
>big.

That's bad, don't do it.

See: http://sheldonbrown.com/derailer-adjustment.html#chain for the correct procedure.
>and too long for the small small.

You should never ride in small small, so the fact that the chain may droop in that gear is of no importance.
>
>If the adjustment screw for the body angle is set to take up most of the
>slack so I can use the small small combo it struggles onto the small rear
>cog when using the middle and large front chainring which are combos I want.
>
>If I reset the body angle adjustment screw to allow the body forward and
>very close to the small cog

That is the correct setting, make it as close as it can be without interference between the derailer and the big sprocket.
>the problem is solved for the mid chainring but
>still persists in the large chainring.

If it's sluggish upshifting, this is likely related to cable friction.

See: http://sheldonbrown.com/cables.html
>I am using a Sedis Sport Chain and Shimano twist tooth cogs.
>
>When using a Shimano Road DeOre the with the same chain length the problem
>of dropping into the smallest cog goes away but there is chain noise from
>the bottom pulley wanting to not track the chain angle.

Could be a bent derailer hanger.
>I am going to try a shorter bb axel to move the chainrings closer to the
>stays in and retry.

Measure the chainline first, see: http://sheldonbrown.com/chainline
>Presently the front is a 26x36x46 and the rear is 14,16,18,22,26,32 Is this
>past the useable range of the VISTA?

No, that should be fine for a VGT. They were commonly speced with 34s in back, though usually a somewhat smaller range in front.

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