H
Hugh Johnson
Guest
Last week I graduated from a Rocket to a V-Rex, because, I guess, I'm just hungry for speed. So I've
been sprinting around on the V-rex ever since (still too wintery for a serious ride), and I've been
feeling a little let-down by the small chainrings. I thought I'd have to get some bigger rings at
high cost, but then I saw a closeout deal on complete Rocket cranksets, so I bought one, just for
the rings.
Haven't installed the rings yet. It's not a simple swap, after all; there are complications. I'll
need to replace my front derailleur with a "bottom-swing" type, to move the cage higher than the
top of the mounting tube (the mock seat tube), and I'll have to add a few links to my chain, and
maybe a new shift cable, and who knows what other problems will crop up. But, I've been eyeballing
it, and imagining my granny with 9 more teeth, and thinking it over, and there's something I'm
wondering about...
What if I could keep my current granny ring, or better yet, keep all my current rings, but move them
inward with spacers -- and then just put the big Rocket 62t ring in the outtermost position? I would
have four chainrings, not three. If I can find a bottom-swing derailleur with a sufficiently wide
range of movement, and either a very long cage or a cage that I can lengthen (maybe add a steel
stiffener if necessary), this should be doable, should it not?
Obviously there will be lots of chain slack when I'm using the granny, but the V-rex rides high
enough to keep it way off the ground, and I won't use the granny very often anyway. The granny,
being spaced inward close to the bike tube, might cause the chain to chaff a bit in the front idler
pully, but again, it's not going to happen very often, and the granny puts the least strain on
things anyway. My front shifter is indexed for a nine-speed cassette (SRAM does that so they're
interchangable for southpaws, I think), so there should be plenty of ways I can adjust it to a
4-ring crankset...
Well, I guess that's one of the big questions I have. Will I be able to tweak my shifter for these
four chainring positions?
And where can I find the sort of derailleur I need? Do they exist? What do I ask for?
And the biggest question: has anybody done this before? Is it doable? Are there any big drawbacks?
Or just tell me what you think.
Thanks in advance.
been sprinting around on the V-rex ever since (still too wintery for a serious ride), and I've been
feeling a little let-down by the small chainrings. I thought I'd have to get some bigger rings at
high cost, but then I saw a closeout deal on complete Rocket cranksets, so I bought one, just for
the rings.
Haven't installed the rings yet. It's not a simple swap, after all; there are complications. I'll
need to replace my front derailleur with a "bottom-swing" type, to move the cage higher than the
top of the mounting tube (the mock seat tube), and I'll have to add a few links to my chain, and
maybe a new shift cable, and who knows what other problems will crop up. But, I've been eyeballing
it, and imagining my granny with 9 more teeth, and thinking it over, and there's something I'm
wondering about...
What if I could keep my current granny ring, or better yet, keep all my current rings, but move them
inward with spacers -- and then just put the big Rocket 62t ring in the outtermost position? I would
have four chainrings, not three. If I can find a bottom-swing derailleur with a sufficiently wide
range of movement, and either a very long cage or a cage that I can lengthen (maybe add a steel
stiffener if necessary), this should be doable, should it not?
Obviously there will be lots of chain slack when I'm using the granny, but the V-rex rides high
enough to keep it way off the ground, and I won't use the granny very often anyway. The granny,
being spaced inward close to the bike tube, might cause the chain to chaff a bit in the front idler
pully, but again, it's not going to happen very often, and the granny puts the least strain on
things anyway. My front shifter is indexed for a nine-speed cassette (SRAM does that so they're
interchangable for southpaws, I think), so there should be plenty of ways I can adjust it to a
4-ring crankset...
Well, I guess that's one of the big questions I have. Will I be able to tweak my shifter for these
four chainring positions?
And where can I find the sort of derailleur I need? Do they exist? What do I ask for?
And the biggest question: has anybody done this before? Is it doable? Are there any big drawbacks?
Or just tell me what you think.
Thanks in advance.